p.49 #1 · A thinner sensor stack may be possible after all!
rscheffler wrote:
I primarily shoot Leica digital M - M240 and M9 and own both M mount versions of the 15mm. I have shot some comparisons on the Sony a7 series cameras with a range of RF lenses, including the first 15mm M mount version (optically identical to the LTM version). You can see how it does on the a7R and a7S. Both of those links include comparison images with the lens on the respective digital Leica I owned at the time.
Bottom line is I think the CV15 vII performs very similarly on unmodded a7 series cameras compared to digital Leica, with respect to edge smearing.
I recently acquired the CV15 vIII and did a side by side test of it on the Leica M240 against the previous version (haven't gotten around to publishing it). I assume M240 results will be very similar to a modded a7 series camera. The biggest difference was complete elimination of the edge color shift without any special processing by the camera or in software afterwards. Distortion correction was also better in the new version. Otherwise, in respect to color, contrast, sharpness, etc., I barely saw any differences. Peak central sharpness was already by f/8, but if focused centrally, edges needed f/11 for improvement. I haven't looked into this much, but am guessing the vIII also has some field curvature and that focusing somewhere between the center and the edge will improve 'average' focus/sharpness across the frame at f/8.
Is the vIII worth it? Yes, if you hate correcting color shift in post (which I believe results in additional artifacts and some quality degradation). The convenience factor here is huge. Otherwise, I don't see a noticeable image quality improvement other than better distortion correction. I dislike how much larger the lens has become. If you can live with the color shift and get a decent copy, the LTM (both 12mm and 15mm) is so much more compact, where it's almost no thought about bringing one or both along. But with the M versions, particularly vIII, the lens is to the point where it is fairly chunky (for an RF lens), particularly thanks to the built-in hood... With the 3D-Kraft a7RII preview, I suppose it might be possible the color shift with the older versions of the lens will be less problematic, which will be very interesting to see once the camera is out in the wild.
As for Cosina quality control of the Voigtlander lenses.... my impression is it has improved with the latest lenses I've bought, such as the 35/1.2 II, 21/1.8, vs. the older lenses I also own or have tried. When I bought the 12/5.6 LTM, I tested a couple and one was horrendous... not sure it's an indication of general QC problems with Cosina back then, but if you're buying an older Voigtlander lens, you definitely want to test before committing....Show more →
Thanks for all the information.
Your samples on your webpage is certainly the most comprehensive I've ever come across.
The comparison with the M9 is especially useful as it gives a rough idea that maybe that would be the IQ with a thin filter modded A7.
I've tried my friend's CV15viii.
Very nice lens indeed.
As you mentioned, no more color cast.
Same feeling about the size though.
p.49 #2 · A thinner sensor stack may be possible after all!
Update from today.
I had some doubts about the CV15 v1 test above.
Perhaps that sort of distance with atmospheric haze and sheer distance had made it too hard to judge the results.
So here is a simple reshoot at f8 with closer distances where its easier to differentiate differences.
All shots straight off the AWB of both cameras and in RAW processed in LR with the same settings.
No corrections done for the lens.
Quite apparent differences this time round.
Certainly sharper for the A7K.
A bit more 'bite' in the image with the better edge definition and a bit more texture detail.
p.49 #4 · A thinner sensor stack may be possible after all!
One of the great frustration and IMO unmentioned things (not FM but on some other forums ) about some of these RF lenses on A7 is that its mostly only center good.
Yes, part of this is certainly due to the lens characteristic, however, the thick filter stack is certainly adding to this.
A lens that has caused me some frustration with this is the Voigtlander 35/1.4 Nokton.
Yes, its quite a marvel of a lens, tiny for a 35mm with f1.4.
Problem is that on the A7 (unmodified), just past the center, in the rules of thirds area, its smeared.
This often poses a problem when one composes with the subject in the thirds or in a group shot where at least one or two persons will end up off center where the sharpness is (and hence smeared, even though they are on the same plane of focus)
So here are some test shots between the A7 and A7K.
Handheld, but shot multiple times to make sure about the focus.
This will certainly make me use my CV35/1.4 more often now, as it becomes a decent 'all rounder', compared to a 'special effects/occasion/purpose' lens on the unmodded A7.
p.49 #7 · A thinner sensor stack may be possible after all!
zhangzp120 wrote:
OMG... I just got my 7s and going to send it out for mod........Now I have to hold on that.....
Why? Unless you want to get the A7RII... Even so, I have my A7s modded, and the A7RII would follow soon if a) it doesn't help with the smearing and b) Ilija finalizes his 2nd gen. mod routine.
p.49 #8 · A thinner sensor stack may be possible after all!
hiepphotog wrote:
Why? Unless you want to get the A7RII... Even so, I have my A7s modded, and the A7RII would follow soon if a) it doesn't help with the smearing and b) Ilija finalizes his 2nd gen. mod routine.
Hi Hiepphotog,
I cannot afford to keep both A7rii and 7s,
I would like to see the edge smearing comparison on an original 7s vs original 7rii.
If the 7rii is significantly out performance 7s before mod. I will sell my 7s and go for mod a7rii.
p.49 #9 · A thinner sensor stack may be possible after all!
zhangzp120 wrote:
Hi Hiepphotog,
I cannot afford to keep both A7rii and 7s,
I would like to see the edge smearing comparison on an original 7s vs original 7rii.
If the 7rii is significantly out performance 7s before mod. I will sell my 7s and go for mod a7rii.
From my preliminary testing, the A7RII behaves the same as the stock A7S . However, I believe it is a hair better at vignette and color cast control than the A7s.
p.49 #11 · A thinner sensor stack may be possible after all!
sootyvrs wrote:
Does the Kolari mod make any difference to the sensor reflections (usually night shots) that is a known problem for the A7?
He already worked out the coating part. However, due to the current low supply at Schott's factory, he can't offer it right now since coating has to be done in large batch. The reason I mention about coating is that depending on the camera, you might get more reflection, like my A7S. I have not noticed any complain from A7 and A7R users.
p.49 #12 · A thinner sensor stack may be possible after all!
hiepphotog wrote:
He already worked out the coating part. However, due to the current low supply at Schott's factory, he can't offer it right now since coating has to be done in large batch. The reason I mention about coating is that depending on the camera, you might get more reflection, like my A7S. I have not noticed any complain from A7 and A7R users.
Thanks.... How does one keep up with updates and developments about the new coating?
p.49 #14 · A thinner sensor stack may be possible after all!
hiepphotog wrote:
From my preliminary testing, the A7RII behaves the same as the stock A7S . However, I believe it is a hair better at vignette and color cast control than the A7s.
Thanks for reply,
If that is the case, I will contact Kolari to start my 7s mod.
BTW, I saw you mention about coating, how serious is the 7s mod reflection? If it is lighter than a7 unmod, then never mind
p.49 #15 · A thinner sensor stack may be possible after all!
I found the UWA really difficult to test properly because it's so hard to find the critical focus at infinity. For example, at first I was thinking the ZM18 was better but corners still had some issues. Then I found one of my shots with everything perfect, infinity and the corners.
The Sony EVFs, once a revelation, now lack well behind the Panny EVFs like you see on the Q.
But here's my real question:
Who has tried the Leica 35/2 asph and how does it do?
p.49 #16 · A thinner sensor stack may be possible after all!
zhangzp120 wrote:
Thanks for reply,
If that is the case, I will contact Kolari to start my 7s mod.
BTW, I saw you mention about coating, how serious is the 7s mod reflection? If it is lighter than a7 unmod, then never mind
I just attached my test shot here so you can decide. I'm not too familiar with the A7 degree of reflection. The shot was made with the Contax G 21 at ISO 16k.
p.49 #17 · A thinner sensor stack may be possible after all!
Hello everyone,
I want to thank all of you for being a part of the development process with the thin filter mods that we have been performing, your feedback has been invaluable to honing the service, it has been an ongoing development. I would like to announce that we are now officially supporting the A7 II, we've been waiting on launching until we could have the IBIS performance independently verified. We are also now developing the service for the A7R II, we think we will be able to achieve the same level of corner improvement as the previous four A7 series cameras. Any questions or suggestions are always very welcome! Fastest way to reach me is through our website email.
p.49 #18 · A thinner sensor stack may be possible after all!
No comparative samples between stock A7 and A7K, but here is a test shot using the CV21/4 on the A7K.
Both images corrected for color cast on the corners and LR lens profile used.
To see the full sized image, just get it on my Flickr.
p.49 #19 · A thinner sensor stack may be possible after all!
Jen, as I suspected, even at f/8, the field curvature of this lens is still very prominent. You get sharp corners but soft foreground edge. f/4 is totally unusable for landscape based on that bicycle shot
p.49 #20 · A thinner sensor stack may be possible after all!
hiepphotog wrote:
Jen, as I suspected, even at f/8, the field curvature of this lens is still very prominent. You get sharp corners but soft foreground edge. f/4 is totally unusable for landscape based on that bicycle shot
I focused using the off center and at the distant buildings, not catering for the foreground, so I wonder if it can get any better.
That said, I do think it becomes reasonable enough to use as a general walkabout lens with the 'not too critical' snap of a wide cityscape/landscape while during the walk.
I do agree though that if I was on a more specific cityscape/landscape shoot, I'd not choose this lens to put in the bag.
This is a friend's lens.
I was tempted about getting one because of the size, but with some cool logical thinking, I think I will stick with my Pentax M20/4 which isn't really that big and gives me better IQ and no color cast to fix.
. However, I believe it is a hair better at vignette and color cast control than the A7s.
. I check back with him at least once a month. And any question you have, he's obviously the best guy to ask.
