Honestly? Its a difficult subject, because it depends very much on the way you are used to work with pics.
Usually people from OS that talk about photography use the tools on very few fotos or on graphics... The OS tools are maybe enough for that purposes, but not good enough, when we talk about huge amounts of photos!
(I am refering for example to the new gimp exportdialogue disaster)
1) I use usually Canon DPP within wine (in Virtualbox, it doesn't open the photos, don't know why... quite annoying!)
DPP is fast, uses multicore, has good presets and picstyles and it is easy to apply changes to a bunch of photos!
It has lens correction and lots of tools. Its free for canon users.
2) I think rawtherapee is a good tool. My Second choice!
One senses, that there is still development and the general options are very good.
ct tested rawconverteres a while a go, and rwa therapee was best (!) in recovering overexposed (white) parts in photos.
What I really do not like are the presets... they are too neutral and not very useful,
If I work on a studioshooting with 600 photos its not a problem. Find settings for key-pictures and then apply to every photo.
Latly it was very unstable and crashing a lot here! But I had this with some more software too (iceweasel, gimp - so it could nbe another problem)
If the light settings differ a lot, like in outside photography, you need a lot of klicking and adjusting!
3) rawstudio and darktable seem to work... but are (for me!) less intuitive and have fewer options. Darktable may become better in the next time. I see a lot of good development there...
There have been comercial tools, like Bibble for Linux... PPl told me, that it was very good. The successor is Corel AfterShot Pro. I don't know if it is still available for linux. The name Corel is maybe not the best in graphical environments...
Devil: If you need only some photos, you can try with gimp and dcraw.
Even Digikam has raw options! If you have few photos that should be enough... But when I remember correctly, Holger said recently, that there are actual problems with digikam and its tools)
At last I like to add that Lightroom from adobe is now very cheap and for professionals the best tool around! Lots of features like Lens Correction, selective picture manipulatian, slideshow movies and many more. It should cost under 100Euro, if I remember correctly.
If you need more infos, send me an email or here in the forum
