E-M5 at ISO=200 - Plain as day if you have a look.

Started Jul 18, 2012 | Discussions thread
Steen Bay
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Re: E-M5 at ISO=200 - Plain as day if you have a look.
In reply to Detail Man, Jul 19, 2012

Detail Man wrote:

Steen Bay wrote:

Detail Man wrote:

LTZ470 ,

Here is the way that I see it. The prospect of recording RAWs and JPGs with the E-M5 is not a propostion of "either", it is a matter of "or", as in - one must choose whether they want to record in JPG format, OR in RAW format. This is because of the way that Oly chose to design the E-M5 ...

The RAW-level Blue channel is a linear (derived from the sRGB non-linearity) ratio of around 1.913 EV lower than the JPG-level Blue channel. That is the way that Olympus has chosen to design this camera. As gollywop has aptly shown on this thread, fiddling around with in-camera JPG settings is very likely to not significantly alter the fact that (at least, in shooting situations such as your air-show shots) the recorded RAW signal-level is around 2 EV below the recorded JPG signal-level.

The other E-M5 ORF RAW you emailed to me is almost exactly the same story (2 EV of difference).

As was mentioned here, to optimize the RAW image-file, you would have needed to increase Exposure (the Shutter Time divided by the square of the F-Number at the given light-level) by around 2 EV (which would have been Exposure Compensation of 2 Ev greater than your -1/3 EV, or +1.66 EV). As you can imagine, the JPG would have been rendered unusable had you done that (due to JPG color-channel clipping). Thus, you would need to choose one only - JPG OR RAW

As a result of this situation, one cannot expect to be able to say "I prefer one or the other". Each recording (JPG or RAW) require vastly different Exposure settings. Note that ISO Gain is not an element of Exposure. There is no good reason (at all) to have used any ISO Gain higher than base ISO=200 in the case of those shots. Have fun with your E-M5 JPGs. Simplicity has it's virtues (or at least conveniences). JPGs made (in RAW processing) from E-M5 RAWs with +2 EV higher Exposure would have a 1 EV higher Signal/Noise Ratio due to lower Photon Shot Noise levels relative to max. signal levels. But, according to some, the image-sensor is so good that we don't see yellow blotchy noise in blue sky areas. Maybe a printer will smudge it all together and make it go away real pretty.

What if looking at e.g. DPR's and IR's studio test shots (RAW + ooc JPEG). Are the E-M5 RAWs significantly more 'underexposed' than the RAW files from other cameras?

We all await the result of the analysis that you've assigned to yourself as soon as you post it here.

I'm not the one performing such analysis, you are. It was a good suggestion to use some of the many controlled testshots that are available, but whether you want to do it, that's up to you of course.

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