Author Topic: [WONTFIX] Canon 7d HDR  (Read 2959 times)

markymark

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[WONTFIX] Canon 7d HDR
« on: April 02, 2013, 09:41:54 PM »
Hi,

   This was asked before in the 7D forum, but gonna put it in here as a request. Okay when in shoot mode could we have the images taken in HDR mode be able to set to more than 9 (say to maybe 30), the reason is that when I shoot HDR I tend to shoot in a 3rd of a stop increments as this tends to give less noise and being able to shoot more than 9 images would help me do a large range on the number of stops.

Cheers

Mark

a1ex

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Re: Canon 7d HDR
« Reply #1 on: April 02, 2013, 10:25:56 PM »
Just change it in the config file or from a script. It would break the UI and I don't feel like rewriting all that code. 1/3 stops is hard to implement, you have to match exactly Canon's rounding algorithm, otherwise you'll run into weird bugs.

garry23

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Re: [WONTFIX] Canon 7d HDR
« Reply #2 on: April 03, 2013, 08:16:44 AM »
Surely we have this in the form of auto bracketing. In other words select auto and the Ev step and ML will take as many brackets to cover the dynamic range of the scene. I have seen auto bracketing take 15 images. In other words you are not limited to a max of 9, you simply can't specify or predict the number of brackets past 9!

Marsu42

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Re: [WONTFIX] Canon 7d HDR
« Reply #3 on: April 03, 2013, 10:53:09 AM »
the reason is that when I shoot HDR I tend to shoot in a 3rd of a stop increments as this tends to give less noise and being able to shoot more than 9 images would help me do a large range on the number of stops.

Imho that isn't necessary: the dr "space" in a 18mp sensor raw file is at least 1, usually 1.5ev, so that's what I set as spacing - you can recover a good amount of highlights out of the raw file afterwards, no need to card space and shooting time on site.

So with this you're getting nearly 14 stops of hdr space around the original point - and that's usually not even necessary since most of the time the high dr is in one direction, so you can ec the starting point and save even more shots.

hjulenissen

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Re: [WONTFIX] Canon 7d HDR
« Reply #4 on: April 03, 2013, 12:53:56 PM »
...when I shoot HDR I tend to shoot in a 3rd of a stop increments as this tends to give less noise
If the DR of the sensor is 10-11 stops (at optimal ISO etc), then shifting exposure by 1/3 stop should give minimal improvements. If you see significant IQ improvements, I would guess that you are:
1. Running the camera at very high ISO
2. Use some strange, quirky HDR developer
3. Apply very nonlinear curves/tonemapping operators.

-h

markymark

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Re: [WONTFIX] Canon 7d HDR
« Reply #5 on: April 03, 2013, 08:14:31 PM »
Hi All,

       Thanks for all the info, will have a look at setting it on auto to see how that works out. Me try to change the config file or write a script is not gonna happen as I would not know where to start so unless Alex is able to send me some sort of guide on how to do it I think it's gonna be a problem. The only time when I really notice the noise it is when I am shooting a night scene so maybe this could have something to do with it. The software that I use is Nik HDR pro2 so think it's not a software issue and I only shoot a t low iso (100 or 200) so don't think that's the issue.

Cheers

Mark

garry23

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Re: [WONTFIX] Canon 7d HDR
« Reply #6 on: April 04, 2013, 01:50:45 AM »
Regarding the 10-11 stop DR range above, I believe this always creates confusion.  If you take where Canon sets the black point and the max value of a 14-bit histogram, then the camera is only able to capture about 5-6 stops of tonal data, as measure in Ev from the top of the histogram.

In other words half the tonal range is held in the right Mose 'stop', and then half again in each stop until he black point is reached, hence ETTR strategies.

I think using Auto bracketing solves most problems, other than a desire to shoot fast brackets.

Of course I could be totally wrong!