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Sony Zeiss 16 - 35

carstenw

carstenw

Active member
Thanks for the response, Edward, but it is not possible to properly evaluate the corners from downscaled images, and to some extent, even from full-size JPGs. This is why I was asking if someone could post a raw file to examine. Just one best-case scenario would suffice, I am just curious how good this lens gets.
 
carstenw

carstenw

Active member
(Edward sent me two raws to examine, taken with the 16-35 at 16mm, one Thai comical statue @ f/6.7, the other a wooden walkway running away from the camera, @ f/9.5, both seen in this thread (shots 3 and 2, respectively, from Edward, on page one))

I opened them both in RPP (Raw Photo Processor), a package which is very quirky but gives stellar results. It is used, among others, by the world-famous architectural photographer Rainer Viertlböck, and is quite capable of extracting maximum detail.

In general, I am extremely impressed by the pixel-level sharpness of these files, which approach, and possibly match, my M8 results viewed at 100% with most lenses, but possibly not the very best, like the 90AA. The M8 has no AA filter, so that is quite an accomplishment. The colours also look very nice and natural, quite a difference to Canon, and, I gather, Nikon.

The corners are interesting. In each shot, there is one corner which is very sharp, but in an unusual way. The plane of maximum sharpness appears to curve back rapidly starting perhaps 3/4 of the way into the corners, so the usual kinds of shots with foregrounds coming to the camera will always be soft in the corners. However, subject matter further back than that (a river below the walkway, a tree behind a tree next to the statue) suddenly come into sharp focus in the extreme corners.

The lens is otherwise very impressive.

I think it would be quite a challenge to get really good results in the corners in most normal scenes. However, in certain kinds of scenes, it could help. On the other hand, the soft corners in the foreground are also not disaster zones, but just mildly soft. They would be quite acceptable in most shots, and adding a little vignetting in PP could help.
 
edwardkaraa

edwardkaraa

New member
Nice review Carsten :) I have to fully agree with all what you said, I have also come to the same conclusions. It is interesting to note that the 24-70 acts somehow similarly, and that with both lenses, field curvature is constantly changing whenever you zoom in or out. However, I believe that after sometime with this lens, after getting to know the curvature characteristics, one would instinctively compose the shot in a way to maximize corner sharpness and to include at least one very sharp corner as Carsten very well pointed out.
 
douglasf13

douglasf13

New member
This stuff is really interesting. Thanks, guys. Edward, I'm really buying into your Zeiss 3D theory in relation to this field curvature. It would make sense, considering different objects at different distances seem to "pop." Very cool :clap:
 
carstenw

carstenw

Active member
Edward, have you done any tests where you slowly zoom out, taking pictures the whole time, and watch the curvature? I wonder if there is somewhere close to 16mm where the corner curvature suddenly moves forward a lot, to help make certain kinds of shots.
 
jonoslack

jonoslack

Active member
carstenw said:
Edward, have you done any tests where you slowly zoom out, taking pictures the whole time, and watch the curvature? I wonder if there is somewhere close to 16mm where the corner curvature suddenly moves forward a lot, to help make certain kinds of shots.
Click to expand...
Hi Carsten
I don't have this lens, but on the Olympus 7-14 this is certainly the case - the curvature of field actually seems to 'flip'
 
edwardkaraa

edwardkaraa

New member
carstenw said:
Edward, have you done any tests where you slowly zoom out, taking pictures the whole time, and watch the curvature? I wonder if there is somewhere close to 16mm where the corner curvature suddenly moves forward a lot, to help make certain kinds of shots.
Click to expand...
No I haven't but that would make a good assignment for this weekend :D

I know for certain that the 24-70 has a very flat field curvature at 35mm setting. It would be interesting to see if the 16-35 has a similar setting.

I am going to take another look at www.lemondedelaphoto.com reviews of both lenses. It is very easy to judge the field curvature from the resolution charts since a drop in the corner resolution clearly indicates stronger curvature.
 
carstenw

carstenw

Active member
What are we looking at here, is this the entire bottom strip of a series of images? What is the aperture, f/2.8?

If the answer to both questions is yes, then it looks like the backwards curvature of the field is already much improved by 20mm, perhaps enough to handle with a slightly smaller aperture, like f/5.6 or f/8. At least in this image. However, the angle from the camera to the floor is a bit different from the camera to the horizon in your wooden bridge. Being able to angle the camera down a little puts the backward curving corners more into the ground, if I am thinking right, hiding them a bit. A flatter angle would make the problem a bit worse again.

Anyway, maybe try to shoot for 20mm if the corners are important. If not, then 16 is quite good anyway. Shooting from a higher vantage point also helps, so a taller tripod or standing on something when possible would help.

I have not done this much analysis on other similar lenses, except perhaps the Tri-Elmar 16-18-21mm (which has an unfair advantage with the short register distance and smaller zoom range), so I don't know how this compares to similar lenses, like the Canon 16-35 II or 17-40, or the Nikon 17-35, but to my surprise the French review site rated the corners of this lens as very good at f/5.6-f/11, so I guess this problem is very common on such lenses, for this performance to rate so high.
 
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S

SeattleDucks

New member
carstenw said:
The corners are interesting. In each shot, there is one corner which is very sharp, but in an unusual way. The plane of maximum sharpness appears to curve back rapidly starting perhaps 3/4 of the way into the corners, so the usual kinds of shots with foregrounds coming to the camera will always be soft in the corners. However, subject matter further back than that (a river below the walkway, a tree behind a tree next to the statue) suddenly come into sharp focus in the extreme corners.
Click to expand...
The Zeiss MTF charts show this complex wavy field curvature. I had the 16-35mm for a short time, was thrilled at the prospects for this lens on my A900 as part of my landscape shooting kit, but even at f/11 most of the corners and some of the edges were unacceptably soft for me, most especially at 20mm and 24mm (although the performance was excellent at 28mm and 35mm). Of course the center sharpness was stunning and the microcontrast very high. I ended up going with Minolta legacy glass, the 20mm f/2.8 and 28mm f/2.0 which had cleaner corners at f/8-f/11 but do have a mellower drawing style compared to the snappy Zeiss.

I had to return the Sony 70-300mm everyone raves about because testing against the Minolta 100mm f/2 and 200mm f/2.8 revealed (at least with my copy) the 70-300 to be quite poor in some corners and edges even at f/8, although central sharpness was high. Full-frame is very demanding on optics and it was no different when I shot the D700 where I had to return two copies of the renowned Nikkor 24-70mm f/2.8 (but not as bad as the corner/edge atrocities with Canon L glass on my 5D a few years ago).

Joseph Holmes has detailed in a recent article the optical problems he's encountered with lenses for his medium format digital, so I guess it's not unique to DSLRs. I think I was spoiled from the years of using well-corrected glass on 4x5 where there have essentially been no issues to speak of even in 40x50 prints. But the joy of shooting the A900 in the field more than compensates :thumbup:.

Cheers,
Ross
 
carstenw

carstenw

Active member
When you say Minolta 20mm, do you mean the Sony 20mm which is a Minolta design, or a different lens?
 
S

SeattleDucks

New member
carstenw said:
When you say Minolta 20mm, do you mean the Sony 20mm which is a Minolta design, or a different lens?
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Hi Carsten,

I acquired the Minolta 20mm f/2.8 which was manufactured several years ago. From what I have read the current Sony branded 20mm is the same Minolta design but with supposedly better coatings suited to digital.

Cheers,
Ross
 
douglasf13

douglasf13

New member
Agreed about the Minolta 20mm. I have the RS version, which is the newer Minolta version that directly preceded the Sony (they look identical,) and it's corners are sharp at f8-ish or so, but it doesn't have that punchy drawing style of my 24-70ZA. I will probably bite the bullet and end up with the 16-35 at some point though, just to play around with 16mm :)
 
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