Shoot digital? Exposure a worry?
Discussion
Seeing as most of the users here are amateurs looking to learn, I came across this and thought it would be appreciated by the PH collective. I know its been useful for me:
www.luminous-landscape.com/tutorials/understanding-series/understanding-histograms.shtml
Thanks
Matt
www.luminous-landscape.com/tutorials/understanding-series/understanding-histograms.shtml
Thanks
Matt
Very good.
I always wandered what that was for in the info menu, now i know.
Let me see if i got this right though. The dark areas are the information.
if they are bunched up to the left of the histogram then it is underexposed and to the right, overexposed?
Looking at the histotgram after taking the shot will tell me roughly how it will turn out.
Right ( 10 mins later) Been reviewing my pics in canon digital file viewer because it has a historgram for every pic. Also one on the camera in info mode.
Am i right in saying that even if you have a tower of black in the middle of the graph then you have a correctly exposed picture? the same way as if tour graph is spread from left to right?
Also that the amount of black ie how tall it is doesn't matter because that is simply the information recorded? So long, of course as it's not bumped up to the left or right.
Although the more left/right the information isthe more under/over - exposed the picture is?
ARGH!!!! gonna look at the examples again. I think i get it though.
i do like the way the person says he barely looks at the shot in the screen, just the graph. I was just doing that....Under,under, under, over, just right!
>> Edited by bilko on Thursday 9th December 00:01
Got any more mister!
>> Edited by bilko on Thursday 9th December 00:02
I always wandered what that was for in the info menu, now i know.
Let me see if i got this right though. The dark areas are the information.
if they are bunched up to the left of the histogram then it is underexposed and to the right, overexposed?
Looking at the histotgram after taking the shot will tell me roughly how it will turn out.
Right ( 10 mins later) Been reviewing my pics in canon digital file viewer because it has a historgram for every pic. Also one on the camera in info mode.
Am i right in saying that even if you have a tower of black in the middle of the graph then you have a correctly exposed picture? the same way as if tour graph is spread from left to right?
Also that the amount of black ie how tall it is doesn't matter because that is simply the information recorded? So long, of course as it's not bumped up to the left or right.
Although the more left/right the information isthe more under/over - exposed the picture is?
ARGH!!!! gonna look at the examples again. I think i get it though.
i do like the way the person says he barely looks at the shot in the screen, just the graph. I was just doing that....Under,under, under, over, just right!
>> Edited by bilko on Thursday 9th December 00:01
Got any more mister!
>> Edited by bilko on Thursday 9th December 00:02
Right think iv'e sussed it!
just had a play with an image that had a peak right in the middle of the hisorgraph in PS.
using Levels in Adjustments i pulled the left and right arrows to each side of the peak in effect leveling out the exposure(information) across the whole of the picture and making it soo much better.
the samish can be done in curves in so far as demonstrating gray or 180 ( or whatever it was ) the middle anyway. By pulling the live so it's horizontal across the curves graph you ar left with a completely grey picture..
SO; i think he means a nice spread of black across the historgraph is good although a peak is acceptable so long as it's in the middle.
???am i right?
Iv'e got a new toy to play with now!
Why when i look at the histograph in info mode on my camera does it flash certain areas at me though?, Is it showing the over/under exposed areas to me? and if so how do i overcome that?, by using metering?. No forget that i think, one think at a time.
Thanks that was interesting.
Ian
just had a play with an image that had a peak right in the middle of the hisorgraph in PS.
using Levels in Adjustments i pulled the left and right arrows to each side of the peak in effect leveling out the exposure(information) across the whole of the picture and making it soo much better.
the samish can be done in curves in so far as demonstrating gray or 180 ( or whatever it was ) the middle anyway. By pulling the live so it's horizontal across the curves graph you ar left with a completely grey picture..
SO; i think he means a nice spread of black across the historgraph is good although a peak is acceptable so long as it's in the middle.
???am i right?
Iv'e got a new toy to play with now!
Why when i look at the histograph in info mode on my camera does it flash certain areas at me though?, Is it showing the over/under exposed areas to me? and if so how do i overcome that?, by using metering?. No forget that i think, one think at a time.
Thanks that was interesting.
Ian
One more thing though., Just looked at the moon and snow covered tree in your mans examples as these demonstrate real life pics with the historgraph at extreme left or right.
How close to the edge is acceptable?, Or am i being anal here?
After all he did say there is no so thing as a good or bad historgraph, they just are.
Waiting for my damn battery to charge up now although i will probably go bed soon. On leave.
Thanks again as this could prove pretty helpfull in me developing my own photography.
ian
, Just looked at the moon and snow covered tree in your mans examples as these demonstrate real life pics with the historgraph at extreme left or right. How close to the edge is acceptable?, Or am i being anal here?
After all he did say there is no so thing as a good or bad historgraph, they just are.
Waiting for my damn battery to charge up now although i will probably go bed soon. On leave.
Thanks again as this could prove pretty helpfull in me developing my own photography.
ian
I find it bizarre that highly complex and advanced digital cameras with space-age metering systems can take a picture and then display a histogram proudly showing that they got it all wrong.
If they are capable of showing this mistake and its exact nature, then they should be capable of getting it right first time!
If they are capable of showing this mistake and its exact nature, then they should be capable of getting it right first time!
But there is no "right" and "wrong" exposure, and I'd hate my camera to decide it knew better than me how the images was supposed to look. We pay all this money for SLR cameras that let us get some control back - there's no way I'd pay even more to have the camera do everything again!! 
The histogram for a photo of a white cat playing in the snow will be way over to the right, whereas a black cat playing in a coal celler will be all the way over to the left, but both images would be correctly exposed.
A camera would want to expose each image as if the cat was medium grey, so if you exposed the image so that the histogram was in the middle, the black cat photo would be over exposed, and the white cat one underexposed.
The histogram for a photo of a white cat playing in the snow will be way over to the right, whereas a black cat playing in a coal celler will be all the way over to the left, but both images would be correctly exposed.
A camera would want to expose each image as if the cat was medium grey, so if you exposed the image so that the histogram was in the middle, the black cat photo would be over exposed, and the white cat one underexposed.
ehasler said:
A camera would want to expose each image as if the cat was medium grey, so if you exposed the image so that the histogram was in the middle, the black cat photo would be over exposed, and the white cat one underexposed.
I agree. The best judge of exposure is the Mark 1 Eyeball, for that is how the picture is really seen. Correct highlights, correct shadows - what more do you need?
To take the black cat scenario, you could spend ages re-taking it until the histogram was 'correct', then look at the image and see that it was totally wrong.
Histograms 0, eyeball 1.
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