Hello,
Is there any advantage of using FITS format instead of RAW with DSLR (I use Nikon, NEF)?
FITS: Larger files (66%), bayered. But shown in FITS viewer with available histogram and also shown in the summary tab.
RAW: Native format, smaller files.
Any advice?
Thanks!

You nailed it. The FITS format is easier to transfer to other software in the processing chain (such as the viewer), but you may want to process raws in a very specific way. In terms of compression, you should be able to receive gzip-compressed FITS from the driver.

-Eric

Just to make sure. FITS conversion does not alter the data, right? It's as good as RAW?

FITS data is debayered. This therefore is not the original data.

-Eric

Edit: sorry I realize I'm suddenly not so sure about this. There are CFA_* FITS keywords with the Bayer pattern. Thus I'm not sure anymore whether it is debayered or not.

Its for Stellarmate but still applies stellarmate.com/support/ekos/17-support/.../36-fits-viewer.html

It is my understanding from a long time ago (perhaps 2 years so this may have changed) that converting from RAW (both NEF for Nikon and CR2 for Canon) to FITS implies a file conversion which always implies data loss. I think that weighs up against being able to use the FITS viewer. There is a DSLR viewer as well which can display at least the CR2 files (sorry, I only have experience with Canon cameras) but I assume NEF as well since they are supported by libgphoto2 as well. The viewer is more crude than the FITS viewer but it should be able to zoom in and out in it though I never got that to work in VNC using a trackpad. It should work with the middle mouse button though.

My advise: stick to the file formats supported by your camera as much as possible. There is not a data processing software that I know of that doesn't support NEF files so avoid data loss and stick to NEF.

/stepping off the soap box now


Wouter

Yeah... That's what I thought and was actually doing..

Thanks!

Sorry, but conversion doesn’t means always data loss. In fact, when you shot on RAW but store it as FITS, no data is lost. Each pixel read is store as it is without debayering.

In fact when you store it as FITS you have a lot of advantages in post processing. For example, applying darks, bias or flats could be done directly before debayering (at the CFA matrix), so you can easily remove hot pixels in the channel where it appear, without touching nearby pixels, so without introducing color contamination (as it happens when you apply calibration after debayering)

Like I said, my info is quite old. Having said that, I also wrote "There is not a data processing software that I know of that doesn't support NEF files" so the same advantages (applying darks, bias or flats could be done directly before debayering) apply to NEF files as well.