C-Mount lenses - alternatives to Ebay?

[sergio lovisolo]

Could you post a 100% crop of eg left-down corner please? TIA.

The two shots are slightly different, so I selected a point with detail slightly higher than the corner for two 100% crops at 5,6. Let me know if you need also F2.

Xenon

Summicron

If you prefer exactly the corner, I'll repeat the shoot tomorrow morning. (just outside my window,so no problem.
I am evaluating a number of C mounts that I happen to own.

Regards.
Sergio

 

[nugat]

Thank you Sergio. I am trying to confirm wheteher Xenon can really be sharper than Summicron, allegedly the sharpest photo lens in the world. On the other hand cine 16mm glass like Schneider is known to have been of extreme sharpness (60 cycles/mm not uncomon). It would not be impossible for Schneider to be sharper in the center, however cine 16 lens on m43 have the known issue of losing resolution (and other artefacts) away from the center. From Summicron designed to cover a 43mm image circle, m43 takes only half that diameter. The Xenon on the other hand is designed to cover max 14.5 mm (in case of super 16) and has to stretch its image circle a lot. Not uncommon with a 50mm cine16 lens, but some loss of quality in the corners should (theoretically) be apparent.
The way to check it is shoot both lens wide open and at 5.6, best on tripod (or real fast) and with focus bracketing. Then pick corners (more than 2/3 away from the center) on the diagonals for a 100% crop. Then we would know about resolution. Thanks again for your input.

 

[sergio lovisolo]

So this time I went for a big brick wall in full sunlight. I can confirm that Xenon 50 is the sharpest up to the corners even at F2. ( have a complete series, but posting only two 100% upper right extreme corners, no sharpening except the standard ACR5.

Summicron

Xenon

The summicron is slightly longer, perhaps 52mm.

This evening I'll post crops from the full shoot.

Regards.
Sergio

 

[nugat]

wow! that's all I can say. Leica should not be happy. The sharpness difference is very visible.I am at loss for an explanation. The only thing that comes to my mind is that paradoxically the 50mm Xenon turns out to be tailored made for the 4/3 sensor too (image circle 22mm, frame 13.5x18mm). (Full telecentricity at the 50mm f-length?). On the other hand the Summicron having twice the image circle probably is built for a uniformly high delivery across the full frame (36x24mm). Say 50lp/mm for the Summicron and 60lp/mm for the Xenon could account for the difference. But that's pure speculation.
Thanks again Sergio.
PS. Will be looking for a copy myself now!
PSPS. Any chance to do the same with a contemporary 4/3 glass, like Zuiko 50mm macro or even the kit 14-45mm zoom ?

 

[sergio lovisolo]

I suspected the same thing, but that's not the case. The same shot with summicron at F2 on the M8 shows that it is soft on corners and gets sharp going towards the center. The summicron gets better stopping down, and is very sharp an the full frame at 5,6 while the xenon is good over the 4/3 format full open, and gets better but not to much stopping down.
The 3 following 100% crops are cron with M8 at F2 from corner to center.

Don't have a Zuico, but tomorrow will try with the Pana 14-45

BTW the summicron is a new one 6 bit and was sent to Solms for a control,
and reported fine.

Regards.
Sergio

 

[Jonas]

The two shots are slightly different, so I selected a point with detail slightly higher than the corner for two 100% crops at 5,6. Let me know if you need also F2.

Xenon

Summicron

If you prefer exactly the corner, I'll repeat the shoot tomorrow morning. (just outside my window,so no problem.
I am evaluating a number of C mounts that I happen to own.

Regards.
Sergio

Sergio, here I see more details in the Summicron image. The exposure is different, were the lenses also focused differently?

 

[sergio lovisolo]

Jonas, yes in this one the exposures were different for the passage of a cloud.
Focus was manual with both lenses, with focus magnification, and I did my best but results are converging after many tests.
At 5,6 the two lenses are so good that it is difficult to see a difference. But what is notable is that I have in front of me the 100% enlargement of the church made with the xenon 50 at F2 and at pixel level it is sharp corner to corner. A very very good little lens.
I am now testing also the Xenon 25 1:0,95 that obviously shows a completely different character.

Regards.
Sergio

 

[Jonas]

Thank you Sergio,
Uncontrolled light is a pain when trying out lenses. So, you are testing the Schneider Xenon 25/0.95 ?! I hope you post some results here, showing both the image quality and how it covers the sensor.

regards,
/Jonas

 

[nugat]

I found this in-depth review of the summicron which might explain partly the poorer performance at 2.0

http://lenstip.com/205.1-Lens_review-Leica_Summicron-M_50_mm_f_2.0-Introduction.html

 

[apicius9]

I didn't want to open a new thread for my quick question, so I took the first c-mount thread I could find, I hope you don't mind:

I recently found this really nice small c-mount bellows with a Schneider 80/2.8 Xenotar in almost mint condition. Now, getting the bellows connected to the camera is a bit of an issue. If I screw it directly into the adapter, I can't get the adapter on the GH1 because the bellows bumps into the protruding front part. Fortunately, I have a few c-mount tubes, and with the 15mm it works. Since this is for macros anyway, I don't think the tube piece would have any adverse affect besides minimally increasing the distance between lens and sensorn- or would it?

But, of course, the bellows is not in the right position once I attach it to the camera. I am also a bit worried about the extension tubes, they seem to be aluminum and 'grind' a little bit, I'm afraid I'll get small metal particles on the sensor. Now my thought is to sacrifice one c-mount adapter and glue it to the tube piece so that the bellows will sit correctly when I attach it. I could also use that combination with all my other c-mounts for macro shots, and I wouldn't have to modify the bellows in any way. Is there any other easy solution I am overlooking?

Stefan

 

[photoSmart42]

I am also a bit worried about the extension tubes, they seem to be aluminum and 'grind' a little bit, I'm afraid I'll get small metal particles on the sensor. Now my thought is to sacrifice one c-mount adapter and glue it to the tube piece so that the bellows will sit correctly when I attach it. I could also use that combination with all my other c-mounts for macro shots, and I wouldn't have to modify the bellows in any way. Is there any other easy solution I am overlooking?

The easy solution for me is to attach the lenses to the adapter first, then mount the adapter+lens combination to the camera. I had the same concern about screwing some old, mechanical thread just millimeters from the sensor. Another easy step is to thoroughly clean (blown air, brush, etc.) the c-mount thread on the lens side to get rid of as many particulates as possible.

To me, c-mount lenses don't exactly lend themselves to quick changes, so when I shoot with those lenses I normally dedicate an entire session to a specific lens, which isn't really much of an issue given that I do that normally in any event. That means I minimize any potential issues that might arise from changing lenses a lot. Certainly if you only have one c-mount lens then it makes some sense to keep it attached to the adapter at all times even though it'll take up more storage space.

 

[Marcuz]

Hello i've just registered to this forum, and since my problem is related to the discussion here, i preferred to following with a reply instead to start a new thread; i hope that's fine.

i just bought me an E P-1, with the 14-42 kit; while i'm not a particularly good photographer, i'm loving it and i'm reading a lot about micro four thirds, and seeing samples of the various cine lenses here and on flickr.

So, i wanted to buy a 25mm and at first i was attracted by Switar; since i was costantly outbid on them on ebay, i was considering also a Wollensak and other. But i'm a bit confused at this point in which could suit me better.

basically i'm looking for a soft bokeh and as little vignetting as possible, i do mind less, in comparison about barrel distorsion.

I would like to use them to film a little also, and so far i have seen outstanding movie results (in regard of resolution/clarity) for the Switar and (in regard of warmth of colors, bokeh) for the cine-nikkor 1.4

do you have any advice?

In addition to your advices, i would like to ask a couple of specific questions for which i haven't found answers on the www:

Are the Wollensak Velostigmat and the Raptar much different in regard of the above?

Are the two models of Cine-Nikkor 1.4 and the 1.5 different in any other way other than the aperture stop? Would be the Cine-Nikkor 1.4 worth the major cost on ebay in respect to the Wollensok, at the same condition?

I'm sorry if this post is not very professional, but i would be really happy to have some doubt solved and to learn to use the camera better.

thanks!

 

[Marcuz]

Are the two models of Cine-Nikkor 1.4 and the 1.5 different in any other way other than the aperture stop? Would be the Cine-Nikkor 1.4 worth the major cost on ebay in respect to the Wollensok, at the same condition?

argh! i meant 1,4 and 1,8! mistype :/