Question: Does Adobe DNG convertor lose image content?

[Simon]

I'm looking over my DNG files and comparing them to the original CR2 (Canon) files today. The RAW came from a Canon 20D.

I'm looking at them in MS Expression Media, aka iView media Pro.

The CR2 file shows 3504x2336 pixels, 180 pixels/inch, 48 bit depth
The DNG file shows 3596x2360 pixels, 72 pixels/inch, 32 bit depth

I set the convertor to give me a fullsize preview.

I'm currently converting my work over to DNG and archiving off the CR2 files to DVD. The DNGs are staying on "live and local" external drives.

But I'm really concerned that the DNG files are going to be a lot worse if I need to generate decent images later.

Is it normal/OK to lose half the resolution and 1/4 of the bit depth?

any thought appreciated.

Simon

[peterkrogh]

Simon,
It's a bit confusing.

The pixel resolution shows bigger in the DNG, since the DNG counts the Black Mask Pixels as part of the image.
The Resolution is irrelevant - it's the number of pixels that matter.
THe bit depth refers to the Raw data (sort of) for the CR2 (it's actually 12 bits per file - or maybe 14, but not 16)
The bit depth that it is telling you about the DNG is the embedded preview.

So, no, you are not losing anything, just getting a readout that's not totaly useful.
Peter

[Simon]

Thanks Peter.

I was worried that I somehow screwed up my DNG export and would need to do them all again.

appreciate the help.

Simon