micro four thirds: four fifties flare

For no apparent reason I decided I would test my lenses for flare. I'm not sure if this method is the most ideal, but I lined up the lenses against my kitchen wall under a fluro tube. I put a black circle with a hole cut in it on the left and a lens bottom cap (with the depth of the bucket facing me) on the right.

Lenses are:

• Canon FD 50mm f1.4 (top left)
• Canon FD 50mm f1.8 (top right
• Pentax 110 50mm f2.8 (bottom left)
• Olympus OM 50mm f1.8 (bottom right)

Method

all lenses were tested wide open and the camera (Panasonic G1) set to AWB and, camera on a tripod unmoving between each shot. (Note the Pentax 110 lens does not actually have any aperture control, so wide open is all you can pick from)

results

firstly lets look at the overview of each image, then zoom in for details:

overview

I find it interesting the colour renditions are quite different between the lenses. The lens absent from the group confirms which lens is on the camera at the time (to help me remember

the focus point
I used the following lens to confirm focus as best as I could using the magnifier to focus.

what is interesting here is at screen sizes the Pentax 110 looks to have the best contrast and sharpness, but when pixel peeping (click any image to load a full screen snapshot) I would have picked the FD 50 f1.4 ... just goes to show you need to evaluate things at something other than 100% magnification to see other factors than total resolution.

the rubber ring



The lower row seems to show better contrast to me than the top row, but the Pentax 110 lens (lower left) has significant CA purple fringing on the high contrast area, but mainly towards the outer side (away from the lens center). Makes sense.


the base cap

again purple fringing CA on the 110 lens shows up, but with better contrast than the two FD's

outside of the extreme contrast of being against the fluro the CA stops being obvious and you can get some detail in the blacks inside the caps.

Lastly, it was pointed out to me that perhaps my exposure was too short for reliable colour rendition on artificial light. Since its snowing outside and there is plenty of ambient light spill from all the street lights I would try one last thing.

On this I set the colour balance manually to be "cloudy" and manually focused the lenses to infinity. I used an exposure of 2 seconds for all of them and set all to f2.8 This puts the Pentax to a disadvantage as f2.8 is wide open. I then picked up my 3 led ultra-bright headlight so that it shone straight into the lens for the entire 2 seconds of the exposure. I tried to hold the torch in exactly the same spot.

Below are the results


Its interesting looking through the halo of light trying to see my face and how big the halo is. Then there is the secondary flare ... man the FD1.4 is really flaring. Interestingly there is a really large though less obvious purple flare on the 110 lens (lower left)

There are still colour differences, although its really hard to see colours in the outside in that sort of light.

conclusions

Well personally I like the OM and the itty bitty better and the FD's least. The FD 1.4 and 1.8 are almost dead ringers with the 1.8 showing better colour rendition in this situation to my eyes. I know from previous tests however that the FD 1.4 cleans up immensely when stopped down to 1.8 or 2 and shows itself as being much better than the 1.8 in a typical outdoor sunny day.


See my other tests of some of these lenses:

• FD 1.4 compared to OM 1.8
• FD 1.8 compared to OM 1.8
• Pentax 110 lenses

So, hope this was useful to someone (as it was to me). If you have a better suggestion for contrast and flare testing please put a comment in and I'll try to do that if I get time in the future (like I have now)

I think I'll have to try this again on a sunny day ...

---

Post scriptum (today is sunny) so I thought I would repeat this with better "natural" light.

Please note that the order is:
Top row FD 50 1.4 left and 1.8 right
Bottom row OM50 f1.8 left and Pentax 110 50f2.8 right
(this is also visible on the frame in the names)

some 100% segments from the middle of the frame


and some 50% segments up closer to where the flare is stronger

Again I find myself liking the looks and contrasts of the Pentax 110 lens wide open better than the others.

Next I picked a strongly backlight scene and put the tree trunk to block the direct sun from hitting my lens:

overview


zooming in on the segment on which I focused ...

its clear that the Pentax (lower right) has better contrast (the FD1.4 is softer at 1.4) and the DoF is less (because its a f2.8 lens).

Throwing the Kit zoom into the mix:


which (being 45mm) has a smaller feature size and looks harsher and of course at 5.6 has different DoF ...

Lastly (for what its worth) there are complete image overviews of each of these images linked to a flickr account

fifties - FD 1.4 compared to OM 1.8

Fifties are nice lenses on micro 4/3. I have a few (as you may know from reading my blog) , for instance the OM 50 f1.8 Its beautiful not only in image quality but in build. Its compact mechanically elegant and a pleasure to use.

Being curious I spent a few bucks and bought an FD 50mm f1.4 to compare to my OM 50mm f1.8 (which I bought after seeing how lousy the FD 1.8 I have is ..)

Essentially I find the FD 1.4 is equal to the OM 1.8 in terms of quality ... both wide open. However the FD has some advantage in reduced DoF. Firslty here is an overview of the image ...


I guess the leaves in focus are about 10 or 20 feet away. Below is a couple of central image segments to get a feel, these link to 100% pixel samples and are about a central portion of the image.

FD 50mm @ f1.4

OM 50 f1.8

notice the difference on the bark?

I don't know if the 1.4 vs 1.8 makes much difference in portraiture or other uses, if it makes things better or worse but I don't expect it'll be hard to stop it down if 1.4 is too shallow for an application ;-)


I ponder if I'll sell either ... but as they only cost me $50 and $12 its hard to see the point. Besides I use the OM lens on my Canon EOS body when I use film.

comparing legacy 35mm adapted fifties

One of the great things about the micro 4/3rds cameras (and as of this moment there is only the G1) is that not only do they make using older manual 35mm lenses possible, they make it easy. On the 4/3rds sensor camera good old 50mm lenses become nice medium portrait lenses, with these being as cheap as chips (and often you'll have one floating around) its really quite attractive to add one to your camera.

However, some decades ago I changed over from using more or less manual cameras to the modern Autofocus cameras like the Canon EOS, for one reason or another I just don't have any manual focus gear anymore. So if you're like me you might not have any manual 50mm lenses lying around.

But never fear eBay is here, and there's a whole wealth of stuff to choose from.

So, where to start?

Background

Well, back in the 70's and early 80's when 35mm SLR cameras like the Pentax MX or the Olympus OM-1 were the cameras to have I used Olympus. I liked the OM-1 and I personally thought that the 50mm f1.8 was quite a good standard lens. Years later I bought into the Canon EOS system and have been using it since 1989 with (at first) film bodies and (later) digital bodies.

When Canon changed from FD series to EOS they changed a few things which meant that FD lenses couldn't be used on EOS bodies without an adaptor which required a lens in it to correct for the different distance between the lens flange and the camera body mount (with the EF mount being some 2mm longer). This seemed to be a show stopper for many and FD lenses just dropped away in price with eventually the entire series becoming worth peanuts.

It wasn't just because of the change to digital either, as many people keep using Pentax and Nikon lenses on their digital bodies even though they do not have autofocus (just see eBay for some market price comparisons in the same focal length).

Being a Canon user (and hearing many glowing stories from some professional Canon users I knew pre EOS) I thought "why not pick up some bargains" for putting onto my G1.

Remember that micro 4/3rds is significantly smaller than a 35mm film frame, and so the "crop factor" means that the angle of view of a lens is essentially equal to a lens with double the focal length.

What this means is that if I want to see what 50mm lens looks like in a 35mm camera viewfinder I need to put a 25mm lens on it.

Well Canon don't make and FD 25mm, but they do make a 24 and a 28. Since the 28 is much cheaper than a 24 I thought I'd go for a 28mm and a 50mm pair of lenses and an adapter to fit them onto the G1.

For one reason or another (a future blog article on this one) I have decided to start re-acquiring Olympus lenses, the humble old Olympus 50 f1.8 is among my first. Naturally I wanted to compare the Oly to the FD and see what was what.

Method

Unlike comparison back in the film daze this was going to be easier, cheaper and more accurate. To even the comparison field even more (we're already using the same sensor on the same camera) I decided to do the following:

• mount the camera on a tripod
• use RAW capture
• use dcraw to decode the files in a uniform way
• focus on the same point using the "zoom tool" in manual focus
• take images at f1.8, f4 f8

It seems that the 'crowd' using lenses by adapter seem particularly fond of shooting wide open. I can understand that for trying to obtain shallow DoF more in line with what one expected on 35mm (well so few of us remain these days, and full frame is too exotic for most folks) but it is often the worst to show what any lens can do ...

Since these lenses typically only work in stop down mode (meaning that the aperture is closed down just like when the camera takes the picture) it is more difficult to obtain your focus precisely on what you are wanting to focus on when focusing at f8.

While the G1's wonderful EVF certainly makes that easier by compensating for brightness you still end up focusing when using the greater depth of field, making critical focus more difficult (more on that later). So for these tests I focused at f1.8 using the manual assist magnifier in the EVF for very accurate placement of the focus plane.

Results

So, first an overview of what I photographed with the Olympus OM 50mm @ f1.8


Then the Canon FD 50mm @ f1.8


even at this overview size its clear that the Olympus lens is much sharper than the FD lens and has better contrast too.

Now for all images I focused on this patch of yellow flowers. Please click on any of the images to load a full 100% pixel screen snapshot that I've loaded.


The image above is at f1.8 and in my opinion the Oly is just streets ahead. Lets look at some other apertures.

f4

f8

At f4 the gap is closing, and by f8 its nearly gone, but you know, the little Oly 50 is still just that bit better. The funny thing is that the FD 50 is the same design as the "Nifty Fifty" prized by EOS shooters presently while the Zuiko 50 f1.8 was occasionally known as the standard body cap. Anyway, before we get to any conclusions, I'll show you the rest of what I found.

While we're at f1.8, lets look at the upper middle left of the image.


then at f4



then at f8


the gap is certainly closing, and if you weren't looking at a digital capture I'd say that any differences would well be lost in printing. But if you have to make a call, the Olympus 50 is still ahead to me.


The Olympus is so far better than Canon away from the center, so lets look right at the center (where both lenses should be at their best)

f1.8

f4

Conclusions

No matter where you look in the image the olympus lens performs better at every f-stop (the one below is at f8).


Now this brings back memories of the times (I was in my 20's then) and I remember many people saying that Olympus (Zuiko) lenses were by and far the best lenses short of Leica lenses.

It really leaves me asking just why it is that Canon developed such a market lead. Was it:

• the better automation in their bodies?
• price?
• professional perception? (all those Olympic games and Footy matches)
• ignorance of people in being able to compare lenses?

I can't be sure of that, but what I am sure is that FD lenses are not a match for Zuiko lenses

Since I've got a couple of other duplicate focal lengths I'll be making comparisons with other Oly and FD lenses in future pages. As well I'll publish soon a comparison of the Olympus 50mm on my EOS body compared to the EF50 f1.8

meantime, I hope that this has made your legacy 50mm lens purchase decision easier.

PS:

This was essentially the first comparison I did with adapted lenses on micro43 (and look at the date in the URL). I have subsequent to this put together some other comparisons of 50mm lenses which can fit onto micro43 cameras with an adapter here. That article focuses on contrast and flare, but also shows the differences in contrast. If you are interested in adapted lenses on micro43 you can find some other articles of interest here on:

• Pentax 110 lenses under this tag
• more general searching on legacy (mostly manual focus) lenses here
• and things related to adapters here.

 (although there will be some overlap in those tags)

:-)