Our Friend The Histogram

[another view]

I have a request: I would love to see a "before and after" representation of the effect of monitoring your histogram. For instance, your snow scene shooting normally, and then shooting with an exposure adjustment based upon the histogram.

I stickied this for you, I assumed you are too humble to do so

Thanks Rick - I'm not worthy!

Actually with the snow scene the first shot was pretty good - this goes back to shooting a lot of slide film before I went to digital. A +1 compensation is pretty much standard for this, so based on this it's where I started and the histogram was where I wanted it. So - I cheated here. In the RAW converter screen, I put in exposure correction just to show where the histogram would go. This is that screen in Photoshop - first is at -1 and second at -2. This histogram is a little different - it shows individual red, green and blue values instead of a "master" that you saw above. But see how the whole thing moves to the left with the underexposure? Looking at it now, I might have used a +1.5 exposure compensation. That might make a little more sense - it was obviously a while ago...

[photophorous]

AV,

Thanks for the excellent explanation. I will definitely start using my histogram now. This has helped my understanding.

I noticed the histogram on my camera is divided into four vertical segments. Do you know if that is meaningful, or is it just there as a point of reference? Seems like you'd want to divide it into segments that correspond with f-stops, so you could just look and quickly tell how much to change your exposure...but, I'm hoping my camera has more than a four stop range.

Paul

[another view]

Thanks Paul, glad to help. I'm really not sure about the vertical lines. It may be close to a one stop difference between a pair of lines, but I doubt it's exact. At high ISO's, images seem to be have a lot more contrast than low ISO (compare 100 or 200 with 1600 in the same light conditions), so maybe they're accurate at low ISO's but not quite at high ISO's... Just thinking and typing...