p.66 #1 · Official: Sony A7 and A7R Fullframe Mirrorless
Steve Spencer wrote:
I did see the MTFs somewhere and they didn't look good. Specifically the 40mm lines were quite low in the corners, but I can't find where I saw them.
p.66 #2 · Official: Sony A7 and A7R Fullframe Mirrorless
No wonder they removed the MTF graphs from the official site. I mean the above MTF will only serve to scare people away. MTF might not be everything, but I personally would never ever buy a lens with such MTF.
p.66 #3 · Official: Sony A7 and A7R Fullframe Mirrorless
Probably sent Zeiss post haste back to the drawing board, lol. That 24mm/f8 result looks like the examples of RF wide angles shot on the first NEX, Zeiss were saying 'look what happens' with symmetric wide lenses - the detail tan lines fall away to very little detail.
Lines falling together is often FC, but this lot looks pretty crook.
'I personally would never ever buy a lens with such MTF.'
I agree Ed, and we would not be Robinson Crusoe in that respect.
p.66 #4 · Official: Sony A7 and A7R Fullframe Mirrorless
Unappealing MTF curves, I agree. But I wouldn't consider it a gravestone yet.
The real life output from the 24MP a7 could be acceptable - less so on the a7r. They went for 40 lpmm where most manufacturers go with 30. Not to mention that things might look much better at, say, 28mm.
p.66 #5 · Official: Sony A7 and A7R Fullframe Mirrorless
I figured they must have their act together on that 2470, which may have a bit optimistic, lol, last night I was comparing the few samples with the 2870, and it looked as good or better. Yikes.
Well it's a long while till February, so they've got time to make it worth 1200, and if they don't they'll never hear the end of it.
I just tweeted the zeiss team a link to our fretting, lol.
p.66 #7 · Official: Sony A7 and A7R Fullframe Mirrorless
edwardkaraa wrote:
No wonder they removed the MTF graphs from the official site. I mean the above MTF will only serve to scare people away. MTF might not be everything, but I personally would never ever buy a lens with such MTF.
Hi Ed, you bought the 24 mm f/2 ZA SSM lens, didn't you?
That ZA 24 perfectly reflects my experience with two samples of that lens at the borders/ corners at medium to longer distances. The only thing not shown by that MTF is the slight de-centering present on both copies. Other than that and a little CA, the performance was fine (though not up to what I expected. Guess I should have gone by the MTF more).
p.66 #9 · Official: Sony A7 and A7R Fullframe Mirrorless
The MTF of the 24-70 FE is in fact very similar to the Canon 24-70 F4 L IS at 24 mm F/8.
See if you can find the thin blue dashed line, it represents 30 lp/mm at f/8 Tan.
It fits nicely between the 20 lp/mm and 40 lp/mm Tan lines for the 24-70 FE.
Now the Canon lens is regarded as a very fine lens at the wide and tele ends, and sligtly less hot at 50 mm. This is what you get with the Canon, and the TS-E 24 II added for reference and it is not very scary. While the corner is not razor sharp, it is well defined and the CA behaved.
Nov 14, 2013 at 08:13 AM
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p.66 #10 · Official: Sony A7 and A7R Fullframe Mirrorless
alundeb wrote:
The MTF of the 24-70 FE is in fact very similar to the Canon 24-70 F4 L IS at 24 mm F/8.
See if you can find the thin blue dashed line, it represents 30 lp/mm at f/8 Tan.
It fits nicely between the 20 lp/mm and 40 lp/mm Tan lines for the 24-70 FE.
Now the Canon lens is regarded as a very fine lens at the wide and tele ends, and sligtly less hot at 50 mm. This is what you get with the Canon, and the TS-E 24 II added for reference and it is not very scary. While the corner is not razor sharp, it is well defined and the CA behaved.
I would hope that the FE Zeiss 24-70 would be better than the Canon 24-70 f/4L IS. If it isn't that will be a bit disappointing to me at least and I won't be interested in the zoom. The bottom line for me is whether the zoom could be an alternative to quality primes at wide angle, since there isn't a prime wider than 35mm in native mount at the moment. I know that is a tall order for a zoom, but other Zeiss zooms have lived up to it (e.g., the C/Y mount 35-70). The MTFs make me very skeptical that this zoom will fit that bill, and I don't think the Canon does either.
p.66 #11 · Official: Sony A7 and A7R Fullframe Mirrorless
I own the C/Y 35-70 and am familiar with its performance. It does as well as it does because it is a 2X zoom. It is unique among Zeiss zoom lenses. But behold, the MTF chart (measured and not directly comparable with the FE, but still) at 35 mm is not so hot. There is a dramatic cut-off in the extreme corners.
p.66 #12 · Official: Sony A7 and A7R Fullframe Mirrorless
alundeb wrote:
The MTF of the 24-70 FE is in fact very similar to the Canon 24-70 F4 L IS at 24 mm F/8.
See if you can find the thin blue dashed line, it represents 30 lp/mm at f/8 Tan.
It fits nicely between the 20 lp/mm and 40 lp/mm Tan lines for the 24-70 FE.
Now the Canon lens is regarded as a very fine lens at the wide and tele ends, and sligtly less hot at 50 mm. This is what you get with the Canon, and the TS-E 24 II added for reference and it is not very scary. While the corner is not razor sharp, it is well defined and the CA behaved.
p.66 #13 · Official: Sony A7 and A7R Fullframe Mirrorless
Albi86 wrote:
[Unfortunately comparing MTF charts from different manufacturers is far from being a safe experiment...
The point was not to compare, but to illustrate that categorical rejection based on MTF charts with a drop in tangential 40 lp/mm lines is neither safe, nor consequential.
Nov 14, 2013 at 10:12 AM
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p.66 #14 · Official: Sony A7 and A7R Fullframe Mirrorless
alundeb wrote:
I own the C/Y 35-70 and am familiar with its performance. It does as well as it does because it is a 2X zoom. It is unique among Zeiss zoom lenses. But behold, the MTF chart (measured and not directly comparable with the FE, but still) at 35 mm is not so hot. There is a dramatic cut-off in the extreme corners.
Actually the MTF at f/5.6 is phenomenal. Any drop off is only in the far extreme corners out past 20mm from the centre and the 40mm lines show outstanding micro contrast. This is prime level in terms of MTF (compare it to the C/Y mount Zeiss 35 f/2.8 and you will see it is a bit better). The Sony/Zeiss 24-70 is nowhere in this league and suggests corner weakness starting before 15mm, which I think of as a huge difference. From the MTF (and the Sony/Zeiss is theoretical and not measured) it seems the Sony/Zeiss FE mount 24-70 won't be anywhere in the league of the C/Y mount Zeiss 35-70.
Nov 14, 2013 at 10:13 AM
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p.66 #15 · Official: Sony A7 and A7R Fullframe Mirrorless
alundeb wrote:
The point was not to compare, but to illustrate that categorical rejection based on MTF charts with a drop in tangential 40 lp/mm lines is neither safe, nor consequential.
I don't think you made your point. Perhaps others will find this argument convincing, but I don't.
p.66 #16 · Official: Sony A7 and A7R Fullframe Mirrorless
I own also the C/Y 35-70. The only 'weak' spots I can't see are the distortion a bit high at 35mm. and the corners through all the focal range from f/3.4-f/4.
By f/5.6, corners ( and center of course ) are top notch. At 35mm and f/8 no dramatic cut off at the extreme at all, like those MTF curves might suggest..
At the time, I foolishly disregarded the MTF thinking they only represent a part of the whole picture. Indeed those MTF are calculated for infinity, where this lens is far from stellar. At medium and close range, this lens really shines as it has the smoothest bokeh I have ever seen from a UWA lens, and the most corrected field curvature short of TS lenses. This is a people's lens not a landscape lens. That is why I said MTF are not everything, and it helps a lot to actually know the design philosophy and what the lens is intended for, even though the manufacturers rarely give away this information. The 24-70 may very well be a people's lens and its performance might improve dramatically at closer distances, but I still stand by my statement that I won't buy a lens with similar MTF.
Nov 14, 2013 at 10:36 AM
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p.66 #19 · Official: Sony A7 and A7R Fullframe Mirrorless
alundeb wrote:
It is an open discussion and I am also open for more convicing arguments.
If we take the average of Tangential and Sagittal MTF at 0mm, 10 mm and 20 mm image height, we get:
24-70 FE @ 24 mm f/8: 73%. rejected.
35-70 C7Y @ 35 mm f/8: 60%. phenomenal.
I am not convinced
Come on you know that isn't a fair comparison. The FE is theoretical and the C/Y is measured. You also know that is cherry picking numbers in the extreme and creating a summary that distorts the overall pattern shown in the charts. It is looking at the MTFs as a whole that I see even the theoretical MTFs for the FE (which don't account for diffraction and thus are grossly inflated) the corners look pretty bad especially the 40mm lines. This is convincing to me that the FE 24-70 is likely to not be a great solution for landscapes at the wide end. Perhaps it isn't convincing to you, that is fine, but I think quite a few other people were worried about these MTFs as well
I wonder how many 200% over estimates for preorders represents. That and how it compares to the number of Leica M240 cameras that have been delivered to this point.
).