Author Topic: "Save Photo As" vs "Extract JPEG from RAW file" ?  (Read 5001 times)

Offline jock

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"Save Photo As" vs "Extract JPEG from RAW file" ?
« on: January 30, 2008, 11:57:54 AM »
I need some clarification: (Mac OSX 10.4.11)

I know that when using the "Save Photo As" command in PM that you get the functionality of a "Save AS" command - which you don't get when you use the "Extract JPEG Previews from RAW Photos" command.

I also understand that when the "Save Photo As" command is used - PM is using Apples system level I/O image processor to convert the RAW files.

So what is happening when the "Extract JPEG Previews" command is used - is PM just using the jpeg data embedded in the RAW file and is that any worse than going through Apple's RAW converter?

What I am trying to get at here - is there any difference in the quality of the JPEG file that PM generates in either case?

For example: If the "Save Photo As" command is used to save RAW files as max quality JPEGS - will these files be better or different in any way than JPEGS produced by using the "Extract JPEG Preview" command?

AND is there any difference in quality between allowing PM to Extract the JPEG Previews from RAW files - compared to the camera generated JPEG file when shooting RAW + JPEG?

Thanks for any insight!

Offline Kirk Baker

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Re: "Save Photo As" vs "Extract JPEG from RAW file" ?
« Reply #1 on: January 30, 2008, 02:32:46 PM »
I need some clarification: (Mac OSX 10.4.11)

I know that when using the "Save Photo As" command in PM that you get the functionality of a "Save AS" command - which you don't get when you use the "Extract JPEG Previews from RAW Photos" command.

I also understand that when the "Save Photo As" command is used - PM is using Apples system level I/O image processor to convert the RAW files.

So what is happening when the "Extract JPEG Previews" command is used - is PM just using the jpeg data embedded in the RAW file and is that any worse than going through Apple's RAW converter?

What I am trying to get at here - is there any difference in the quality of the JPEG file that PM generates in either case?

For example: If the "Save Photo As" command is used to save RAW files as max quality JPEGS - will these files be better or different in any way than JPEGS produced by using the "Extract JPEG Preview" command?

AND is there any difference in quality between allowing PM to Extract the JPEG Previews from RAW files - compared to the camera generated JPEG file when shooting RAW + JPEG?

A lot of this depends on the quality of the embedded JPEG in your camera's RAW files.  Some cameras put full-resolution JPEGs inside the RAW files.  Some put half-size or smaller previews in their RAW files.  Some just put in only a tiny thumbnail.

The Image I/O-developed image will most definitely be different from the embedded JPEG.  Is the quality better in one versus the other?  The question is entirely subjective.  Some would say the embedded JPEG would be the best.  Others would rank the Image I/O version higher.  It's really up to you to decide.

-Kirk


Offline jock

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Re: "Save Photo As" vs "Extract JPEG from RAW file" ?
« Reply #2 on: January 30, 2008, 03:59:12 PM »
Kirk:

Thanks for the reply - I am working with Nikon NEF files from a D2x and D3. Obviously the D3 files are an issue at the moment - which is what prompted my question. In the past when I have used the Extract JPEG from RAW option - the jpg files have been the same size as those produced by the camera - so am I correct to conclude that the NEF files contain a full res jpg?

Offline Kirk Baker

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Re: "Save Photo As" vs "Extract JPEG from RAW file" ?
« Reply #3 on: January 30, 2008, 04:27:19 PM »
Thanks for the reply - I am working with Nikon NEF files from a D2x and D3. Obviously the D3 files are an issue at the moment - which is what prompted my question. In the past when I have used the Extract JPEG from RAW option - the jpg files have been the same size as those produced by the camera - so am I correct to conclude that the NEF files contain a full res jpg?

Yes, I believe that the D2x does, and I am certain that the D3 does.

In 4.6 you will be able to use Save As with the embedded JPEG to create new images.

-Kirk