Bob, you're still attached to the original idea (which is erroneous) of multiple sun angles. The example image you posted originally is not an amalgam of multiple exposures at different times of day (and thus different sun angles), it is several exposures taken very close together and then combined and tone mapped in a program like Oloneo. This is a very common and widely used technique these days. Not that combining images with multiple sun angles is a *bad* idea, it's just not what was done in the example you provided, and it's unnecessary if that's the effect you want to achieve.
But if you're already doing 2 renders, you don't need to save it as EXR. You can just save as TIFF. The reason I suggested EXR is because it is a high dynamic range format, and you can make multiple captures from it at different exposure levels (mimicking the process of taking several shots of a real-life scene), saving each as e.g. TIFF. This avoids the extra time to render multiple versions of the scene at different exposures. You can then combine these "low dynamic range" images into a single high dynamic range image and do tone mapping in Oloneo as originally suggested. But again if you're already doing multiple renders, there's no point in saving to EXR and going through the intermediate step of the Photoshop conversion. The point with the EXR and Photoshop workflow is to make *multiple exposures from a SINGLE file*. Not to render several times and save to EXR then convert to TIFF and merge back into HDR.
- Oshyan
