Very poor performance from Zeiss 135 F2 APO

Started Jun 1, 2013 | Discussions thread
Dave Throgmartin
Contributing MemberPosts: 750
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Re: At f2.0 there is
In reply to Jay A, Jun 6, 2013

Jay A wrote:


At looking at your results, its clear you don't quite understand focal length and effects on the image, in fact the lens is working perfectly fine doing what it should do.

With all due respect, I have been doing photography since 1963, have two degrees in it, taught at both the college and graduate levels for 15 years and have worked as a pro for twice that amount of time. I think I understand focal length and effects on the image...as a matter of fact, the same exact shots done with my Canon 135 F2 are focused beautifully. My reason for posting here was to get any sense of whether or not others have experienced anything like this with this lens thinking with an open mind that maybe there IS something that I am missing. But no, it's not a depth-of-field issue,at least definitely not in the first shot, nor is it a lack of understanding on my part, sorry. For that matter, these and other subject in the area are my usual go to subjects to use when testing out lenses. I have used the same subjects to test out dozens of lenses in the past year or so. This is the first time I have seen results this bad.

The first shot was focused on the green electric company box from across the street, but clearly shows the focus to be on some of the objects about 40-50 some odd feet behind that box instead. Even at F2 this has nothing to do with depth-of-field. For some reason, the focus is completely missed altogether. If it had been an auto focus lens, I would point to severe back focus. The second shot was done with care and a tripod but shows nothing even close to being in focus.The same shot done on manual focus with my Canon 135 looks fine. Yes, there is little depth-of-field but at least some of the flowers are sharp.

What I WOULD admit is that my eyes may just be getting too old and cannot judge properly while manually focusing using the current screens that are put into the Canon cameras. I usually don't have issues (I currently use the Zeiss 18 and 50 makro planar) but do admit that it is difficult to get things just right when depth-of-field is very shallow as it is in the flower shot. But the first shot? No way.

Look again at that first shot. Look at the left hand side where the lights are at the back. You will see good focus there, or reasonably good.The electric box and the mail boxes are way off. For you to say that the lens is doing what it should makes me wonder just what you are looking at.

I shot about a dozen of these test shots with this lens yesterday. Every shot at F2 showed similar results. When stopped down to F5.6 the results were a bit better, but still look like they had come from a much inferior lens than what a Zeiss 135 should be.

After sleeping on this overnight, I have concluded that there is something misaligned in the lens. There is no reason in the world why a properly performing lens should show good focus on subject matter 40-50 feet behind the subject that was focused on in the viewfinder. Yes my eyesight may be a factor too but something is definitely wrong with this copy of this lens.

Jay,

The stock Canon focusing screens aren't able to show depth of field with aperture wider than, I believe f/4.  I wonder if the thinner DOF than what the viewfinder could display caused the issue?

Dave

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