X-T4 JPEG plus RAW exposure problems

[tc46wine]

When using my X-T4, I have noticed that when taking JPEG plus RAW images that the RAW images, when compared to their companion JPEG images, are significantly under exposed, typically by 1 or 2 stops. This was the case on a recent test of over 40 exposures in a variety of inside and outside lighting situations.  Should this be expected?  Have any others noted this result?  Many thanks.

Tom Carroll

Davidson, NC

 

[jerryy]

How are you comparing them?

What you see from jpegs depends entirely on the in-camera jpeg settings you have active when you press the shutter button, while the raw image simply records the sensor data as applied from things like ISO, f-stop, shutter speed etc. (raw data does contain a small jpeg that it uses for in-camera review, or for processing software to use as a starting point — this also uses the jpeg settings). It is quite easy to get different looking jpegs vs raw images right out of the camera.

[tc46wine]

4 hours ago, jerryy said:

How are you comparing them?

What you see from jpegs depends entirely on the in-camera jpeg settings you have active when you press the shutter button, while the raw image simply records the sensor data as applied from things like ISO, f-stop, shutter speed etc. (raw data does contain a small jpeg that it uses for in-camera review, or for processing software to use as a starting point — this also uses the jpeg settings). It is quite easy to get different looking jpegs vs raw images right out of the camera.

 

[tc46wine]

Yes, I've got all that.  I am fully aware of, and agree with, what you're saying.  Unfortunately, I don't think it is relevant in this case. And here's why:  I have done some more tests and the results are these:  It seems clear that the degree of RAW underexposure relative to the JEPG is simply a function of the ISO.  If the ISO is set to 160 the relative underexposure is almost non-existent.  If the ISO is set to 3200, the relative underexposure is from 1 to 1.5 stops.  Also, if the ISO is set to AUTO, the relative underexposure is at least 1 stop or more.  I am using Capture One to process imagery.  Capture One is deeply in bed with Fuji.  As a result, when viewing RAW files, Capture One invokes the film preset used by the camera when making the exposure.  I don't know if Capture One invokes other camera settings when interpreting RAW files.  I haven't yet done those tests.  But it is clear that RAW exposure in Capture One is a direct function of the ISO setting used by camera. 

[jerryy]

Just about every raw convertor nowadays, even Raw Therapee, is using the in-camera created embedded preview / review as the initial start for their process. RT used to start with the linear raw data, but they have changed. If I recall correctly, you can use it to see how the linear — actual raw data appears. There are other apps that you can use to get at that raw, linear data if you wish.

What you are seeing could be from how Capture One wants to present its starting place with its version of how the non-linear tone curves, etc. should look.

Try with other raw convertors — many of them are also ‘well known, even friendly’ with Fujifilm and see if you get similar results.

How are you testing to come up with the differences you perceive? 

[tc46wine]

Many thanks for comments and suggestions.  I'll look into an alternative raw converter.  I would like to get this little perplexment sorted out.  Again, many thinks.  TC

[dward]

I think you are using the HDR setting for your JPEG output, especially since this diminishes at lower ISO values.

HDR usage requires a higher ISO value to be set (640). The camera exposes at a lower value (160) to protect highlights, and the camera’s JPEG process then boosts the lower mid tones and shadows to the “higher” ISO value set (640). Thus you end up with a JPEG with good highlights and shadows. (In this example an HDR 400 setting is modeled).

The RAW file would not be affected by the JPEG process, so it would display in a RAW program as the ISO 160 image (i.e. underexposed by two stops). Still useful as your highlights are protected and you can recover the shadows and mid tones as you like in your RAW processing program.

I haven’t used the HDR setting in a long time so I can’t recall if the JPEG preview  included with the RAW includes the “boost” or not (suspect it does). 

Hope that helps,

Dave

[tc46wine]

Damn ---- I shouldava figured that out.  I had the D RANGE PRIORITY set to WEAK and that created the mismatch between the Jpeg and RAW exposure results that I have been fumbling with.  I set the ISO to 3200 and took six pictures (Jpeg+RAW) with the D RANGE PRIORITY set to WEAK and six pictures with D RANGE PRIORITY set to OFF.  In the first set of six, the RAW images were underexposed by a stop or more as you suggest.  In the second set of six, the exposure of RAW images were virtually identical to that of the Jpeg images.  The slight differences were caused by the camera settings that impact Jpeg images but not RAW.  Problem solved.  Many thanks. I shoulda known!

[dward]

Glad that helped, reading your post I realized I called it HDR vs Dynamic Range which I guess is the correct terminology. Been a while since I’ve used it.

 

[tc46wine]

Again, many thanks.

TC