The embedded JPEG preview raw file was never intended by the camera manufacturer to be used for the purpose of judging image sharpness. Many camera models don't even embed a full-size preview and all use a low JPEG Quality setting. These settings are not user-adjustable and prevent judging the "sharpness" and "quality" of an actual in-camera shot full-size JPEG image file. The only way to properly evaluate the camera’s JPEG versus raw file sharpness inside LR is to set your camera to shoot raw+JPEG with full-size "highest quality" JPEG selected in the camera settings.
raw file embedded preview, exposure, contrast, color saturation, and white
balance should be very close to an actual in-camera full-size JPEG file.
Having an option in the LR Compare mode to view the raw file embedded JPEG
preview next to the actual raw file with LR adjustments would be useful for making
Develop presets to emulate in-camera picture settings.
I retract my statement, at least for the Canon 5D MKII and presumably most other cameras with full-size embedded previews. You can accurately judge the in-camera sharpening as it would be applied to the JPEG without shooting raw+JPEG. So it's definitely beneficial to have this capability and would be most useful as an option in the Develop module's Before/After compare view selector. This would allow viewing the raw file's embedded preview real-time with the raw file while Develop adjustments are applied.
The following suggestions are based on 45-years of experience in system design engineering, product marketing, and sales. It’s a long read....you’ve been warned!
It appears the majority of DSLR cameras manufactured over the past 10 years embed a medium to high quality, full-size JPEG preview inside the camera raw file. They have done this primarily to enable real-time review of raw files in the camera’s LCD display at up to 1:1 Zoom view. The embedded JPEG preview file’s purpose and function is identical to the Library module 1:1 Preview file. So are there any benefits of making the embedded preview file available inside LR and how should that be implemented? We already have the capability to review the raw file embedded preview in the Import module at up to 1:1 Zoom view. This can assist with culling of rejects prior to actual import, but as Simon Chen commented and I agree he wouldn’t recommend that workflow. So this one availability of “viewing” the raw file embedded preview provides minimal “benefit.”
After thinking about this over the past 24 hours I’ve come up with three new ways (i.e. features) of using the raw file embedded preview inside LR that provide real benefits. Two of these new features are easily implemented and the third is more difficult.
1) Provide an option in the Library module Grid and Loupe views and Develop module Before/After view to select the embedded preview, instead of the Library preview. Also provide an option in the Import and Library modules to use and retain the raw file embedded preview until actual Develop module adjustments have been applied.
-Images can be reviewed with the in-camera picture styles applied, which many users prefer. You could also change the Default Develop settings or apply a Develop preset, but that requires extra work. As camera manufacturers develop more sophisticated in-camera processing differences between the embedded preview and LR Default Develop settings will only become more pronounced.
-Using the Before/After view with the embedded preview next to the raw preview increases the accuracy and ease of adjusting the Develop module controls. It simplifies the creation of Develop presets for emulating in-camera picture styles. It will help new and inexperienced users learn how to use the adjustment controls. Users will also realize the full potential of raw files for going beyond the camera JPEG rendering.
-Enabling use of the raw file embedded preview until actual Develop adjustments have been applied allows reviewing images at 1:1 Zoom view in the Library module without having to build 1:1 previews. Yes, you can do that now in the Import module, but there is no way to choose Picks, Ratings, and other qualifiers. This greatly speeds the process of reviewing a large shoot and creating proofs for editors and customers.....or just plain kin folk! The long wait for 1:1 Preview Building to complete can be put off until you are ready to make Develop edits!
2) Provide an option in the LR Export module File Settings> Image Format selector for “Embedded” to allow export of the raw file’s embedded JPEG as a new file.
-This eliminates the need to shoot and manage raw+JPEG pairs when rendered images are need real-time, such as shooting in “tethered mode.” In addition most cameras achieve a higher burst rate when set to shoot only raw format, which is required for sports and other action photography.
-Full-size Export of the embedded JPEG will be considerably faster than rendering and outputting the raw file. We hear it all the time, “Why is LR Export so slow!” This provides a viable option for quickly creating fully-rendered Export images for review by others.
3) Provide an Auto Tone option that uses the embedded preview image data to determine the Basic panel control settings for the raw file. I have no experience in this area, but it should be possible to create adjustment algorithms that calculate the control settings by matching the raw file data with the embedded file data. Without a doubt this feature is more difficult to implement, but might make the Auto Tone rendering more predictable and useful.
-Allows quickly applying in-camera settings, which some users seem to prefer.
- Should provide less image to image variability due to differences in subject content.
I need to view the embedded JPEG in my Nikon NEF files. I have 80,000+ photos as NEF files, and most have been edited in Nikon's Capture NX  NEF RAW editor. That means the embedded JPEG shows the exact edits I made in Capture NX. When I view them in Lightroom 5.3 all that shows up is the preview version Lightroom created on it's own. If I've used Lightroom to edit the file then fine, show your preview, etc. But for NEF RAW files that were never edited in Lightroom, please give me the option to view the embedded JPEG. There is no way I'm generating a JPEG for, or re-editing 80,000+ existing photos in Lightroom.
One of the main reasons I just bought Lightroom 5.3 was as a catalog program. As I've used it it's become more apparent that with my 80,000+ existing photos, it's pretty useless because the preview image shown doesn't reflect the actual state of the image in the NEF file - which can easily be fixed by you using the embedded JPEG image. Simple things like cropping aren't shown, as well as any lighting, color, etc. effects - some are in black & white and show up as a color image. When I edit in Capture NX it updates the embedded JPEG with all the edits, so the embedded JPEG is exactly what my NEF RAW image looks like. In fact, once edited with Capture NX, the embedded JPEG becomes a full size, high quality JPEG that can be quickly extracted and used, for example by Photo Mechanic.
Again, if I've edited the NEF in Lightroom, then please use your generated preview image, etc. But for existing photos never edited in Lightroom, for God's sake let me view the embedded JPEG. You briefly use the embedded JPEG when I'm doing an import and then throw it away once you generate your own preview. So there's nothing stopping you from using the embedded JPEG, it's just a choice on your part. Give me the choice please, they're my photos, let me view them the way I want, one that perfectly reflects the state of the NEF file.
To Richard Rothwell's point, do realize that if you show the preview from the NEF that it always results in fairly low jpeg quality for the image as the preview in the NEF file is just a medium quality jpeg file. When you export the file from Lightroom you'll get a different result even if Lightroom could use the embedded jpeg as preview. Also, when a file is edited in CaptureNX is not an actual edited image, it is the original camera-produced NEF file with a set of rendering instructions that are only intelligible to CaptureNX. Lightroom will never be able to understand those instructions. Your best bet is to batch export those images to tiff files and use those in Lightroom.
What I would like to see is an option to extract the jpeg preview from a raw file and use them as separate images for very quick release. You can then autostack and use the jpegs as top image but still have access to the nef files if you wanted. That perhaps could be automated at import.
It's always fascinating for me to hear how many different ways we approach the raw workflow. '-}
You can also use Steve Sprengel's suggestion to lock the JPEG in the secondary display window to allow viewing it while making adjustments to the raw file. You can do this with a single monitor, but it's less than ideal. You can also use the secondary display window in its Compare mode with the raw and JPEG files selected. This is identical to the Before/After view with a few exceptions. The Histogram eyedropper tool, Red/Blue Overly Clipping Indicators, Tone Curve targeted adjustment tool, and HSL targeted adjustment tool cannot be used in the secondary display. So you would need to make those adjustments "visually." With the exception of those limitations it works very well for matching the raw file to the embedded preview. Here's an example: