So... I finally come to a decision to go with the OM-D... Is there any big hand users out there?

Started Mar 13, 2013 | Questions thread
texinwien Veteran Member • Posts: 3,326
Re: A very interesting answer

texinwien wrote:

scott_mcleod wrote:

My only "lingering misconception" is that if you need to set ISO 200 on an E-M5 to get the same exposure as you would from (say) a D800 at ISO 100 with aperture and shutter speed held constant (I am using for this example the RAW files from IR, who used f/8 and 1/20s on these respective cameras), isn't "ISO performance" a rather worthless metric if taken at face value?

My sincere apologies here, Scott - I'm not trying to inundate you with responses, but I would like to follow up on this part of your reply.

Are you implying that one would "need to set ISO 200 on an E-M5 to get the same exposure as you would from (say) a D800 at ISO 100"?

I had a look at the D800 and E-M5 RAWs at IR and didn't see any evidence in them that suggests one would, indeed, need to do that. Perhaps you could clarify your intention here or else offer links to the specific files you have in mind that would illustrate the need to do this.



I looked closer and found the images you were referring to, I believe. The short story - IR's reference lens for Nikons (a Sigma 70mm f2.8) has a known problem at f8 in combination with several Nikon bodies, including the D800. That lens, when set to f8 on the D800 (as well as a few other Nikons) is open wider than the EXIF shows, meaning that actual exposure is significantly understated in these circumstances. This is mentioned with some degree of detail in IR's D800 review - scroll to the 'sensor' section, to the second paragraph under the bank of 4 pictures.

This confounding factor is discussed in more detail in this DPReview discussion.

Furthermore, if we compare IR studio shots taken at other f-numbers, we see the apparent discrepancy all but disappear.

In short, the EXIFs are lying to us, and one WOULD NOT "need to set ISO 200 on an E-M5 to get the same exposure as you would from (say) a D800 at ISO 100".

I hope this clears up your last remaining misconception to your satisfaction. Please let me know if you have any other questions!


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Panasonic Lumix DMC-GM5 Olympus E-M5 II Olympus 12-40mm F2.8 OnePlus One Canon EOS 300D +20 more
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