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Great rgarrigus 2007-05-31 14:52

Adam,

Your two minute exposure certainly made this shot. It gives me the super peaceful feeling of watching the clouds gently caressing the mountain tops juxtaposed with the glassy lake surface. The rocks in the foreground are simply an audience watching the play of light. I absolutely love the moody blue color.

New guy question: Since the 5D has an RGB histogram ( I think) do you still need to use the "expose to the right" principle?

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Old 06-01-2007, 12:11 AM
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Default To rgarrigus: Hi

Thanks for your comments on the shot. Sorry but Ive never heard of the 'expose to the right' principle? Maybe that answers your question. What is this principle?

Adam.
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Old 06-01-2007, 09:28 AM
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Default Re: To rgarrigus: Hi

Hi Adam,

If you're not using it then it isn't important and that alone helps me. When you get fed up with my completely incomprehensible explanation there is a better one here:

http://www.luminous-landscape.com/tutorials/expose-right.shtml

I'm probably not smart enough to explain it well but it entails improving the overall signal to noise ratio of digital RAW captures by actually overexposing a tad - short of blown highlights. You make your exposure and get the histogram as close to the right as you can without blowing highlights unacceptably. You then adjust levels in ACR (or another RAW software package). I guess the principle was devised (or at least pointed out) by Photoshop/ACR creator Thomas Knoll and is based on the fact that the first f stop actually contains over half the information in a digital image:

Within the first F/Stop, which contains the Brightest Tones 2048 levels available
Within the second F/Stop, which contains Bright Tones 1024 levels available
Within the third F/Stop, which contains the Mid-Tones 512 levels available
Within the fourth F/Stop, which contains Dark Tones 256 levels available
Within the fifth F/Stop, which contains the Darkest Tones 128 levels available

In exposing to the right the idea is that you can capture more photo detail provided you don't let the highlights blow out. I was taught this in a course on RAW image processing but I can't claim any expertise yet. I find that, like all things photographic, it can often be helpful but is not in anyway a "rule".

The histogram part of the question is based on my 350D giving me the JPEG (luminousity) histogram even when shooting RAW. The 5D histogram is RGB so it is a more truthful representation of the RAW exposure. I'm really trying to shore up my argument to my wife to purchase a 5D :)
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Old 06-01-2007, 10:44 AM
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Default Re: To rgarrigus: Hi

Hi Bob,

Thanks for your explanation. I purposefully try to avoid the histogram being really near (but without clipping) the right. Reason for this is I went through a phase of doing just that, and when I downloaded the RAWs into Rawshooter the software histogram would show a different histogram and show the exposure as being overexposed, or clipped.

Very weird - I dont know why the histogram for a single shot would be different from the camera to the software. I am really not that technical to understand. So I am always aware of this when shooting and try to keep the histogram a little further to the left than before. There is nothing I detest more than spots of overexposure!

regards,
Adam.
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Old 06-01-2007, 07:04 PM
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Default Re: To rgarrigus: Hi

So true,

This is especially hard when shooting in low light like the Piopiotahi type shot at sunrise or sunset. I think the only thing I detest more than overexposure are sensor dust spots! (my next week project).

I only recently learned that the histogram I use is really for the JPEG Luminousity reading vice the RAW file. For that reason on my 350D it can sometimes show clipped highlight warnings in camera but then not in ACR.

I'm trying to understand as much as I can technically without losing site of the real important bits - vision and shooting the scene.

Much appreciated.
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Old 07-04-2007, 07:06 PM
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Default Re: To rgarrigus: Hi

Very interresting and instructive discussion.
Thanks guy
Charles
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