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image based mxi and bracketing

Posted: Wed Dec 17, 2008 9:09 am
by kreffell
Hi,

When an image is saved as an MXI file and used for lighting, does it then contain all the bracketing a normal HDRI would hold?

Many thanks,
Keith

Posted: Wed Dec 17, 2008 4:17 pm
by Mihai
MXI is also a hdr type image so the lighting info from the hdr would be retained.

Posted: Wed Dec 17, 2008 4:25 pm
by kreffell
Thanks Mihai,

To clarify:

If I create a JPG in photoshop (not HDRI) and then save as MXI, would this new file contain the same information as an HDRI and be useful to light a scene with?

Regards,
Keith

Posted: Wed Dec 17, 2008 4:30 pm
by Mihai
No, in that case the data would just be stored differently but there is no more information contained in it, speaking about range of lighting info, than the ldr jpg had. So if you do this, HDR lighting looses it's meaning. It could still be useful for using as an MXI emitter though, for TV screens etc.

Posted: Wed Dec 17, 2008 4:34 pm
by kreffell
Thanks,

Do you know of a suitable program to auto bracket my jpg image - I understand the full version of photoshop can create HDRI but not Elements.

Keith

Posted: Wed Dec 17, 2008 5:01 pm
by Mihai
There is a list here:

http://wiki.panotools.org/HDR_Software_overview

But I don't see why you would want to do this from a jpeg image. You won't be able to extract any more info from it by 'bracketing' an ldr image. You need several photos taken at different exposures to make a proper hdr from them.

Posted: Wed Dec 17, 2008 5:32 pm
by kreffell
I was looking to create custom studio lighting HDRI files - similar to this:
Image

Is there a better way?

thx,
Keith

Posted: Wed Dec 17, 2008 6:03 pm
by Mihai
Ah, in that case it's ok just converting a jpeg.