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A few questions after reading the book: (Read 3458 times)
CognizanCe
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Curious Apprentice

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A few questions after reading the book:
01/22/15 at 17:46:05
 
I just finished the (fantastic) eBook and have these questions:

1: Can bracketing for HDR IBL creation be done with setting the  exposure compensation (the little +/- button on the camera) while keeping the same shutter speed?


2: Or are angular projected panoramas significantly better that spherical?
If so, why are spherical projected panoramas the norm?

3: I have to touch my camera a few times to get exposure values ranging from
-6 -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5 +6
with auto bracketing.
Would that be redundant for IBL? Should I just focus on
-6 -4 -2 0 +2 +4 +6?
I seem to remember the book saying increments of +1 or +1 can help make the image look more surreal or dreamy and smooth visually, but they don't make much of a contribution to IBL, and should be done in increments of 2 instead.
PLEASE correct me if I'm wrong.

I'm using a Nikon D7000.
4: Is it possible to go beyond -6/+6?

5: Should back plates be HDR or LDR?
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Rork
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Re: A few questions after reading the book:
Reply #1 - 01/27/15 at 13:22:54
 
1. Yes, and there's a lot to be found on 'hdri bracketing sheet':
http://www.digitalcameraworld.com/2013/11/13/exposure-bracketing-how-to-do-it-ma...
If you're going to do a lot of HDRI photography, I do recommend a Promote or alike for speed and ease of use.

2. The 'norm' for 3D is mostly longlat, or a 360/180dgr. pano. But there's more ways to skin a cat...

3. It depends. I normally shoot with +/-1 incr. when inside, and +/-2 when outside. When there's low light I like to have a bit more steps to have some more control on image noise.

4. I think you mean 3 step -/+2?
Not with your camera. Only some camera's do that with stock ROM's, or are programmable to make your own.

5. If you're just compositing your 1 frame 3D render on the backplate, you -could- do it all in so called 'floating point' or 'non-linear'. That is, when you shot the backplate in brackets as well.
But normally, when compositing in moving footage, the backplates (video) is a non-hdri (non 32 bit) format.
It's a whole other discussion about bitdepth, color spaces, white balance etc.

rob
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CognizanCe
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Curious Apprentice

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Re: A few questions after reading the book:
Reply #2 - 01/27/15 at 17:13:43
 
Quote:
5. If you're just compositing your 1 frame 3D render on the backplate, you -could- do it all in so called 'floating point' or 'non-linear'. That is, when you shot the backplate in brackets as well.
But normally, when compositing in moving footage, the backplates (video) is a non-hdri (non 32 bit) format.
It's a whole other discussion about bitdepth, color spaces, white balance etc.

rob


Thanks.
I can understand why video would not be hdr/32bit, but what about still images?
(Sorry, I should have specified).
For still images, I guess it all comes down to what's more visually interesting (regular ldr image vs hdr image from brackets converted to 8bit tonemapped ldr),
or simply what kind of background the client/compositor would like their model composited into.
Correct?
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Rork
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Re: A few questions after reading the book:
Reply #3 - 01/27/15 at 17:47:11
 
Correct.

But most compositors, even the free Natron, work internally with 32 bit.
And with compositors I don't mean Photoshop.

So you could shoot a single backplate with brackets, and make a 32 bit file out of it. Render your 3d in .exr or alike and composite.
When you're finished , render out the composite to a ldr format like jpg, png, tif or alike.
That way you'll stay in 'float' until the end of the 'line'.

rob

again, this is a whole other discussion Wink
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mike mcelroy
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Re: A few questions after reading the book:
Reply #4 - 04/15/16 at 10:56:12
 
Is the book can be reprinted for personal use?
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