Sony Zeiss 24mm f1.8 Sonnar available at B and H

[skinnypix]

Philber, what are the issues with the ZM 25 on an NEX 5N?

I understand the NEX 3,5,7 have issues with this lens (color shift in the corners, & perhaps some corner smearing) but to my understanding, the 5N handles RF wide angle lenses well.

I'm was hoping to see that the ZM 25 might have the clinical sharpness that, according to others, the new native Zeiss 24mm for the NEX lacks.

Thanks, Alan

The Zeiss ZM 25 presented some compatibility issues with the NEX 5N, so was ruled out despite its formidable reputation...

 

[philber]

Alan, the ZM 25 has border smear, and corner performance is worse yet. The reason is that Zeiss Biogons are symmetrical designs, the most likely to cause such problems in a NEX, unlike the Distagons. Which explains why ZM 18 is fine, but ZM 25 is not. This is explained in detail in Dr Nasse's paper on designing wide angle lenses on the Zeiss site blog.

 

[douglasf13]

It's a tough call, because many of the ZM Biogons and Distagons aren't true Biogons and Distagons, and they're all kind of somewhere in the middle, but, as Philber said, the ZM 18 seems to be just "Distagon" enough to work better than the 21 and 25. The Zm 35/2, despite being called a Biogon, has a much longer exit pupil to sensor distance than the other ZM Biogons, so it works pretty well on NEX, too.

 

[Vivek]

There problem is not with the ZM25. The Ricoh GXR does a fabulous job of recording what this lens projects.

 

[douglasf13]

There problem is not with the ZM25. The Ricoh GXR does a fabulous job of recording what this lens projects.

Of course not. We're talking about how the lens behaves on NEX. I'm currently looking into removing the 5N's AA filter, which should make the edge issue much better with these Biogons. If the GXR had a tilt up screen, and maybe a better EVF, I'd buy one tomorrow. It's got a great sensor setup for M lenses.

 

[Vivek]

Of course not. We're talking about how the lens behaves on NEX. I'm currently looking into removing the 5N's AA filter, which should make the edge issue much better with these Biogons.

Me too.

The idea that Nex-5N (unlike the other NEX') has offset micro-lenses thus promoting the use of lenses with short focal length has to be put in its context.

If you remove the AA filter (impossible I would say- see below why)* in NEX-5N it will still not measure up to what happens in GXR.

* The AA filter is firmly epoxied to the UV/IR cut filter. If you get rid of the whole thing then it is back to the M8 story all over, in a very big way.

 

[douglasf13]

Me too.

The idea that Nex-5N (unlike the other NEX') has offset micro-lenses thus promoting the use of lenses with short focal length has to be put in its context.

If you remove the AA filter (impossible I would say- see below why)* in NEX-5N it will still not measure up to what happens in GXR.

* The AA filter is firmly epoxied to the UV/IR cut filter. If you get rid of the whole thing then it is back to the M8 story all over, in a very big way.

According to a gentleman in the industry, Joakim, on another forum, both the microlens arrangement and IR filter that Leica advertises for the M9 are relatively pedestrian, and their importance is more a matter of marketing. As Dr. Nasse talks about in the recent Zeiss wide angle paper, the sensor toppings are causing much of the issue at the edges with these symmetrical wides, and removing the AA filter is a big part of that equation. I don't expect Ricoh's fill factor on the GXR M module to be much better than the 5N's, but that AA filter in the way certainly seems to be causing astigmatism on the 5N. I'd bet that an AA-less 5N would be comparable to the GXR in the corners.

The companies that remove AA filters from DSLRs, and potentially NEX, remove the AA/IR filter pack, and replace it with a new pack that only contains the IR filter (and, for DSLRs, and clear glass cover, so metering doesn't change.) I am going to request no clear glass cover, since metering is done on sensor, but we'll see if they do it.

link to Joakim's thoughts on the M9 sensor and IR filter: http://www.fredmiranda.com/forum/topic/893332/8&year=2010#8504636

 

[Vivek]

Because I understand what you are saying, I say this. Very nice quotes that have their own merit in the context they are written.

I do not think your assumptions (Ricoh does not have a better fill factor- ie better offset arrangement of the microlens array- thus making the corners better) and the reading of some of the quoted writings are correct.

Some folks have talked about Leica choosing something "cheap" thus creating problems. I do not think that is correct at all. The cyan glass has many problems when it comes to physical and chemical stability. I have about a dozen different ones. Only a few show the ability withstand the environment for more than 6 months. In addition, not all can be AR coated.

Also, the NEX5n sensor still would have a cover glass which is firmly epoxied (in principle removable, a few do it but it would cost you more than the price of a NEX-7 on eBay) to the sensor casing.

All that said (with the best intentions), good luck with your attempt and I would love to hear what you achieve.

 

[douglasf13]

I've not really seen any evidence that the GXR does a much better job in the corners than the M9 does cropped to aps-c. Either way, even if we don't extrapolate this info in regards to the GXR, I think we can say that an aa-less 5N should do at least as well as the M9 cropped to aps-c size. Maybe I'll have to be the guinea pig.

 

[philip_pj]

"It may be that my being used to seeing shots from superlative lenses with my 5N (Contax G, ZM 18, Leica R Makro) has made me more sensitive/demanding/intolerant than is good for me."

Many thanks, philippe, that is just the info I was after, and thanks for your candour. In a nutshell, the new 24/1.8 seems to lack brilliance and colour tranmission, and noticeable CA is not a good sign in a $1000 lens from this maker. Zeiss are adamant that the new 25/2 Distagon has superb CA control..

Vivek, 'alts' is the abbreviation for 'alternative lenses', i.e. non-native mount lenses, usually (but not exclusively) high end manual focus lenses. I have a Sony full-frame I use with around ten alt lenses and 1-2 Sony lens, for example. Why be restricted to the 'Sony/Minolta look' or the Canon or Nikon 'look' just because you use the body of that maker? NEX takes that to a supercharged level, of course.

I should add that, whereas many or most users are content with the usual 'this lens is sharper than that one' opinions, seeing the vast improvement in image quality you get from the lenses that best match what you want in your output can make a hugely satisfying difference. Many do not want to go back, ever.

On the sensor issue:

I feel that Sony will be very keen to produce a factory fix for the issue. They are not people to walk away from innovation, quite the contrary, so it may just be a matter of time. The NEX7 will sharpen their interest in it, no doubt.

It's over my head, but common sense and the cautionary principle may get you there, douglas, so do keep us informed if you go ahead, and good luck if you do.

 

[weinschela]

"My first impression was that this lens underexposed, which is technically impossible with a LiveView camera, at least to my understanding. Hence the desire to compare, which I don't usually do. This showed that the ZA 24's pictures were indeed darker than those of other lenses, a darkness that I couldn't correct to my satisfaction in PP. They have some kind of darkish hue, not unlike, for want of a better description, of a grey and gloomy day with low clouds and rain in late autumn."

I have not seen this darkening on my copy of the ZA 24.

 

[Ocean]

"My first impression was that this lens underexposed, which is technically impossible with a LiveView camera, at least to my understanding. Hence the desire to compare, which I don't usually do. This showed that the ZA 24's pictures were indeed darker than those of other lenses, a darkness that I couldn't correct to my satisfaction in PP. They have some kind of darkish hue, not unlike, for want of a better description, of a grey and gloomy day with low clouds and rain in late autumn."

I have not seen this darkening on my copy of the ZA 24.

Alan, were you using the ZA 24/1.8 on your NEX 5N or NEX 7? I think Phillppe was using it on his NEX 5N.

 

[PeterA]

Some pics from the people who dont like the lens woudl probably carry a lot more weight than the next 5000 words.

Looking forward to it all.

T@

Pete

 

[philber]

OK, so here goes. I tried a number of lenses, some of which I own and some not. Methodology was: from tripod, with timer, in RAW, processed in LR 3 (default settings), SOOC, fixed f:5.6., significant crop close to centre of image, all shots as closely spaced as possible to minimise light change. Out of a total of 9 lenses, spread over three sessions on three separate days, I will show "only" the Zeiss 24mm ZA, and a Leica 24 Elmar f:3.5 (same session). Please note that for some reason the EXIF is not always correct, the ZA shwong as "24mm" and not its full indentity. Also, being disappointed at the first quick ad dirty shots was so unexpected that I tried two copies of the ZA to eliminate chances of a "bad copy". They were essentially identical.
For reference, in total I did 3 types of shots, one close up, one at mid distance, one at infinity, all findings concurring. And I am usually very Neiss with Zeiss, as 11 out of the 12 alt lenses I own are from them, this being the first case of my not buying one of their designs. As a consequence, I ordered a Leica Elmar 24 (slower, MF, twice the money), so I wish the ZA had lived up to my expectations.
DISCLAIMER. I am not a tester. I stand to gain nothing from posting these shots. No link to any Website with advertising. No interest in self-aggrandizing self-promotion. I have no vested interest in this matter, as I have already tested the lenses to my satisfaction, so, if I am doing it, it is with the intent that sharing will let others think and (maybe) learn something of value to them. If you flame me because (a) I did not do the "right" shot, or (b), I did not do it "properly", or (c) I did not come to the "right" conclusion, all you will achieve is that I will no longer post a comparison like this on this forum, which takes some time. But you are entirely welcome to disagreeing in any way you feel appropriate, as I do not, sadly, have any copyright on "the truth", much as I wish I had...
Fist pic is Leica Elmar, second is ZA 24.

 

[jfirneno]

Philber:

That was a very interesting comparison. I could see the darkening that you described. Would you say that exposure compensation during the exposure would eliminate the problem?

 

[philber]

No, it is not an exposure issue; If a lens is simply "darker" than another one, light going through the lens to the light meter will be less and the meter will instruct the camera accordingly. So how "ligh" of ho"dark" a lens is makes no difference to exposure. This is more a question of colours, with a darkish hue, like a dark, cloudy day. Light that up, and it does not become sunny...

 

[Show Performance]

There is clearly a brighter light source in the first image as witnessed by the variation in reflections on the green glass window panes that is not present in the zeiss shot.

 

[philber]

Nope, it looks that way, but that is the lens. I know, I was there. Ans hsots before and after prove that.

 

[Show Performance]

Nope, it looks that way, but that is the lens. I know, I was there. Ans hsots before and after prove that.

Sure it was, the variation in light reflection between the individual panes does not lie. If you can't understand that simple rule of light behavior then these comparisons are immediately suspect in my eyes.

.

 

[philber]

Interesting how that theory also applies to identical results of other pictures without window panes on other days, of which, of course, I have proof. But obviously, one can lead one's horse to water, but not force it to drink. As to your opinion about my abilities -or lack of-, actually, please re-read my disclaimer.