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Lenses and Optics

Sony FE 90mm f/2.8 G OSS Resolution Test

Published May 4, 2015

We got a pre-release set of Sony FE 90mm f/2.8 G OSS Macro lenses in for preliminary testing last week, and I was kind of excited about this lens for a couple of reasons. First it simply gives me a nice short telephoto prime option that has been lacking in the lineup (although the Zeiss 85mm Batis lens will be coming along fairly soon). Second, it gives me a true macro lens at the focal length I prefer.

Image Courtesy Sony, USA

 

I hoped that the combination of a good macro lens with the A7r sensor would turn out to be a winner. We used our Imatest lab to compare Sony 90mm f/2.8 G OSS lenses mounted to Sony A7r cameras, and compared them with Canon 100mm f/2.8 IS Macro lenses shot on Canon 5DIII cameras in our Imatest lab. (For those who are curious, we can’t test Sony E mount lenses on an optical bench because the electromagnetic focus system requires electrical power to operate. Until we do some really geeky, overly complex engineering modifications, the optical bench isn’t an option for Sony E mount lenses.) It would have been nice to also compare with a Nikon D810 and Nikon 105 f/2.8 Micro lens, I know, but our time is limited.

Overview of the 90mm f/2.8 G OSS

First of all, if you’re used to Sony E mount lenses being smaller than their SLR counterparts, you’ll need to get over that. The 90mm lens is very similar in size to the Canon 100mm f/2.8 IS and other SLR macro lenses in this focal range.

 

Canon 100mm f/2.8 IS on 5D III (left) and Sony 90mm f/2.8 on A7r (right). Lens rentals.com, 2015

 

If you’d like the numbers for comparison, I’ve put them in a table.

  Sony 90mm f/2.8 OSS Canon 100mm f/2.8 IS L Nikon 105mm f/2.8 Micro VR
Price$1,098$899$879
Weight (lb.)1.321.381.58
Length (in.)5.144.844.9
Filter size (mm)626762
Min. Focus Dist. (in.)111212
Aperture Blades999
Elements/Groups15/1115/1214/12

The Sony is a bit more expensive, but that’s not unusual for a new release. Otherwise they are pretty similar in specifications.

Test Results

We tested these in our Imatest lab but at two different focusing distances and with two different charts. Remember, the higher resolution of the A7r camera will make the system resolution higher. My thinking when making this comparison was if the Sony lens wasn’t up to the standards of the Canon (which is arguably the best macro lens in this focus range), then the Canon system would be close to the Sony, despite the higher resolution of the Sony camera.

The tables below shows the MTF 50 results averaged for 6 samples each of the Sony 90mm f/2.8 OSS on a Sony A7r compared with 6 samples of the Canon 100mm f/2.8 IS L on a 5D Mark III.

Our first test was using a standard Imatest setup shot at a distance of about 20 feet.

 Canon 100mm f/2.8 IS LSony 90mm f/2.8 G OSS
Center1580 lp/ih2300 lp/ih
Average1340 lp/ih1665 lp/ih
4 Corner avg. 1125 lp/ih1210 lp/ih

We then repeated the tests, using a high-resolution, back lit chart made by Imatest specifically for testing macro lenses. The focusing distance was now just under 2 feet. This doesn’t give us quite full 1:1 macro working distance, but it’s pretty close.

 Canon 100mm f/2.8 IS LSony 90mm f/2.8 G OSS
Center1540 lp/ih2210 lp/ih
Average1290 lp/ih1765 lp/ih
4 Corner avg. 1105 lp/ih1380 lp/ih

At both focusing distances the Sony system is clearly out resolving the Canon system. We would expect that, to some degree, given the higher resolution Sony sensor. But the difference was, quite frankly, surprising to me. It would seem to indicate the new Sony 90mm Macro lens performs at least as well as the Canon 100mm f/2.8 IS L, from a resolution standpoint, anyway.

Summary

Please don’t take this out of context. These are simply Imatest MTF50 numbers. By that standard the new Sony 90mm f/2.8 G OSS Macro seems to be a superb addition to the E mount lineup, and the lens on an A7r should provide superb resolution. We’ll have to look at more in-depth, hands on reviews to see how it actually performs in the field, what the bokeh looks like, how well the OSS performs and a host of other factors to decide how great (or not) the lens performs in the real world. But these preliminary results look very good.

 

Roger Cicala and Aaron Closz

Lensrentals.com

April, 2015

Author: Roger Cicala

I’m Roger and I am the founder of Lensrentals.com. Hailed as one of the optic nerds here, I enjoy shooting collimated light through 30X microscope objectives in my spare time. When I do take real pictures I like using something different: a Medium format, or Pentax K1, or a Sony RX1R.

Posted in Lenses and Optics
  • Gabriel

    Is this FE 90mm @ 2.8 as sharp as say the FE 55mm @ 2.8 as well?

  • Aram Langhans

    And to add to Marcel, when I was shooting Canon, I had access to the canon 100 2.8 L and I had my own Leica 100/2.8 APO. It really was not contest on an 18MB sensor. I imagine the Leica and Zeiss are fairly similar. Manual focus, but who uses auto focus for a macro anyway. I was not impressed with the Canon vs the Leica at all. Now shooting Nikon, and have adapted the 100 APO to Nikon.

  • SamT

    I must concur with Roger. I’ve use this 90mm for portrait and is very sharp straight out at f2.8
    It’s definitely worth the money.

  • Roger,

    We are awaiting a real comparison as suggested by a few others above. You certainly have the experience and equipment. Hopefully you can find time.

    Steve

  • Ilya Zakharevich

    @ Frans van den Bergh:

    What you say is
    • the resolution ratio of SENSORs is ~1.47.
    • the resolution ratio of (LENS+SENSOR)s is very similar. (1.44)

    Contrary to what you say, the conclusion is NOT that the resolutions of the lenses are the same. The conclusion is that the resolution ratio of the lenses is ALSO very similar, about 1.4 or some such.

    MTFs are multiplied when combining! (E.g., if Sony sensor has MTF71 at 2300 lp, and Canon’s MTF71 at 1600 lp, AND if sensor+lens combinations have MTF50 at these values, then the lenses have MTF70 AT THE SAME VALUES: 0.71*0.7?0.5.)

    So, according to YOUR calculations, Sony lens resolves about 40% more (linearly), or 100% more (in pixels)?—??at least near the center?—??in MTFn units, for some high value of n.

  • Roger Cicala

    John, theses were all done at f/2.8
    Roger

  • DavidT

    Roger,

    A question about the focusing: I read a translated review of the lens and it made it sound like the lens was focus-by-wire in AF mode, but when the focusing ring was pulled back to MF it switched to a mechanical focusing operation. Im not sure if this is even possible, but would be an awesome feature as manual focusing by wire sucks IMO. What was your experience with manually focusing this lens?

  • John

    Roger,

    If I may ask, what aperture were these tests taken at? Thanks!

  • henkie

    Roger, wouldn’t it’ve been easier to compare the D810? I don’t know how the Nikkor performs, but the Sigma 105/2.8 should have more or less the same performance as the Canon 100L, as far as I’ve seen in tests. And then you’d have at least comparable resolution numbers for the Sony.

  • Randy

    Roger – I’m not in the market for a Sony but I still wish I had a better idea of how viable the adapter option is. If it’s only some adapters in some situations or even just cheap adapters, that’s reasonable. But if different lenses require different adapters and even then its a crap shoot, this takes away one reason for considering the Sony.

  • Jon Lindemann

    Roger,

    You sure kicked the horn’s nest with this one!

    Thanks for the understandably preliminary nature of this report. Will be interesting to see how the Canon fares with the new 5d.

    Of note, Lloyd Chambers noticed similar issues with edge blur on three samples of the Canon 100mm f/2.8 IS L macro.

  • NancyP

    Somewhat rhetorical question: Why focus-by-wire? Is it just because all other Sony E mount lenses work this way? Most macro aficionados focus manually, and from the minimal experience I have with focus-by-wire, it isn’t optimal for manual focus. No, I know Roger isn’t privy to lens designers’ thoughts.

  • Can you extrapolate any practical implications from your data? For example, at what print size and above would the difference in resolution between these two systems be apparent and beneficial?

  • obican

    Btw, in my experience, Nikon F mount and Sony E mount are pretty similar. Surely there is a bit of play but that might be a good starting point for modifications.

  • Roger Cicala

    obican, sort of. We need it adjusted to be optically flat within a micron or two so we’ll need some outside help for that and something more accurate than an extension tube, but we’re trying to modify one of the machine mounts and using a very long flex attach it to a control camera for focus.

  • Thomas

    You’re probably onto it already, but could you use a system similar to Novoflex’s EOS-RETRO adaptor to extend camera signals to the optical bench lens mount to allow use of focus-by-wire lenses? (https://www.novoflex.com/de/info/download/+/file/12_dabla_eos_retro_e_1011_web.pdf/)

    I actually made myself a similar adapter using parts from scrap lenses and camera mounts, not particularly accurately built but I still had quite a bit of fun taking extreme macro pictures of stuff.

    The lens signalling protocol should be robust enough for a reasonable camera-lens distance; I think mine had a ~30cm (1ft) cable. If it proved to be an issue a repeater would not be difficult to build.

  • Why not test on the Sony a7? Anyway, seems to be an excellent lens given the MTF charts and sample images floating around.

  • Andrey

    What was the aperture in this test ?
    Could you please share results for f8, f11, f16 ?
    Also we would like to see the same test on 5DS 😉
    5d mk3 can be dissmissed )

    Thanks Roger, you are doing a great job.

  • @obican,

    Yes, you are right — my inference was way off.

  • Question

    what is the theoretical maximum lp/in the canon sensor can achieve?

    can the 22 mp sensor with the 100mm macro come close (theoretical) to the results from the sony 36MP sensor + 90mm macro?

    no matter what kind of influence an adapter has… it would be nice to know what a tamron or tokina or the canon macro can achieve on the sony body. in the end that is what people are doing today.

  • KL

    or test with a 24mp sony… or is the purpose of this test to bash canon.. as it is en vogue today by bloggers.

    you don´t need a 2 digit IQ to know that higher res sensors resolve better. and macro lenses are not especiall difisult to build. every macro from tokina to zeiss has great resolutions figures.

  • KL

    why don´t you test the canon macro on the sony body?

    that is what many of us sony users are doing right now.. because there is no good sony macro for now.

  • tn1krr

    Nice work as usual. Though a comparison with a similar Fl Macro (Makro Planar 100/2 or Nikkor 105) on a non-AA 36 MP Nikon body might be more telling. Now that you have the results for Sony 90/2.8 Nikon surely could be tested similarly if you have time 😉

    Personally I do not quite get the hype of Canon 100/2.8L IS. I had the lens smart-adapted to my A7R, nice lens, but not really a world beater it is sometimes hailed as. Makro Planar 100 beats it in sharpness in the dxomark for example (on the very same 5D Mark III body); same goes for lenscore.org custom 200 MP digital back testing.

  • obican

    Roger, can’t we hack some extension tubes and connect them to a cheap Nex body with a flex cable?

  • Roger Cicala

    Lee, it’s a huge issue and we are working on an electronic mount for the bench.

  • Roger Cicala

    Phillip, correct, all at f/2.8

  • obican

    You can’t conclude both lenses to be equally sharp from these results. We know how the Sony resolves on an 36MP sensor but we have no idea how Canon would behave. It might be on its limit at current sensor, we don’t know.

    Only truly meaningful result out of test would be IF the Sony had a lower resolution than the Canon, despite the resolution difference.

  • A quick back-of-the-envelope calculation to compare a7r and 5DIII figures:
    Based purely on photosite pitch, the linear resolution difference between the two bodies is a factor of ~1.28.
    Using a simple model to take into account that the 5DIII has an AA filter (OLPF), versus the a7r without AA filter, gives use a resolution raio of ~1.47 at f/2.8 (green light).

    Roger’s results in the centre show a resolution ratio of ~1.44, so after accounting for the resolution difference between the two bodies, you can conclude that both lenses are equally sharp in the centre.

    Even Roger’s measured “average” scores have a resolution ratio of ~1.37, which is again pretty close to the expected value of 1.47.

  • SteveB

    I think rather than adapt the 100mm f2.8 L IS to the A7r, a better equivalence test, would have been the Sony 90mm f2.8 G OSS on an A7 or A7 II.

  • Marcel

    I never understand why the Canon 100mm F2.8 IS is hailed as the king of 100mm lenses. On my 5D MKIII the corners were always a bit fuzzy (shooting at distance), and it has quite a lot of CA.

    Right now I am using a Zeiss 100mm f/2 Makro Planar, which is near perfect. No autofocus, but the quality is superb. That lens on a D800 or D810 would be a good benchmark against the Sony 90mm on a A7R.

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