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Searching for the best 28mm lens for Sony A7RII camera


peter_roberts4

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Just acquired a Sony A7RII camera. I had tried to shoot with Leica Elmarit-M 2.8/28 and Zeiss Distagon 2.8/28. The results are soft at corners when both of them are wide open to f2.8. With aperture set at f11, the extreme corners are quite acceptable. Enclosed are the photos for your judgement.

 

So far, I am still looking for the best 28mm wide angle lens for A7RII except those Sony native lenses. Please tell me your choice. Manual focus is not a problem to me as I shoot landscape all the time.

 

 

 

cz.thumb.jpg.9fced0072c049c813b9a018314a696b7.jpg

 

cz2.8.thumb.jpg.cba5ee84c2bee80befb4f1db68c83a61.jpg

 

cz11.thumb.jpg.aa5d3b87048cc43e58b3a58ca56c8f8c.jpg

 

leica.thumb.jpg.4a5fc59726a013f24dbbc444302de63d.jpg

 

leica2.8.thumb.jpg.6f603081beae94e7ebcb0f6afbe7f666.jpg

 

leica11.thumb.jpg.d0d495d8855a3b1e0cc6b371853d3497.jpg

 

cz.thumb.jpg.4779b671af92712f1b67bb3500317224.jpg

Edited by peter_roberts|4
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Dieter has a point. The Otus is probably the ultimate manual lens for SLR or the Sony, but heavy and very expensive. The problem with the Zeiss 28/2.8 ZM is that it is designed for film, and with the rear element so close to the film plane, oblique rays toward the edges are distorted into a smeared pattern. In general, lenses designed for an SLR have a longer back focus distance, and perform more evenly throughout the field of view.

 

That said, lenses designed specifically for Sony A7 cameras give the best performance. The Sony 28/2 is very highly regarded, yet inexpensive. However, I would put my Sony 24-70/2.8 against it (or the Zeiss 28/2.8 ZM, which I also own) any day. Another alternative is the Loxia 35/2, or the Zeiss 35/1.4. While not 28 mm, the FOV is similar. Bracketing it a bit, the Basis 25/2 is also a very fine lens, also sharp from corner to corner at any aperture. Both the Sony 28/2 and Loxia 35/2 are small lenses, worthy of their rangefinder heritage.

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I owned the Zeiss Distagon an used it on my Oly E-Pl2 (2X crop factor)along with 5 other manual focus lenses I had. All exhibited softness in the corners wide open, most did well closed down to f/5.6.
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How a lens performs with film vs a digital sensor is a factor you can't ignore. I have tried many various brands that I loved on film and was disappointed on digital. IMO the best lens out there for digital is the discontinued 28mm f1.4 Nikkor AF-D. I've tried Takaumar, Leica, Olympus, Canon, and Minolta. I haven't gotten my hands on a Zeiss yet but from what I read most are disappointed (for it's price). Keeping to a modest price range I'd suggest trying a Minolta 28mm f2 MD, a Olympus 28mm f2, or a Nikon 28mm f2 AI version. Those mentioned will be better than zooms in that range and easy to carry around.

Ask around in the Sony forums, those guys have tried every combination.

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IMHO, your best bet is to have Kolari Vision apply their thin filter modification on your camera. It improves corner and edge performance of adapted WA lenses. I had my A7R modified and it worked wonders -- no more edge smearing for adapted WA lenses.

 

Sony A7 Series Thin Filter Legacy Lens Upgrade - Kolari Vision

 

Without the Kolari mod, the best M-mount 28mm for adapting to the A7 series might be the Hexanon-M 28/2.8.

Edited by photo_galleries
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Applying the "Lolari Vision" modification means you cannot use the very best lenses for the Sony A7Rii, which are made by Sony/Zeiss for that camera. That would be a big mistake, IM, very short-sighted. These lenses perform at a level equal to or better than the best Leica lenses, at a fraction of the cost.
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Applying the "Lolari Vision" modification means you cannot use the very best lenses for the Sony A7Rii, which are made by Sony/Zeiss for that camera. That would be a big mistake, IM, very short-sighted. These lenses perform at a level equal to or better than the best Leica lenses, at a fraction of the cost.

 

Cannot use? That's utter nonsense. I continue to use the FE 55/1.8 (certainly one of the finest FE lenses) and other FE lenses on my modified A7R with no issues whatsoever.

Edited by photo_galleries
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Maybe the Leica Elmarit-R 28mm version 2 (product number 11259) instead, which isn't too big or heavy and has a good reputation? No personal experience with this lens since I don't like the 28mm focal length much (prefer 35mm, which to me is a rather different FL). But never read a bad word about this lens.
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Cannot use? That's utter nonsense. I continue to use the FE 55/1.8 (certainly one of the finest FE lenses) and other FE lenses on my modified A7R with no issues whatsoever.

I meant "Kolari" of course.

 

Dedicated Sony lenses are designed to be used with a (approximately) 2 mm glass cover over the sensor. That cover is also the reason images using rangefinder lenses shorter than 50 mm are smeared in the corners. If you remove the cover glass, dedicated lenses will suffer similar loss of resolution in the corners. LensRentals points this out, and adds a 2 mm thick piece of glass in their test protocol.

 

The lenses will still fit, and auto-focus properly. The AF sensors are embedded in the sensor, so any change in the effective back focus distance is negated.

Edited by Ed_Ingold
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I meant "Kolari" of course.

 

Dedicated Sony lenses are designed to be used with a (approximately) 2 mm glass cover over the sensor. That cover is also the reason images using rangefinder lenses shorter than 50 mm are smeared in the corners. If you remove the cover glass, dedicated lenses will suffer similar loss of resolution in the corners. LensRentals points this out, and adds a 2 mm thick piece of glass in their test protocol.

 

The lenses will still fit, and auto-focus properly. The AF sensors are embedded in the sensor, so any change in the effective back focus distance is negated.

 

"Lolari/Kolari" -- if typos were an Olympic event, I'd be a medalist.

 

In any case, "cannot use" is a far cry from a very minor degradation in corner sharpness. Roger Cicala (Len Rentals) points this out with both the 35/2.8 and 55/1.8, noting that the maximum degradation is 40 lp/IH for the 55/1.8. Is that a significant loss of resolution? When comparing MTF charts, maybe, but out in the real world? To my eyes and in print, I haven't seen anything to complain about. Granted, Roger's tests aren't ideal (he says that himself), but in a limited sample, he's shown that a Kolari thin filter mod significantly improves that performance of adapted M lenses and causes only a very minor loss of resolution in the corners for native FE lenses.

 

A Thinner Sensor Stack

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Let's see some examples, comparing 100% (pixel=pixel) crops from the center and corners. I've done that many times the other way around. The most complete was with 50 mm lenses. Note that results for the Summicron and Nikon are reversed. We pay the "big bucks" for lenses that are sharply over, wide open, unless we have a Nikon and have no choice (I compare Nikon lenses too).

 

I would say that 40 lp/in is pretty low bar for a sensor that is 2600 lp/in. A better measure is pixels/image height. This number runs over 3600 for the best Sony lenses, and 2200 is considered the lowest acceptable value. The Zeiss 35/2.8 ZM runs about 1800 in the corners.

 

Summicron v2 50mm Test | Photo.net

Nikon AIS 50mm Test | Photo.net

Loxia 50mm Test | Photo.net

 

Below is a comparison of native 35 mm lenses on a Sony with comparable lenses on a Leica M9, which has a much thinner cover glass.

 

Resolution | Photo.net

Edited by Ed_Ingold
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Those tests that you cited are not germane to the question at hand:

 

Does the Kolari thin filter mod degrade resolution for native FE lenses on an A7(x) body?

The only valid test to answer that question is to have identical A7(x) bodies -- one as-is and another modified -- and shoot the same FE lenses on both, as Roger has done, albeit on a limited scale. Obviously, doing a before-after comparison on a single body would be valid as well.

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I show the effect of thick (A7ii) and thin (Leica M9) filters and compare FE with Leica and Nikon lenses. That illustrates the principles involved. A one-sided test comparing FE and M or ZM lenses on a converted body would complete the tale. If the FE lens were not clearly better than the Leica-mount version, blame it on the conversion.

 

It's pretty clear that good Sony/Zeiss lenses rule on a Sony body. Leica lenses might perform marginally better on a Kolari modified Sony than an M9, but I'm not holding my breath. A Zeiss 28/2.8 ZM costs twice as much as a Sony 28/2 FE, and isn't as good a lens (even on the M9). What's the sense of that?

 

I might consider converting my A7ii for infrared if I upgrade and move the A7Rii to backup status.

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I think we're 'speaking' at cross-purposes. There is no question that a good Sony/Zeiss lens will be better on a Sony body -- that is a given.

 

It is also clear that adapted M lenses (especially WA lenses) are better on a modified body than a non-modified body, especially wrt corner and edge smearing. Is it sharper? Questionable. Does it remove vignettiing and color casts? No, but those are fixable in post.

 

And again, back to the question at hand, does the mod degrade FE lens performance? Based on available info (from Roger), any degradation is very minor, and in real world use, very acceptable (at least to me as well as others who have had their A7(x) bodies modified.

 

Incidentally, my A7R is not only thin-filter modified but also full spectrum-modified.

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Roger's results are significantly lower than found on Photozone, using the same test method, Imatest. Roger uses an MTF50 cutoff, perhaps Photozone uses something else. That said, the interpretation may obscure differences. The values are so low, the lens would not rate a single star on Photozone (or PC Magazine). If nothing else, it illustrates that tests of this sort have to be regarded with some skepticism.

 

I reiterate, let's see some real world examples, done with the whole drill - tripod, remote release, and careful, manual focusing.

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Neither LensRentals (Roger) nor Photozone describe their test procedures in any detail. It could be that Roger gives the results as "line pairs" and PhotoZone (and PCMag) as "lines". The actual test target consists solid, black rectangles, placed on a slight diagonal throughout the field of view. Imatest measures the number of pixels from black to white for each edge. Since the edges are inclined, uncertainty would create a staircase effect, so the length of the "tread" would provide a more sensitive measure, like a vernier scale. A perfect score, using a Sony A7R and the Photozone method, l/in, would be 4926. If citing lp/in, half of that, or 2463.

 

Carl Zeiss Sonnar T* FE 35mm f/2.8 ZA (Sony SEL35F28Z) - Review / Test Report

 

Even if my assumptions are correct, and LensRentals uses lp/in, resolution in the corners is only half that cited by Photozone. That is sufficient to mask the real difference, with and without the Kolari modification. There are other, undetermined issues in the test method, perhaps the type of target used. Measurements using the standard Imatest target with solid, inclined blocks are nearly independent of contrast and sensor (as long as it is higher than the measured value), merely edge definition. A standard resolution chart, using grids and lines, is highly sensitive to contrast, resolution of the sensor, and that of the lens. (The effects of various factors can be estimated using analysis of variance.)

 

This issue illustrates the reason you can't compare MTF results between labs. A less recognized issue is that uncertainty inherent in the test method can obscure the differences you are trying to measure. LensRentals recognizes that resolution of Sony/Zeiss FE lenses is significantly reduced if the filter is omitted in a standard MTF test, but that's impossible when you are testing the effect of the sensor itself. Putting it simply, if you don't see the difference, you aren't looking at it right. If you measure with a micrometer, mark with a yardstick an cut with an axe, the only thing that matters is the axe.

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As I stated earlier, Roger's test is not ideal and there is certainly a need for more extensive and controlled testing. Until that happens, my current experience tells me two things:

 

1. The Kolari mod has eliminated edge and corner smearing from my M-mount lenses when mounted via adapter to my A7R.

 

2. While the Kolari mod may have degraded corner resolution of my FE lenses, such degradation is evident only in labs and optical benches; it is not noticeable in my practical use nor is is noticeable in my prints.

 

At the end of the day, those 2 things are all that matter to me.

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Some images from my modified A7R, using an FE 55/1.8 and a manual focus zoom. Again, at the end of the day, these are all that matter and they certainly look fine to me.

 

http://www.leonin.net/img/s11/v36/p269863107-4.jpg

 

http://www.leonin.net/img/s/v-2/p49459173-4.jpg

 

http://www.leonin.net/img/s3/v39/p113849772-4.jpg

 

http://www.leonin.net/img/s12/v173/p250934923-4.jpg

 

http://www.leonin.net/img/s6/v145/p216646497-4.jpg

 

http://www.leonin.net/img/s12/v175/p17933877-4.jpg

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Nice photos, but I would like to see something more clinical. In particular corner details at full resolution (pixel = pixel) of a subject with a lot of detail (e.g., leaves), cropped to comply with PNET requirements (1000 px wide or less). That's a small portion of an A7R image.

 

Most photos of the sort you posted have a central subject and the corners are naturally out of focus. Landscapes are a notable exception, and should be sharp from corner to corner.

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I will admit that I have not examined the corners in great detail, but I did conclude that the Sony FE 28mm was at least decent when compared to a lot of manual focus WA lenses I tried in front of my A7. From memory, probably the best MF lens I tried was a version II 35mm Summicron R. I will find the 3 cam Elmarit 28mm R I have and try it again, I thought it was "pretty good" but don't remember thinking it was crazy outstanding.

 

Relatively good, small, light, fast, inexpensive,and convertible to 21mm/2.8 make the FE 28mm/2 a must have, IMO, even if it is not the absolute best.

 

I also use a Nikon 28/2 MF on digital and really like the way it renders, but corner sharpness at or near wide open is not good.

Edited by robert_bouknight|1
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Since Leica R lenses have a long back focus distance for use with an SLR, they are likely to perform very well on a mirrorless camera. Adapters are widely available, but R lenses may be in short supply for this very reason. I went through a period using Nikon AF and AIS and Leica M lenses on my A7ii. The in-body image stabilization works very well, and manual focus is quick and precise with peaking or magnification. I programmed one button to access the focal length setting for IBIS and another to engage focusing magnification. I was ready for a change when the manual Loxia 35 and 50 came out, and much later the AF Batis 25 and 85.

 

I switched from my Nikon D3 to Leica and mirrorless for less weight and sharp wide angle shots. Once Sony filled out their lens lineup, "sharp" took on a new meaning. That was 2014, and I haven't looked back. I recently purchased a Basis 18 for starry landscapes, and find it sharp and aberration-free, even wide open at f/2.8.

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