#16. "RE: Effective Use of Histogram" In response to In response to 15 Mon 14-Feb-11 06:09 PM by elec164
>Thanks for the comment Pete. Could you explain what you feel >is the MOST effective use of the histogram, and also other >ways the histogram might be used to help provide the >"perfect" pic?
When shooting NEF’s the histogram is derived from the embedded JPEG not the raw data. As such one needs to be mindful of the Picture control settings. If you are shooting JPEG’s with the aim of getting it correct in camera through the use of Picture Controls without the consideration of PP later, then you can use the histogram to your advantage. But in doing so you could very well be reducing the DNR and possibly underexposing your capture if you are dialing in –EV to prevent blinkies or a right side wall in the histogram. Reason being is that those blinkies could be the result of the Picture Control settings (boosted contrast, brightness, saturation or sharpening) and not actual sensel site saturation. If your goal is to maximize the DNR an SNR of the sensor by shooting NEF’s and using the histogram to employ ETTR, then you should set sharpening to minimal or zero and the other Picture Controls to neutral to provide a flat response.
Actually there is whole genre of people who wish to squeeze the absolute most their sensor is capable of who take this concept to an extreme. They set a custom WB known as a Uni-WB (I believe it stands for Unity Gain WB). By doing so you can get a better read on if you are getting sensor site saturation and need to dial in negative EV to prevent lost detail. The down side is that the immediate image is unusable until you process it later in an editor. And I believe I read a article by Thom Hogan where he mentioned that when he loaded a Uni-WB into the D7000 he discovered that it has a tendency to under, not over-expose like many believe (although I have yet to relocate that article).
It comes down to preference in shooting style and I feel either way is valid if it gets the results you are looking for. But in Ann’s case (the OP), she was having her images rejected by her stock agency for excessive noise (even base ISO images). She made a thread about this issue soon after she started using her D7000. So in her case, for whatever reason, the camera was slightly underexposing but the PP (either in camera or external editor) was remapping the data to make it brighter, with the side effect of increasing the appearance of noise. So again, if you have the Picture Controls set to boost saturation and contrast and dial up the sharpening to achieve a usable image straight from the camera, then you need to be mindful of how that may affect what is being represented by the histogram.
At least I hope this explanation is clear and precise enough.