Knut. wrote:
It is not LACA. Branches closer to the camera have a slight purple hue, branches distant to the plane of focus have a green tint. This indicates residual LOCA to me. It is very faint, you have to look for it. I see it only at f2.0, and NOT in the central 2/3 of image but in the far corners. Cleans up very fast with stopping down.
It could still be an interaction of the lens with the Sony sensor on my A1 or the thick sensor stack since I cannot see it in Fred‘s images when he tested the lens on a Leica. And it is faint, something more of a curiosity, not really impairing the excellent image quality....Show more →
I don't think we can know if it is an issue with your specific copy of the lens, perhaps caused by slight decentering, or if it is something that happens with the E mount version of the lens but not with the M mount version of the lens. Either way it doesn't seem likely to affect many real world images.
What Knut wrote makes sense and should deserve proper attention: "It could still be an interaction of the lens with the Sony sensor on my A1 or the thick sensor stack since I cannot see it in Fred‘s images when he tested the lens on a Leica."
Voigt lenses are originally designed for Leica sensors. Then they are tweaked, by using some misterious recipes, to work with thicker sensor stacks. The final result is acceptable (I mean, very very good) for sure, but - with fast wideangles - tweaking gets more difficult. At least at the maximum aperture.
Nikon sensor stack is not as thick as Sony's, so it would be interesting to see if LoCA is as visible when using the Z-mount 28/2 Apo on Nikon bodies.
At least Sony and Nikon users ended up with a stronger lens (on-axis at least, lower IQ in outer frames) than the VM users receive. That's some tweaking, they engineered two quite different lenses. Silly me, I would have thought the aim of the exercise was to simply 'optimise' for the sensor differences, not to send VM APO lenses to the back of the class.
philip_pj wrote:
At least Sony and Nikon users ended up with a stronger lens (on-axis at least, lower IQ in outer frames) than the VM users receive. That's some tweaking, they engineered two quite different lenses. Silly me, I would have thought the aim of the exercise was to simply 'optimise' for the sensor differences, not to send VM APO lenses to the back of the class.
Here are the MTF plots of VM and E versions that show what you have written.
I'd add that the VM version shows less astigmatism in the middle of the frame.
Anyway, both the MTF plots show excellent performance of the lens, independently of the mount
P.S.: It would be useful to know how MTF plots vary between different samples with same mount...
Is the copy of the lens that Lens Tip tested decentered on the right side? In this review they didn't photograph any buildings parallel to the film plane - this is the closest. Both sides of the building slope away from the camera at approximately equal angles. Notice how the right side goes more out of focus than the left side?
The other shot that has a big building in it seems to show a similar slightly increased amount of blur on the right side. My copy of the 28/2 Apo has an extremely slight difference between the far left and far right sides of the frame when used for infinity test shots, but not as much as these sample shots appear to have. As I have learned: Test immediately upon arrival (or before buying), return promptly if unsatisfactory.
Fred's review is the Leica version, a lens that came out around six months earlier than the E/Z job. It would be good to see a review of this E/Z lens because reasons. You might want to see how the outer frames look, for instance, and the MTF is certainly different, as reported by the maker.
Keith B. wrote:
The other shot that has a big building in it seems to show a similar slightly increased amount of blur on the right side. My copy of the 28/2 Apo has an extremely slight difference between the far left and far right sides of the frame when used for infinity test shots, but not as much as these sample shots appear to have. As I have learned: Test immediately upon arrival (or before buying), return promptly if unsatisfactory.
I don't think Voigtländer sells huge numbers of the 28/2 AL, so the number of reported cases of lenses that aren't properly centered could be statistically significant and quite annoying, suggesting that the brand's manufacturing standards—which should make the quality of its mechanical construction one of its strong points—are falling apart
Ripolini wrote:
I don't think Voigtländer sells huge numbers of the 28/2 AL, so the number of reported cases of lenses that aren't properly centered could be statistically significant and quite annoying, suggesting that the brand's manufacturing standards—which should make the quality of its mechanical construction one of its strong points—are falling apart
I read your comment a couple of times but still struggle to understand how you can draw your conclusion?
Would you mind clarifying what you mean?
