DxOMark's measured ISOs vs. manufacturer ISOs

Started Mar 13, 2013 | Discussions thread
Martin.au
Martin.au Forum Pro • Posts: 13,276
Re: DxOMark's measured ISOs vs. manufacturer ISOs

olliess wrote:

texinwien wrote:

olliess wrote:

...From the EXIF data it looks as if both shots were taken with the same 50 mm Olympus lens at f/6.3, but the OM-D shot was exposed at 1/800 while the G3 shot was exposed at 1/1300, which is about +2/3 stops more exposure for the OM-D. This would agree with the subjective differences in brightness (and suggest that you would need to dial in +2/3 stop on the G3 to make the shutter speeds match). But what good is this as a "comparison" of images at fixed ISO, e.g., 3200?

Although you would think that to be the case, DPReview has addressed this in great detail and with absolute certainty - the EXIFs on these shots cannot be used to determine relative exposure levels, due to DPReview's testing regime.

So what can we determine from this comparison, if anything?

I find it to be a pretty good way to look at image quality of each camera. There may be some minor differences (and the G3 to OM-D may be an example) due to different exposures, but generally the results I see on DPR, match the results I see elsewhere, where the are shot with similar exposures.

As for the difference in shutter speed on the test scene, If the brightness decreases, you need more exposure to compensate. This is as expected and the complaints about the OM-D having a longer exposure are only relevant if you can guarantee the scene had the same lighting each time. This can't be done, so the complaints are without merit.

 Martin.au's gear list:Martin.au's gear list
Olympus OM-D E-M5 Olympus E-M1 II Olympus M.Zuiko Digital ED 9-18mm F4.0-5.6 Panasonic Lumix G Fisheye 8mm F3.5 Olympus M.Zuiko Digital ED 12-50mm 1:3.5-6.3 EZ +7 more
Post (hide subjects) Posted by
tko
tko
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow