d90 question

I don't think you can get a true RAW Histogram as it always a representation of the Jpeg, and the Jpeg always has some processing applied. To get the truest Histogram you should set your picture style to Neutral imho.

Obviously if you choose to shoot RAW + Jpeg you'd have to decide what your priority was, good Jpegs and inaccurate Histogram or dull Jpegs and more accurate Histogram. :shrug:
 
redhed17 said:
I don't think you can get a true RAW Histogram as it always a representation of the Jpeg, and the Jpeg always has some processing applied. To get the truest Histogram you should set your picture style to Neutral imho.

Obviously if you choose to shoot RAW + Jpeg you'd have to decide what your priority was, good Jpegs and inaccurate Histogram or dull Jpegs and more accurate Histogram. :shrug:
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thank you i will try that.
 
reedwarbler said:
thanks mark i understand that,but i think contrast and saturation settings affects the histogram so how do you no when you are getting a true raw histogram,hope this makes sense?
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If you are shooting Raw with the intention of using 'expose to the right' technique (which you should be ;)) then getting to know how your camera presets affect the histogram and blinkies is an essential part of the process.

My experience is that only the contrast setting makes a significant difference, but that can be quite a lot - like at least a stop, sometimes more. It varies depending on lots of factors, like your camera and individual post processing regime, and the subject of course.

Basically, turning the contrast down to zero will give you a histogram/blinkies that are the closest representation of how much headroom you've got on the Raw before it blows.

Easy to test - camera on tripod and shoot exactly the same scene at the same exposure with different contrast settings. See how the histogram moves. Try the other picture styles etc too, just to see what's what.

Then turn the contrast down to zero and increase the exposure until the highlights are blown for sure. Process those Raws and see which exposure level sits closest to the edge. The histogram that goes with that image file is your reference for what an image on the brink of blitzing looks like.

ETTR is a dangerous game if you're not careful and don't have good knowledge of where the limits lie, but when you get it right, it really delivers wonderful image quality - rich, deep, detailed shadows, and greatly reduced noise :thumbs:
 
thanks for the reply richard ,explains it very well, would you need to go -contrast at any point? or would zero be the starting point.
 
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reedwarbler said:
thanks for the reply richard ,explains it very well, would you need to go -contrast at any point? or would zero be the starting point.
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Sorry, my mistake.

By zero, what I should have said is minimum. So yes, minus!

Ultimately, it doesn't make any difference where your clipping point is according to the histogram, because you are going to make a judgement and push the exposure beyond that.

But it obviously makes the guesswork easier if the histogram is as close as it can be to what's on the Raw. Ideally, when you get to know where you are and are able to read different scenes well, you should be able to crank up the exposure to the point where the important highlight that you want to retain are just only just flashing. Then you can say, I know I've got half a stop above that, or 2/3rds of a stop or whatever, dial that in, and shoot.

That's the theory and the way I try to work it. Then I pull the exposure back a bit just to be safe LOL ;)
 
HoppyUK said:
Sorry, my mistake.

By zero, what I should have said is minimum. So yes, minus!

Ultimately, it doesn't make any difference where your clipping point is according to the histogram, because you are going to make a judgement and push the exposure beyond that.

But it obviously makes the guesswork easier if the histogram is as close as it can be to what's on the Raw. Ideally, when you get to know where you are and are able to read different scenes well, you should be able to crank up the exposure to the point where the important highlight that you want to retain are just only just flashing. Then you can say, I know I've got half a stop above that, or 2/3rds of a stop or whatever, dial that in, and shoot.

That's the theory and the way I try to work it. Then I pull the exposure back a bit just to be safe LOL ;)
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thanks again richard,as a beginner it is a lot to take in,but i think i am understanding it a bit better,raw and exposing to the right seems the way to go,so i thought i might as well try to learn it from the start,rather than rely on the other modes.
 
When using ETTR is there not a massive risk of blowing highlights? I have read about ETTR exposures and understand the principle - but in my experience it is easier to retrieve information from under-exposed areas of the image (albeit with some noise) rather than over-exposes areas of the image where it seems all detail has been lost.
 
futureal33 said:
When using ETTR is there not a massive risk of blowing highlights? I have read about ETTR exposures and understand the principle - but in my experience it is easier to retrieve information from under-exposed areas of the image (albeit with some noise) rather than over-exposes areas of the image where it seems all detail has been lost.
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Yes, there is not only a risk - you will almost certainly blow some highlights for sure. It's not really a recommended technique either for newcomers or the faint hearted. I should have said that.

What you are doing with ETTR is basically saying I don't care if certain highlights blow, and sometimes it's hard to stop that happening anyway - if you have bright reflections in the scene for example. So you make a judgement, and that's both the skill and the danger.

Camera manufacturers tend to play safe, because you usually can pull more detail out of the shadow end in post processing and, as you say, either live with a bit more noise or try and process it away. But there's no denying that, usually, there is more headroom above where the meter will try to set the exposure and there are beneifits in exploiting that, especially in richening the shadow end if that's important. The main upside of ETTR is better tone separation in the shadows with less noise, and a completely noise free mid range - if ultimate quality is your goal.

For example, I just took a snap of the back of the house. A hand metered incident reading was 1/1000sec at f/10, and the camera said more or less the same. Exposure looked fine, and nothing was blowing, big lump in the middle of the histogram. I then lengthened the shutter speed to 1/500sec and the edges of the white window frames started blinking - no problem. I then went to 1/250sec and a bit more of the white frames started flashing, reflecting the bright sun on this glorious morning :)

But nothing else was flashing, and those window frames are white anyway. I don't care if they blow. However, I've just put an extra two stops of exposure in there which is a massive injection of light into the shadows. Taking it one stop further, that's three stops above the meter reading, and a lot of the main image starts to go, so back off from that!

I now know exactly where I am in terms of overall exposure and where the clipping points are in the image, and can make an informed decision. There is no such thing as 'correct' exposure - there is optimum exposure, according to your preference and priorities, camera, processing regime and all sorts of other personal/subjective stuff.
 
has one man,used to say who dares wins! ah ah, it will only cost me a bit of time to try it,nothing to lose by having a go.
 
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