Einst Stein
Leading Member
How is the Leica M wide angle lens compatibility between the two?
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A7II vs. A7RII regarding wide angle Leica M lenses
- Thread starter Einst Stein
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blue_skies
Forum Pro
Corner smearing: same. Think Kolari if that's a problem.
Corner color casts: a7RII has virtually no issues because of BSI. Not that the a7II was anywhere near as bad as the a7R.
Jim
Rol Lei Nut
Veteran Member
Depends which wide angle Leica M lenses (& wide rangefinder lenses in general). Some will do fine on all the A7 series cameras.
Those which don't will have less color shift on the A7RII, but corner smearing (due to the extreme field curvature effect of the sensor stack) will be the same, or at least not very different.
I'm happily using an M Summicron 35mm 2.0 IV (AKA last pre-ASPH) and a 16-18-21 WATE on my A7 & A7RII.
Those which don't will have less color shift on the A7RII, but corner smearing (due to the extreme field curvature effect of the sensor stack) will be the same, or at least not very different.
I'm happily using an M Summicron 35mm 2.0 IV (AKA last pre-ASPH) and a 16-18-21 WATE on my A7 & A7RII.
Hi there
I have both the FE 35/2.8 and the 35mm Summilux fle and have compared them on the a7r and the a7rii and yes, on the A7r the summilux was horrible, with both smearing and purple fringing very evident; on the A7rii things are quite different indeed.
At "every" aperture, from 2.8 onwards, the summilux is sharper at the centre and extremes of the frame, there may be less resolution in the mid-frame due to field curvature but this was not looked at in detail; at f/2 and larger, the extremes got messy very quick but was obviously better than the 35/2.8!
I also have the CV 35/1.2 and again at every aperture from 1.4 onwards, the summilux was noticeably sharper. I was and remain surprised that so many others on the web have not commented on how well the summilux fle performs on the A7rii; it may just be my particular lense copies but I was about to right-off the summilux after its dismal performance on the A7r, but now have it on 90% of the time.
I'm curious to see how it performs compared to the FE 35/1.4?
Additionally, the WATE is a good wide angle lens on the A7rii, but compared to the FE 16-35mm, the Sony is better resolution wise, in particular at the extremes of the frame; this is now my very wide angle of choice.
I have both the FE 35/2.8 and the 35mm Summilux fle and have compared them on the a7r and the a7rii and yes, on the A7r the summilux was horrible, with both smearing and purple fringing very evident; on the A7rii things are quite different indeed.
At "every" aperture, from 2.8 onwards, the summilux is sharper at the centre and extremes of the frame, there may be less resolution in the mid-frame due to field curvature but this was not looked at in detail; at f/2 and larger, the extremes got messy very quick but was obviously better than the 35/2.8!
I also have the CV 35/1.2 and again at every aperture from 1.4 onwards, the summilux was noticeably sharper. I was and remain surprised that so many others on the web have not commented on how well the summilux fle performs on the A7rii; it may just be my particular lense copies but I was about to right-off the summilux after its dismal performance on the A7r, but now have it on 90% of the time.
I'm curious to see how it performs compared to the FE 35/1.4?
Additionally, the WATE is a good wide angle lens on the A7rii, but compared to the FE 16-35mm, the Sony is better resolution wise, in particular at the extremes of the frame; this is now my very wide angle of choice.
Not that I really care about Leica M mount lenses but field curvature is a lens defect and has nothing to do with the sensor (unless the sensor is somehow curved).
Rol Lei Nut
Veteran Member
Google "sensor stack thickness effect on lens performance"...
Has nothing to do with field curvature.
Rol Lei Nut
Veteran Member
I wrote "field curvature EFFECT", as in similar to.
The thickness of the sensor stack causes the corners of some lenses to focus at different distance than others (many those same lenses would have negligable field curvature used on a stackless sensor or film).
Others can give a better technical explanation than I can.
The basic idea is that those are not poorly designed or defective lenses, they just weren't made to cope with what amonts to an extra optical element in their light oath.
My experience indicates, with more than a dozen lenses exhibiting corner smearing, that it is not due to field curvature. If that were true, you'd be able to get a sharp image in one corner by focusing in that corner. In my experience you can't.
I do agree that corner smearing is usually not the result of a bad lens per se, but rather the result of using a lens designed for one sensor stack thickness on a camera with a different thickness. Film has essentially a zero sensor stack thickness.
Jim
Rol Lei Nut
Veteran Member
I don't disagree with that. I'm just saying, if it's got that smeared look, refocusing won't fix it.
Could be. I've not encountered an SLR wide with corner smear on the a7x. I've tested the Nikon 14/2.8 (soft, but not smeared), the 14-24/2.8 (not bad for a zoom), the Zeiss 15/2.8 (great) and the Zeiss 21/2.8 (great). All in Nikon F mounts.
Jim
dotborg is right mate.
Bottom line: anyone's sensor dimensions and characteristics are not off brand lens attributes. Its a component mismatch - like a Frankenstein monster with a different person's head on the body. Don't expect it to work out.
Bottom line: anyone's sensor dimensions and characteristics are not off brand lens attributes. Its a component mismatch - like a Frankenstein monster with a different person's head on the body. Don't expect it to work out.
blue_skies
Forum Pro
As discussed in the FMforum and some old threads here: corner smearing cannot be remedied by a thinner stack. It is inclination angle related - essentially, when the angle is too steep, a 'pixel' projection projects into a larger area than a single pixel, so the pixels 'bleed' into each other, leading to loss of sharpness.
Any SLR lens has by definition a less extreme angle of inclination, so these problems don't appear.
Those that have done the Kolari mod, have noticed that the color shift will be arrested, but not the corner smearing. Best remedy for smearing is to select a sensor with larger pixels (A7s).
Zeiss commented that the stack thickness can be incorporated in the lens design, leading to the conversion from ZM to Loxia lenses, but they also moved the exit pupil upward in the Loxia lenses, which has a big factor on the corner smearing, imho.
(If you look at the rear element, the Loxia lenses have a larger element, brought further back from the lens mount, compared to the ZM lenses, suggesting that the exit pupil is more inwards than with the ZM lenses, hence reducing the inclination angle).
Incorporating the stack thickness allows for better matching of color length, so color shifts, fringing, CA, are arrested.
Notice how the rear element is placed wrt/ lens mount
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Cheers,
Henry
Last edited:
What you are saying is completely counter to my testing, which shows that the Kolari mod can reduce smearing for the a7II, and, for some lenses, the M240 does even better, all at the same pixel pitch.
kolari - the last word
blog.kasson.com
Many of the lenses were are talking about were designed for film, which has essentially zero stack thickness, and exhibit no smearing on film. Smearing is different from isotropic corner softness.
Lenses don't have pixels.
We do agree that a greater angle of inclination makes sorner smear worse on lenses designed for thin stacks.
In my testing, I have noticed no effect at all of the Kolari mod on corner color shifts, although the mod does introduce an overall cast that must we WB'd out.
A better way to look at it is that the stack is part of the lens, whether the lens was designed for it or not.
Jim
Rol Lei Nut
Veteran Member
Rol Lei Nut
Veteran Member
Rol Lei Nut
Veteran Member
Gaaa! On my phone can't find a way to correct post for typos or missing words (travellinf).
I haven't used any of those, so, apparently, we don't have any smear suspects in common. My worst ones are the 35/2 ZM, the 28/2.8 Elmarit-M, the 24/2.8 Elmarit-M, and the 50/1.4 Summilux-M.
Jim
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