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

shawn said:
If you ever do more digital the series III of that lens does very well on digital. Like Dave said, Voigtlander modified the design to work better with digital sensors.

Shawn
Click to expand...

Excellent recommendation. I have the VC 15mm Ver III and used to have the original Ver I. Version I would definitely display color shifts (red) on both sides of the frame but not with V. III but am still surprise that I had somewhat less corner smearing with Ver. I. This was observed with a number samples of each. Of course as a separate issue, it also depends on how well centered a sample was.

Dave (D&A)
 
D&A said:
Excellent recommendation. I have the VC 15mm Ver III and used to have the original Ver I. Version I would definitely display color shifts (red) on both sides of the frame but not with V. III but am still surprise that I had somewhat less corner smearing with Ver. I. This was observed with a number samples of each. Of course as a separate issue, it also depends on how well centered a sample was.

Dave (D&A)
Click to expand...

I only had the series III but I didn't see much smearing on that lens at all. Might be some sample variation there. This is on the A7RII.

48147734022_ef8dc13cdd_h.jpg


Shawn
 
The Version III CV 15mm lens is known to be free of smearing with digital sensors. I really don't think that I will get this lens. I have too many lenses already.
 
D&A said:
Yes, exactly what I described in my post above. Those obtuse angles of rays of light striking the sensor is primarily concentrated at the areas away from the center of the sensor (image). The sides and edges receive the highest concentration.

As I stated, this is not what I observed with the replica lens on the M9 (as explained in previous posts).

Dave (D&A)
Click to expand...

The modern CV lenses somehow manage to avoid such smearing.
 
raid said:
The Version III CV 15mm lens is known to be free of smearing with digital sensors. I really don't think that I will get this lens. I have too many lenses already.
Click to expand...

Shawn, there is a lot of sample variation in the Voigtlander 15mm and this is well know. I've spoken to more than a dozen people with the ver III lens, used on Leica digital cameras, and if they have follage or tree branches/leaves in the corners (such as the upper corners), many of them had a moderate amount of smearing. The same issue has been strongly reported recently by many who picked up the recently new Voigtlander version of the lens specifically for Sony cameras and they too have this issue. I can provide a link from another well known site that discusses this. I suspect as is the case of many ultra wide angle lenses, centering of the many small elements is a very difficult task, and thus decentering occurs, even though the actual design of the lens when centered perfectly addresses this issue.

Years ago I had a copy of the highly touted Pentax screw mount 15mm f3.5 lens. It had terrible decentering (both on film and digital bodies) and was sent back to japan. Pentax said they were only able to center the elements part way due to as it was too labor intensive to take apart the whole lens. They issued a brand new one which turned out to be perfect.

Otherwise the Voigtlander 15mm is a superlative lens!

Shawn, nice shot of the boat (with your Sony).

Erik, I believe I've seen your posting of that image previously and love it every time I see it!

Dave (D&A)
 
D&A said:
Shawn, there is a lot of sample variation in the Voigtlander 15mm and this is well know. I've spoken to more than a dozen people with the ver III lens, used on Leica digital cameras, and if they have follage or tree branches/leaves in the corners (such as the upper corners), many of them had a moderate amount of smearing. The same issue has been strongly reported recently by many who picked up the recently new Voigtlander version of the lens specifically for Sony cameras and they too have this issue. I can provide a link from another well known site that discusses this. I suspect as is the case of many ultra wide angle lenses, centering of the many small elements is a very difficult task, and thus decentering occurs, even though the actual design of the lens when centered perfectly addresses this issue.

Years ago I had a copy of the highly touted Pentax screw mount 15mm f3.5 lens. It had terrible decentering (both on film and digital bodies) and was sent back to japan. Pentax said they were only able to center the elements part way due to as it was too labor intensive to take apart the whole lens. They issued a brand new one which turned out to be perfect.

Otherwise the Voigtlander 15mm is a superlative lens!

Shawn, nice shot of the boat (with your Sony).

Erik, I believe I've seen your posting of that image previously and love it every time I see it!

Dave (D&A)
Click to expand...
Thanks for this information, Dave. Now it is even less likely that I will one day get the CV 15mm III.
 
raid said:
Thanks for this information, Dave. Now it is even less likely that I will one day get the CV 15mm III.
Click to expand...

Raid, when you find a "good one", it is not only a exceptional lens but for the money, a spectacular lens and distortion is very low and sharpness is astonishingly excellent. Its just hard for any manufacturer to to achieve a perfectly optically centered ultra wide angle lens unless cost is no object, so to speak. The Leica 16-18-21 is one such lens (but very expensive) and so is the Zeiss Zm 15mm f2.8 (very expensive) but the Zeiss has distortion and is not rangefinder coupled but most sample have excellent centering and avoiding smeared corners.

Thats why a "good" Voigtlander 15mm Ver III is priceless, so to speak.

Dave (D&A)
 
Anything that fills the frame with details works. I shoot the trees in my back yard. Some people shoot brick walls. Use something that is easily repeatable for you. Edit: Detail the same distance away from the camera makes it easier to evaluate so you can more easily tell if it is DOF vs an optical problem.

Decentering will typically give uneven performance, like 2 corners are great and 2 are awful. Or one side is much better than the other or you can see the DOF shifting to near focused on one side and rear focused on the other. I bought a Rokinon 15 (new B&H) and it was badly decentered. I must have trashed the test shots but it was obviously not right, B&H swapped it out no problem and the replacement was fine.

With the Voigtlander 15mm III mine was very good across the whole frame, even on my Sony.

Any time you try a new way of testing make sure you try it with several lenses so you get a better feel for what is good or bad. Tests like this can show a lens gets softer to the edges wide open (whicih is pretty typical) but that looks different than a decentered lens or a lens that smears on digital cameras.

Shawn
 
Thank you Shawn. I manage doing such tests. I once had such a case with my Canon 50 1.2.
It focused on part of the image and left the other parts unsharp across the plane. Don Goldberg identified an internal glass element had shifted to cause this effect.
 
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