-The original horizon has been removed from the HDR files, and the photos used to make the HDRi re-processed for a smoother, noise free image.
-Radiance (.hdr) and OpenEXR (.exr) file sizes have been optimized to improve loading times.
-16 bit RAW versions of the backplate photos now included to allow greater freedom in post processing.
HDRi skydome panorama in .exr and .hdr format for use as a spherical environment in 3d scenes. Note that these HDRi skies are not complete 360 degree x 180 degree panoramas, only the top half (the sky) is present. 1725 refers to the time of day it was taken.
Sun angle, where 0 means the sun is on the horizon and 90 means directly overhead: 17.3 degrees
Approx 7000px wide, good enough in most cases to be used as the directly visible sky. When you want more control, or the sky is visibly low res, you can use the supplied 12 megapixel .jpg or RAW backplates.
The photos used to make the HDRi are taken at the following exposures: 1/8000, 1/2000, 1/500, 1/125, 1/30, 1/8, 1/2 which is equivalent to a dynamic range of approx. 12 EVs (Exposure Values). A Canon 1Ds MK3 was used and was set to shoot 7 exposures 2 EVs apart.
Actual measured dynamic range for this sky: 10.95 EVs
Comes with a series of straight shots of the sky taken at the same time as the HDRi and with the same color temperature so it matches your render. Photos are in both .jpg and 16 bit .dng format.
*Note that a minimum of Photoshop CS5 or Lightroom 4 is required to open the .dng files
If you are confused by apparent overexposure in photoshop, remember photoshop is displaying a preview of part of the whole dynamic range, you can simply drag the exposure slider down at the bottom left of the image window to view the full range. My HDRi Skies FAQ http://www.peterguthrie.net/blog/2011/07/hdri-skies-faq/ might be a good place to start.
Remember to change the mapping type to environ/spherical environment.
In all HDRs the sun is oriented south>north for easy control of shadow direction. To change the rotation enter a value from 0-1 in the bitmap offset, for example to have the sun coming from the east, change it to 0.25, from the north: 0.5 etc. If you use the VRayHDRi loader, use degrees for rotation instead (0-360).
I usually use the exr in a vray dome light rather than as a max environment map. If you are using a vrayphysical camera then a good starting point would be to set the output of the exr (in the bitmap loader) to 1, set the vray dome light to a multiplier of 1 and leave the vrayphysical camera exposure at default. (F8, 1/200th, ISO 100 ) From there you can adjust either the bitmap output multiplier or the vraydomelight multiplier till you are happy with the exposure. (I find the multiplier can vary between 0.5 and 2.0)
If you use V-Ray, I strongly suggest loading the exr or hdr file using the VRayHDRi loader: it has much better bitmap filtering so even when using a zoom lens you dont see any pixellation in the sky.
Please feel free to visit my blog for my most recent preferred workflow with HDRi skies: http://www.peterguthrie.net/blog/2012/02/hdri-lighting-workflow/CLICK HERE TO PURCHASE – $25