How to set JPG Compression during conversion?

[Archive]

[Originally posted by strayhud on 2009-05-20 05:58:44-07]

I noticed that NEFs converted to JPG with ExifTool appear slightly over exposed as compared to those converted with Nikon's ViewNX.   I assume this is due to a difference in compression being used as the file size is about 5x larger with ViewNX where I select the lowest compression (highest quality) setting.    I haven't seen any params that let me set the compression level in ExifTool, however being a newbie I may have missed it.   Can anyone tell me if this is possible?    

Thanks!
-Steve

[Archive]

[Originally posted by exiftool on 2009-05-20 11:23:52-07]

Hi Steve,

I think you are confused.  ExifTool does not convert RAW images.
The closest thing it does is to extract the embedded JPEG preview image
from a RAW file.  But in doing so, ExifTool modifies neither the compression
nor the exposure of the embedded JPEG -- it is a simple byte-for-byte
extraction.

- Phil

[Archive]

[Originally posted by strayhud on 2009-05-20 13:40:50-07]


Phil,

Thanks for the feedback.   I see that looking back at the docs now.   I guess what led me down that path is that fact it seemed to be working and I only shoot in raw mode.    Although a little underexposed, an NEF must be pretty close to a JPG byte structure-wise.   Either that or NEFs automatically include an embedded JPG??    

Anyway, now that I know I'll move on to look for another tool to do batch JPG conversions.   And use ExifTool for all the other cool things it does.    Truly an awesome program you've written.  Thanks for all the hard work and contribution of your time.

- Steve

[Archive]

[Originally posted by exiftool on 2009-05-20 13:49:40-07]

Hi Steve,

I'm glad you find exiftool useful.  Thanks for the compliments.

The NEF's include an embedded JPEG (as do most RAW formats so the
camera doesn't have to convert the RAW on the fly when displaying
images).

- Phil