25mm c-mount vignetting shootout

[apicius9]

Hi,

I had wanted to do that for a long time, but never seem to find the time these days, so here is just a fast and dirty version of a comparison of several fast 25mm c-mount lenses. Here are the contenders, all 25mm,

top row:
Angenieux M1 0.95
Angenieux Bell & Howell 0.95
Zeika 0.95
Angenieux 1.4
Canon TV-16 1.4

bottom row:
Kern Switar RX 1.4
Wollensak Velostigmat 1.5
Cooke Kinic 1.5
Kodak Ektar 1.4
Pentax 1.4



I was mostly looking for the vignetting, so the motive isn't really exciting. The picture in the background gives you a slight idea how the lens handles OOF parts, the focus is on Elvis' eyes, all at ISO 200. I wanted to do it inside to challenge the lenses a bit, daylight from a window on the left. I selected 3 shots for each camera, one at 4:3 fully open, one at 16:9 fully open, and one at 16:9 at f5.6. Pictures are pretty much jpgs straight from the camera, no cropping, just a minimal bit of sharpening after resizing them.

A few general remarks:

- some lenses are more difficult to focus than others. The focus ring of the Angenieux is very close to the adapter and they are difficult to focus with my big fingers.
- the Wollensak should probably have been cleaned better before the shoot...
- The Wollensak and the Zeika were the most difficult to get sharp, may have to do with the camera sitting at the edge of the minimal distance for those lenses, but that is only speculation.
- From a handling perspective, I like the Canon and the Kodak the best. Not too small, easy to reach aperture and focus rings.

So, here are the shots in the sequence listed above, I am only showing the 16:9 format for now. If you see vignetting there, it will be worse at 4:3...

Starting with the fully open shots, then at f5.6 for each lens:

Angenieux M1






Angenieux B&H






Zeika






Angenieux 1.4





tbc.

[apicius9]

continued, first pic fully open, second pic at f5.6


Canon






Switar RX






Wollensak






Cooke Kinic






tbc.

[apicius9]

Kodak






Pentax






My personal conclusions:

- The ultra fast ones are mostly very soft fully open, so I am wondering if they are worth the price tags.
- I am surprised by how well the 'cheap' little Pentax holds up. I was going to sell it, now I am wondering...
- The Cooke paints a very interesting picture but isn't very good at capturing what my eyes see...
- The Switar RX shows some strange distortion at f5.6 - I have to double check that to make sure I didn't make an error, but maybe it has to do with the RX format?
- The Canon remains one of my favorites after this comparison.

One important limitation: Especially the older lenses would probably benefit from a very thorough inside-out cleaning. I didn't see any obvious haze but most of them are a bit weak in the contrasts. I don't know enough to say that's because of their construction or some kind of slight dirt on them...

I have a few more, but these seemed to be the most interesting ones. Please let me know what you think. If you want any other specific comparisons, please let me know - but be prepared that it may take a while before I get to it.

Aloha,

Stefan

[Vivek]

Originally Posted by apicius9

One important limitation: Especially the older lenses would probably benefit from a very thorough inside-out cleaning. I didn't see any obvious haze but most of them are a bit weak in the contrasts. I don't know enough to say that's because of their construction or some kind of slight dirt on them...

Yes. Cleaning is good not only for the contrast but for the speed! If you have a less than crystal clear 0.95 lens, the speed will not be that but more in the range of ~f/1.2!


On the question of "if they are worth it"? only you can decide!

Here is a shot through the Senko 25/0.95 (not as fast as the Navitar 25/0.95 though both samples are brand new!). As shot- with no crops in camera or outside the camera.




100% crop.




It is not only the focus that is important but also the exposure- in particular when one is using super fast lenses. For hand-held shots, I would recommend atleast 1/250s shutter speed (assuming there is little subject motion).

[valtof]

It's indeed a wonderful job, and very helpful... Congratulations Stefan !

Here are my conclusions from what I see (and from what I know by myself...).

With the subject you choose we can judge sensor covering (image circle) which was your purpose, but also distortion, which is generally the other main weak point of c-mount lenses when mounted on a G1.
What is more difficult to appreciate is indeed the ease of use but especially the character of the lens. I'm still convinced that an Angénieux f:0.95 has a much more attractive bokeh than the little Canon TV16 even if this one compete very well, and not at the same price of course.

Anyway, if I only consider sensor covering and distortion, here is the classification I would suggest :

First prize ex-aequo : Cooke Kinic and Angénieux f:1.4
Second prize : Pentax
Third prize : Wollensak (even with its quite pronounced pincushion distortion)
Fourth prize : Canon

The two Angénieux f:0.95 and the Zeika are equally OK but not covering the sensor, as for the Kodak but with much more barrel distortion.

The Kern Switar is definitely out.

For my personal concern, I would love to see a side-by-side comparison between a lens I already own, Canon TV16, ans a lens I'm looking for, Angénieux f:1.4.
But in other circumstances like : a bigger main subject (a bike for example) focused not to closely (2 or 3 meters) framed in such a way we get an important OOF background field (a bit low-angle shot with horizon ideally) - wide open or/and f:2 and uncropped, of course.

Anyway thanks again, Santa Klaus, for this very interesting benchmark.
Cheers
Christophe

[slosync]

Thank you Stefan....

Very nicely done. I was especially interested in an overall test of this sort (e.g. same subject, same light, same settings).

I have the Pentax now and a Kern Switar on it's way..... I'm wondering about the Switar results you posted. Will be anxious to hear back if you get a chance to double check if something went wrong with your test.

I have a Cosmicar 25mm f/1.4 that needs some modification to get it to mount correctly in the Hawk adapter. I don't know if it's related in anyway to any of the lenses you tested, but I'm hoping it works as well as the pentax.

Here's a portrait shot using the Pentax 25mm at 1.4 of my granddaughter. I may have been just a little to close to get critical focus. I may have posted this before, please forgive the redundancy.


Regards, and thanks again
Don

[apicius9]

Thanks for your comments, everyone. I agree, there is much more to it than sensor coverage, and I plan on taking more pics before I decide what to sell and what to keep - I'm really more a user than a collector...

The two that I personally want to find out more about are the Wollensak because I think it is really promising (I only got it very recently and haven't had a chance to try it out much) and the Zeika 0.95. That has the best coverage of the 0.95 ones I have but I seem to have trouble focusing it wide open, and I am not yet sure whether that is because of a long minimal focus distance, the lens being very soft wide open or some problem with the lens, I just have to play more with it.

The one that keeps fascinating me is the ancient Cooke lens which has very interesting effects when shot wide open, they mostly disappear stopped down. Here is an example:



I have to admit that I really only got interested in photography again with the appearance of the G1, so I do lack a lot of experience and skills here. For example, I am not sure I am the best person to take apart and thoroughly clean my lenses on the inside - would anybody know of a service where I can send my lenses for that? I haven't found anybody locally either (Honolulu)...

Thanks,

Stefan

[Photomorgana]

Hi,
thank you for your comparison test.
I do own most of Angenieux and Switars and some Cookes and based on my files Im reviewing, the images I have are sharper wide open than yours.
Switar lens is probably defective. Just my thought... (I havent encountered a bad Angenieux or Switar lens so far, and I have used and still use almost all of them including C-mount, exakta, Arri. I used many Cookes and love them too, but I never used the Kinic that you have. (I believe Kinic is not top of the line for them, Ivotal or panchro would be much better)

But as a rule of thumb none of 25mm lenses you trying will be as good as Lux-D 25mm for example. Those are creative lenses and not for pixel picking... You know what I mean...
If vignetting or distortions are more important than color reproduction, bokeh and lens signature than you have to move on to 75-100mm FOV.

[apicius9]

You know, I was wondering about the sharpness because I had expected that to be a bit better than what I saw. Next weekend I will try to look at that again and make sure I don't have any systematic error in there somewhere. Maybe - don't laugh! - I need stronger prescription glasses, I have seriously been wondering about that but tried to ignore it as unwelcome signs of aging

As for the effects, I fully agree, these are not the lenses of which I expect ultimate sharpness or complete sensor coverage at all cost. The vignetting question just kept popping up, that's why I got curious and wanted to have a look into that. For myself, I would like to narrow it down to a total of 4 25mm lenses out of the 20 or so that I currently have - one for low light, one with full coverage, one with a nice and/or unique character and one that is very easy and fast to handle. That should fill the gap between the 35mm Schneider Xenon that I have and the 20/17 Panasonic that may show up at some point in the future.

That Switar also puzzles me, I'll check that out again - also one of the more recent ones that I hadn't even taken out to the real world, yet. Should the IQ be different between AR and RX versions?

Stefan

[petermcwerner]

Hi,



May I add the 26mm/1.1 Macro Switar at infinity, f/5.6. The blades of the diaphragm are currently blocked, it has to go for repair, so I cannot contribute one fully open. I have posted this before, but I thought it is useful to post again in this thread, please forgive the redundancy.

Cheers
Peter

[Y.B.Hudson III]

Switar 26mm Macro @ f/1.1

[seb33]

[IMG][IMG][/IMG][/IMG]Macro-Switar 26mm @ f/1.1


video shot with it on the Panasonic GH1 and macro switar @ 1.1 here :

http://vimeo.com/6429907

[Photomorgana]

Excellent videos and great lens.
Thank you.

[Leica 77]

Originally Posted by slosync

Here's a portrait shot using the Pentax 25mm at 1.4 of my granddaughter. I may have been just a little to close to get critical focus. I may have posted this before, please forgive the redundancy.




Regards, and thanks again
Don

This is a beautiful portrait!

[pellicle]

nice work !

thanks for posting, dinner looks good though too

[petermcwerner]

Sunflowers
Macro Switar 26mm/1.1 - ISO=100 - 1/320 @ f/5.6 - Raw Therapee



Grapes
Macro Switar 26mm/1.1 - ISO=100 - 1/4000 @ f/5.6 - Raw Therapee



Grapes - Crop from previous shot
Macro Switar 26mm/1.1 - ISO=100 - 1/4000 @ f/5.6 - Raw Therapee

[madmaxmedia]

That close-up on the Switar looks great. You didn't happen to take the same shot wide open, did you? Just curious how it would look then.

You can see through the grapes. With good lighting that's a good macro subject...

[petermcwerner]

Originally Posted by madmaxmedia

That close-up on the Switar looks great. You didn't happen to take the same shot wide open, did you?

Thank you. Wide open, the lens is much softer, not suitable for macro. The great thing about this lens is that you can use it for soft portraits wide open and it gets very sharp at f/4 and more.

[hakkalo]

Originally Posted by Photomorgana

Hi,
thank you for your comparison test.
I used many Cookes and love them too, but I never used the Kinic that you have. (I believe Kinic is not top of the line for them, Ivotal or panchro would be much better)

.

Cooke Speed Panchro 1" F2 ELC C-Mount (Sharp & full coverage )

[RichA]

Originally Posted by apicius9

Kodak

My personal conclusions:

- The ultra fast ones are mostly very soft fully open, so I am wondering if they are worth the price tags.
- I am surprised by how well the 'cheap' little Pentax holds up. I was going to sell it, now I am wondering...

Stefan

People who buy fast for things like night shots should do an experiment. Shoot with the lens wide open at a set ISO. Then, close the lens down two stops and shoot at an ISO two stops higher. Run the second shot through noise reduction software and then decide which shot is better. Sometimes, the wide open shots are so soft, lacking in contrast that the higher ISO shot turns out better. Therefore, the faster lens speed is not worth using in such a case.

[madmaxmedia]

Since most all lenses are softest wide open, I wonder how lens makers arbitrarily draw the line at what the max. aperture is for a lens.

For example, in C-mount there are a few lenses that come in f/1.5 and f/1.9 apertures (or other numbers, but half to one stop apart.) Is there that much difference in the lens designs, or is it mainly just that the blades on one lens opens a little more than the other?

Or perhaps 2 different such lenses could have the same basic design, but the tolerance for the glass elements and overall manufacturing is tighter for the faster lens. Because of this the wide open fast lens is similar in image quality to the wide open slower lens.

[madmaxmedia]

Originally Posted by RichA

People who buy fast for things like night shots should do an experiment. Shoot with the lens wide open at a set ISO. Then, close the lens down two stops and shoot at an ISO two stops higher. Run the second shot through noise reduction software and then decide which shot is better. Sometimes, the wide open shots are so soft, lacking in contrast that the higher ISO shot turns out better. Therefore, the faster lens speed is not worth using in such a case.

This is a good suggestion, though for real low light shooters I think they will always take whatever extra stops they can get.

I actually have both a Wollensak 1.5 and 1.9 coming, and will try to do a comparison. I guess that's about 2/3 stop difference.

[milapse]

Great comparison. Thanks for the effort!

The 25s are all over the place for sure. I have a wollensak 1.9 which continues to grow on me despite the tiny factor.

At the end of the day, like others here... I'm totally in love with the 26/1.1:

[RandySmith]

I am brand new to this web site, but have been selling c mount lenses on eBay for a few months. I just got a G1 body and have just started to use it with some of the lenses I am selling (they mostly go to Hong Kong).I have posted some photos of a cooke ivotal anastigmat 1" f1.4 on photobucket, along with some others. I will post some photos here as soon as I get a chance. I am an old nikon guy and really only got the G1 for marketing, but it's starting to grow on me. Randy
http://s478.photobucket.com/albums/r...Lenses/Ivotal/

[MRfanny]

Originally Posted by RandySmith

I am brand new to this web site, but have been selling c mount lenses on eBay for a few months. I just got a G1 body and have just started to use it with some of the lenses I am selling (they mostly go to Hong Kong).I have posted some photos of a cooke ivotal anastigmat 1" f1.4 on photobucket, along with some others. I will post some photos here as soon as I get a chance. I am an old nikon guy and really only got the G1 for marketing, but it's starting to grow on me. Randy
http://s478.photobucket.com/albums/r...Lenses/Ivotal/

some fine lens examples. at the risk of giving away your trade secret, where does one generally go to source old c-mount lenses? I notice the ebay sellers seem to have a never ending supply, they must be sourcing from somewhere? I just only want a few for myself without paying through the nose...lol You can PM me if you like =)

[apicius9]

Originally Posted by MRfanny

some fine lens examples. at the risk of giving away your trade secret, where does one generally go to source old c-mount lenses? I notice the ebay sellers seem to have a never ending supply, they must be sourcing from somewhere? I just only want a few for myself without paying through the nose...lol You can PM me if you like =)

No, No, we all want to know!

Stefan

[laptoprob]

Well, I have a Pentax 25 coming to me from CCDWorld and an adapter from China.
So then I will have a few fast primes besides the slower Panny zoom.

[MRfanny]

Give us a heads up on the condition of the "used" lens as I'd like to pick one up too. its the $45 one yeah?

[laptoprob]

Yep. Probably will do some vignetting, smeared or unsharp corners wide open. Maybe I will restrict the use to squares...

[ggibson]

Looks to me like the Pentax is the winner wide open.

I'm curious what the appeal of a c-mount 25mm lens is over the Panasonic 20mm? It seems like such a minimal change in length. I'm more curious about fast legacy lenses in the 35-50mm range. My father owns a 40mm Summicron-C f2 which I've been eager to test out, but don't have the adapter yet.

[madmaxmedia]

The biggest difference is price, at least compared to the Pentax.

Other c-mounts can of course be even more expensive than the Pana 20mm.

[ggibson]

Yes, price I figured is a good incentive =)

One thing that appeals to me is the unique bokeh from some of these lenses. Like apicius and milapse's images above. Very cool.

[seb33]

GH1 and C-mount Computar TV lens 25mm 1:1.8





here a link of a video I've made with my GH1 and C-mount Computar TV lens 25mm 1:1.8 :
http://vimeo.com/6898873

[MRfanny]

i notice some c mounts have that radial blur like above. is it a general common characteristic of a c mount or is it lens/brand specific. It makes me dizzy sometimes looking at images like that so id like to avoid it if possible when buying.

[thearne3]

Originally Posted by MRfanny

i notice some c mounts have that radial blur like above. is it a general common characteristic of a c mount or is it lens/brand specific. It makes me dizzy sometimes looking at images like that so id like to avoid it if possible when buying.

Not sure I'm seeing what you are seeing...it looks like the dog is in focus in the foreground, all else less so. It IS true that frame edges for some c-mounts are less sharp, but I don't have the impression that's what you're talking about.

Best,
Tom

[MRfanny]

Originally Posted by thearne3

Not sure I'm seeing what you are seeing...it looks like the dog is in focus in the foreground, all else less so. It IS true that frame edges for some c-mounts are less sharp, but I don't have the impression that's what you're talking about.

Best,
Tom

Really? I get a very distinct vision of radial blur/bokeh where the centre is in focus but it looks like the pics been spun the more you go out. It is very different to something just being in or out of focus to me. Sebs examples the first pic is fine but the other two i see it. It could just be the characteristic of the bokeh that creates this illusion. then again it could just be me but I have seen alot of c mount pics that show this characteristic.

I also see it strongly in Apicus's flower example too. All the other pics look normal to me which leads me to believe it could be brand/lens specific characteristic.

You really don't see it?

[madmaxmedia]

I believe it is due to angle of light hitting the edge of the sensor, due to the short distance between back of lens and sensor. This is not an issue with film, but digital sensors are sensitive to this. The same issue happens with wide angle Leica rangefinder lenses on M 4/3.

The Leica M9 corrects for this with offset microlenses on the sensor.

[Jonas]

Originally Posted by MRfanny

(...)
I also see it strongly in Apicus's flower example too. All the other pics look normal to me which leads me to believe it could be brand/lens specific characteristic.

You really don't see it?

"Swirling bokeh" You see it in many lenses wide open, stopped down things go back to normal again.
The effect is caused by optical vignetting (and can so bee seen as the known Cat's Eye effect).

Here you have it in post #6 and several in post #7. Another example is here and you can follow the discussion about it.

So, it is not specific to the mount, but to the lens. Many fast lenses show it ised wide open or near wide open. To not do it they would need larger elements right through the whole lens and then have the largest ooening locked down to a smaller than maximum value.

Originally Posted by madmaxmedia

I believe it is due to angle of light hitting the edge of the sensor, due to the short distance between back of lens and sensor. This is not an issue with film, but digital sensors are sensitive to this. The same issue happens with wide angle Leica rangefinder lenses on M 4/3.

The Leica M9 corrects for this with offset microlenses on the sensor.

This is something else and simply called border smear, or corner smear. Smeared corners can be a problem for many images, and doesn't nother at all in other situations.

Now if I got everything wrong it is because I didn't read Vivek's book vlose enough. Please correct me!

[madmaxmedia]

I think you got both right. The swirling bokeh can also be seen on the Noctilux, right? Now you can get that look with C-Mount for 1/100 of the cost!

I think it is not necessarily bad, depending of course on what you are going for.

What is Vivek's book?

[Jonas]

Originally Posted by madmaxmedia

(...)
What is Vivek's book?

Vivek recommended a book in a thread discussing f and T values here.
I remember it as I have been close to buy it a couple of times. But the price... In the meanwhile I sometimes go toothwalker's site here instead (earlier known as Vanwalree's site). OK, I'm now officially a cheapskate obviously not striving to know it all, a dangerous sort.

/Jonas

[Vivek]

Jonas, It gets even more complicated as the number of glass plates (and their thickness) in front of the sensors get to be huge factor. A lot of mush is generated from these and exacerbate any aberrations inherent in the lenses.

[Jonas]

Originally Posted by Vivek

Jonas, It gets even more complicated as the number of glass plates (and their thickness) in front of the sensors get to be huge factor. A lot of mush is generated from these and exacerbate any aberrations inherent in the lenses.

Oh yes. But I don't think the filters of all sorts does much for optical vignetting MrFanny asked about (except for add to the blur in general).

The smearing is another thing. There was an, to me, interesting post by Alex over at FMForums discussing a (Hasselblad) way of measuring the lens' pupils and then relate the result to the risk of smearing. I don't know exactly what bearing this has to our 4/3 and µ4/3 cameras. I would like to see the numbers for the CV15mm.

[MRfanny]

Hey thanks guys for clearing it up for me at a beginner level..ha I thought i was talking crazy talk for a moment there.

That link you posted up Jonas has got me interested in it now. I particularly like the swirls from the Biotar and even the Helio's too. Seems like the finer smaller objects in great numbers like small flowers,grass,pebbles make me dizzy the most. Those shots with the larger objects like bigger leaves and such in relation to the object in focus look wonderful.

So what kind of adapter would i need to mount a biotar or helios to a gh1? Or any suggestions to a c-mount with this characteristic? should i start a new thread?

cheers.

[Y.B.Hudson III]

Originally Posted by MRfanny

So what kind of adapter would i need to mount a biotar or helios to a gh1? Or any suggestions to a c-mount with this characteristic? should i start a new thread?

cheers.

(M39 to) M42 to m4/3 adapter...

[Jonas]

Originally Posted by MRfanny

Hey thanks guys for clearing it up for me at a beginner level..ha I thought i was talking crazy talk for a moment there.

(...)

So what kind of adapter would i need to mount a biotar or helios to a gh1? Or any suggestions to a c-mount with this characteristic? should i start a new thread?

Hmm. Yes, swirly bokeh can be nice. But...
The lenses you mention are made for FF cameras. There isn't much left of the effect if you use the center quarrter of the image only. I guess, no absolute knowledge here, that you are better off looking for some good C-mount lens with this character.

Yup, I would start a new thread. I hope you can find something!

/Jonas

[seb33]

Originally Posted by Vivek

Yes. Cleaning is good not only for the contrast but for the speed! If you have a less than crystal clear 0.95 lens, the speed will not be that but more in the range of ~f/1.2!


On the question of "if they are worth it"? only you can decide!

Here is a shot through the Senko 25/0.95 (not as fast as the Navitar 25/0.95 though both samples are brand new!). As shot- with no crops in camera or outside the camera.




100% crop.




It is not only the focus that is important but also the exposure- in particular when one is using super fast lenses. For hand-held shots, I would recommend atleast 1/250s shutter speed (assuming there is little subject motion).

Do you have to modify the lens to fit to the C mount adapter or is it ok directly ? Thank you

[seb33]

GH1 + C-mount Cine-NIKKOR 25mm 1:1.4
Video test here :
http://vimeo.com/8206569

[seb33]

GH1 + M1 Angénieux 25mm f:0.95




first video test here :
http://vimeo.com/9435241

[eooojj]

Just came back from Bali with my GF1 with Cine Lens Angenieux 25mm f0.95
























http://www.flickr.com/photos/carlerfur

[eooojj]

http://www.flickr.com/photos/carlerfur