[New test photos released] Leica Summicron 35/2 Eight Element copy made in China

[Erik van Straten]

The top shot is shot on f/2 and the other is on f/2.8. On f/2 there is some vignetting (see the black corners) and some, what the Germans call, Bildfeldwölbung (field curvature): the woman is sharp, but so are the branches of the trees in the extreme corners of the image. This effect is very often seen with old wide angle lenses (and also on normal lenses).

On f/2.8 these effects are still there, but I would like to see the same shot on f/5.6 or f/8. Then everything should be more ore less in focus with a 35mm lens.

Erik.

 

[D&A]

What are in the end the definite conclusions on the replica lens design changes (or not) and the associated wave shaped focus profile? Is it an issue only with the later made lenses that have been made with half click apertures or is it a universal issue? Is it a "problem" issue? This thread was loaded with praises for the lens. I feel that such unresolved issues may negatively impact the future of replica lenses at RFF.

Raid, no worries. As with any lens that out for a while and used by a greater number of people, we all learn the ins and outs of a lenses characteristics. Whether the recent copies have been slightly optically changed hasn't been determined nor has it been determined if that one copy that seems to have more of a wavy depth of field is a "one off" or a characteristic wavy depth of field now is a characteristic of recent copies of the lens. I any case its a extremely fine lens as shown by virtually everyone and is a remarkable achievement in many respects in my opinion.

Dave (D&A)

 

[D&A]

The top shot is shot on f/2 and the other is on f/2.8. On f/2 there is some vignetting (see the black corners) and some, what the Germans call, Bildfeldwölbung (field curvature): the woman is sharp, but so are the branches of the trees in the extreme corners of the image. This effect is very often seen with old wide angle lenses (and also on normal lenses).



On f/2.8 these effects are still there, but I would like to see the same shot on f/5.6 or f/8. Then everything shoeld be more ore less in focus with a 35mm lens.


Erik.

Erik, If the top shot is f2, then from what I can see, all looks normal and as expected and except for those very sharp upper corners, I don't see evidence of wavy field curvature when I look at all areas of the image (and I do know what to look for. As for the vignetting, especially in the f2 shot, of course this is normal and to be expected. I too would have liked to have seen a whole series of shots at all major f-stops such as f2, f2.8, f4, f5.6 and f8. Other from these images, the lens matched exactly what I observe with my copy and doesn't seem to display the large focus shift as the OP original described previously.

Dave (D&A)

 

[raid]

Raid, no worries. As with any lens that out for a while and used by a greater number of people, we all learn the ins and outs of a lenses characteristics. Whether the recent copies have been slightly optically changed hasn't been determined nor has it been determined if that one copy that seems to have more of a wavy depth of field is a "one off" or a characteristic wavy depth of field now is a characteristic of recent copies of the lens. I any case its a extremely fine lens as shown by virtually everyone and is a remarkable achievement in many respects in my opinion.

Dave (D&A)

Thanks, Dave. I agree with your assessment here. My lens is a very good lens and I compared it with the original Cron.

 

[rscheffler]

What are in the end the definite conclusions on the replica lens design changes (or not) and the associated wave shaped focus profile? Is it an issue only with the later made lenses that have been made with half click apertures or is it a universal issue? Is it a "problem" issue? This thread was loaded with praises for the lens. I feel that such unresolved issues may negatively impact the future of replica lenses at RFF.

Hi Raid,

I just heard back from another photographer I know who received delivery of the replica in November when I was supposed to, but my lens was sent back to the factory after Kevin's QC check (for cosmetic reasons). Therefore his lens and my lens likely were in the same, or similar production time period.

Here is what he found based on more thorough testing:

"While I do see some focus shift as I did before I feel that center of the frame remains sharp so overall I think it's ok for me.

I did see the field curvature much clearer this time though in some of the shots."

It would be good to get more feedback from others with the new lens (with the equal aperture stop spacing), but based on his comments and that he considers the lens to be working adequately, I'm leaning towards the probability my copy is an outlier.

So I'll reiterate what I've requested before: especially for those who have received a lens recently, it would be appreciated if you could rangefinder focus the lens on an object and do a quick aperture sequence without refocusing the lens. As the lens is stopped down, does the center of the image remain sharp? If it is sharp at f/2, becomes soft in the range of f/4-5.6 and begins to recover at f/8 and is good at f/11, then it performs like my copy. If it remains acceptably sharp throughout the sequence, then it is working normally.

Even a single test shot would be adequate, preferably at f/4 or f/4.5 where I see the greatest central image softness with my copy.

Thanks!

 

[james.liam]

iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii

Looks like a row of candles. Very festive

I really don't understand what all the hand-wringing is all about. Sounds like the lens is an artful 'authentic homage' rather than a precise replica. Which is perfectly fine because you just can't go out and spring for the 'real thing' on a whim.

 

[Erik van Straten]

Even a single test shot would be adequate, preferably at f/4 or f/4.5 where I see the greatest central image softness with my copy.

rscheffler, maybe it is helpful if you post the image with the woman above taken with the f-stops 4, 5.6 and 8 too - if you have them. Thanks!



Erik.

 

[rscheffler]

Erik, If the top shot is f2, then from what I can see, all looks normal and as expected and except for those very sharp upper corners, I don't see evidence of wavy field curvature when I look at all areas of the image (and I do know what to look for. As for the vignetting, especially in the f2 shot, of course this is normal and to be expected. I too would have liked to have seen a whole series of shots at all major f-stops such as f2, f2.8, f4, f5.6 and f8. Other from these images, the lens matched exactly what I observe with my copy and doesn't seem to display the large focus shift as the OP original described previously.

Dave (D&A)

Hi Dave and Erik,

Sorry if I caused some confusion with those two images. What I meant was the the top, wide open image, shows lower contrast, especially at the center of the frame, which I think is just the character of the lens and not a defect. It would be caused by spherical aberration combined with some veiling flare. In hindsight that example might not have been the best because I used aperture priority for that sequence and the camera adjusted the shutter speed only a half-stop though the aperture was changed by one stop. This was due to the strong vignetting of the lens wide open tricking the camera's exposure meter and something I noticed in other sequences where I used aperture priority to speed up the process of shooting the test images. I should have kept it at manual exposure for consistency.

rscheffler, maybe it is helpful if you post the image with the woman above taken with the f-stops 4, 5.6 and 8 too - if you have them. Thanks!



Erik.

Erik, in that sequence of images, at f/4 and f/5.6 the woman is out of focus.

If you want to see a sequence where the field curvature in my lens is very evident, go back to my post on the other page with the link to the photos on Google Drive. About halfway down, just after the sequence with the large white building, is a set of a tree in the middle of the image and a bench on each side. In that sequence you will see that as the lens is stopped down, the tree becomes soft and the background, including a small white cabin, far behind it, becomes sharp, yet the benches on each side of the tree remain sharp.

If the lens was behaving normally, the tree would remain in focus as depth of field deepened to compensate for focus shift and field curvature effects. That is how I believe the lens should function based on some recent feedback.

I believe the strong field curvature seen in the corners of the frame is normal for the design, which you have also stated. It's possible it's somewhat stronger than normal with my copy due to its odd focus shift/field curvature behavior.

 

[rscheffler]

Here is a link to the sequence of the tree and benches: https://postimg.cc/gallery/RBTmYtV

At the top of the gallery page you'll see the a download option, which you will need to do to properly evaluate the images. If you click on a thumbnail and use the 'zoom' button, it just enlarges a 1280 pixel wide web-res image which won't be sharp enough to evaluate.

 

[Erik van Straten]

Erik, in that sequence of images, at f/4 and f/5.6 the woman is out of focus.

Yes, I understand that, but it would be nice to see this in this picture because it makes for me the problem so very clear, more clear than in the picture of the trees. But thanks anyway.


Erik.

 

[Bendj]

I have just done a quick test at minimum focus distance with my recently received copy and it is sharp from f2 all the way to f5.6 (centre). Mine is a chrome copy with a serial number of 500139.

 

[raid]

I have just done a quick test at minimum focus distance with my recently received copy and it is sharp from f2 all the way to f5.6 (centre). Mine is a chrome copy with a serial number of 500139.

This is good to know. Thanks.

 

[Bendj]

I will take some more sequences tomorrow when there is daylight. I have to say though I have been really happy with my copy, I haven't noticed anything untoward in everyday use though I am mainly taking pictures of people.

 

[raid]

In Post #2515+: I had a comparison between replica and Summicron.

 

[rscheffler]

I will take some more sequences tomorrow when there is daylight. I have to say though I have been really happy with my copy, I haven't noticed anything untoward in everyday use though I am mainly taking pictures of people.

Thanks, good to know. Even if taking photos of people with my copy, if it's at f/4 of f/5.6 and the person is in the center of the frame, they will be out of focus, but correctly focused at f/2. If you haven't noticed anything like this, then it sounds like your copy is functioning properly.

Are you using film or digital?

 

[Platinum RF]

What is the reason behind some SN use xxx/500 (the early batch), and some SN use 500XXX format? since the customer letter limited to 8 characters, the space should not be the problem. It is kind strange the format is not uniform.

 

[raid]

I think that the change in how the serial numbers are listed coincided with the optical tweaks done. I nay be wrong. The other possibility is that serial numbers are duplicated this way.

 

[D&A]

rscheffler said --->"Erik, in that sequence of images, at f/4 and f/5.6 the woman is out of focus"<<<

Of that's the case then there is something amiss. The women in that sequence should have been sharp...as much or maybe more so than at f2.8.

I just looked at your sequence of those images with the tree in the middle of the frame. I easily saw massive back focus. I urge those who are interested to have a look. That is not normal and I've never seen a replica show that.

Dave (D&A)

 

[rscheffler]

Thanks. Yes, that has been my point all along. MY copy, when rangefinder focused at f/4 or f/5.6, misses focus by a lot because focus has shifted considerably behind the subject. Too much for depth of field to cover. Yet at f/2 rangefinder focus is accurate.

The more feedback I get from others with the replica, the more I feel it's a problem with my copy and not necessarily indicative of later production versions.

That said, I would strongly suggest all who are still waiting for their lens to ship, test it for this problem. If present, it will be very clearly noticeable. I noticed it within 10-20 shots just by reviewing images on the back of the camera...

 

[yossi]

Thanks. Yes, that has been my point all along. MY copy, when rangefinder focused at f/4 or f/5.6, misses focus by a lot because focus has shifted considerably behind the subject. Too much for depth of field to cover. Yet at f/2 rangefinder focus is accurate.

The more feedback I get from others with the replica, the more I feel it's a problem with my copy and not necessarily indicative of later production versions.

That said, I would strongly suggest all who are still waiting for their lens to ship, test it for this problem. If present, it will be very clearly noticeable. I noticed it within 10-20 shots just by reviewing images on the back of the camera...

@rscheffler,

Just to confirm once and for all if there is focus shift, I had gone out and found a tree, put it dead centre of the frame and took 4 shots at f2, f2.8 f4 and f5.6.

Shot with M9 Monochrom on tripod. jpeg untouched. last 2 digits of the filename indicates the f-stop. You can view them HERE. (click on "view original" at the left top of the page to see image in full-size).