Understanding Histograms
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HoppyUK
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That's a good link
To get the most out of the histogram, switch on blinkies - the highlight over exposure warning, in the menus. Brilliant invention.
Also be aware that the histogram is generated off the JPEG and so is affected by picture styles. In particular, the contrast setting stretches and moves it quite a lot, like a stop or more. If you want to maximise the exposure and squeeze every last drop of data on to the sensor (which is a good plan - 'expose to the right' technique) then turn down the contrast setting. You really need to work with Raw for that though.
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sep9001
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HoppyUK said:That's a good link
To get the most out of the histogram, switch on blinkies - the highlight over exposure warning, in the menus. Brilliant invention.
Also be aware that the histogram is generated off the JPEG and so is affected by picture styles. In particular, the contrast setting stretches and moves it quite a lot, like a stop or more. If you want to maximise the exposure and squeeze every last drop of data on to the sensor (which is a good plan - 'expose to the right' technique) then turn down the contrast setting. You really need to work with Raw for that though.
Thanks. I think I have the blinking bit already on.
fatboy1000
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This is a really really useful link, and should be automatic reading for anyone (like me) looking to understand histograms. Coupled with http://www.luminous-landscape.com/tutorials/expose-right.shtml these are the two most useful tutorials I've read.
Thanks for linking!
yannick_reveur
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it basically gives you a good indication of the light in your picture
more spikes on the left gives and you took a dark picture. too much spikes on the right and it is probably over exposed.
a good balance is to have dark and light, but it there is no spike then the picture will be probably too flat ( taking grey sky for exemple)
more spikes on the left gives and you took a dark picture. too much spikes on the right and it is probably over exposed.
a good balance is to have dark and light, but it there is no spike then the picture will be probably too flat ( taking grey sky for exemple)
HoppyUK
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Erm no.
You can't generalise like that. It depends entirely on the subject, and how you want it exposed.
brubaker
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That's a good link
... (which is a good plan - 'expose to the right' technique) then turn down the contrast setting. You really need to work with Raw for that though.
Hi Richard, I wonder if you could expand upon this?
Thanks.
HoppyUK
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Yes, Expose To The Right (of the histogram) technique is the way to get optimum exposure with digital. Link to Luminous Landscape here http://www.luminous-landscape.com/tutorials/expose-right.shtml
By carefully over exposing with Raw, ie pushing the histogram as far to the right as you dare, you maximise signal to noise ratio and drag the hidden shadows into the light so they get some tone separation, minimal noise, and a deep richness when you knock the tonal values back down to where they should be in post processing. With most subjects, compared to a normal meter reading you can add at least a stop with no worries, usually two, sometimes as much as three with a benign subject.
You need to enable blinkies (highlight over exposure warning, in the menu, should be permanently on anyway
) and check them in conjunction with the histogram because you almost always need to let selected (and unimportant) highlights blow using this technique.Since the histogram and blinkies are generated off the JPEG which is always tagged to the Raw file, they are both subject to picture styles and other camera pre-sets. You need to know exactly what they're telling you, and it's the contrast setting in particular that stretches the histogram and alters the point at which the blinkies start to flash by a stop or more.
ETTR is a great technique but since you're living right on the edge, and sometimes over it, you need to be know exactly where you stand with your particular camera and post processing regime.
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HoppyUK said:
That's a great link, and I know that I often forget to check the histogram after a specific shot, so as from today I am going to make it a priority to do so after every shot until I make it a habit.
Steve
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fatboy1000
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I was out yesterday evening and this morning playing with my new lens, and was consciously checking the histogram and blinkies after every shot. It very quickly became a bit of a habit and I'm not quite sure how I managed to use the manual setting before! Looking forward to getting them on the computer and seeing how "exposing to the right" worked out.
brubaker
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Yes, Expose To The Right (of the histogram) technique is the way to get optimum exposure with digital. Link to Luminous Landscape here http://www.luminous-landscape.com/tutorials/expose-right.shtml
By carefully over exposing with Raw, ie pushing the histogram as far to the right as you dare, you maximise signal to noise ratio and drag the hidden shadows into the light so they get some tone separation, minimal noise, and a deep richness when you knock the tonal values back down to where they should be in post processing. With most subjects, compared to a normal meter reading you can add at least a stop with no worries, usually two, sometimes as much as three with a benign subject.
You need to enable blinkies (highlight over exposure warning, in the menu, should be permanently on anyway
Since the histogram and blinkies are generated off the JPEG which is always tagged to the Raw file, they are both subject to picture styles and other camera pre-sets. You need to know exactly what they're telling you, and it's the contrast setting in particular that stretches the histogram and alters the point at which the blinkies start to flash by a stop or more.
ETTR is a great technique but since you're living right on the edge, and sometimes over it, you need to be know exactly where you stand with your particular camera and post processing regime.
Richard, Many Thanks.
It illustrates I have quite a lot to learn about understanding histograms. The link was most informative too, now to try and apply that theory to practice.
HoppyUK
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You're welcome
All I would say is, with ETTR technique don't get too worried about the whole of the histogram - just get to know the right hand end, how that relates to blinkies with your picture styles/contrast settings, and how much headroom you've got in post processing.
ETTR technique is basically a version of 'expose for the highlights and let the shadows take care of them themselves' as you would with slide film - but with a twist. The difference is, you can decide which highlights are important and must be retained, and decide which ones to allow to blow to white. You're over exposing, but in a very controlled way and then of course you restore everything to its correct tonal value in post processing (which you can't with film) but with the benefits of the additional exposure lifting the shadows and reducing noise.
The downside of ETTR is it means you are effectively exposing at a much lower ISO than normal, so you can run into trouble with long shutter speeds that way.