spraynpray said:
Q's - Do I gather there is more exposure data in the file which removes to some extent the need to get the exposure exact (say within 1-2 stops) as errors can be corrected in PP?
Are there any other advantages to shooting in raw?
Following the advice above I re-installed the ViewNX software that came with the camera so at least I can now see the pics I shot at Avranche in March. The pics do seem to look 'nicer' in raw or is that my imagination?
Can anybody here recommend a very good book about modern digital photography? I guess the published date would have to be later than 2008 to qualify as useful. I badly need to smarten up on most aspects of PP.
Hope I am not hijacking this thread.... :-)
As-You're right that you have some extra exposure latitude in raw. Think of it as being able to change the ISO in post-processing, though. That's not technically true, but it is practically true. What this means is that you'll get extra noise by boosting exposure in post (and you'll get less noise when you decrease exposure in post! more on this later). It's still important to get exposure as close as you can. Optimal exposure changes for raw compared with jpg, though, as you'll want to live on the edge of overexposure where your highlights are -almost- blown (they will look blown in the histogram). You have to experiment and find how much you can overexpose and still save by decreasing exposure in post, and that can depend on not just your camera but also the software you're using. With my D90 and lightroom, I can overexpose by at least 2/3 a stop keep highlight detail. If you want to know why you can still get detail in an improperly exposed raw file that you can't from a jpeg, it's because converting from raw to jpeg throws away a lot of information even before(!) the jpeg compression happens. Most of the information thrown away is shadow detail and highlights, and you don't notice it's gone until you need to make major changes to the image. Still want to know more? http://www.adobe.com/digitalimag/pdfs/linear_gamma.pdf
The other advantage I can think of is that raw is the most compact way to store all the information that the sensor captures—because it stores only one color channel per pixel, it's automatically 3 times more efficient than a tif file with the same information.
It may be your imagination, but it's possible you saw a difference depending on your in-camera jpeg compression settings. The raw file has no jpeg compression artifacts (blocking) because it's never been compressed. You will be able to tell a difference if you ever have to change the white balance or exposure more than minor tweaking. Raw will look like it was just taken that way, and the jpeg will have obvious problems (posterization, highlight clipping, extra noise).
Here's Thom Hogan's raw spiel:
http://www.bythom.com/qadraw.htm
As to books about post-processing, I think you first need to find something you like because there are a lot of program-specific tricks. Lightroom and Aperture are my favorites (and I use LR because I'm on a PC). Lots of people like Capture NX. You can download free trial versions and see what works for you.
