Bruce From United States of America, joined May 1999, 5035 posts, RR: 17 Posted (5 years 9 months 3 weeks 2 days 16 hours ago) and read 2150 times:
When you process a canon RAW image you have options for adjusting exposure comp as well as levels, with histograms for each. What is the proper adjustment - do levels first, then compensation? Or the other way? And when you look at the histogram you move the right-side slider (brightness) so that its right at the edge of the histo curve? And how do you know if you even need exposure compensation - can you tell from the histogram?
Bruce Leibowitz - Jackson, MS (KJAN) - Canon 50D/100-400L IS lens
Garry From United Kingdom, joined Feb 2006, 183 posts, RR: 3 Reply 2, posted (5 years 9 months 3 weeks 2 days 15 hours ago) and read 2119 times:
Hi Bruce - these are very good questions.
It's hard to get your head around some of these terms but I'll try to explain. Firstly, it's important to understand that Levels is the distribution of tones in your image from black to white and generally speaking the graph of these tones should fall off at the end points.
If the graph is blocked at the black end, the image is underexposed, you have blocked the shadows. Conversely, if you have a large spike right at the white end, the image is over exposed.
It is by reading the histogram that you would then use your exposure compensation - so if the shadows are blocked add some exposure, you will see as you do this the histogram change. The opposite happens with over exposure.
Always allow yourself some headroom so you can fine tune once you have converted the raw image and move to say Photoshop.
I'd encourage you to make this alot easier for yourself by checking the histogram on the back of your camera, it's a key guide to how you are setting your exposure.