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35 FE Sonnar - Decentering. Who else?

Guy Mancuso

Administrator, Instructor
Even though mine is pretty good I may just sell it immediately and get the Zeiss 35mm F2 which I really liked. My son is bringing me the box and such from home to me here in LA but if someone wants it I can go 725.00 and Ill order a used 35mm F2 from B&H. Its not that I don't want a AF lens its more about having a complete manual kit for the A7r and a AF kit for the A7 which I will just use zooms there.
 

turtle

New member
I wonder about that too. Do manufacturers toss them out, rebuild them... just repackage them? Same for any manufacturer.

I'm still astounded by how light it is. It feels like they forgot the glass! If Leica built a lens this light, their chief engineer would add lead to make it feel 'better' :D
 

fmueller

Active member
Could someone post a few pics depicting the de-centering on your lens?

Just trying to get an idea of what is setting off the alarm bells.

Also, I can confirm that the CV 35 1.2 II is superb on my A7r but HEAVY.
 

turtle

New member
Sure, these were shot wide open. I have a very handy rug with not only a grid, but good texture. This allowed me to align everything perfectly along the top edge of the frame. I also did the bottom edge, a vertical shot onto the rug and a number of outdoor scenes. All returned the same result: right side slightly softer overall and top right very poor. Its close to acceptable by f8, but....

The samples do differ in the lighting (not something I could change easily) and have had reasonable sharpening applied. I'll put up with some imperfection if, when sharpened it it not really an issue. Even at 5.6 the difference is obvious and its not a tiny tip of the corner either, but a substantial portion. Looks exactly like the sample someone else posted of a river with wooded banks. The branches were all mushy in the top right at F5.6 and I reckon our two samples have the same error.

Could someone post a few pics depicting the de-centering on your lens?

Just trying to get an idea of what is setting off the alarm bells.

Also, I can confirm that the CV 35 1.2 II is superb on my A7r but HEAVY.
 

fotografz

Well-known member
I purchased the grip to use my 555g ZA 24/2 distagon. The additional camera weight makes heavier lenses so much more pleasurable to use handheld.

Graham
LOVE this lens on the A7R!

Although I do not find this lens + EALA4 all that big on the camera, I may give the grip some more thought since I view the A7R as two cameras in one ... kinda like a Puffer fish ... small most of the time, but we can "puff it up" to take the A mounts from 16mm to what-ever mm.

Thanks!

- Marc
 

fotografz

Well-known member
Could someone post a few pics depicting the de-centering on your lens?

Just trying to get an idea of what is setting off the alarm bells.

Also, I can confirm that the CV 35 1.2 II is superb on my A7r but HEAVY.
I checked both the FE55 and FE35 like I do most of my lenses ...

I subject them to the "Chicken Test"

An old antique sign we have in the kitchen that I use because it has a round motif I can use to be reasonably sure I'm squared up (circle goes oval or oblong if I'm not fairly flat on and squared up). I also use a round clock face on a Grandfathers clock, and so on.

BTW, I used a canned profile in LR to fix vignetting and distortion ... while LR4 doesn't have these lenses listed, Irakly and I found the 35 and 50 Ziess ZE profiles do a reasonable job with the FEs when we were testing a dump truck full of lenses we own between the two of us yesterday.

Both of my FEs did a reasonable job in the corners @ f/2.8 up-close for an apples-to-apples f stop comparison. Obviously f/5.6 is even better.

A7R, ISO400, 1/100, available light, handheld (even though the light changed a bit, I kept the camera settings the same).

I'm only showing the FE35 top right corner that seems to be in question ... looked okay to me on my 30" screen at 100%. The other 3 corners were also fine. FE55 did fine ... all 4 corners shown below.

Also discovered the Leica M 21/1.4 ASPH does vignette (as one would expect from a lens this wide, but does not exhibit color shifts or multi color vignetting like other WAs Irakly and I tested ... easy fix in post. Have to test that lens for corner acuity yet. Same for my M 35/1.4ASPH.

Most of Irakly's Zeiss WAs failed, as did my M28/2ASPH. But I'll leave that to him to determine as he took all the files with him to play with more.


PICs: For reference, the sign is 11.5" wide and the circle is 10" in diameter ... so these are close shots which I think is a bit of an acid test. Unfortunately, I'm the only one that has the actual sign to compare to a print ... but both lenses are reasonably accurate right out to the edges. Good copies for what I do.

The Chicken proves I'm a Lucky Duck I guess :) But I'm sure someone will disagree and find some fault some where in all this ... :watch:

- Marc
 

turtle

New member
Lets face it, many lenses are a touch decentered, but its a question of whether its within your tolerances. The fact that my just arrived 28-70 Sony kit lens is better in the top right corner on the A7 than the 35 Sonnar is on the A7R says it all, however.

If I had to be absolutely hair splitting, there is something imperfect about my 5D III and 24-70 L II combo, but the issue is so trivial and performance overall still so spectacular that you'd have to be mad to care. It still shames all but my Leica primes and gives some of the symmetrical Leica wide angle designs a spanking at the wider apertures. Its going to be very interesting to put this lens on the A7R because it clearly outresolves my 5D III.

Walking around the 'Wildlife Photographer of the Year' exhibition at the Natural History museum in London, there were a few landscapey shot that showed some decentering, with one quite glaring example. The shot was still stunning, however, I did wonder if the photographer had noticed one corner was obviously very soft.

C'mon Mr Courier, bring me my replacement 35 Sonnar!
 

turtle

New member
Update: The second 35 Sonnar is spot on. Thank goodness. As a 35mm fan, this lens will get a lot of use.

I forget who it was that posted online somewhere that this lens is 'complicated' in terms of curvature at various distances and he's not wrong. That was very evident from this last batch of testing, but aside from the considerably CA, its a cracker. 120g too... made for travel.
 
I gave mine the brick wall test and found that at 100% magnification, the files show it to be the least bit OOF in the upper right corner, but so slight that I consider it a keeper. I've tested a number of other 35s (Lux FLE, pre-A Lux, Cron v4, CV 1.2, and 40 Cron) the same way, and it's the best for its match of resolution, absence of corner smearing, and zero color vignetting. Some of theother prime lenses are about the same, and I remember my Canon 24-105 was much, much worse in all four corners. So I have about 98% of the advantages of a prime.

As to rendering, the FE is very sharp, very contrasty, very useful, and what I'd call 'modern-style boring.' To my eyes the 40 Cron and even the pre-A Lux offer a more attractive rendering, and are sharp enough especially when stopped down to 2.8: almost as good in the corners, lower contrast, and a kind of roundness-of-forms, in contrast to the pores-and-nosehairs detail of newer lenses. But these are just subjective preferences. I value the 35 FE for the times I want autofocus.
 

Arne Hvaring

Well-known member
FWIW my copy has excellent sharpness and minimal CA over most of the field, but the left hand side of the image (some 15% of the whole) has distinctly poorer sharpness than the rest. Here one sees double contours at wide apertures, but it cleans up reasonably well at f 5,6-8. Sony will send me a second copy as soon as they become available. If the new sample is better, fine, if not I can (just) live with the present lens because of its quality overall.
 

tashley

Subscriber Member
Update: The second 35 Sonnar is spot on. Thank goodness. As a 35mm fan, this lens will get a lot of use.

I forget who it was that posted online somewhere that this lens is 'complicated' in terms of curvature at various distances and he's not wrong. That was very evident from this last batch of testing, but aside from the considerably CA, its a cracker. 120g too... made for travel.
I plead guilty. The trick is to focus deep.
 

tashley

Subscriber Member
In truth, a long answer is required but the short version is that the field of focus seems shaped a bit like an opened umbrella held out directly in front of you, and that if you focus deep into the scene, the umbrella is pushed further forward so that the edges are in focus.
 

D&A

Well-known member
In truth, a long answer is required but the short version is that the field of focus seems shaped a bit like an opened umbrella held out directly in front of you, and that if you focus deep into the scene, the umbrella is pushed further forward so that the edges are in focus.
Tim, I'm trying to get a visual on what your described. There is one medium format 35mm lens in particular I reviewed where the lens has a substantial amount of field curvature to that when one focuses deep in the center of the frame, such as at infinity (as you suggested), the edges sides are soft at infinity but the edges sides at closer range are very sharp. This is analogous to the umbrella shape you mentioned. I'm trying to understand what you mean by the umbrella is pushed further forward, the edges are in focus. Do you mean the edges at infinity are in focus or the edges at a closer range than infinity?

Thanks for clarification.

Dave (D&A)
 

tashley

Subscriber Member
Dave, I can't be much clearer without writing an epic but I will try: imagine that you are facing a 1cm thick curtain of water, an exactly flat, perfect waterfall. You point your open umbrella at it and move slowly forward until the ferrule pierces the curtain. Only that spot of piercing is 'in focus'. Now edge forwards. An increasingly large circumference of the umbrella pierces the water until, optimally, the largest circumference the brolly has to offer is parallel to the waterfall. Now, left to right and top to bottom are 'in focus' and, were the umbrella a fancy pyramidal design with a square base, so would the corners be.

There will be a whole range of distances between you and the water at which some or much of the central area of this image circle would be in focus, but to get all of it in focus you'd have to 'focus deep' by thrusting your umbrella a long way forward.

Massive simplification of course. I wrote a piece with Roger Cicala on field curvature and how to focus a tricky lens and it has diagrams and much more detail but forum rules prevent me posting a link to it.
 

D&A

Well-known member
Hi Tim,

"ferrule", "brolly", all those English words are confusing for someone who barely understands "American" :)

OK, your explanation is concise and clear. It's similar to what I've experienced in a select number of lenses, especially wides, that exhibit fairly hefty field curvature. The one aspect of your description that I still have a bit of difficulty understanding, is if you first focus on a point centrally located on that flat field waterfall, I presumed it's already at infinity, so how can you focus any deeper...unless the lens being used is collimated such that it can focus past infinity.

If you example represents focusing on a flat field waterfall that is closer than infinity, then if one focuses deeper than the waterfall, then the sides and edges of the flat field of a lens exhibiting field curvature, will start to come into focus (depending how deep you focus and the f-stop being used. I think what might have confused me in your original posting is when you said "focus deeper" but I assumed the subject was already at infinity.

I have a medium format wide angle lens that is a classic representative of this field and curvature principal and its easy to demonstrate by the principals you outlined.

Next time try writing an epic. :ROTFL:

Dave (D&A)
 

jagsiva

Active member
...but to get all of it in focus you'd have to 'focus deep' by thrusting your umbrella a long way forward.
Tim,

Not sure I can thrust this well:) but, are you not at risk of having the centre back-focussed when you "focus deep" to get the edges sharp? I always thought this was one of those compromises we had to make on corner vs. centre sharpness given a particular lens.
 

D&A

Well-known member
Tim,

Not sure I can thrust this well:) but, are you not at risk of having the centre back-focussed when you "focus deep" to get the edges sharp? I always thought this was one of those compromises we had to make on corner vs. centre sharpness given a particular lens.
Although this question was for Tim...if I could take a stab (with the ferrule of course) at the answer....(like one jabs with the point of an umbrella or as Tim like to say "brolly" :)), the center with a wide angle is sufficiently at distance so hopefully focusing deep will keep the center somewhat in the zone of focus (or depth of field). Correct me if I am wrong please.

Dave (D&A)
 
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