Monday, 28 July 2014

The Panasonic 20mm f1.7 (now I own one)

Because with a 20mm f1.7 on a GF it may be worth it because of size.

When the Panasonic 20mm f1.7 first came out I owned a G1 and had already had bought a 28mm f2.8 manual focus legacy lens to play with. I wrote a blog post about it at the time having tried one in a shop and gone away to think about it. I wrote a post then subtitled do I really need one. That post could probably also have been subtitled instead: "will I see a benefit"...

Given that it was €400 I was a bit shy with parting with my money I felt at the time that having the kit 14-45 (quite a good lens really) and a OM28mm f2.8 I thought it wasn't worth it.

Later when the Sigma 30mm f2.8 came out I thought I'd try that out to compare with my OM28mm f2.8, expecting them to be quite similar. Which they were (see this link). I initially thought that the Sigma may work well on my GF (which I didn't have back when I first looked at the 20mm) but to be honest its physical size gave me nothing much to love about it over the 14-45. When used on my GH (an SLR-ALIKE camera) there was equally little benefit as the OM28 was optically quite equal at f2.8 and manual focus worked better for me when I was after critical focus anyway.

So how am I looking at this?
Essentially I'm interested in:
  • differences in angle of view between the OM28 and the Pana 20
  • shallow depth of field on the lenses
  • clarity on the lenses
If there is a benefit to me I'll be keeping this lens and re-acquiring a GF1 (and probably the 14mm f2.5 and the GWC1 - 0.79x adaptor for that lens) as a compact and light weight camera system (I'm such a gear yo-yo).

So whats it look like?

I like "normal lenses" for working at "normal" distances and taking "normal" sorts of shots (you know, not particularly wide, not particularly telephoto). With a f1.7 lens working outdoors in full sunlight will challenge the shutter speeds even at ISO 100, so I took a shot of my mate Bob working in his shed.

All images are taken with each lens "wide open"

Firstly the Panasonic 20mm

then the OM 28 taken from exactly the same spot.

I guess its pretty clear that the focal length difference which I identified in my 2010 blog post is still exactly what it was. To make that clearer here it is in this instance again:

the red frame in this shot is about what you get with the 28mm and the whole shot is of course taken with the 20mm.

So, some difference, but nothing which is staggeringly different. In some ways this sort of thing is what can easily be achieved with "zoom with your feet"

So in the shot below I moved back a bit and took the shot again to get a framing with the OM28mm equivalent to that of the 20mm (standing that bit closer)...

Open the images up in different windows and switch between them, I'm sure you'll agree that the character of the 28mm and 20mm are quite similar and the background relationships between them (caused by change of focal length and shifting position) are not specifically drastic.

Of course the background snuggles closer while Bob remains the same in the focal plane. Depth of Field is not significantly altered. So unless you have a specific plan it just may be that for things at "normal distances" the 20mm is a nicer tool in some ways. Like it does give you f1.7 vs f2.8 which could give you 100th of a sec VS 30th of a sec ... or enough to make a hand held shot sharper. These were all taken with a tripod.

So this begs the question of "can I crop the 20mm lens image back to equal the 28mm lens (or maybe just equal to a much more expensive 25mm)?

Well here is the 20mm cropped back to the view of the 28mm

Which is surprisingly similar to the original 28mm lens image.

So, what have we lost in details by cropping? Well that's a good question as the Panasonic 20mm lens should be a much sharper tool than the OM 28mm lens (designed for 35mm so many decades ago now) so lets have a look at the 100% pixels from a cropped 20mm upsized back to 4000pixels wide:

and the original capture of the OM28mm at 100% pixels

which is not too far apart and unless you were doing a very demanding print to put on a gallery (in which case you'd probably plan ahead better).

Also interesting is that the DoF of the 28mm @ f2.8 is almost the same as the DoF of the 20mm @ f1.7 when you factor in the changes in shooting distance.

The 20mm cropped and upsized shows that it does well and would do better if we were only cropping it to equal the Panasonic 25mm f1.4 field of view (of course that lens is bigger, brighter, more desirable and more expensive). I'm not sure I'd want that lens on my GF1 but it would be good on the GH...

As I was writing this
It occured to me that what I should also have done is to take a shot with the 20mm stepping closer to the subject rather than just with the 28 stepping back (to equalise the 28 to the 20). This would give the effect to be seen of the 20mm in closer from where the 28mm was taken from. Luckily we used a tape measure on the floor :-)

As the light had changed I took another set of two shots. So

The 28 taken from the same place as the first 28 shot was taken from:

Then the 20 stepping in a bit closer...

Same sorts of background / foreground perspective changes, but now that we're in closer the DoF from the f1.7 makes the background softer (check out the CH of the top row of the business card behind the screwdrivers).

As long as you're not shoving the camera in his face the facial distortions from trying to capture in too tight with a normal (making a portrait use of it) the differences between 20mm and 28mm are barely apparent.

To me the last shots clinched it for me, the 20mm with "zoom with your feet" is quite equivalent to the 28mm (and probably the 25mm too) and so I feel I've answered that question.

So, what'll I do ... I'm not sure. I happen to like this little lens, so I think that to do it credit I'll have to take some shots with it for a while and see.

Ultimately I think its not worth it to me on the GH body as it brings little advantage to me in its size. If the AF is not to be relied on for shallow DoF work (and picking focus right exactly where I want it to be) then its of reduced usefulness to me.

To me the question is now this;
will I be better served with a GF1 (still the best GF if you ask me) with this lens + 14mm + 0.79 wide adapter than I will be with selling it on again and just buying the 25mm f1.4?
I could still buy a 14mm and a GF1 for less than the extra required to have bought a 25mm f1.4 over this lens.

Sure its not just a question of the lens and is it good enough as without doubt the Panasonic 20mm f1.7 is a great lens, it also happens to be a compact pancake lens and makes the GF camera actually achieve its potential of being compact.

All of which most of the newer micro43 cameras seem to fail at (with the exception of perhaps the GM).

Hope someone has found it interesting to see the Pana 20mm up against a legacy 28mm lens and also seen that the DoF difference between them is not what calculations may have revealed.

Wednesday, 16 July 2014

Bar ends on my round town MTB

There is of course no end to the variety of handle bar grips on bikes. However I get tired of them going 'mankey' with sweat and humidity around this neck of the woods, so I thought I would try something different this time.

I got some padded road bike corking tape off eBay for about $4 posted. It came in two lengths (left and right side right) and I used about a third of one of the lengths to fit up my bar ends.

I secured it with a little bit of self anealing silicon tape (called tommy tape, used about 6cm of that) and they work great.

Cycling was meant to be cheap.

Like me ;-)

Sunday, 22 June 2014

Post #666 - God made the beast too

My Blogger dashboard has been telling me for some time that it was leading to this, and to be honest I haven't known what to "Grace" the Six hundred and Sixty Sixth post with. But now I do. God made everything we see and experience in this world, and yes God made the Beast too.

People say "Fear God" : well that's always seemed like a crock of shit to me.

To me fear is for people who are afraid of something, more succinctly in my view afraid to lose something. Commonly people in power have fear, fear that people will discover their lies and deceit. They fear the truth.

I was afraid to lose something once, but I lost it. Now I fear nothing much. I recognised how delicate and frail the purity of my wifes spirit was and I was afraid that evil people may harm her (thus destroying that) but I had enough faith in her and in myself to be comfortable that such was unlikely. We lived and loved in a happiness which I feel will never be repeated in my life. Having lost that I really do not care about the rest.

In the end God took her, or to phrase it how I feel, I feel that God robbed me. God it seems to me was the asshole I needed to be watchful of.

Enter the Contradictions

Now the fruitloops who tell me they understand God better than me (and based on what I ask?) tell me that its all part of Gods Plan.

Contradiction 1- Free will: apparently God so values free will that God allows all manner of shit to go on in the world. Because he loves us and one day we'll see that really God did this for us. Well ok, I'm willing to agree that much shit goes on in this world due to free will, but Anita was killed (by God) using a weapon of a cancer. This cancer was a fast growing cancer of the brain (which effects many it seems) and we as yet have totally no idea as to what causes it. We only know that being found to have it is a death sentence.

I'm not seeing free will much at work there. To me that's a design flaw or a little switch that God can activate to kill some one. Ok, so maybe Anita has been taken to a wonderful place (and no doubt, she was a wonderful woman whom many loved and admired) but he's orchestrated cutting out my heart and squeezing a pimple into it.

God killed her because he loved me? To me such "love" is child abuse. I do not fear God further because I see he has done much harm to me already. Looking into the future I can see possibility for further harm, but I don't fear it. I look forward to a time when I can stand before God and ask "OK, so what's the Fuzz here"

Contradiction 2 - Almighty God: God didn't kill Anita it was beyond his control. God could have saved her, but to have intervened would have been a miracle (and Gods pretty capricious in handing them out it seems).

Having demolished "Free Will" as part of the cause of Anitas death I can only put down "bad design" or "action (either deliberate or accidental)". Bad design could be in the design of the human body or in the design of the universe where some stray gamma particle smacked her and triggered it. Either way its bad design. If there was an "error" somewhere it makes a slight subtraction from the Almighty aspect of God.

If God is not Almighty then perhaps we should start to ask more questions.

There is no point in me going on further about the problems with a Perfect God who is as we are taught, for these two points alone appear to demolish the views of many of the simplistic views of God (backed up with the "just have faith" in the things you don't understand).

I think its pretty clear at this point that I do believe that there is a God, for if I did not then I would not be having this discussion from this perspective.
I believe that the Universe (the one we can see) was created, but that such creation was not done in a way where every detail was planned. Rather it was seeded and grew as perhaps does a plant. When you plant a pumpkin seed you know what the plant will look like, but not where it will have each leaf and where each pumpkin will grow. But you do know that from that seed will grow a pumpkin and not corn.
I believe that much goes on in Creation which God did not intend, and which God winces at when God sees those accidents causing suffering.

I do not believe God to be Almighty, perhaps God could extinguish the Universe, but that just gives Him the power of destruction. I don't believe God can intervene on a more delicate level.

But deep down I believe that God cares and God shares our suffering. God does not seek our suffering but equally God is powerless to stop it.

To me this makes more intuitive sense than the contradictions. I struggled with this until I discovered (some months ago) this video, where a Jewish Rabbi discuses aspects of the Jewish faith where it seems they recognise that God does seek atonement for the sins committed by his universe on the innocent. I recommend you take the time to watch it, whatever is the flavour of your faith.

My message today is to not fear God, but to instead just live your life as honestly as you can, to love and enjoy the beauty you find, to not do anything you do not believe is right.
Do not expect good to come to you, do not expect God to assist (probably its impossible) or indeed expect anything.
Know that what you build will be destroyed except for what you build in your heart.
For what is in your heart is something which I believe lives on beyond this matter of which we are made.
Pain does not go away and things are still fraught with danger. But there is nothing to fear in that.

Living in this way (unlike the conniving and obsequious men who build lives on lies and theft) you then have nothing to lose, nothing to be afraid of...

...and perhaps everything to gain.

Thursday, 19 June 2014

T-Max - further electrical mysteries (updated, maybe solved even)

I went to start my T-Max the other day and it was barely able to turn over the starter motor. Having only relatively recently had similar issues which led me to change the alternator stator (which was burnt out) I became instantly suspicious about what was going on.


I believe that I have now explained the issue, but still have not resolved this issue. I am sure that multiple short trips in the day will cause the battery to gradually be drained of charge as the discharging will be greater than the charging.

moving on

Anyway, going back to the other day, it started on the second go and so I gave the battery a quick charge (half an hour) and started it up again without trouble. So I did my trip and when I got home thought I'd check out the on battery charging circuit. As before it seemed to be "ok" but still a little under spec at 13.68V (which is 14V at 5000 rpm according to the manual).

So I then decided to pull the earth off and measure the current while the bike was turned off (and the ignition in the OFF position). I was a bit stunned to find that the bike was pulling 0.5 Amp

I started disconnecting things (by pulling fuses) and found fairly quickly (lucky) that the drain was brought to a halt by pulling out the (curiously named) Backup fuse.

Looking at the wiring diagram we can find the source of the issue.

So in the above diagram a few things are permanently connected to (and powered by) the battery irrespective of where the ignition switch is. One is the seat light, the other is the auto chokes.

On the left hand side we have the fuse (68) the seat light and switch (4 and 5) while over on the right we have a Thermo Switch and the powering of the Auto Chokes.

So I started doing some research and found the following:
Auto Chokes: the resistance across them, they should be 16-24ohms at 20 degrees C
Thermo Switch: switches OFF at at less than 55 ~ 60 degrees C and ON at greater than this.

So when you are sitting around cold (all things being normal) there should be no drain on the battery, but when you first come back from a ride there will be a drain on the battery from the chokes. This should stop when the bike cools down (which can be a while on a hot day after a long ride...).

Currently I'm still working this out, but for the interested you can measure easily if the battery is still being sucked dry by the following method. Be sure to have an amp meter that will cope with 10A and set it up right (plug the right lead into the right slot if needed).

  1. Lift the seat, and open the battery cover so you can get to the fuses. 
  2. Pull the Backup Fuse.
  3. Measure the amps flowing across that fuse terminals
If its zero (or less than 0.1Amps) then all is pretty good, the switch has indeed cut off (as it should) and all should be right with that circuit. Typically my bike has been sucking power when I get back in, and its up to 0.9Amps before it gets cut off by the thermo switch.

Please note: this circuit also powers the clock, so when you pull the fuse the clock will stop and need resetting.

If you wish to examine the setup on your bike and make measurements, the stuff can be found under the dress trims in front of the seat. So take off this cover.

You can just see them there in the middle. The brown bit there is the plug that connects the circuit (14 on the diagram).

In closer you can see the plugs to allow you to measure the resistance of the chokes, and you can just see the Thermo Switch and its bakelite (alike) plug at the bottom of the picture.

You can see it more clearly here (perched atop the housing for the engine thermostat). To disconnect the plug on the Thermo Switch (to then access the switch for testing) it disconnects with a press on a securing clip while pulling and can be seen easiest from the left hand side of the bike

However its bloody hard to get down in there and you'll need longer probe leads (and access it from the right hand side).

Note the hose? That takes water to the carbies to heat them ... gosh isn't this just wonderfully complex? Just keep the coolant changes up to this (and do not use plain water) because if you get corrosion from electrolytic reactions you just don't know what'll screw up.

The auto chokes (well where they plug into the carbi) will be visible now too.

This does not need to be removed unless you want to (I don't see why - and doing that may just make things worse).

So, whats the Fuzz

Right now, I don't know, I doubt its the battery being gumbie. So to sum up:
  1. things seem to be within tolerance but then there is the issue of why is my battery slowly winding down? Is it just because I've been making lots of short trips? (thus draining the battery while its cooling down but not operating for long enough to charge...)
  2. When the motor is hot (and the switch open) the charging voltage is 13.6, but 14 but when  motor is cold and the switch closed. This implies to me that the charging circuit isn't able to cope with this extra load (which is about 1 amp, nothing compared to the high beam) - why?

I'll post more when I have some better data ...

The Fuzz

Ok, so now I've done some more measurements and some unplugging and testing everything and thinking and I have come to the conclusion that this is the Fuzz.

If you do a number of short trips on a T-Max (well, at least my series) you'll really challenge the battery.


Well when its hanging around cooling its sucking power out of the battery to power the AutoChokes (which aren't actually doing anything) because they are solenoids and are powered by the independent supply circuit governed by the "Thermo Switch". This will continue until the temperature drops below 55°C

I took some measurements of the temperature and the battery when I got home to sus this out. I intended to have more measurements but I got a phone call and got distracted. So this is what I have.

Essentially the cooling rate of the bike at rest is relatively linear (and that's reasonably correct from a basic thermodynamics perspective until the bike gets closer to ambient temperature, but thankfully its not 60°C here) for the part of the range that's of interest to us (like 55°C when the thermo switch goes open circuit).

This graph suggests (and that's about my observation too) that the bike takes about 45 min to cool down enough to cut off the thermo switch (and stop draining the battery).

I pulled the Backup fuse out of the bike as soon as I got home so as to not cause the bike to suck the battery much more and to see what my battery stabilised to (to see if my battery was holing up to this). My battery was at 13.3V as soon as I got home (and shut the motor down) but at 30 minutes (without the drain) had stabilised to 12.68V which is pretty good.

However during the 45 or so minutes every time I sampled (see the graph for those 3 points) the battery needed to feed the chokes with about 700mA (actual values varied between 420 and 900mA - because as the copper cools its resistance changes and actually sucks more current [amps] as its resistance lowers as it gets closer to room temperature).

This means that if you do a number of short trips during the day the bike may spend more time sucking power from the battery while cooling down than it does getting charged. For instance you may reach operating temperature of 90°C in 15 min going to the supermaket but then spend 45 min cooling down and then ride 15 minutes home to spend another 45 minutes cooling down (sucking power out of the battery).

Depending on what you do with the bike this may not be a problem. Before this I used to ride it for 30min to work and then 30min back again. So I'd say that during that time the balance of recharge equaled the discharge of sitting around while it was cooling. Now however I'm using it differently, where trip times are about 15 min (just enough to get to full operational temp) and sit around and suck the battery times are still what they were (45min). Clearly this is resulting in more drain than charge and the battery is barely able to turn the bike over after two or three weeks.

So if your T-Max seems to run the battery down about once a month (so it starts sounding slow on the turn-over on starter) then the problem may be caused by the effect described above

But Wait, there's more

When I first started looking into this, the battery was charging at a rate slightly under the spec. I observed that it charged at spec when cold but under spec when warm. Interestingly this changed after I plugged and unplugged everything and its now charging at 14.2V all the time.

Why could that have done anything?

Well Ohms law (remember this is about electricity right) says that E (voltage) is the product of I (current) and R (resistance). So if by unplugging and re-plugging those connectors I essentially 'cleaned them' of corrosion then its possible that I altered the resistance of them a small amount.

from 13.68 to 14.25 V is actually a small amount too.

So it seems that (like so many things) the answer to this problem was unplug everything and plug it back in again. No matter how much I hate that as a solution its the only reason I can come up with as to why its now charging properly.

Of course this doesn't change the fact that the discharge to your battery will happen. T-Maxes it seems are demanding on batterys and more deeply cycle them than (say) cars. The charging issue seems to be almost unrelated to the "why is my battery getting flat over the week" issue.

So bottom line

If you use your T-Max for a number of short trips during the day you'll need to consider putting it onto a charger for a couple of hours every now and then (and you'll know because the starter motor will sound slow).

If your T-Max is not charging quite right, maybe unplug and re-plug the major items and see if that fixes it.

Best of Luck