Canon CR3 format

[ameerat42]

I just know you mean the Canon EOS 90D (don't you?)

What Nardes said about doing the conversion is right - [unless you've got something else that'll do it] use DPP
(Light, I think) that comes with the camera. I know nothing about the other two image editing programs you
mentioned, but they should be fairly capable of working on tiffs and jpegs. There are a few other freebies that
can get you by...

Don't be surprised that TIFFs can be that large. It is quite normal - which leads to talking about IQ loss and compression.
This camera has a C-raw recording mode that I can't see the use of since it is stated that it can attenuate shadow detail.
So, use the NORMAL raw file recording. (You didn't mention what their typical size is.)

And the point is, you can use two different tiff compressions, called LZW and ZIP, resp. Both are lossless. They are good for
file sizes on disk, where space can be a problem. Read here about 'em.

Two free image processors I use are Faststone Image Viewer (FIV) (and editor in fact), and an old version of Adobe Photoshop,
version CS2, available here.

Another one to mention is GIMP (q.v. - and not "The GIMP", unless it becomes your pet.) I don't use it for my own reasons,
mainly because I think its operation is unnecessarily arcane, but many others swear by it, rather than at it as I do
One obvious advantage is that it is rather up-to-date in features, but my contention is that these are of limited value if you
do not understand the basics of image processing.

FIV is mainly for browsing through the images (much like DPP lets you do) where you're looking at the embedded jpegs of the
CR3 files.

CS2 is for working on TIFFs and jpegs saved from the raw files, although FIV can also do a fair bit of what CS2 does.

When you know one image processing program you learn a lot of ideas that you can transfer across to other such programs.

Finally, to stress an important point made by Nardes: do as much processing as you can on the raw file before you save it
as a TIFF or jpeg, and the corollary: leave your raw files as they are (although changes to them are usually non-destructive).

That's enough for now... Ask if you want any clarification.