BatchFoxGoogle how to shrink a RAW library and the first answer you'll get is "convert to DNG." It's not bad advice. It's just a bigger decision than it sounds, so here's what you're actually signing up for.
What DNG is
DNG is Adobe's open RAW format. Converting takes the file your camera wrote and writes a brand new file in Adobe's format. It's free, and pretty much every editor opens it.
The two kinds of DNG
Lossless DNG keeps all the sensor data. You save a modest amount.
Lossy DNG is where the big savings are. It gets there by throwing data away. On a lot of photos you won't see the difference, but you can't undo it.
The part people miss
Either way, what you've got afterwards isn't the file your camera wrote. It's a new file.
Most of the time, for most people, that's fine. It matters when:
- a client, a contest or an agency asks for the original camera file,
- you want to use your camera maker's own software down the road,
- you just want to know that what you archived is what you actually shot.
You can tell the converter to tuck the original inside the DNG so you can pull it back out later. That works, but it adds the whole original back on, so you've saved nothing.
So should you?
If you're sure you'll never need the original camera file and you want the smallest files possible, lossy DNG is a fair choice. No shame in it.
If you want to keep your originals though, converting isn't really a storage answer. It's a format change.
What I wanted instead
I've only tried DNG a handful of times, and I always backed off for the same reason. To actually save space with it, I had to let go of my original. To keep my original, I had to give the space right back. Either way I was giving something up.
I wanted smaller files AND my exact originals, both at once. That's why I built BatchFox Archive. When you restore on the default Exact setting you get your original camera file back byte for byte, checked with a SHA-256 fingerprint. On the Sony files we've promoted so far it makes them up to 71.69% smaller, and most shots land around half.
And getting your photos back is always free. Restore works on every plan, even after the beta.
BatchFox is in beta, sign up at batchfox.app.
Have you converted to DNG? Did you keep your originals too?