Poor NEX 5 + ZM lens review

[Peter^]

Anybody see this?

Does anyone have an explanation why such two great lenses (using film) rate so poorly when used with a NEX?

http://www.sonyalpharumors.com/zeiss-biogon-28mm-and-35mm-lenses-tested-on-the-nex-5-photozone/

 

[gavinlg]

The NEX mount is too close to the sensor, so the light from the lenses hits the sensor at a very oblique angle, and therefore makes corner performance quite poor. This is why the NEX-7 is rumored to have offset micro lenses on the sensor, and why the zeiss 24mm f1.8 is so large.

 

[Peter^]

The NEX mount is too close to the sensor, so the light from the lenses hits the sensor at a very oblique angle, and therefore makes corner performance quite poor. This is why the NEX-7 is rumored to have offset micro lenses on the sensor, and why the zeiss 24mm f1.8 is so large.

ok, but the distance from the lens to the sensor or film is always the same, isn't it? How does the M9 do it? The problem would even be worse with a larger sensor, wouldn't it?

Another question: The "offset micro lenses" rumored to be in the NEX 7: will these also help in when using ZM lenses?

 

[michel v]

The M9 does it …with the micro lenses. 🙂
The M8 encountered the same kind of trouble, but was less ready to handle them (a bit like the Nex 3/5 generation).

 

[Field]

We use to call this fall off.... People apparently forgot at wide open sometimes fall off is big.

The pictures I have seen of the 45mm were great, so who says it is all of them? How do the ZM lenses for M or G do on M4/3 by comparison?

 

[douglasf13]

Sony is already improving edge issues with the new NEX-C3, and presumably the new NEX cameras being announced next week. Photozone is going to need to retest everything.

 

[cookedart]

The M9 does it …with the micro lenses. 🙂
The M8 encountered the same kind of trouble, but was less ready to handle them (a bit like the Nex 3/5 generation).

The m8 has offset microlenses as well. The sensor's only issue was the ir filter was too thin. The m9 still runs into issues though... Red corner drift with wide angle lenses, for instance.

 

[brbo]

I find it strange that corner sharpness numbers on photozone.de for Biogon 35/f2 are quite a bit better than 35/f2.8. Center sharpness numbers are in line with previous observations (C Biogon 35/2.8 a bit sharper than Biogon 35/2).

What is the word on corner sharpness between those two on film?

 

[douglasf13]

I find it strange that corner sharpness numbers on photozone.de for Biogon 35/f2 are quite a bit better than 35/f2.8. Center sharpness numbers are in line with previous observations (C Biogon 35/2.8 a bit sharper than Biogon 35/2).

What is the word on corner sharpness between those two on film?

The 35/2.8 has a shorter exit pupil and more extreme light angle at the edges, so this doesn't surprise me. The good news is that, I saw someone on dpreview post shots with the 35/2.8 on his new NEX-C3, and the lens performed better at the edges than with his NEX-5. It seems Sony is doing some micro lens adjustment without advertising it.

 

[Bruin]

It could simply be that Sony reduced the thickness of the sensor toppings.

 

[Rune]

I have the ZM Zeiss 25/2.8 and there are no problems with the corners on my Nex-3. The main limiting factor is usually not the lens, but the photographer, but with the Zeiss 25mm I've turned into a brilliant photographer 😀

 

[semilog]

The 35/2.8 Biogon-C has a back element that sticks pretty far into the camera body, meaning that in the corners the light hits the sensor at a very acute angle. That alone could easily account for a poor numerical showing on a digital sensor, especially one not optimized for that optical geometry (as the M8, M9, and X100 all are). As Rune says, for practical purposes it probably won't matter much.

 

[Field]

What about m4/3? The lenses probably are perfect on them since the censor is smaller.

Weird how digital sensors mimic problems with film lenses... increasing diffraction representation and something like falloff.