Author Topic: Newbie HDRI questions  (Read 2969 times)

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Offline danclarkwcp

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Newbie HDRI questions
« on: February 23, 2012, 10:10:24 am »
We are a commercial photography studio, starting to work with KS. I'd like to hear from others, photographers in particular, about their methods for lighting in KS. Brian Townsend, from KS, was kind enough to share his equipment and software info, but I want to dig into this a bit deeper. So, in no particular order ...

-  For product rendering, what percentage of the time are you using HDRI environments supplied with KS without changing them, what percentage are custom shot HDRIs you take yourself, and what percentage are created and/or tweaked in Photoshop or HDR Light Studio?

-  Brian's shooting method is as follows - "I generally shoot a total of 12 shots 7 exposures each. I'll do 360 degrees in 60 degree increments with the camera angled at 30 degrees up for my first 6 shots, The next 6 shots are with the camera angled 30 degrees down and I do the 360 in the same 60 degree increments.  This is how I deal with the 15mm not giving you a full 180. You could shoot 360 degrees around without the camera angled up or down and then shoot two final shots. One with the camera straight up and one straight down. That works as well. The only reason I use my method is for the extra resolution."  In the test shots we've been doing, I'm wondering how important it is to shoot the 30 degree up and down angles, as opposed to just shooting one set with the camera at zero degrees. I know that won't give me 180 degrees of vertical view, but it seems to me that it would be easy to retouch the small "holes" at the top and bottom, especially since I'm getting a big chunk of my rotational head at the bottom of the frame anyway. Retouching, or even just pulling/stretching a little bit of the top and bottom of the image, doesn't seem as if it'd create problems in rendering, but maybe that is just wishful thinking on my part.

-  Since KS wants Environment images that are 1X high by 2X wide, is it better to make the image conform to the shape in whatever you're using to create the pan (we're trying out PTGui, for example), or just do a slight resize in Photoshop?

-  What resolution is good for high quality renders? When we shoot products, we shooting at about 4000 pix by 5500 pix, or 5000 by 6000, and I'm looking for similar image quality in our renders.

-  When shooting custom HDRIs, how may exposure brackets are you using for your HDR pans, and how do you tell you're shooting the correct exposure range? Is it necessary to capture detail everywhere from the darkest shadows to the absolute brightest highlights?

I think that's all for now,
Dan Clark
www.weinberg-clark.com

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Re: Newbie HDRI questions
« Reply #1 on: February 23, 2012, 11:14:26 am »
The lighting information is the same independent of the size of the HDRI. If you are mostly concerned about lighting, a small HDRI will suffice. If reflections are important as well, then you want higher resolution in your HDRI. If you want to place your object "in context" then you want to use a backplate in addition to the HDRI. The backplate will not affect the lighting of the scene nor the reflection in the object.

Offline danclarkwcp

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Re: Newbie HDRI questions
« Reply #2 on: March 05, 2012, 12:13:19 pm »
Thanks for your reply, Thomas. Looking forward to hearing from other photographers who can share their insights.

Dan Clark
www.weinberg-clark.com