Can anyone refute that Fuji inflates its ISO numbers?

Discussion in 'Open Discussion' started by Ray Sachs, Apr 5, 2013.

  1. Ray Sachs

    Ray Sachs FujiXspot Veteran

    485
    Feb 1, 2013
    Near Philadephila
    I was one of the original X100 owners since day 1 and have had an X-Pro pretty much since the first day you could get them in the US and now I'm in the process of testing an X100s for a month. For most of the time I had the X100, I didn't have anything else that was even particularly close to it in terms of low light performance, so the idea of ISO inflation never really occurred to me and I never checked it out. But once I was shooting the X-Pro (which was about a stop better than the X100 in low light) and was also shooting an OMD and a Ricoh GXR-28 and now that I've also had the chance to shoot with a Sony RX1 and a Nikon Coolpix A, I've come to the conclusion that the Fujis tend to inflate their ISO figures by around a stop. I'm not the most technical guy in the world and I may very well be missing something and I haven't precisely measured the actual exposure of the resulting files (part of not being the most technical guy in the world). So I'll toss this out there for consideration...

    I've done some testing of The X-Pro against the OMD and GXR-28 and the Nikon "A" and now against the X100s with the 28mm adapter lens. I determined that when shooting identical low light scenes with a 28mm equivalent lens at the brightest common aperture that the OMD and the GXR-28 and the Nikon "A" always chose basically identical shutter speeds at the same ISO. At 1600, the same, at 3200, the same, at 6400 the OMD and Nikon were the same (the GXR tops out at 3200). The X-Pro with the 18mm lens, OTOH, chooses a shutter speed almost exactly one stop slower than the other cameras. And now, testing the X100s against both the X-Pro, Nikon "A", and GXR-28, the X100s chooses an even slower shutter speed than the X-Pro. Which brings me to the conclusion that Fuji's ISO 3200 is very similar, if not quite identical, to ISO 1600 on the other cameras. And that Fuji's 6400 is very very close to ISO 3200 on the others.

    I've also briefly tested the X100s against the Sony RX1 at 35mm equivalent focal lengths at their common brightest shutter of f2.0. The same basic phenomenon applies. Shooting both of them at ISO 6400 at f2.0 into the identical low light scene, the RX1 chose a shutter speed of 1/400 of a second and the X100s chose 1/150 of a second! My guess is that if I'd had a similar 35mm equivalent lens for the X-Pro, it would have probably come in at about 1/200 based on its relative behavior to the X100s at 28mm. Again, the Fuji seems to be inflating its ISO by slightly more than a stop here, at least relative to the RX1. I haven't tested the RX1 directly against the Nikon, or OMD or GXR-28 because the focal lengths are different, but based on its comparison to the X100s and the way the others compared to the X100s at 28mm, I'd bet the RX1 and the other cameras I've checked here are very very close to identical - consistent in the way they pick exposures at a given ISO. The Fuji's are clearly the outliers with the X100s more of an outlier than the X-Pro.

    Again, I haven't analyzed the details of the brightness/exposure of the resulting images. They all look basically consistent, but its possible that someone with a more trained eye or calibrated testing equipment could say that one tends to under-expose a third of a stop and others may not. So I'm not holding these numbers up as absolute or precisely correct. But there's an undeniable patten here that suggests to me that the Fuji X-cameras are very good low light cameras, but not appreciably better than cameras that we thought they were initially, and are demonstrably less good than the RX1 and I'd contend the Nikon "A" also. The RX1 is just astonishingly good up to its 12,800 - I'd say better than the Fuji at its 6400, which may not be 6400 at all. And the Nikon has a native ISO 6400 (the higher ISOs are jpeg concoctions) that compares well to the Fuji 6400 which, if its actually more like 3200, gives the Nikon a roughly one stop advantage.

    So, tech experts, what am I missing here? I love the Fuji cameras and I'm more than willing to be convinced I'm wrong - that what I'm observing is somehow not real. But I can't see where it falls apart. Any thoughts, suggestions, evidence that suggests otherwise? Etc...

    BTW, I'll be shooting with the X100s, the RX1, and the Nikon "A" in New York City this weekend. Hopefully I'll have a more detailed set of overall impressions of the X100s early next week. My initial impression is pretty favorable but not overwhelming, this issue aside. But I need more time with it...

    -Ray
     
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  2. Tdp

    Tdp Guest

    For portraits with remote off camera flashes and long exposure waterfalls I shoot all manual and will often have more than one camera with me. My 5DII shoots about 1/3 stop brighter than my OMD, and my X-E1 shoots about a full stop darker than than my OMD (at the same ISO/shutter speed/f stop). I don't really consider it a problem, just a mannerism of the camera that you learn to work with.
     
  3. Ray Sachs

    Ray Sachs FujiXspot Veteran

    485
    Feb 1, 2013
    Near Philadephila
    I'm not suggesting its a problem once you have the camera and you're using it, particularly when you're using flashes and aren't really limited by available light. But if you do a lot of low light shooting, its potentially very important information when comparing cameras and their low light capabilities.

    -Ray
     
  4. Tdp

    Tdp Guest

    Oh I got you now. If Fuji's light sensitivity @ 6400 is actually the same as another camera's 3200 then the other camera still has a full stop to go up. Makes sense.

    It is kind of like how some automotive manufactures are cooking MPG numbers.
     
  5. tol1l1yboy

    tol1l1yboy FujiXspot Rookie

    11
    Feb 11, 2013
    Maybe Im missing something and maybe this is besides the point but when I shoot at ISO:3200 on my XE-1 it looks much better (ie details are better and significantly less grain) than when I shoot my OMD-EM5. So wouldnt that seem to indicate that the Olympus is in fact one stop WORSE than my xe-1. Im not super technical so I could definitely be wrong but from what I see it sure looks like my fuji is much better in low light.
     
  6. Ray Sachs

    Ray Sachs FujiXspot Veteran

    485
    Feb 1, 2013
    Near Philadephila
    Well, if you're just comparing 3200 to 3200 without taking the exposure into account, yeah. But if the XE1 needs to expose a full stop more at 3200 to get the same shot as the OMD at 3200 (ie, at twice as slow a shutter speed with equivalent aperture), then what you should be comparing is the XE1 at 6400 to the OMD at 3200. At which point the OMD file looks at least as good as the comparable XE1 file and there's no actual advantage to the XE1. I first started questioning this when I was finding that despite the X-Pro looking better at head to head 3200 or 6400 shots than the OMD, I found myself getting as many low light keepers with the OMD as the X-Pro, given similar focal length lenses. And I couldn't understand why until I started doing these back to back tests and finding that the ISO's weren't really equal. And, in fact, the cameras are actually pretty damn close in low light capability despite what seemed to be an advantage for the Fuji.

    -Ray
     
  7. zapatista

    zapatista FujiXspot Regular

    130
    Feb 6, 2013
    Denver
    Mike
    The stuff I've read is about the same and testing with a Canon EOS M and XE-1 show near same shutter speed with EOS M ISO@ 3200 and the XE-1 @ ISO 6400...both using kit lens with the same aperture. Then again ISO 6400 still looks better on the Fuji than the Canon @ 3200.
     
  8. drewbot

    drewbot FujiXspot Regular

    138
    Feb 1, 2013
    Toronto
    There was a huge flame war going on at DPR regarding the X100s' studio samples vs. the typical competitors.

    I don't know if you read it all, but the general consensus was that at high ISOs, the X-Trans APS-C sensors (ie. in the X-Pro1, X-E1, and X100s) required slower shutter speeds at the same "nominal" ISO ratings. I believe the extra exposure time required equated to around 1/3 to 1/2 of a stop.
     
  9. Gary

    Gary FujiXspot Top Veteran

    698
    Feb 15, 2013
    SoCal
    Gary
    It also makes a difference if you use a handheld meter.
     
  10. Ray Sachs

    Ray Sachs FujiXspot Veteran

    485
    Feb 1, 2013
    Near Philadephila
    A third of a stop I could easily write off to slightly different metering or exposure - some cameras I routinely dial in a negative third of exposure comp, some I leave on neutral. But I'm finding a round a stop with the X-Pro and consistently more with the X100s.

    -Ray
     
  11. Gary

    Gary FujiXspot Top Veteran

    698
    Feb 15, 2013
    SoCal
    Gary
    I've just preformed some absolutely and completely unscientific measurements. But, my last measurement, being in a shaded patio reading off gray concrete is as follows:

    Everybody was at 1/250 and ISO 400

    OM-D/A = f/3.5
    OM-D/B = f/3.5
    1DsMKII = f/3.5
    X-Pro1 = f/2.4
    Minolta IV (incident) = f/2.8

    That was generally about par for the other tests. So yeah, the X's seem to under report.

    Gary
     
  12. Ray Sachs

    Ray Sachs FujiXspot Veteran

    485
    Feb 1, 2013
    Near Philadephila
    And also about a full stop relative to the OMD... Interesting. I wonder how the DPR folks were getting 1/3 to 1/2?

    -Ray
     
  13. WT21

    WT21 FujiXspot Regular

    166
    Feb 1, 2013
    Hmmmm.... I see these "mis-stated" ISO claims a lot on DPR, and learned to ignore them. They often come down to 1/3 of a stop, and there's so much passion on either side about companies being "dishonest."

    One full stop is pretty significant, though...
     
  14. jloden

    jloden FujiXspot Top Veteran

    708
    Mar 9, 2013
    Hunterdon County, NJ
    Jay
    Interesting... that'd explain why Fujis seem to have such good high ISO performance even when compared against FF sensors. If you are throwing the results by a stop of exposure or thereabouts it'd certainly skew the results. (EDIT: just to be clear, I personally doubt this is malicious or diabolical on Fuji's part and more likely comes down to different technology/implementation)

    To me the important question would be how does this translate to real world use; i.e. after choosing an appropriate exposure and post-processing, how do the Fuji files hold up against other cameras' output for noise and overall quality.
     
  15. Gary

    Gary FujiXspot Top Veteran

    698
    Feb 15, 2013
    SoCal
    Gary
    While I agree that it may not be malicious, I do think that Fuji knows how to properly calibrate a light meter and how to set up the software to read light and report said light measurements to reflect world-wide conventions and calibrations.

    I haven't a clue why Fuji consistently reports approximately a stop- under Canon and Olympus ... or the need for them to do so ... but I am curious about the answers. But all-in-all, other than a bit of curiosity ... I really don't give a rats ... it is what it is. (But then again, the camera is still new to me, we'll see what I say after some low light shooting.)

    Gary
     
  16. jloden

    jloden FujiXspot Top Veteran

    708
    Mar 9, 2013
    Hunterdon County, NJ
    Jay
    Gary - agreed on both counts. I'm not accusing them of a conspiracy to inflate ISO performance (yet :biggrin:) but I am interested in how it translates to real world use since I do shoot a lot of indoor and low light stuff.
     
  17. Gary

    Gary FujiXspot Top Veteran

    698
    Feb 15, 2013
    SoCal
    Gary
    One more observation ... it's been months since I've used my FF cameras. Man, was I surprised how about the weight of the ID with the 70-200. It is a monster ... it felt like tank, in a good way. I so do appreciate the OM-D.

    Gary
     
  18. Armanius

    Armanius FujiXspot Top Veteran

    691
    Feb 1, 2013
    Texas
    Muttley
    Ray, I also got faster shutter speeds on the Nikon A vs the X100S while shooting the same subject under the same lighting at the same ISO. The X100S' images also appeared slightly underexposed compared to the Nikon A.
     
  19. Armanius

    Armanius FujiXspot Top Veteran

    691
    Feb 1, 2013
    Texas
    Muttley
    You will just have to use higher ISO than other cameras to achieve a given shutter speed in the Fuji's.