Thursday, 30 January 2014

a different slant on things

Back in December I was near an old log cabin and thought I'd ferret around for a nice angle. I ended up liking this one:


I was still farting around with the Sigma 30mm f2.8 at that time and wanted to see if it would work for me (without my glasses) on the GF and automagically pick the right thing to focus on. Naturally I was shooting at f2.8 just to make it clear to me if it had picked focus where I wanted it.

Wondering if it was worth taking my Toho 4x5 out there I thought today I'd whack my 'tilt adapter' onto the Olympus OM28mm lens and take the GH1 instead. Well the sun has risen in the sky since the solstice (duh) and so I didn't get that same lovely light (drat), but the effect of the tilt is perhaps really quite clear


Now its important to note that both images were taken at f2.8, but note the totally different DoF that is visible here? This is actually why Large Format cameras employ tilts / swings and shifts, to allow such control over the focal plane.

So when the subject is at a slanted angle, you tilt the lens to alter the focal plane. This is called the Scheimpflug principle (if you didn't know that already) and is a cornerstone of Large Format photography.

This diagram suggests tilting so as to get all the ground in focus (common in landscape photography), but can equally be applied sideways to get a receding wall in focus too.

The idea is not the same as Depth of Field, as it actually changes the plane of focus.

In a typical camera the focal plane is totally parallel with the sensor (film or CCD) and so the focus is exactly in a line across the picture more or less equal distance from the camera. When you tilt the lens you get to change that to any angle you like.

Looking closely at the segment from the Sigma lens (not tilted) ..


its pretty clear that only a very narrow portion of the image is in focus. Classically it becomes more blurry either side of that focal plain

But in the lens tilt example:


it is clear that the focus follows different rules. Look for instance at the metal hinge and the barbed wire. The hinge is clear further away from the wall in this image, but its base is blurry. Compare that to the image above where as its further away from the barbed wire (at an angle receding from the plane of focus) it gets blurrier (as does the wall).

The reason I bring this up (well aside from that its interesting) is that I get tired of the foaming at the mouth Kingdom of Wang people who are not even one-eyed, they're blind (you know, Wangers), who go on about how infinitesimally accurate lens adaptors need to be or the image will just be crap. You know, down to microns (Daddy, what's a micron? Well Son its smaller than a mites antennae), while this image was made quite with some mm of tilt. And yet this vintage 1976 OM28mm lens (taken hand held even) still gives sharpness like this (100% crop, right click to open in a new window as its scaled a little in blogger):


The problem with Wangers is they focus (hey that's a pun) on how lenses perform on test targets (where such alignment will make a difference because the board and the camera are square), not on how they render images. However for those of us who take photographs of "things" or people such issues are irrelevant.

The reason I love micro43 is because I can get creative lens choices that are simply not possible in Full Frame and for peanuts.

I don't know about you, but I'm into photography as a creative outlet .. not to brag about my lens test chart results. I leave that to the Wangers.

bottom line

start focusing on your creative juices not on the camera specs. Go grab any adapter you want on eBay and use it with the legacy lenses you want to help your creative vision and your enjoyment of photography ... and stop looking at charts.

I hope you've enjoyed this brief introduction into Lens Tilts ... I'll leave you with an image taken with my LF camera to demonstrate Tilt to a mate.



Lastly a very rough and ready video showing the effect as it happens. Sorry its rough and pardon my voice-over



:-)

Wednesday, 29 January 2014

ice crystals like ferns

Sometimes here in Finland we get to see ice crystals forming on the lakes, mostly we don't get to see it because the lakes are covered in enough snow to prevent it. The last time I saw it was back in December 2009 when we had some deep cold but no snow. Then we had a whole lake covered in it in our area

This is how it looked on that day.



a beautiful "ice cover" of plant like ice structures.

Walking on them you could hear the smashing of the ice (as it was still -17°C). I felt quite guilty destroying such beauty.

Today I was out skiing (it was about -19°C or so) and came across a small area where someone had cleared away the snow and they'd started to grow again (given a patch of bare ice).


From where I was standing they looked like tiny replica ferns or perhaps herring bones. With a macro shot (sorry, just my Nokia) you can clearly see the crystalline structure of water. A 100% view of the little ferns to the left


Totally wonderful structures from just water. They even start growing on your face if you're out for long.


BTW, my flash lookin orange coat is a plain old Norwegian Military winter coat that I've tie-dyed orange ... I like orange.

I like it because unlike the modern 'membrane' GoreTex stuff it allows my sweat out when I'm skiing and therefore keeps me warmer. That its cotton is not a problem when its really cold because (simply) its not going to get wet.

The key to staying warm is to stay dry. So I have a multi layer approach.
  • thin technical synthetic layer close to the skin
  • thin merino wool layer (long johns) over that
  • light fleece over that
  • the canvas over that
and as a bonus its actually really cheap too.

win win

Saturday, 25 January 2014

bubbles locked in amber

I have good friends. They often tell me that "I'm not alone, because they are there for me". While I have no doubt of their genuine intentions and efforts too, the problem is that frequently I still feel very much alone.

When I go to sleep at night, when wake in the middle of the night, when I wake in the morning, when I spend most of the hours of the day, heck even when doing things around the house - I'm just alone. Over a year later and I still simply feel empty at her absence. I still feel the desire to be able to do something for her - yet I can not.

So despite the words of "you're not alone" ... you know ... I feel that I am. Perhaps we are all always alone, perhaps its just a state of mind that we are actually with anyone.

I don't know if I'll ever completely stop feeling this way. Like bubbles trapped in amber, gradually filling the empty void left by her absence I reckon that there will remain quite a few bubbles that will be forever empty, even if the amber never sets.

Even tipping something in to mix with the existing treacle of my life I don't expect that will fill those voids completely.

I'm just saying ...

Tuesday, 21 January 2014

Contrast masking goes phonecam

One of the things I happen to find useful in digital imaging is what variously goes under the names contrast masking or tonemapping.

Since HDRI developed a few years ago it has perhaps put a sour taste in many mouths by the "slap-dash" hyper attenuated HDRI images which people seem to be pumping out there. Stuff which is about as subtle as suddenly screaming in a restaurant "what do you mean you fucked my brother!" Personally I've done stuff like this with it ... when photographing an interior for a business.


Its Artificial?

Humans are dreadfully conservative in the main and Photographers are no different. If its a camera feature then its 'kewl' if you do it on your PC then its some sort of  'artificial processing' and like Dr Tyrells owl...



... somehow less because its ... artifical (and you know, proper digital photographs look just like the real thing).

So while "proper" fotographers (NB photographers who mainly participate in fora and don't take photographs) argue about if "tonemapped" images are proper the next stage of digital camera evolution is happening outside of the Kingdom of Wang, in the wild, out on the streets, right in the palm of the hand of ordinary folks. Phone cams and software like instagram!

A friend of mine visiting London the other day snapped this on her LG and shared it on FarceBook.



I immediately saw the hallmarks of HDRI and contrast masking and so asked her about it. She said that it was done with Instagram and no it wasn't HDR setting. So she sent me the original, which is below.

 

I think its pretty clear that the shadows are brought up (footpath beside bike) and there is  colour in the ferry over there just 'under' the bridge as well as the red 'fence' over on the left. Not to mention the difference in contrast in the water and even the clouds.

She didn't think they were much different, but I'm willing to bet that she thinks the top shot is the better of the two and that somehow Instagram has done a good job.

Negative

This will come as a shock to people but this is what has been happening in colour photography for decades before digital with the inbuilt contrast mask provided in colour negative. This is one of the reasons why people (like me) still find value in using Negative film, because it actually does a lot of contrast control straight out of the box for you.

Saves me having to fiddle around in Photomatix like this:


P1100906

into this...

young Kookaburra

as outlined in this blog post.

Evolutionary paths

Of course no one (least of all a scrooge like me) wants to upgrade their camera bodies anywhere near as much as people upgrade their phones (and I'm not even using an Android or iPhone phone yet). Ask anyone who knows much about it, and they'll tell you that aside from one or two phone companies the majority are loosing money every quater. So this sort of evolution is savage - think creative destruction.

For some years I've advocated that people always use RAW and that all the in-camera effects are just there to satisfy the sufferers of the camera disease CFO or Camera Feature Obsession. A basic JPG could be recorded and embedded into the RAW (as it is already actually...) and then when you connect your camera to your PC to download your pictures and can then on the PC side and use (more powerful) processing implement any filter you like by just clicking on a thumbnail preview. This would then save image the to JPG for you. You could then go back and alter it at will to be anything.
  • "Natural"
  • High Contrast
  • Black and White (either panchromatic or monochromatic, or even colour filtered)
  • Sepia

Maybe I should just write this myself?

In the mean time, phone cams are killing compacts for all the right evolutionary reasons.

:-)

Friday, 17 January 2014

Heart Valve choices - information for choices

about me / introduction

I've been around in the heart valve issue for a while. I was actually more or less born into it. I was diagnosed with a heart "murmur" when I was about 6, had some early 'catheter' surgeries when I was 7 or 8, had my first OHS at about 10, which is today called something like a "valve sparing" operation, had a valve replaced with another humans (a homograft) at about 28 years old and lastly had a mechanical valve put in at about 48. These pages contain my thoughts and understandings (based on my experiences, professional medical advices and readings). So let me present my thoughts on...

The debate of: should I choose a tissue prosthetic or a mechanical prosthetic.

This is here because I take issue with the section of the "Aortic Valve and Ascending Aorta Guidelines for Management and Quality Measures" which says that there is no difference at all between valve type and survival.

I will present my view of their data (that they presented in the current guidelines) and suggest that with that the debate does not solely revolve around Tissue Valve (lack of) durability VS Mechanical Valve and anticoagulation therapy.

Discussion

So you find that you need to choose a heart valve. The news itself is probably a bombshell and you're shocked. Probably as a responce you've turned to google and dove into the internet and come up with all manner of sites and information about all manner of issues, as well as conflicting information.

My advice to you is (after reading this) consider these things:
  • no one via their own research will be able to learn as much as the surgeon and cardiologists you are seeing now already know. So sit back and take their advice. I know you won't do that, so here is the second bit of advice
  • only read trusted sources: these are peer reviewed journals and not websites run by herbal remedy or tiddlywink vendors.
  • focus your reading on working out what are questions to ask them.
What I say here is based on a reading many journal articles, some of my own experience and education in then having a good look at a publication in The Annals of Thoracic Surgery. This is not some winkydink little web site from a mob that makes a product, this is the writings of people who are highly trained medical professionals. Further their writing is reviewed by their peers.

Do you trust them? Well I guess you trust them enough to cut through your chest, lay your beating heart bare and cut into it right? Well then you should probably trust the rest of what they say and do. However that doesn't mean there aren't divergent opinions within the medical profession and divergent reasons as to why they hold those opinions.

No matter how much you trust the skills of the team, its also important to consider issues like: patient psychology (and how that may effect the Dr's messages to you) and business models.

background

It is important to keep in mind that there is no cure for heart valve disease, only very successful options. I think it was best phased as there is no "cure" for heart valve disease, only to exchange heart valve disease with prosthetic valve disease. However this is well understood and can be managed.

So if you are deciding between a tissue prosthetic valve and a mechanical prosthetic valve keep clearly in mind, you are never going to go back to life as it was (ignorance can be bliss) and that you will be offered choices on how to manage. Then ask youself the following questions:
  1. do you want to live: do you have a strong will to live?
  2. Are you a competent person able to take care of themselves (or can you learn to be)?
  3. Can you follow instructions and do what is needed?
If you answered yes to all those then despite what you may think (or how old you are) as an adult a mechanical valve may be the best for you.

The case for mechanical valves is skewed highly towards the negative in its presentation (especially in the USA) primarily because of the fear of anticoagulation therapy. Why? well I believe because people profit more from fitting you with a tissue valve than with a mechanical valve. As well people today seem to be far more anxious and frantic and short term minded. So businesses can play on that.

This is not to say there is no case for tissue valves, because there is. These are laid out in the guidelines, so if you're female and wanting to have kids, unable or unwilling to manage yourself, mentally feeble (like say intellectually impaired) or just the sort of person who has lost (or never had)  capacity to take responsibility for themselves: then I recommend you put yourself in the hands of those who will take care of you and just accept what happens. Just be a Patient.

Many Surgeons only think in terms of a year or a few years, almost no older studies concern themselves with data after so 5 or 10 years. So if you get 10 years then you're out of their interest horizon. That may be perfectly good for 60 year olds who (without surgery) would not have got another 2 years. For me (at 28) it wasn't.

Its up to you ...

Arguments

On reading the latest version of guidelines for aortic valve surgery (published in 2013) titled:
Aortic Valve and Ascending Aorta Guidelines for Management and Quality Measures. some questions on the decisions and data presented in this come to mind. Given that few people actually crawl through stuff like this (and just read the abstract) I thought I would. I encourage you to read the entire text to verify that you agree with what I have found in my interpretation of reading it.

This 68 page document has been 'co authored' by an impressively large committee of medical specialists. To wit




It being a committee it would stand to reason that not everyone in that list totally agrees with everything. I mean even if you have a bunch of really good friends I'm sure even finding 100% agreement on something as simple as a date for a drink will be impossible.

So its with interest that I read on the first page such a bold statement as:
there is no difference at all between valve type and survival



So to make this clear they didn't write:
  • small difference or
  • statistically insignificant difference
they wrote "no difference at all" ... what's more interesting is that barely two pages later they present some graphs of their data. The analysis of this data will suggest that this assertion is 'shakey' at best and to any reasonable assessment of the data, wrong.

This is significant because it changes the guidelines primary argument that the debate revolves around tissue valve (lack of) durability VS anticoagulation. In fact I think it will become clear that anticoagulation is the key factor in managing valve disease and that avoiding it and mismanaging it can cause you more harm than good.

I thought I'd start with the age group of < 50 years old group because that's what I'm in (and the one which seems to have the greatest debates among people who are about to undergo a valve surgery).


I don't know about you, but I see differences there. What is more important is the first thing I see is  'variance' bars that are supplied at the ends of each of the data. Pericardial tissue prosthetics (I have coloured it over in green to make it clear) would seem to have the best results at first glance, however some things bear a closer look. Looking closely at Pericardial  data we can see a remarkably noticeable change occurs in the survival rates at just before 10 years. Why is this so? I mean if you've ever chosen to plot a graph of statistical data you know that you get a cloud of points and its a matter of 'debate' where you put your "representative line"

The next thing that stands out to me is how big the variance range is for the Pericardial valve data. Seriously its so large as to fully encompass the best of the best and the worst of the worst. That the available data does not extend as far as Porcine valves makes one wonder how much that range will 'enlarge' as time goes by.

Next we see quite different end points. Why? It would imply that data did not exist for these valves beyond this point. I can see  Mechanical prosthetic valves (red) we see a significantly longer line than pericardial, yet it does not extend to the full period. Why? Surely not from lack of data. Porcine is however plotted right out to the 15 year mark. It therefore suggests that no data exists for the other valves past those durations of time (or they excluded it).

Something is fishy with this data as this is just not right, mechanicals have a very long history and reoperation on them is much rarer. It makes (or should make) one ask questions. For example
If the mechanical valve data was plotted out to the same length of time as the porcine would it make it clearer the trend it followed gave a significant difference in survivablity. 
Perhaps it would ... I can only feel that the data was presented in this manner to make someone 'happy'.

Ok, looking at Allograft data (which also ends shorter), I had an Allograft in 1992, and I was part of an extensive study, so clearly that was more than 15 years before 2013 (about 21 years actually) and I was by no means the first recipient of an Allograft. This means that it is not because of data availability. 

Again looking at this data what emerges is that it is hard to say you see no difference at all.

This is interesting because it fits in with a presentation and criticism of an earlier version of these guidelines by the Mayo Clinic (presented in 2010 URL ) also discussed this exact topic and the presenter took issue with the 2006 guidelines which said:
"On the basis of these considerations, most patients over 65 years of age receive a bioprosthesis. There are no data involving narge numbers of patients that clearly show one type of or fo any individual prosthesis over another."

His opinion on this was:
"when you see something like this in a guideline then you know there was a very strong persuasive personality in the room... Because this was put in there with no supporting data ... and that person seemed to hold the day or at least last longer in the guidelines session than anybody else."
He goes on to provide analysis of study after study which presented quite similar graphs to the one above.

I guess that the "strong personality" (perhaps it was a corporate personality?) was again in the room for the 2013 guidelines. The difference is that this time some data was supplied at least in the form of graphs.

So lets go back to the latest guidelines and see the other graphs.

This graph (obviously) looks at patients who had operations at between 50 and 70 years of age, and once again we see that after 10 years survival of the mechanical valve cohort moving higher than the others after 10 years. Allograft did well, as well as mechanical but Porcine and Pericardial were (again) at the bottom of the chart.

Still willing to chant the mantra of "there is no difference at all between valve type and survival".

Ok, so lets go onto the data for the group who (according to conventional views) should have the least to gain from a mechanical, that is those who were 75 years of age and older at surgery.

yet it would seem looking at the data that they gained more. We see that after 10 years the mechanical valve recipients kick up substantially higher in survival rate. Sadly the Pericardial group drops to zero. Which I expect means that they died. Mechanical still has survivors at 15 years.

So back to the point of : there is no difference at all between valve type and survival ... well, except for that found in the data. It becomes clear that it should be restated as:
no significant difference between valve type and survival for the first ten years.

Something for the elderly in the Mayo Clinic review above is this (from my notes taken viewing to that presentation):
Presenter poses the question:
"So why is that that tissue has higher mortality than mech?"

His view is that the reason for mortality increase is two part
1) reoperation risks

"its not true that the risks of reoperation are the same as the first operation."
"if somone tells you that run don't walk the other way"

2) this is a little more complex:

case a: 77 yo had severe heart failure. It could be said that this was
 'Gods hand' for 77 year olds. Its not true that tissue valves don't
 thrombose, they do. If not identified it can be confused with heart
 failure.  Patient is now anticoagulated. This patient would have died for lack of diagnosis of thromboembolism. A diagnosis overlooked because of the pervasive medical view "tissue valves don't thrombose.

case b: another patient 56yo (an MD) had neglected aortic regurgitation
 (EF was21%) he also had rejected a mechanical and wanted a tissue
 "because he's too young and active for a mechanical"
 * reoperated at 2.5 years is now anticoagulated

case c: another patient 22yo had a tissue (wanted a family) and came back 3 years later with
 thrombosis of the tissue valve.
 * patient repoerated at 3 years and now antiocoagulated


Which of course brings us to the importance of Structural Valve Degradation. Under the "Cons" section in Tissue prosthetic valves is this:


So (for patients aged less than 40 years) at 15 years 40% of these patients will have had to have their valve replaced for structural degradation. Now, lets revisit the first chart and consider these points and again examine their data. Certainly the 'trend lines' of their data does not fit the above description of  Structural Valve Degradation which "begins to accelerate after 10 years and continues to increase" and that leaves "40% of patients aged less than 40 years" in SVD . So allow me put in trend lines which follow that description.

Please note that I also kept within their stated variance bars too. I also extended (in red) the mechanical data following the same trend it was following. So now looking at those data trends that are adjusted to fit their own descriptions of the data we see even more significant variance in "late survival" than before.

Actually it will only look worse for this (for tissue prosthetic valves) if you are female, and or have a larger valve size and or you have hypertension.

hmmm ....

You can find people who have had mechanical valves implanted once and 30 years later they're ticking along fine. With no other surgery required ... often with no hassles at all. You can not find that in any person with a tissue valve.

So with the choice of a tissue valve in mind lets move on to the inevitable point ...

Your next surgery

Now lets do something different to the usual analysis of "how risky is a redo surgery" (which does contain more risk than the initial surgery) and that is the subject that surgeons hate to talk about: Surgical Infection rates.



So, if you get an infection while you are in hospital then the mortality rates are not what I would like to see for myself. It is also very interesting to look at the costs associated with these, seen over in the second last column. Seems to be good business for US hospitals (who after all in the main take people who pay).

Ok, lets look at where these infections are commonly had:


so the largest slice of infections after cardiac surgery (in this data set) is at the surgical site. And from above there is an uncomfortable level of mortality associated with an infection.

The alternative of course is to not have a second surgery, which of course means considering a Mechanical valve. Lets now have a quick look the mechanical valve issue of (insert Hammer Horror music) anticoagulation.

Since you're still reading then its clear you are interested in alternatives. As discussed, the first page of that report says:
...there is no difference at all in late survival and thus the debate revolves more around valve durability and anticoagulation.

Since we have looked at late survival, then looked at valve durablity, lets now look at anticoagulation.

The main argument against mechanical valves is the risk of thromboembolism and of bleeds and the requirement for anticoagulation.

This is the boogy man which surgeons who advocate tissue valves and serial redo operations bring out to scare you. Frequently this is portrayed as being a horror story, yet strangely it seems that its only a "known problem" among those who are not on it.

Currently Warfarin (brands like Coumadin or Marevan) is the "Gold Standard" for management of Anticoagulation therapy. It is a "narrow therapeutic range drug" which (like sleeping pills) work well with just the right dose: will do nothing if too little and will hurt you if you take too much.

Almost every case of warfarin anxiety I read about in forums about heart related issues follows the same pattern, that is:
  1.  initially afraid, 
  2. started it, nothing happened, 
  3. discovered it was no big deal.

For instance some advice I saw recently posted on a forum for heart valve patients.
"I was very nervous about the drug going into my surgery, and most of it was generated by Google. I think the best advice I could give to someone looking into a surgery would be to disconnect from the internet and listen to your doctors as you ask lots a questions and get lots of answers, as a lot of misinformation and biased information is available at the search engines. I also know that if someone had taken away my internet I would have gone ballistic, so I understand where you are at!"


The medical facts are that if you learn to manage your dose yourself (just like diabetics do, you will test and maintain an INR range)and use a machine (and there are a few on the market) to monitor your INR you will be in a much safer situation than if you rely on a clinic (data presented in a moment below). Yet in the USA the medical establishment (including the medical insurance companies) prefer you to attend a clinic which will most likely use exactly the same machine you would buy yourself (for about $500).

The money facts are that warfarin is a very low price drug (people in the US even buy it at Cosco) and self management is also very cheap. Clearly there is no money to be made in encouraging people down that path. Interestingly the best possible outcome for you is also the cheapest outcome for you.


But its important to remind you that choosing a tissue valve will not mean you are free from anti-coagulation therapy. There is a chance (especially if you are elderly you will be prescribed it for other reasons such as atrial fibrillation).

So (in my view) without mitigating 'co-morbidities' (meaning you're a regular healthy adult), get a mechanical, maintain your INR yourself and live long and prosper.

The risks of taking warfarin are of a bleed or a thromboembolism (clot leading potentially to a stroke).As is stated in the medical literature (and even in this report)  the decision of Tissue or Mechanical comes down to balance of choice of tissue valve and its required reoperation or mechanical valve and anticoagulation therapy.

It is this spectre of anti-coagulation therapy which is rattled out by some surgeons (who is it doing the operation again btw?) , with suggestions that anti-coagulation may be as risky as reoperation.
Ok, firstly go back up and re-examine the data on infections ... then consider that the worst possible results from anti-coagulation therapy come from mismanagement of INR. The data on events being poor comes primarially from the results of people who are managed by a clinic rather than who self test. The effective management of INR is not in itself rocket science. Yet the medical system in the United States (where this report comes from) seems to frown upon self testing. This is despite a rather large and growing body of evidence that Patient Self Testing is more cost effective and yeilds better results.

Studies have shown that Patient Self Testing  reduced the bleed complications from 11% to 4.5% and Thromboembolic events from 3.6% to 0.9%.

Yet Tissue prosthetic valves are not free from Thromboemolic events nor are the patients free from bleed complications. The article suggests that:

Thromboembolic rates with biologic valves in the aortic position are approximately 0.6% to 2.3% .

So the risk of Thromboembolic rates for Tissue prosthesis is greater than that for well managed INR and Mechanical valves.

On the subject of structural degradation of Tissue prosthetic valves with age The article suggests that:
Observational studies show that the Structural Valve Deterioration rate for current porcine and bovine pericardial bioprosthesis used in the aortic position begins to accelerate after approximately 10 years and continues to increase there after in patients aged more than 65 years
Yet they do not mention how much more rapid this onset of valve failure is in younger patients. And the younger you are the more rapid failure is.

So now, how well does the argument against anticoagulation stack up to you?

With modern western life expectancy as it is (assuming you are 60 or less you have another 20 or more years), why on earth would you choose a tissue prosthetic when you are clearly setting yourself up for another operation in the later years of your life?

Well, one of the reasons I typically read (on heart discussion forums) is that "I want to get over this and go back to my life as it was". Well guess what? Your life will forever be changed by this process (for a start you're alive) and it is generally much better to take the wake-up call and use this as an opportunity to see your life differently. Is taking a pill every day so onerous? Does it make you feel older? Is denial of this worth that much to you?

Of course there are clinical reasons why you may need to choose a tissue prostheses (such as the desire to get pregnant {although I'd have thought that to be reduced in women over 60Yo})

With respect to the initial surgery, the choice of a mechanical valve can make the surgery easier for the surgeon the document states:
Currently available mechanical aortic valve prostheses have several advantages
  • ease of insertion,
  • safety,
  • durability,
  • excellent hemodynamics
  • long-term track record of performance
  • all relatively easy for cardiac surgeons to implant.
  • Structural dysfunction of currently approved mechanical heart valves is extremely rare, current mechanical aortic prostheses have endured accelerated bench testing without destruction for the equivalent of several patient lifetimes.

Something else

Money talks (often with the loudest voice), it is commonly said that if you want to understand a business, follow the money. So within that report is the following table (which I suspect has a typo in it)



some things stand out in a quick glance:
  • 16,780 valves were mechanical
  • 75,734 valves were tissue
  • Total (it says tissue) valve costs (I assume this is their cost to the patient, its not mentioned) is $435,716,947

Lets look at those numbers in another (perhaps clearer) way

so this means that over 80% of valves sold to 'consumers' in the USA are of the type that will need replacement. In fact its quite probable that some of the valves sold in 2011 were for replacement.  Since its quite rare to replace a mechanical valve selling more tissue valves gives greater possibility for then selling another tissue valve. Repeat business is good for business.

Looking at the data sales of tissue valves gives rise to something like $348,573,557 in valves alone (think of the extra revenue generated in hospital treatments).

On the other and if the consumer (that would be you) got a single operation which gave them a valve that lasted for life where is the business sense in that?


I encourage you to read the guidelines yourself in a careful and critical way. Further I encourage you to read more from trusted sources and most importantly discuss these issues frankly with your surgeon and cardiologist.

Lastly

Ultimately the choice of what valve a patient chooses is significantly up to the patient, unlike buying a washing machine the choice of what valve you choose is something which impacts your life. Do you not owe it to yourself to consider the choice carefully? As the article says:
there are few, if any medical procedures that are as effective in relieving symptoms, improving quality of life, and also increasing long-term survival as much as Aortic Valve Replacement for aortic stenosis or aortic regurgitation
Given how the surgery interrupts your life, how anxious patients and family are when this happens, shouldn't you consider the facts carefully? And I mean the facts not the 'stories'.

Anyway, enough about you, think for a moment about your family.

My wife was distraught at the thought of my surgery (more so than me), she was beside me every step of the way. She said to me in recovery that some of the happiest moments of her life were in seeing me get better every day.

She put on a brave face, but the fact is that she was scared shitless that I would die and she would be left without me.

She was so pleased because she was so relieved. I would not want to put her through that again. If you are a reasonably healthy adult, and you choose a tissue valve you will for sure be putting your loved ones through it again.

Is that something you want to do to them?

Tuesday, 14 January 2014

a window to the soul

when I was a kid I often heard people say that the eyes were like a window to the soul. These days however I think that its probably the internet (and facebook / twitter / news media comments).

People really open up and show you what they're made of.

I read this article and it struck a chord with me. However sadly I soon read that the story of his kindness brought out the "trolls" who inevitably pick anything to make nasty and unkind remarks about.

Having been myself wondering about the afterlife significantly more lately and wondering about the possible basis for it in our current scientific views of the world (for example here), it occurs to me that negative people will perhaps be around to provide torment and anguish and pain to anyone they can lay their hands on (just as they do now).

I wonder if these ugly spirits become the tortured in hell, and that the toughest ones become the demons? Of couse I don't know, but it stands to reason.

These people are so unable to see anything except exploitation that perhaps, no matter how long they exist for, they can't change. To them everything will be about fuck you. Sadly these people seem unable to understand love. Even if they experience it given to them, it seems that they just turn it into a convenient way to exploit the person who loved them.

Perhaps hell is a place that they create by their own choice?


I feel sorry for them (for what they do to themselves) and for the hurt they cause others. To the nice people reading this who are tormented by something, or by others unkindnesses - I hope you find peace

Monday, 13 January 2014

a Negative printing experience

I normally don't get my negatives printed until I've scanned them. This is because quite simply the places who print your film are incompetent (I really can't think of what else to say). Today because the shop didn't listen (more evidence to support my hypothesis) I ended up getting prints with my 24 exposures.

I glanced at them quickly and thought FFS

Item of Evidence 1


Now looking at the timber of the desk it looks like I see it here ... so my scan of the negative.


The blue light on the snow is classic up here, and as the sun is going down the sky was lit with low cloud and lovely reds. That's why I took the picture.

If I was a person learning about photography and all I saw was the print I'd be so disappointed with the my camera or me or something. But the issue is firmly at the shop. For if I take my file there (in sRGB colourspace) and print it, then it will look like my scan.

Item 2


shit, the ends of my glasses have more colour than this print.

My scan:


now I want to emphasize that I did fuck all to these scans aside from my usual process:
  1. scan as positive and set levels conservatively to not loose data
  2. invert in photoshop
  3. trim up levels
  4. apply some gamma to each channel
So its no wonder that people think prints from negatives don't look as good as digital prints. The real irony here is that negative was designed with printing in mind, not scanning.

I don't mind paying 5 bucks for the negative developing but the extra for the prints of this quality is just insulting. Sometimes you just don't get what you pay for.

Sunday, 12 January 2014

the old mill

I thought I'd go out and see what was to be seen with the camera today (despite -10°C and quite a wind chill from a strong wind coming from the iced over lake) and have some reason to play with a RAW file in the evening. I took about 5 shots (and nearly froze my hands) and I liked this shot the most.


Despite the 'blinking blown highlight' warning on the JPG (which is what you'd get if you weren't using RAW) I ended up processing this with a few clicks from the RAW file.

I think I'll have to drag the Large Format camera out here ... (*when there's less wind that is ;-) as there is some good material to be had.

A shot from before winter.



*the astute may spot a white horizontal fleck in the lower portion of the rusty saw mill from today, that's some "horizontal traveling snow", and this was 500th of a sec exposure 

Saturday, 11 January 2014

Pixels to Perceptual Mega Pixel (data review)

I thought that I'd follow through with some of the data I've compiled to me suggests that to increase the effective (or Perceptual) megapixels on needs increasingly more actual pixels with each sensor format but that with increase the return value is small.  So with a smaller sensor like a APS or 4/3 sized sensor you need to have way higher increases of pixels to get perceptually much increase.

camera MPix/P-Mpix Native Mpix
GH1 (4/3) 1.33 12
GH3 (4/3) 1.45 16
40D (APS) 1.68 10
7D (APS) 1.99 18
5D (FF) 1.16 13
1DsIII (FF) 1.4 21
5D III (FF) 1.3 22
Sony RX1 (FF) 1.33 24

With micro4/3 some quick observations (which seem to be representative) are found in such lenses as the Olympus 75mm f1.8 and their 45mm f1.8. These lenses give 9 and 7P-Mpix (respectively) on the GH1 and 9 and 11P-Mpix (respectively) on the GH2. For the This is a ratio of 1.33 and 1.44 Pixels/P-Mpix for the Oly 75mm lenses on the GH1 (12Mpix) and GH2 (16Mpix) bodies, demonstrating that as pixels go up the 'return ratio' of perceptual megapixels gets less. This is otherwise known as diminishing returns.

I suspect that the data on DxO is insufficient (unverified and uncross referenced tests) for a good analysis (to allow for removal of measurement error by proper statistical samples). From my reading of the data on the APS cameras the results seem to follow the pattern. I expect diminishing returns will flatline when you ultimately hit the "aerial resolution limits" of the lens (as one would normally do in MTF testing)

With the Full Frame stuff the 5D was the low hanging fruit, with a very good ratio of yeild per sensor pixel. However as the desire to increase output quality went higher the requirement for capture pixel to Perceptual pixel ratio when higher too. The Sony RX1 for instance has 24Mpix to get its 18P-Mpix

It would seem to me that an appropriate 'storage' compression here would be to downscale the captured RAW file into a DNG (or the like) from the captured Mpix to the reasonable limit of real IQ. There would be little or no loss as observed in my previous post.

Back in the past designers seemed to not be restricted to sensor size and just moved up to a slightly larger film format 35mm - 645 - 6x7 - 6x9 ... and larger

Perhaps the best answers here are really the same?

I would love to see some tests of the Leica S2 system.

Wednesday, 8 January 2014

a Perceptual Mega Pixel explained?

Well and some other thoughts too...

Espeically beginners who have read just a few internet discussion groups before 'buying in' tend to focus on bodies, features and megapixel counts. They ignore lenses and don't grasp the importance of sensor format size. Frequently people buy the best body they can afford and get a crummy zoom. They justify this variously with:
  • "I'll get a good lens later"
  • "I really want to take good pictures so I bought the best camera"
  • "the images look really good" (but I've never actually compared them side by side)
Yet both Lenses and Cameras are needed to take a pictures of higher quality.

Long ago I wrote a WWW post about what I called Megapixel Madness and I thought that it was about time to take that notion further with the new metric which DxO has introduced: the Perceptual Megapixel. In this blog post I thought I'd explore that and provide what I hope is a tangible representation on what it is that I think DxO are on about.

summary of findings

For those who don't have time to read:
  • Perceptual Megapixels as a metric seems to make sence in terms of end product image evaluation
  • If you are obsessed with every last skerrik of image quality at capture, then you'll need top lenses and >24Mpix Full Frame digital a tripod : or you've got your hand on it.
  • if not using Full Frame don't expect much more than effectively (perceptually) 13Megapixels no matter what's written on the camera specs, but in most cases 8
  • there isn't much difference between 4/3 and APS-C (gosh, as the maths would indicate)
  • its going to cost you a lot to get a lens to get the high Megapixel counts (and some focusing accuracy and probably a tripod too)
  • if clarity and contrast are your gig, why aren't you using Full Frame (it may even be cheaper)
  • for light weight, compact versatility and access to interchangable lenses NEX and micro43 are hard to beat

going forward

Now first I'd like to introduce a new term, the bajillapixel camera. This if of course dervied from the numeric bajillion (following on somewhere after million....). From Wikitionary

Noun
bajillion (plural bajillions)
  1. (slang, hyperbolic) An unspecified large number (of).
    • 2003 27 August, connie, “Tomatoes . . .”, rec.food.preserving, Usenet:
      However, I have a bajillion cherry tomatoes. Is it worth it to try to make spaghetti sauce from them, or will it take 10 bajillion cherry tomatoes to make any quantity of sauce?

So without getting all detailed and accurate on ya I reckon any camera that has more than enough pixels is a bajillapixel camera.

its just a jump to the left..

Beginners (and sadly more experienced photographers too) go on about "image clarity" as it it was something obviously quantifiable. Yet at the same time these folk shy away from metrics - after all its the picture quality which counts right? All this quantative stuff is just hard to grasp and gets in the way of the photographic journey ... then a step to the right. Put your hands on your hips ...

Ok, so too much is never enough ... sure ... well if you're buying the media cards and HDD storage and downsizing for www .... Well anyway, before we get bogged down, what is "more than enough"?

Let me go out on a limb here and say - if the lens system you're using provides the limits to the maximum number of megapixels obtainable then a body that captures more than 1.3 times that is "more than enough".

DxO provides this nifty metric (ok, go get the garlic and crucifixes I said metric) called the Perceptual Megapixel which uses the lens on the camera and gives you a rating. Ok ... sounds great but what does it "look like". To answer that question I have done what I think demonstrates what they are trying to encapsulate in a single number. So presenting my

Virtual Perceptual Megapixel

Fig 1 - workflow
Basically the idea is simpler that it sounds in description, so I hope that the diagram I have to the left here makes it clearer.

Assuming you start with  12 megapixels (or 4000 x 3000) and your camera + lens rating is 7P-Mpix then it would be the same as if you scaled down the image to 7 megapixels (which is 3150 x 2363, and yes the diagram is to scale) and then upscale that image in software (which please recall results in detail loss, if there was fully 12Mpix present, because upscales can not create what is not there, if they could then you could just buy a 1Megapixel camera and upscale all the time).

So lets have a look at this experimentally.

Method

To do this I thought that I would capture a scene which has a (nearly) "Perfect Mexapixel" content. I then scale it back as above and then scale it up as above and compare to an actual capture.

So, how to get a perfect capture? Well stitching a 4 x 4 array of images taken with a x2 focal length (resulting in something like 8000 x 6000) wold do that. For instance, this scene (taken with the Panasonic 14mm f2.5 lens)


when taken with a x2 longer focal length lens, and combined in stitched format (before its properly joined) would have 4 12mpix images:

and would then scale back divided by 2 (to 4000 x 3000) to produce a nearly perfect 12 Megapixel capture.

Since I am going to be pixel peeping major league here I didn't bother with doing all that (well and you can't see a 8000x6000 image on the web anyway) and just took one image with the 14mm and one with the Sigma 30mm f2.8 and work with just them at pixel peeping levels. For the curious I also used the following methods:
  • capture in RAW
  • used the lenses at f2.8
  • illuminate by bounce flash (camera set on manual exposure) to ensure that effective shutter speeds (that would be the flash duration, which would be about 1/5000th of a second) removed any shutter bounce
  • mount camera on tripod
So, here we have 100% pixel crops of the outcomes


since that might not look clear enough on these monitors (btw, use the middle mouse button to "center-click" the image to open in a fresh tap at a proper 100% viewing) I thought I'd look at them at 200% in photoshop.


which shows to me that the "virtual perceptual megapixel" still holds a wee bit more detail than the 7PMpix I chose.

This suggests that either I'm wrong in my theory or that the Panasonic 14mm f2.5 isn't as sharp as people whack on about (and that's my experience with this lens btw). As there is no DxO rating that I can find for the Panasonic 14mm I'm left in the 'lurch' on this one for actual data (AKA your guess is as good as mine). However its also possible that the 'perfect' megapixel capture is more perfect than possible because the stitching actually reduced the effect of the anti-alias filter.

None the less it does show the sorts of degradation which are at least what you'll see.

If the theory works then one should be able to scale back the actual capture of the 12Mpix and then scale back up without loss, as there is in theory no extra data there to lose.

So I took the 14mm image and downscaled it to 7MP saved it (as a TIFF) then opened and enlarged it back to 12MP using 'nearest neighbor'. Assuming there was only 7MP (or less) then this "compression" should not create much in the way of loss


So, in blind testing, you tell me: which is which?

I have one further point to add on the creation of the "perfect" 12Megapixels and that is the the role of the anti-alias filter will be reduced (making it a little less soft) than if you had a way of perfectly getting light to the sensor in a 12Megapixel manner.

Discussion

So were you surprised?
Did all the changes  (looking at the above Fig 1 of workflow) result in as much change in clarity as you may have expected? I suspect not.

To me this shows that the differences between 7 and 12Mpix are perhaps less than people appreciate (something I've been banging on about for a while) and that to see really significant differences you need to go up more than x2 in dimensions, meaning that you need a good 36 megapixels to see any substantial increase in clarity. I'd call that diminishing returns.

Now think about that for a while. How big is that file going to be, how large will it be in memory, how long to demosiac how much to store? The answer is basically x4 ... because to see a x2 improvement in image detail you need x2 on each dimension (as well as the lens systems able to capture it).

To be honest, how often are you going to actually print anything big? I know from personal experience that I have taken images that were 4000x3000 and had them printed at 150dpi will yeild a print that is 68 x 50 cm or 27 x 20 inches. Do you really want your camera to be capturing 8000x6000? Thats 48Megapixels.


With what we've seen above lets look at a few Lens / Camera combinations in the DxO listings.

Some top rated micro4/3 lenses



Nothing higher than 9P-Mpix, and that is a prime. In the zooms (which people froth on about as being 'stellar') are quite limp in reality at 7 and 8.

For those smug "well I've got APS-C not that winky dink 4/3 sensor" folks let me present that as a compare:


So on a camera like the 18Megapixle 7D your total capture still only gives you 9PMpix ... looks bad even with one eye to me. This backs my view that back about the 12Mpix times on the APS cameras we were hitting limits

The problem is actually capture size.  Bigger is Better in that area (and I mean area not just cutting your pizza into more slices), a well known point among photographers with any training. Lets look at some full frame examples. I chose the EF 35mm f2 lens as I also used that to look at the 7D above:


So the trusty old 5D 12Mpix full frame gives 11 P-Mpix (nearly a perfect match with the sensor) and there just isn't a lens combo that gives you this IQ in APS even though the bodies are mostly the same size.

Even with Full Frame, its a diminishing return as each higher MPix cound gives progressively gives less Perceptual image quality. So as the camera M-Pix goes up to 21Mpix the end result is still only going up to 17P-Mpix. Diminshing returns to me, unelss you are willing to pop some BIG BUCK$ on some Zeiss lenses.

I'll leave it up to the reader to determine the ratio of dollars / P-Mpix for you to work out if you (like me) would be happier with a $500 full frame that gets 80% of the image quality of a $2000 body and some $5000 lenses.

To drive this point in (*of format size being the most important factor for end result IQ), I thought I'd compare a EOS 40D (10 MPix APS camera) with a couple of Full Frame cameras with various lenses.


So with a lens that's much better than the reglarly purchased "kit" lens (meaning on a lesser lens you'll get less P-Mpix) the 40D is down from its real10MPix to 6P-Mpix and the 36MegaPixel Nikon D800 only gives its best with a uber expensive Carl Zeiss lens (and giving a piss poor 13P-Mpix with an expensive Nikon lens that people will probably go 'ooooh' over).

My point here is that if you are going to get a Full Frame camera with a high megapixel count then you'll need to back it up with actually stellar lenses. So the DxO P-Mpix rating actually gives you a good tool  to help in that decision making process. My other point is there is little point in getting a APS or 4/3 camera sensor in much higher than 16Mpix because you're not going to get any benefit.

This suggests that in reality (something I've argued for a while) that a good 6Megapixel image is really quite enough for most things and certainly more than we need for our big screen HDTV's our phones or our tablets. These 12Megapixel captures (on either of the smaller sensor formats) are showing Perceptual Megapixel values of 9P-Megapixels and that's not really far from a really good 6Megapixel.

Chasing IQ

So far I have not even touched on the other significant issue, and that is of camera shake. Even IF you have a potential for 28P-Mpix on the Nikon system (or on some other system) you just won't get that high IQ without the camera on a tripod and attention to things like shutter bounce. So its quite possible that your hand held images are in reality back down to 12P-Mpix if done hand held or with a crummy tripod. Even tripods are not all equal as I discovered some time ago with problems I had with my (then) new Manfrotto 190.

Basically as soon as you start humping a good tripod about you can kiss goodbye to any weight or size savings in the camera body. So if you're after image clarity as a goal you really need full frame and a tripod.

This raises the ugly question of "if you're going to hand hold, why the hell would you hump around bloated DSLR cameras which only have APS sensors in them?" The evidence is that you won't get observable IQ differences (refer again to the above images) using such cameras.

This is exactly the reason I dumped my EOS 20D, didn't go further in EOS APS and got into micro43.

To me the only reason to hump around a bloated APS sensor camera like a Canon 70D is because you're into the feel of a heavy camera. There is perhaps also the argument to be made of better AF speed on telephoto work (read sports) and being able to get better 'telephoto effect' from the same telephoto lens as compared to Full Frame.

To me unless you're using a tripod and care, then cameras like the NEX and the micro43 cameras yeild all the image quality with significantly less weight and so unless there is some utility to be gained from the brick in your hands, you will be better off with Full Frame (especially perhaps with a Sony A7) than a bloated APS camera.

So hopefully this new metric from DxO will allow photographers to plan what they need and make better informed purchases of both camera bodies and lenses. Wangers of course won't be worried about how the images look because they're more worried about being seen with the right gear ;-)

A classic from WhatTheDuck to sum up


what I'd like to see as outcomes

Based on these findings I would love to see (as I have since 2001 when disappointed with the EOS D30) more of a push for larger sensors (full frame) but with no major emphasis on pixel density (12Mp is enough for most) and instead a greater emphasis on actually giving better bit depth. The current RAW formats are under used and even adding another most significant bit depth to the data would make for better highlight handling and enable us therefore to get better shadows (by exposing to the right).

This analysis makes it clear to me that not only do larger sensors do a better job of getting Higher Image Quality (IQ) in terms of effective pixels but all my previous experience shows that larger sensors also give better contrast and bokeh.
:-)