I recently purchased the Nikon D200! Love it so far! It has an RGB histogram feature. I need to know what the advantages are to using it. If, for instance, the green is clipped but the others are not, what does that mean? What do I do to adjust the photo? Thanks for any input!
Alice, I'm coming at this from a Canon point of view, so I hope everything is similar with Nikon. The short answer to your question is "it depends". Remember, the histogram you see on the camera back is a 'processed' image. That means whatever jpeg parameters you have set in the camera get applied to the image and resulting histogram. If your contrast or saturation is set high, your resulting histogram may show evidence of clipping (in one or more channels) even though the RAW file can be recovered during post processing. On my Canon 1D MkIIN, I intentionally have the contrast set to -1 to give me a histogram on the camera more representative of what I can expect in post processing. My saturation is set at the default 0 (normal).
Ultimately you want to produce a histogram that isn't clipped in any channel. If you've set your in-camera parameters correctly and still get a clipped channel, then the next step is to use exposure compensation to correct it - minus exposure comp to correct over exposed clipping, positive exposure comp to correct under exposed clipping. Typically, if only one channel is clipped, a third stop adjustment in exposure compensation will correct it.
Thanks Bob. I still wonder what the advantage is to the different colors. I understand just the regular histogram...but why do I need to red vs green vs blue?
A composite histogram can look good with one channel clipped. Seeing all channels gives you the most information available about your exposure. Here's an example where it's come in real handy for me - a bright red bird, like a cardinal or scarlet tanager in open sunlight. The red channel is easy to clip in this situation, especially if you only look at the composite histogram.
But, it's not for everyone. Sometimes TMI (too much information) can get in the way of getting your photos taken. Only you can decide if it's right for you. I know plenty of good photographers who don't bother with the RGB histogram, at least until they get the image into a RAW converter.
Alice, on my Nikon D2x the contrast control that Bob mentioned is called Tone Compensation and is in the shooting menu. By default it is set to Auto so that logic in the computer's firmware applies a curve appropriate for the image. I leave it there, but could set it to Less Contrast.
Shooting landscapes I find that checking the RGB histogram keeps me from blowing out the red channel on sunsets. A blown red channel will result in a sunset more yellow than red/orange. Have fun with your new camera. I look forward to seeing the results.
Alice,
I also shoot with a D200. In my experience, I've found a two pronged approach to work best:
1) First, I use the "highlight" screen on the LCD to make sure the top end is not blown out.
To me this is critical as I aim to land the bars of the histogram as far right as possible.
(I read somewhere that more data is captured at the high end... don't ask me where.).
2) After exposing correctly for highlights, I turn to the RGB histogram. Here you can check
the relative position of shadows in the three channels. In other words, you already know
that your highlights are good (not blown out) . Now look to see if your shadows are
"acceptable". Are they stacked to far to the left? If so, you're probably underexposed and
need to open up.
I hope this helps you. It works for me. Your website is nice... you must be doing something right!!! Regards, Todd
Discussion
6 repliesUltimately you want to produce a histogram that isn't clipped in any channel. If you've set your in-camera parameters correctly and still get a clipped channel, then the next step is to use exposure compensation to correct it - minus exposure comp to correct over exposed clipping, positive exposure comp to correct under exposed clipping. Typically, if only one channel is clipped, a third stop adjustment in exposure compensation will correct it.
I hope this helps and makes sense. Let us know.
And congrats on the new camera!
But, it's not for everyone. Sometimes TMI (too much information) can get in the way of getting your photos taken. Only you can decide if it's right for you. I know plenty of good photographers who don't bother with the RGB histogram, at least until they get the image into a RAW converter.
Shooting landscapes I find that checking the RGB histogram keeps me from blowing out the red channel on sunsets. A blown red channel will result in a sunset more yellow than red/orange. Have fun with your new camera. I look forward to seeing the results.
I also shoot with a D200. In my experience, I've found a two pronged approach to work best:
1) First, I use the "highlight" screen on the LCD to make sure the top end is not blown out.
To me this is critical as I aim to land the bars of the histogram as far right as possible.
(I read somewhere that more data is captured at the high end... don't ask me where.).
2) After exposing correctly for highlights, I turn to the RGB histogram. Here you can check
the relative position of shadows in the three channels. In other words, you already know
that your highlights are good (not blown out) . Now look to see if your shadows are
"acceptable". Are they stacked to far to the left? If so, you're probably underexposed and
need to open up.
I hope this helps you. It works for me. Your website is nice... you must be doing something right!!! Regards, Todd