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[Sony A7R5]

Ok, this is more about confirming what I think is true.

I know that the metering mode doesn't make a difference to the RAW files when I'm shooting in manual because I'm setting ISO, Shutter Speed and Aperture myself.

However, when I've done some testing it does seem to affect the JPEG preview image that appears on the screen, and the histogram derived from that image.

Since I might make changes to my manual settings based on that preview image, would it be correct to say that while the metering mode does not affect the RAW files directly, different modes could lead me to use different manual settings which would affect the RAW image?

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  • \$\begingroup\$ At the very least, please include the camera you're using. \$\endgroup\$
    – Philip Kendall
    Aug 25, 2023 at 20:58
  • \$\begingroup\$ When you do your "testing", do you leave aperture, exposure time, and ISO the same? Or do you modify them based on the reading of the meter in each of the various modes? \$\endgroup\$
    – Michael C
    Aug 28, 2023 at 4:09

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...would it be correct to say that while the metering mode does not affect the RAW files directly, different modes could lead me to use different manual settings which would affect the RAW image?

Yes, if you are relying solely on your meter reading to tell you how to set ISO, aperture, and shutter speed, just as the camera's auto-exposure modes do.

Having your metering mode set to Multi vs. Center vs. Spot can easily change the metering reading, and if you set consistently based upon the meter reading, that would also end up changing your exposure settings.

The metering mode settings are for you to tell the auto-exposure system whether you want the metering to account for the whole frame (Multi), or to bias towards the center of the frame readings (Center) or to only use a small area you define (Spot). If you're using one of the latter two settings, and you're asking the camera to meter an area of the frame that's darker/lighter than the overall average brightness of the scene across the whole frame, the metering will not read the same as in Multi.

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  • \$\begingroup\$ I'm commenting in support of this answer, that someone felt the need to downvote. This is the exact correct answer. Literally anything that may influence one's choice of exposure setting, even in full manual mode, will indirectly affect what pixels are written to the raw file, in exactly the same way as it would affect what would have been written to film. But, normally, those should have the exact same apparent effect on the jpeg and the viewfinder preview. Perceived differences in post may be caused by your software's raw processing algorithms. \$\endgroup\$ Aug 26, 2023 at 13:29
  • \$\begingroup\$ @GrantRobertson, except that the OP stated setting the exposure based on the preview/review on camera; not the metering reading... \$\endgroup\$ Aug 27, 2023 at 13:33
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    \$\begingroup\$ @StevenKersting, actually, I don't think they made it explicit that they were comparing RAW/JPEG from the same shot with the same settings. Testing methodology is the most-likely culprit for most folks. \$\endgroup\$
    – inkista
    Aug 28, 2023 at 22:09
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The short answer is yes, your settings absolutely affect the raw image file that is saved.

The long answer is that speed, aperture, and ISO don't only affect image brightness and contrast. Speed also affects motion blur. Aperture affects depth of field. And while ISO is more closely related to brightness, and while it may seem this can be adjusted freely while editing, it also affects how the sensor's captured data is read, and can affect how much noise ends up saved.

Let's say you're taking a portrait of a person against a very bright or white background. If your metering mode is set to most of the frame, you could be deceived into adjusting your settings because the camera is saying the frame is too bright, resulting in an image where the subject's face is darkened. You could end up losing detail in the face. But if you change your metering mode to select part of the frame, like the center, your exposure compensation guide numbers will be different, and you may change your settings accordingly, resulting with better exposed facial contrast and detail - though your bright background may be blown out.

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However, when I've done some testing it does seem to affect the JPEG preview image that appears on the screen, and the histogram derived from that image.

There is absolutely no reason the metering mode alone should affect the jpeg review/preview image with fully manual settings any more than it should affect the raw file. The metering mode in itself does nothing...

The only way metering mode alone could affect the jpeg differently than the raw file is if it caused something like the auto D-range function to kick in. But all of those types of functions are disabled in full manual mode.

The answer must be that your testing methodology was flawed; and therefore the conclusion is also flawed.

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To answer your question about the differences between the jpeg and raw files:

The raw file does not contain the exact same data as the jpeg. We know that. The raw file, out of the camera, is not actually viewable without additional processing. Your camera did it's own processing to generate the jpeg. Your software did it's own processing on the raw file to give you something to look at. These two, entirely separate, algorithms rarely provide the exact same results. Even if the camera embedded a profile into the raw file in an attempt to tell your software the default settings to use for the raw file processing, the two algorithms are still going to be different.

RawTherapee claims to be able to analyze the jpeg (either the embedded jpeg or a separate jpeg file) to make the raw file look as close to the way the jpeg looks, as a starting point. But they acknowledge that it will still never be perfect.

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