Is it computer up-grade time

[xpatUSA]

Ted,

thanks. I'd be interested, but your profile seems to be set up not to accept PMs.

Dan

Sorry about that. I've just changed it. Please give it a try and let me know what spreadsheet app. you use.

[proseak]

Chauncey, are you stacking 8 or 16 bit images?

[chauncey]

They follow my usual protocol which is 16 bit.

[proseak]

Try it with 8-bit images.

[chauncey]

Are you suggesting to drop down to 8 bit and then, when stack is finished go back to 16 bit?
Seems kinda counterproductive.

[ajohnw]

Are you suggesting to drop down to 8 bit and then, when stack is finished go back to 16 bit?
Seems kinda counterproductive.

Why if the 8bit images are "correct"?

John
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[DanK]

Why if the 8bit images are "correct"?

John
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It's pointless, as Chauncey suggests. Most cameras, if I recall, actually record in 12- or 14-bit. If you convert to anything less than that, you throw out data. Assume 12-bit to be conservative. If you convert a 12-bit image to 8 bits, you discard 93.7% of the data. (12-bit is 2^12=4096 values; 8-bit is 2^8=256 values.) Converting an 8-bit file back to 16 bits doesn't find the discarded information and merge it back in. It just creates a bigger file.

I haven't done a timed comparison, but I think in the past I have stacked 8-bit images, and it did go a lot faster (as it should). So that is certainly an option, but once you go to 8 bits, that's where you are stuck.

In fact, if I remember right (I don't use the default settings, so I can't confirm), the Zerene Lightroom plugin will export the temporary files as jpegs, which are of course 8-bit and contain even less information than 8-bit TIFFs because of the compression.

[chauncey]

Thank you Dan for the explanation...this is a more visual example.
http://www.bing.com/videos/search?q=...DC1EF6B900458F

[DanK]

Thank you Dan for the explanation...this is a more visual example.
http://www.bing.com/videos/search?q=...DC1EF6B900458F

that's a great example.

[proseak]

What do you plan to do after the stack?