p.35 #1 · A thinner sensor stack may be possible after all!
hiepphotog wrote:
I think I nailed the WB this round .
Xavier: The Biogon G 21 is a tricky, yet lovely little lens. But I think I finally manage to squeeze the most out of this lens . However, I would like to stretch the importance of getting the infinity focus spot-on. When I did the test this morning, my infinity is a little off and I couldn't manage to get a satisfactory result (to be honest, was thinking of selling the lens). However, being curious and quite in love with this lens, I decided to run the test again with infinity adjustment. My G21 was already converted to M-mount with distance scale by Hawk. Using Hawk's M adapter, I got the exact infinity point....Show more →
Thank you for the tests! Way back on page 19 you mentioned the C-Biogon 21/4.5 performs well with the mod. Is there much difference between these two lenses stopped down at infinity with the thinner cover glass?
p.35 #2 · A thinner sensor stack may be possible after all!
Thank you guys! I'm glad you guys found it helpful. I hope more interest would help Ilija looking for better glass alternative or offering certain additional services.
@artur: I don't rely on focus scale for these tests. What I meant is before I set the adapter to the exact infinity spot, I couldn't get rid of the fuzziness in the extreme corners at f/11 as what I am getting here. Right now, with the normal framing, I can shoot away at f/8 and for a less critical scene, f/5.6 is no problem. For close-distance, WO is certainly usable.
@Archimedes: It is hard to determine due to the different scene, different resolution and much more color cast on the A7R.mod. But I don't think the details in the corners of the C-Biogon is that convincing; it still has a bit of fuzziness in the corners even at f/11. The best way is you need to subscribe to Lloyd's Leica blog to determine it for yourself.
p.35 #3 · A thinner sensor stack may be possible after all!
rscheffler wrote:
Congrats! I'm sure you'll love its image quality, let alone the much smaller size. It's one Leica lens that seems to have some Zeiss in its rendering. Have you guys noticed much color shift with it on the various a7 cameras? (This was probably discussed already, so sorry for asking again, if it's indeed the case.)
It's also interesting to see your progression through various lenses over the past year or so...
Thank you Ron and Charles.
SEM 21 is indeed one small lens (small for 21mm) and one of a few light ones that doesn’t tip down my A7R. Comparing to Zeiss 2.8/21 it does require extra CornerFix and post processing steps due to its heavy purple shading, but I believe similar processing is done in-camera on M systems too. As often, it’s a trade-off between low weight + compactness vs. extra PP work – something that indeed influences my lenses selection in recent past
p.35 #7 · A thinner sensor stack may be possible after all!
hiepphotog wrote:
Jack, excellent sharp shots. Which aperture were these at?
Thank you. Both were shot at f/8.
In the whole excitement I forgot about focussing tip from few pages back and focussed only on the center area. This resulted in degraded sharpness in outer zones comparing to the center (dah!) This morning I took few test shots and focusses on various points of a frame.
p.35 #8 · A thinner sensor stack may be possible after all!
How is you infinity calibration for the 21/3.4 Jack? If it's all good, then there might still be a slight edge with a digital Leica body. Then again, you're dealing with 36MP vs. what I'm used to seeing at 24. Scaling it down to match and a bit of sharpening likely will diminish any differences even more.
p.35 #9 · A thinner sensor stack may be possible after all!
Jack, excellent example of where to focus. Hiep also provided compelling shots too.
I have a feeling with the increased MP's and viewing at 100% will show weaknesses that may have been missed before. With the new A7rII on the horizon, possibly 50MP we will see more clearly the issues again.
I do know that the focus point is very important, and it is not always the center that is optimal even with infinity calibrated. I have had similar issues with Loxia 35/2 and the A7II which should be well matched.
p.35 #10 · A thinner sensor stack may be possible after all!
Ron, on VM-E adapter the lens focusses past infinity and on A7R this allow me to quickly move focus point to desired and critical point of a frame. Will try my other M -> E adapter next time, just in case.
Charles, agree - at this level of MP everything counts particularly shooting discipline. I wish the light was better so the shots were above 1/60-1/125s 'shake region' of A7R while still at base ISO. Will try again once the weather improves.
p.35 #11 · A thinner sensor stack may be possible after all!
Hi Jack, I suspect that having a minimum shutter of 1/125s and above is a lot of the issues even with the wide angles! For myself I know that my technique cannot lapse in holding the A7r steady, otherwise I will notice when I download the RAW files. It is percentage thing, that if I maintain a higher a shutter speed, that is above 1/125sec for 50mm and less, there are very few issues due to shake/vibration when I am holding the cam.
p.35 #12 · A thinner sensor stack may be possible after all!
Jack, I did squeeze a little bit more out of the Contax G 21 with correct infinity setting. My G 28 actually performs worse than the G 21 at all apertures, and I suspect that's because the Fotodiox Contax G is shorter than it should be.
Charles, I agree that focus on the center only might not be adequate for a lot of lenses (especially those with wavy field curvature). However, with LV'ing anywhere on frame nowadays, I can spend less than 20 minutes to learn exactly where on the distance scale I should set for the best performance across the frame at a respective aperture. It's much quicker now to learn about all the quirks a lens has. Back in the day, I would say you need to spend more than a few rolls of film and sizable amount of time to figure that out.
p.35 #13 · A thinner sensor stack may be possible after all!
hiepphotog wrote:
My G 28 actually performs worse than the G 21 at all apertures, and I suspect that's because the Fotodiox Contax G is shorter than it should be.
the g28 doesn't have a floating element so the adapter thickness shouldn't make a difference as long as you are choosing the optimal focus point in LV.
p.35 #15 · A thinner sensor stack may be possible after all!
sebboh wrote:
the g28 doesn't have a floating element so the adapter thickness shouldn't make a difference as long as you are choosing the optimal focus point in LV.
You're right if the adapter is too short. Instead, if it was too long, that means no infinity and we'd be in trouble..
p.35 #16 · A thinner sensor stack may be possible after all!
hiepphotog wrote:
@Archimedes: It is hard to determine due to the different scene, different resolution and much more color cast on the A7R.mod. But I don't think the details in the corners of the C-Biogon is that convincing; it still has a bit of fuzziness in the corners even at f/11. The best way is you need to subscribe to Lloyd's Leica blog to determine it for yourself.
Ah okay, I thought your earlier post meant you tested the 21/4.5 C-Biogon yourself. I'm wondering if Lloyd had problems with his focus, like you initially experienced on the Contax G lenses, and whether the C-Biogon would catch up to or even surpass the Contax G 21mm once the same technique is applied to both.
p.35 #17 · A thinner sensor stack may be possible after all!
karlfoto wrote:
I was just wondering how the kolari mod on the a7 would affect a lens like the canon 17 tse that i use on my 5dii when doing architecture?
Thanx
I'll be testing my 17 TS-E on my A7rM when it comes back. No A7M though.
p.35 #19 · A thinner sensor stack may be possible after all!
DavidBM wrote:
In theory the Kollari mod should make the 17 tse very slightly worse shifted; the canon filter stack is about the same as the Sony.
In theory yes, but experience has shown that the TS-E performs a tiny bit better on the 5DIII for instance, than on the A7/A7r - difference is negligible but present - in the corners. I just hope it is not horrible on the A7rM as it is my favorite lens.
Mar 23, 2015 at 08:07 AM
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p.35 #20 · A thinner sensor stack may be possible after all!
beetlephoto wrote:
In theory yes, but experience has shown that the TS-E performs a tiny bit better on the 5DIII for instance, than on the A7/A7r - difference is negligible but present - in the corners. I just hope it is not horrible on the A7rM as it is my favorite lens.
Are you sure that the difference between the A7/A7r and the 5DIII isn't due to the adapter? I think this is a lens where the adapter may need to be shimmed to get optimum performance.
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