[jfrancis]

Intrigued by mxi emitters (I know I'm late to that party) I'd like to find out more about how to take a bunch of bracketed photos and make an mxi.

I know Photoshop can do some HDR stuff, but does it leave the finished HDR image spanning many f-stops? Or does it tone-map it all down into visible 0..1 space?

And what would happen if the exposures were deliberately warmed in color temperature as they rise in brightness? (or cooled, since higher energy light is bluer?)

All of this is with the intention of using the finished image as an mxi emitter.

[jfrancis]

And is it really best of all to assemble the LDR images into an HDR one using

http://www.hdrshop.com/

?

[simmsimaging]

You can use Photoshop to merge to HDR for sure. If there is no movement between frames it should be fine. There are many programs out their to do it and they offer variations on how they handle ghosted movmement (figures/shapes moving between exposures, or occasional things that pop up in only one two brackets - like a flying bird or passing car etc)

The final image will not be a tonemapped LDR unless you choose to convert and output that format. Save to HDR, EXR, 32 bit TIF or PSD etc and it will maintain the full range of stops that you shot. Personally, I find a 5 stop range is pretty good (normal, -1,-2, +1, +2) for most purposes, but if you are just making light source images and are not worried about time etc then go more. It can't hurt to have too much, but it's very arguable how much will really show in your final workflow and images. When shooting light boxes I did more like 9-10 stop range.

I think it's probably better to try and merge from RAW files too btw: they capture a pretty good dynamic range as it is these days, and if you process them out you will already be losing a bit of that. That said, I have done many with processed images and it's not that big of a deal.

I have never tried intentionally varying colour etc between exposures but I can't see it being an issue - but it may not work out quite like you expect in the sense of a gradual shift. The colour may be averaged instead - something you'll have to experiment with I guess.

/b

[jfrancis]

The final image will not be a tonemapped LDR unless you choose to convert and output that format. Save to HDR, EXR, 32 bit TIF or PSD etc and it will maintain the full range of stops that you shot.

Thanks.

Good to know I can use it after all. I was afraid Photoshop wasn't going to be sufficient.