Really Useful Software Preview Extractor
Many Nikon SLR cameras allow you to shoot in RAW+JPEG mode so you can have the best of both worlds. You get JPEG files for quick review and evaluation, and NEF (raw) files for ultimate quality so you can make the most of the really good ones. But there's really no need to clutter up your compact flash cards with both formats. Embedded in every raw file you shoot is a full sized jpeg preview image that you can easily extract when you are done shooting.
Preview Extractor for the Nikon Raw (NEF) files
Shutter Count Extractor feature in Preview Extractor
To do so, you will need a great free program called "Preview Extractor" created by Jaewook Chung. You can download a copy from a straightforward page labeled "Really Useful Software for Nikon DSLRs" on Jaewook's site here. While the program is free, the author does accept donations so if you like his handiwork, do let him know.
The program has no install process — you can just download it and run it. Pick your Source and Destination folders and away you go. Preview Extractor can show you a thumbnail of each image as it gets processed, but turning this feature off makes things go even faster so unless you just like watching a quick slide show of your images as the program does its thing, I'd suggest turning this off. Options are also available to tell the program whether or not you want to overwrite existing output files should they already be there, whether you want to rotate images based on the orientation tag written by the camera and a few other things.
Preview Extractor has one other unique feature that may make it worth downloading even if you don't need jpegs from your raw files. It can read the meta-data that is also embedded your images and tell you how many shutter activations the camera that shot it has had. This works both for NEF files as well as jpeg images shot on Nikon SLR camers. Technically, this information is stored as part of a meta-data area known as the Nikon Type 3 Maker Notes at hex offset 0x00a7. If that's completely Greek to you, no worries since Jaewook handled all the details by adding the Shutter Count Extractor feature into Preview Extractor.
Yes, you could also use your favorite raw converter to create jpeg images from your raw files, but opening each and converting them would be time consuming. The Photoshop Image Processor created by Russell Brown in conjunction with Adobe Camera Raw can automate the heavy lifting but converting a lot of files would still keep your computer occupied for a fair while. The advantage of the Preview Extractor is that it is quick and easy. You can extract the jpeg from hundreds of raw files in just a few minutes.
The embedded preview is a full-sized basic jpeg which is suitable for many purposes. If you want the best jpegs you can get, you would still do best to shoot jpeg or RAW+JPEG but most people don't really need the highest quality jpegs possible. They just need a quick and easy way to preview their images. It can take a lot less time to extract the embedded jpeg from a bunch of raw files and evaluate them at full size than it would to do so with a raw converter.
Based on the resume on his website, Jaewook is a Korean cryptographer attending the University of Waterloo in Ontario, Canada. And he just happens to be a photographer who shoots Nikon.
There may well be more than one program that can extract the embedded jpeg, but if you shoot Nikon there's no need to search for other options since Jaewook did such a good job with Preview Extractor. If you shoot another brand of camera, you're on your own.
Truth in advertising: Really Useful Software indeed. Thanks Jaewook!