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Author Topic: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art  (Read 1067 times)

Kirk_C

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Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« on: March 11, 2019, 10:52:27 pm »

I was just about to buy the Sigma 135mm Art and I still may but damn look at these MTF results for the new Sony !
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BernardLanguillier

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #1 on: March 12, 2019, 03:59:09 am »

I was just about to buy the Sigma 135mm Art and I still may but damn look at these MTF results for the new Sony !

Yep, this sounds like a wonderful design, well done Sony!

Cheers,
Bernard

kers

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #2 on: March 12, 2019, 07:17:10 am »

Sony just found out a new way to attract pro-costumers....
Sigma, Canon and Nikon have now a very serious competitor...
With the 2020 Olympics in Japan ahead there will be more to come for sure.
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faberryman

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #3 on: March 12, 2019, 07:26:05 am »

Amazing what you can achieve with a small throat diameter.

BernardLanguillier

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #4 on: March 12, 2019, 08:14:43 am »

Amazing what you can achieve with a small throat diameter.

This is a very good example of a focal length for which the mount has probably very little influence.

Nikon's 70-200 f2.8 E FL is the best DSLR tele zoom lens of all brands although the F mount is clearly inferior to the EOS mount.

I has never crossed my mind to use that fact as a proof point that DSLR mount size isn't relevant to lens performance... possibly because that wouldn't make any sense...

Can we keep this thread on topic and speak about this brilliant lens?
 
Cheers,
Bernard
« Last Edit: March 12, 2019, 09:09:58 am by BernardLanguillier »
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Paul Roark

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #5 on: March 12, 2019, 11:16:28 am »

For some perspective, I just posted a copy of the Leica-M 135mm at http://www.paulroark.com/BW-Info/Leice-M-135mm.jpg, which, via an adapter, I use on my Sony.  Of course, it's slower and manual, but also rather small and light.

Paul
www.PaulRoark.com

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Telecaster

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #6 on: March 12, 2019, 03:31:15 pm »

1 kilogram +. Too freakin' heavy for my taste…I'll stick with the Batis at just over 600g and no meaningful real-world res difference.

-Dave-
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Rado

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #7 on: March 12, 2019, 03:38:49 pm »

The Sigma 135 Art is over a kilogram too and I really like using it, so I'm imagining Sony portrait shooters will be very happy about this lens.
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David Eichler

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #8 on: March 12, 2019, 05:26:04 pm »

For most applications, it is the level of sharpness accross the entire field that is most important to me, and I will trade a bit of center sharpness for better edges, which will almost always be less sharp than the center anyway. Looks to me as though, overall, the Sigma is very slightly sharper at the edges. However, do these MTF charts show performance in the extreme corners? That can be a separate area of performance, especially if a lens is not very precisely centered.
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kers

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #9 on: March 13, 2019, 08:40:04 am »

For most applications, it is the level of sharpness accross the entire field that is most important to me, and I will trade a bit of center sharpness for better edges, which will almost always be less sharp than the center anyway. Looks to me as though, overall, the Sigma is very slightly sharper at the edges. However, do these MTF charts show performance in the extreme corners? That can be a separate area of performance, especially if a lens is not very precisely centered.
As i understand the MTF is made with focus at infinity; So yes the Sigma is slightly better on the edges. Not sure what will happen at other apertures, but both are excellent lenses.
Still have not seen any other comparisons on aberrations , coma etc... and not to forget : real life performance.
« Last Edit: March 13, 2019, 09:00:54 am by kers »
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mcbroomf

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #10 on: March 13, 2019, 08:52:20 am »

.... However, do these MTF charts show performance in the extreme corners? That can be a separate area of performance, especially if a lens is not very precisely centered.
They measure to the corners (20mm from center, so within 1mm) and the graph shows the average of 10 lenses.  So far as I recall you are also seeing the average of all 4 corners as well as the 10 lenses but I'm not 100% sure about that, the info is probably buried deep in the blog somewhere.
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Eric Brody

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #11 on: March 13, 2019, 07:34:18 pm »

I do not doubt for a moment that the Sony 135 is superb, measures as such, and will be the gold standard for a long time. Were I starting from scratch I'd order it but for two reasons. If the wait for the 24mm f/1.4 GM is an example, (it's still not available even after being out for some time) most people will be waiting a LONG time to actually get one, and... I already have the Batis 135. I suspect, and it's really not sour grapes, that most of us could not tell the difference at less than billboard size print, or at f/2 ;)
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shadowblade

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #12 on: March 16, 2019, 07:10:26 am »

I wouldn't trust these results and would wait until they re-run the test with ten random, retail lenses.

These aren't ten randomly-selected lenses - they're ten lenses loaned to LensRentals for the express purpose of MTF testing. As such, they likely represent optimal lenses of this design, rather than what can be expected from a random lens pulled from the shelf. MTFs - especially data regarding sample variation - of randomly-selected lenses will be much more telling.

Re: edge sharpness - comparison with Sigma is incomplete without information about field curvature and use-case scenarios.

The test that was published considered a lens focused on a subject at infinity in the centre of the field of view at f/1.8 (or, in one case, at f/2.8). Off-centre points were not measured at their peak sharpness (i.e. focused on a subject at infinity at that point) but at their sharpness when the lens is focused at an infinity subject at the centre of the image circle. In other words, if there is any field curvature at all, the off-centre points were measured when they were out-of-focus.

But that is not how a 135mm lens tends to be used. At f/1.8 - or even f/4 - you wouldn't expect the whole image to be in focus. You're probably shooting a specific subject - a portrait, a small object or a feature in a larger object - expecting sharpness where you're focused, but fading to an even blur where you're not focused. You're probably also not shooting at infinity. In this case, it's not the corner/midframe sharpness when the centre is in focus that matters - it's the maximal sharpness at any given point that matters. So what you need is not the currently-displayed MTF charts, but the MTF charts corrected for focus - that is, the maximum sharpness achievable at any given point, not how sharp any given point happens to be when the middle is in focus.

If, on the other hand, you're shooting a landscape and expect the whole scene to be in near-focus, you're probably not shooting at f/1.8. With a 135mm lens, you're likely shooting around f/8, or even narrower. For such a scenario, MTF charts wide-open have little bearing - it's the f/8 chart and the field curvature charts that matter.
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budjames

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #13 on: March 16, 2019, 07:52:15 am »

The advancing technology of current lenses is fantastic, however, the lenses seem to get larger and heavier with every iteration. That's the main reason I moved from Canon pro DSLRs to Fuji X APS-C cameras and lenses.

I still marvel at the IQ from my Leica primes on my M10 body.

Regards,
Bud James

Please check out my fine art and travel photography at www.budjames.photography or on Instagram at www.instagram.com/budjamesphoto.
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Bud James
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David Eichler

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #14 on: March 16, 2019, 02:38:02 pm »

I wouldn't trust these results and would wait until they re-run the test with ten random, retail lenses.

These aren't ten randomly-selected lenses - they're ten lenses loaned to LensRentals for the express purpose of MTF testing. As such, they likely represent optimal lenses of this design, rather than what can be expected from a random lens pulled from the shelf. MTFs - especially data regarding sample variation - of randomly-selected lenses will be much more telling.

Re: edge sharpness - comparison with Sigma is incomplete without information about field curvature and use-case scenarios.

The test that was published considered a lens focused on a subject at infinity in the centre of the field of view at f/1.8 (or, in one case, at f/2.8). Off-centre points were not measured at their peak sharpness (i.e. focused on a subject at infinity at that point) but at their sharpness when the lens is focused at an infinity subject at the centre of the image circle. In other words, if there is any field curvature at all, the off-centre points were measured when they were out-of-focus.

But that is not how a 135mm lens tends to be used. At f/1.8 - or even f/4 - you wouldn't expect the whole image to be in focus. You're probably shooting a specific subject - a portrait, a small object or a feature in a larger object - expecting sharpness where you're focused, but fading to an even blur where you're not focused. You're probably also not shooting at infinity. In this case, it's not the corner/midframe sharpness when the centre is in focus that matters - it's the maximal sharpness at any given point that matters. So what you need is not the currently-displayed MTF charts, but the MTF charts corrected for focus - that is, the maximum sharpness achievable at any given point, not how sharp any given point happens to be when the middle is in focus.

If, on the other hand, you're shooting a landscape and expect the whole scene to be in near-focus, you're probably not shooting at f/1.8. With a 135mm lens, you're likely shooting around f/8, or even narrower. For such a scenario, MTF charts wide-open have little bearing - it's the f/8 chart and the field curvature charts that matter.

If you had read their testing methodology, you would see that they vary focus to account for field curvature. In any case, high-quality lenses of this type (medium telephoto) tend to have very low field curvature, and I would expect that to apply to these lenses.

As to focus at infinity for the tests, I don't see where you get that from. It is impossible to shoot a test target at literal infinity.

We should all note that this test is a very small part of the overall story, since they are only testing at the widest aperture, and it is often the case that lens performance will improve as the aperture becomes smaller (until the point that diffraction starts to progressively degrade quality). However, if a lens performs really well at its widest aperture, it is clearly a superior lens.
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mcbroomf

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #15 on: March 16, 2019, 04:50:22 pm »

If you had read their testing methodology, you would see that they vary focus to account for field curvature. In any case, high-quality lenses of this type (medium telephoto) tend to have very low field curvature, and I would expect that to apply to these lenses.

As to focus at infinity for the tests, I don't see where you get that from. It is impossible to shoot a test target at literal infinity.

We should all note that this test is a very small part of the overall story, since they are only testing at the widest aperture, and it is often the case that lens performance will improve as the aperture becomes smaller (until the point that diffraction starts to progressively degrade quality). However, if a lens performs really well at its widest aperture, it is clearly a superior lens.

They use an optical bench and do test the lenses at infinity according to their blog.  I know they've published testing where they've changed focus to account for FC but I didn't think they did it in the normal tests they publish (would be great if they did it both ways I think).
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shadowblade

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #16 on: March 17, 2019, 01:27:07 am »

If you had read their testing methodology, you would see that they vary focus to account for field curvature.

They don't. Some of their tests have separate MTF charts for 'best at any given point' sharpness, but most don't. Read these two articles for further information:

https://www.lensrentals.com/blog/2017/11/testing-lenses-finding-the-best-average-focus-point/
https://www.lensrentals.com/blog/2017/11/testing-lenses-best-individual-focus-mtf-curves/

Quote
In any case, high-quality lenses of this type (medium telephoto) tend to have very low field curvature, and I would expect that to apply to these lenses.

When you're measuring MTFs at 50lp/mm, every small misfocus counts. Small focus errors which would probably not be noticeable in a typical photo (with certain exceptions) show up as big differences in measured numbers.

Case in point - try taking a photo of a night sky, with discrete, individual stars. Your focus needs to be perfect - even the slightest misfocus turns the pinpoint stars into mushy blobs. Use the same degree of misfocus in typical landscape photo and you'd never notice.

The optical bench measures pinpoint dots of light - just like stars. Tiny focus errors turn into big differences in measured MTF. Look at the 'average MTF' (focused on centre) vs 'best focus MTF' (focused on point being tested) for the Sigma Cine 85/1.5 here. This is a lens with a very flat field of focus, yet there is a dramatic difference between the average and best MTFs measured.

Quote
As to focus at infinity for the tests, I don't see where you get that from. It is impossible to shoot a test target at literal infinity.

They use an optical bench to generate an infinity target. Incoming light is parallel to the axis of the lens, equating to an infinite target distance.

Quote
We should all note that this test is a very small part of the overall story, since they are only testing at the widest aperture, and it is often the case that lens performance will improve as the aperture becomes smaller (until the point that diffraction starts to progressively degrade quality). However, if a lens performs really well at its widest aperture, it is clearly a superior lens.

Not necessarily. Unless there is a clear-cut difference where one lens is better than another in almost every measurement at every point, use case matters a great deal.

Consider two lenses - Lens A, a 500mm f/4 lens which is extremely sharp in the centre, but drops off significantly towards the edges, and Lens B, a 500mm f/4 lens which isn't quite as sharp in the centre, but which maintains its sharpness right out to the corners.  Lens A will give you an extremely sharp centre, with softer corners, while Lens B will be moderately sharp throughout. Not an uncommon situation - but which is the better lens?

Remember, these are large supertele lenses, likely being used for sports and wildlife, often with teleconverters (which essentially take the middle portion of the image circle and magnify it). It will be rare for the entire field of view to be in focus, and rare for the point of the focus to be in the outer parts of the image circle. When using a teleconverter, the outer parts of the image circle won't even be in the frame at all. In this case, Lens A, with the sharp centre and average corners, is probably a better lens - in most cases, the edges will be out of focus anyway, but you want extreme sharpness in the central portion for fur/feather/scale detail and for teleconverters. Lens B will just give you some very sharp out-of-focus details in corners.

Now take the same two lenses, with exactly the same MTF charts, but make them 24-105mm f/4 lenses instead. Which one is better now?

These are now all-purpose, relatively slow wide-to-medium-telephoto lenses, being used to shoot everything from portraits to landscapes (possibly even some pseudo-macros, depending on maximum magnification), likely with more of a focus on travel and landscape photography than being dedicated portrait lenses. Lens A still gives you a great centre and so-so corners, while Lens B gives you good, consistent sharpness corner-to-corner. Out of these two lenses, Lens B is probably the better one. Same MTF charts as the 500mm f/4 example, but the different purpose of the lens makes the priorities and desired characteristics different.

Now consider a pair of 70-200 f/2.8 lenses. Lens C is super-sharp in the centre at f/2.8, with so-so corners, which improve to being sharp corner-to-corner at f/8, while Lens D is sharp across the frame at f/2.8 (without being as sharp as lens C in the centre), with slight-to-moderate general improvement across the frame at f/8. Which lens is better? Probably Lens C. At f/2.8, it's probably being used for portraits or similar shots, where focus is on a specific person or feature, rather than the scene as a whole. The corners are likely going to be out of focus anyway, so Lens D's across-the-frame sharpness adds nothing there. When shooting a landscape or other scene where everything is in focus, the lenses will probably be stopped down to f/8 or narrower. Both lenses likely perform similarly here, but Lens C's sharper centre when wide open gives it the edge due to versatility (being better for portraits while being just as good for landscapes).

Now make them 14-24mm f/2.8 lenses instead, with the same MTFs. Now Lens D is probably better, because every shot is likely to be in focus corner-to-corner anyway, with wider f-stops being used more for shutter speed and low-light situations than for DOF control. Lens C will give you mushy corners and be all but unusable at wide aperture, while Lens D will be much more usable without having to stop down. Compare and contrast Canon's 16-35 f/2.8L II (not the current Mk III version) with Nikon's contemporaneous 14-24 f/2.8 - Canon's was sharper in the centre but had mushy corners, while Nikon's was better across the frame. Nikon's was widely regarded as the far better lens.

MTFs are meaningless in isolation, without considering the overall purpose of the lens - including lenses with different purposes at each end of the zoom range or at different f-stops. What constitutes a good MTF curve varies greatly depending on intended use - do you need corner-to-corner sharpness, or a super-sharp centre? A lens with a 'worse'-looking ETF than another may actually turn out to be a better lens once you consider what it's actually going to be used for, even without considering non-optical characteristics such as AF or weather sealing.
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faberryman

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #17 on: March 17, 2019, 01:38:27 pm »

Wow. What a diatribe.  Do you think the Sony 135 is not a good lens?

shadowblade

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #18 on: March 17, 2019, 06:36:09 pm »

Wow. What a diatribe.  Do you think the Sony 135 is not a good lens?

Nope - I'm saying that the current LensRentals MTFs are unreliable. Not because they're inaccurate, but because they done on a group of lens hand-selected by Sony and submitted for testing. Measurements performed on 10 randomly-selected copies may be somewhat different. Lensrentals themselves have said that they will re-test it with randomly-selected copies once the lens is released.

Re: edge sharpness differences between Sony and Sigma - you'd need to see 'best focus MTF' charts for both lenses before reaching any conclusions. The current MTFs only show what the corner sharpness is like when the centre is in focus - not when the point actually being tested is in focus. So any field curvature will throw it right off. When actually taking a photo, you focus on the subject, no matter where that may be in the frame. If the subject is halfway out to the edge, your point of focus is there, not in the middle. So what you really want to know is the maximum sharpness achievable when the point of interest is in focus, not the sharpness measured at any point when the middle is in focus.
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kers

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Re: Sony FE 135 MTF Beats Zeiss Batis and Sigma Art
« Reply #19 on: March 17, 2019, 07:40:56 pm »

Nope - I'm saying that the current LensRentals MTFs are unreliable. Not because they're inaccurate, but because they done on a group of lens hand-selected by Sony and submitted for testing. Measurements performed on 10 randomly-selected copies may be somewhat different.

 Lensrentals themselves have said that they will re-test it with randomly-selected copies once the lens is released.

Exactly, and i do not think SONY wants to be caught cheating.
So a good chance the results will stand with other random copies.

The summary of Roger Cicala :
"This has been an MTF test. It has only been an MTF test. If it had been an actual lens review, I would have 762 images showing you pretty models, dramatic landscapes, and bokeh examples. Lens reviewers will do that in a while; be patient.
But as far as the test goes, the results are pretty simple. This is the sharpest lens we’ve tested. Period. (At last count, that’s out of 300+ lenses tested.)"
« Last Edit: March 17, 2019, 07:49:50 pm by kers »
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