DNG Version for Students

Question

I'm teaching a Lightroom class for our camera club and plan to give them dng files to work on as part of the class. Everyone should have LR 2 or 3 updated to the latest version (but this does not always happen). Looking at the DNG Converter, I can select a variety of dng versions and am unsure which version I should use for compatibility with the students. It seems to me that Camera Raw 4.6 would be a good choice as anything from LR 2.1 on should have compatibility just in case they have not updated to the latest LR version. In addition, if I later teach Photoshop, this would provide compatibility back to CS3. I'm looking for comments on this and if I did this, what would I find missing if a student used LR3 (or CS5). Thanks.

Answer 1

The version compatibility goes like this:
ACR 2.4 / LR 1.0 / DNG 1.0 — the initial DNG version that had some flaws (masked pixels, JPEG specs) that had to quickly be fixed in the next version. Looks like this version is not really in use today.
ACR 4.1 / LR 1.1 / DNG 1.1 — a quick (couple of months) update of the initial specs. Fixes flaws of the previous version. This version lasted long and is still used for in-camera DNGs. One should not use a version older that this.
ACR 4.6 / LR 2.1 / DNG 1.2 — introduces the concept of DNG camera profiles.
ACR 5.4 / LR 2.4 / DNG 1.3 — introduces the concept of opcodes, or, for any practical use today, "manufacturer-enforced" lens corrections. If you have a file with lens corrections applied behind the scenes for cameras like Panasonic LX3, any m4/3 cameras, etc. and convert to a spec older than this, the raw data will be lost and converted to a flat demosaiced 16-bit file, sort of like a TIFF.
I think you should go with the latest version. First, if your students all use LR2 or LR3, there's no reason one should stay with, say, LR2.2 when LR2.7 is available for free. Second, even if you use a latest version, a dng might well be compatible (and most often it is) with older spec dng readers if they do not use features introduced in new versions.