highdesertmesa
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 Re: FM Review: Voigtlander 35mm f/2 APO-Lanthar | |
Fred Miranda wrote:
highdesertmesa wrote:
Fred Miranda wrote:
highdesertmesa wrote:
Fred Miranda wrote:
highdesertmesa wrote:
Fred Miranda wrote:
highdesertmesa wrote:
Fred Miranda wrote:
highdesertmesa wrote:
Fred Miranda wrote:
highdesertmesa wrote:
I just mentioned that some might appreciate getting true infinity focus at the hard stop by using an M camera.
Definitely a pleasure to set the focusing ring to the lens' hard stop and get perfectly focused images with the Voigtlander 35mm f/2 APO and 50/2 APO VM lenses. It does not always work though, as this is dependent on perfect calibration. For example, I've tried multiply copies of the CV 35/1.2 III and CV 21/3.5 VM lenses and could not achieve infinity focus with them in multiple Leica M bodies. Most lenses are fine though.
The 21 3.5 didn’t work for me, either, so I returned it for the 21 1.4, which did work. Thankfully my 35 1.2 III also is good at infinity hard stop.
It would be the first I've seen.
Since you can adapt it to the Sony, do you mind taking a picture at infinity and compare to the hard stop using the 35/1.2 III on the Leica? If you do, resize the Sony image to 40MP so we can compare the center crop at pixel level (100% mag.).
I could never find a 35/1.2 III VM copy with perfect hard stop infinity calibration.
I don’t have a Sony but rather a GFX 50R and R5. I have a Novoflex M for the GFX and Kipon M macro/helicoid for the R5. But since all adapters are designed to let the lens focus past infinity, this would only test if the lens on the M10-R isn’t turning far enough to actually reach infinity — the exact opposite issue I had with the 21 3.5, which quite obviously in both the Visoflex and the rangefinder was reaching infinity before the hard stop. I can use the Visoflex on the M10-R to verify the 35 1.2 III isn’t reaching infinity before the hard stop, but I don’t think that’s the issue we’re looking for here, right? That would mean my lens was incapable of infinity on the M, and I wouldn’t be getting sharp results.
Does that all make sense?
EDIT: checked the lens again today, looking at the rangefinder patch much more carefully this time. It does look like it hits perfect alignment just a hair before infinity, and I mean just barely. I took two shots at f/5.6 at hard lock and at what the rangefinder was saying was perfect infinity, and indeed the shot made according to the rangefinder was sharper. So I stand corrected on this lens. I’ll check my others more carefully, too. The 21 3.5, though, it focused much more noticeably past infinity.
If the hard stop focuses beyond infinity (like with your CV 21/3.5), it's not ideal but it's fine because at least a subject at infinity can be critically sharp.
The issue I had with my CV 35mm f/1.2 III VM copies is that the lens could never reach true infinity at the hard stop since it never reached true infinty. At first, I though Cosina optimized the hard stop for smaller apertures since the lens has focus shift but even at f/5.6 , a subject at infinity would be more in focus on the Sony compared to the Leica when comparing center crops.
If does not matter which camera you try as long as you have an adapter for the Voigtlander VM. So you could focus with your GFX or R5 on a subject at infinity distance (using high magnification to make sure), Then on your Leica, just focus the same scene using the hard stop and compare the center crops at 100%. If they are equal, that means your CV 35/1.2 III is indeed focusing correctly.
Follow-up on our 35 f/1.2 III infinity focus on M body discussion below.
NOTE FOR EVERYONE ELSE: This is not with the 35 APO!
Center crops from both systems @ f/5.6 below. M10-R focused to the hard stop, GFX 50R focused using high-magnification live view in the EVF.
Given the GFX 50R microlenses are so small and equal magnification is harder on the M10-R, I think these show the 35 1.2 III is correctly focusing to infinity on my M10-R.
Nice!
But f/5.6, I expect DOF to somewhat mask issues with focus but the real test is at f/1.2 (wide open). Do you have some of those?
NOTE TO EVERYONE ELSE: This is not the 35 APO. We're having a separate conversation about the 35 1.2 III at Infinity on M bodies.
Here's a comparison at f/1.2 – infinity hard stop on the M10-R versus best I could do with high magnification on the 50R.
M10-R was obviously overexposed given the 1/4000 sec. shutter speed + ISO 100 limit, so it's been recovered in post. The 50R was the electronic shutter around 1/11,000 sec. – Camera was braced on the top of a fence for both.
The EVF quality on the 50R is not really up to the task for f/1.2 + infinity on a lens like this that's not really super sharp wide open at infinity. I took several and picked the best – they were all about the same.
Normally with this lens at infinity in low light, I would probably choose to raise my ISO and go with f/2.8 as the maximum aperture. Even with my RF 50 f/1.2, which is very impressive wide open at infinity, I usually go no wider than f/2.
Thanks for this! 
It does not quite reaches infinity at hard stop but it does better than all other copies I've tried. Consider yourself lucky! 
You think it's not reaching infinity here? I thought the M example looked sharper. I'll repeat the test when there is less atmospheric distortion, and maybe we can see any differences more clearly.
Or are you saying the lens doesn't reach infinity period – on either?
Yes, it does not quite reach infinity. I think the 50R crop is sharper.
One more, this time without the midday heat distortions. It was easier to see focus on the 50R in these conditions.
35 1.2 III shot at f/1.2 on M10-R and GFX 50R. Hard stop on M10-R / high-magnification EVF focusing on the 50R. Both 1/1000 sec., both mechanical shutter (M only has mechanical). Both cameras were braced on the top of a fence.
In post, I did these differently than the last set. This time, each was post-processed for sharpness the way I normally do any landscape file: as much as possible without looking over sharpened. This is really the only way to have a fair comparison between these cameras since 1) the GFX is 10 more megapixels, 2) GFX has smaller microlenses, which greatly increase apparent sharpness, and 3) GFX 50S/R are known for higher native RAW file sharpness than most cameras.
What I did here too, was not just provide a 200% crop from near-center, but also 200% off-center, but still within a 35mm frame and still not close to the edge of a 35mm frame. In that crop, the GFX sharpness falls off like crazy, which I assume is due to the thicker sensor stack of the GFX compared to the M, and the CV lens being optimized for the M sensor.
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