Updated specs on the EOS 6D

Started Sep 16, 2012 | Discussions thread
Great Bustard
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Re: Exposure.
In reply to qianp2k, Sep 17, 2012

qianp2k wrote:

I don't need and don't want to pull shadow 4-5 stops so it's not that critical to me.

In a correctly exposed shot you would rarely need to lift shadows...

The only reason a "correctly exposed" shot would not require shadow lifting is because the shadows are displayed dark per the tone curve applied to the photo.

Shadows are shadows as your eyes see.

Not even remotely true. There are many scenes where what I "see" is significantly different from the photo the camera records.

Exposure is displayed in histogram. Towards left is under-exposure while towards right is over-exposure.

It's a jpg histogram, unfortunately, instead of a RAW histogram.

...but look at it from the other side. You may wish to recover blown highlights.

This is impossible, by definition. Anything blown is blown. Period. What you can do, as you suggest in the paragraph immediately below, is use a lower exposure (as opposed to "underexpose") to preserve the highlights and then apply the appropriate tone curve to the photo.

Not quite true. You always can recover some details in highlights unless it’s well beyond 18% grey-level.

No. If a pixel is blown, it is blown. A blown pixel can be completely blown (all color channels beyond the saturation capacity of the pixel or pushed outside the bit depth of the capture file by the ISO setting), or partially blown, where one or two color channels are blown but the third is not.

If the camera offers you 4-5 stops cleaner shadows you can underexpose to save the highlights and pull the whole image back to what it should look like, without getting much noise.

As I said above, this is not "underexposure", but rather using a lower exposure to preserve the highlights, in combination with the desired tone curve to render the desired photo.

This is not a free ride but comes with the price of extra noises after lifting shadow. Your lower exposure is the same as under-exposure from the perspective of histogram as most people understand.

That's the whole point of a high DR sensor -- lower read noise means less noise penalty when pushing.

The whole notion of "underexposure" and "overexposure" only have meaning in terms of the visual properties of the final photo. An "underexposed" photo means that a higher exposure would have resulted in a better photo, and an "overexposed" photo means that a lower exposure would have resulted in a better photo.

From the perspective of histogram.

No -- from the perspective of the final photo. I have taken many photos where I intentionally blew much of the scene to have less noise for the portions of the scene that mattered more.

If a lower exposure results in a better photo, then the lower exposure is not "underexposed". This is more than semantics -- it is central to photography, and directly tied to the DR capabilities of the sensor.

That tactic (that exposed on highlights then pull shadows extremely) or extreme shadow pulling doesn’t result better photos as we have seen enough. It usually results to HDR surreal look and more noises in shadow areas. That usually destroys color tonality and accuracy.

Actually, I have seen numerous examples of quite the opposite. In fact, there was a thread posted here with many such outstanding examples of it, but it was pulled. Here's my thread where I asked the OP to repost his pics:

http://forums.dpreview.com/forums/read.asp?forum=1032&message=42251961

Unfortunately, the photographer never saw my thread. The "destruction of color tonality and accuracy" is a result of excessive read noise.

It doesn’t replace the traditional better photography techniques such as using GND filters on highlights and expose on mid-tone if you could.

Well, there's that "if you could" clause that causes problems with any scene where there is motion.

It’s largely the mid-tone determines IQ not shadows nor highlights areas.

Any photo taken at higher than base ISO has more and more of the photo in shadow. That's what the ISO control on the camera does -- it pushes the entire photo so that it has the desired brightness.

Personally I also more care highlight recovery and only need to pull shadow moderately on my taste.

Like I said, there's no such thing as "highlight recovery". A blown pixel is blown. What you can do is use a lower exposure and push the shadows with the desired tone curve if the highlights matter more than the noise. A sensor with more DR will have more lattitude in the amount of pushing that can be done before the noise becomes objectionable.

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