CHDK Fine and Super Fine... test

Started Dec 19, 2010 | Discussions thread
PhilM oz Senior Member • Posts: 1,328
Controlled testing - CHDK 'RAW Develop'

One of the problems with trying to test the difference between in-camera processing settings is the need to take two shots with different settings. It is very difficult to ensure that everything other than the setting you want to alter remains identical.

In the two new images posted CMaxx2 there is a noticeable difference in camera position for example. When comparing the images it is then very difficult to know if any differences are the result of the camera processing or some other factor.

CHDK has a feature that makes this sort of testing a lot more controlled - it's called 'RAW Develop' and you can read the details here:

http://chdk.wikia.com/wiki/CHDK_firmware_usage/AllBest#RAW_Parameters_.3E_RAW_Develop_.28Build_100-15_or_Later.29

Essentially you can take a RAW image and then get the camera to re-process the same image data multiple times with different settings. In this case you can process the same RAW data and create both a fine and super-fine JPEG image. This way you can eliminate all other factors and know you are comparing just the changes due to image settings.

This can also be used to compare changes to the sharpness, saturation and contrast settings and even noise reduction (shoot at high ISO and then process at a lower one).

It's also useful if you want to apply some of the camera effects (e.g. miniature) to an image at a later date or with different settings.

One thing to be careful of is to not use auto ISO and auto WB as these can cause the camera to re-calculate settings that will change the image processing.

So here's a quick example (this isn't meant to prove anything about fine V super-fine, it's just an example of how you can compare them).

Original (somewhat boring) image:

After creating fine and super-fine JPEG images, I generated an image that is the difference between the two:

As you can see the difference is not all that visible

However if I then boost the image levels to bring out the details I get this:

Now you can see that there is a difference; but as I said in my previous post it's details that are not easily seen by us poor humans.

Regards,
Phil.

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