A9 - shoot uncompressed RAW = (2024)

I'm thinking hard about what is better - to shoot in uncompressed ARW format and then convert to DNG or to just shoot in compressed ARW format (and maybe also convert to DNG but maybe not since file size is no longer a factor)?

I've read a number of reports that says Sony's uncompressed ARW format is a higher bit depth then its compressed, and when you later convert the uncompressed to DNG you don't lose those extra bits. If that's true it seems worthwhile doing, but if it isn't true it may just be a big waste of time and SD card space.

I don't necessarily want to get into a whole debate of RAW vs DNG here, but if the above is true it seems like that would trump (I'm sorry to use that verb) any other pros or cons for the RAW vs DNG debate.

Thoughts?

David

This seems pretty damning:

https://stephenbayphotography.com/blog/sony-raw-compression-artifacts-real-examples/

Just double-checked with RawDigger: a lossless DNG conversion of an uncompressed raw file of the Sony A7Rm2 shows 14-bits resolution, just like the original raw file.

But really, check this article before you decide to replace your raws by DNG files; there's no way back!

addieleman wrote:

Just double-checked with RawDigger: a lossless DNG conversion of an uncompressed raw file of the Sony A7Rm2 shows 14-bits resolution, just like the original raw file.

But really, check this article before you decide to replace your raws by DNG files; there's no way back!

So the OP cites an article showing that compressed raw are bad, you cite an article that says that there is no reason not shoot compressed raw and that is what everyone should do. Also the article you cite appears to be 4 years old so some of the comments about compatibility are no longer accurate. Bottom line is there is no clear cut answer either way.

Seems to me that the risk of losing metadata by converting to DNG is nowhere near as bad as the risk of losing pixels in a lossy RAW format, right?

2

dschamis wrote:

I'm thinking hard about what is better - to shoot in uncompressed ARW format and then convert to DNG or to just shoot in compressed ARW format (and maybe also convert to DNG but maybe not since file size is no longer a factor)?

I've read a number of reports that says Sony's uncompressed ARW format is a higher bit depth then its compressed,

That's tru. 13 bit precision compressed, 14 bit precision uncompressed.

and when you later convert the uncompressed to DNG you don't lose those extra bits.

That's also true.

If that's true it seems worthwhile doing,

Depends on the situation. I shoot 95% or my a7x and a9x shots in compressed raw.

The reason to avoid compressed raw in some circ*mstances has nothing to do with precision in the case of the a9. 13 bits is plenty with the amount of noise the a9 has. The reason to convert some images is to avoid compression artifacts from the delta-modulation portion of the craw compression algorithm.

but if it isn't true it may just be a big waste of time and SD card space.

I don't necessarily want to get into a whole debate of RAW vs DNG here, but if the above is true it seems like that would trump (I'm sorry to use that verb) any other pros or cons for the RAW vs DNG debate.

Jim

An interesting take on this for Sony versus Nikon or Canon:

https://photographylife.com/sony-a7r-ii-uncompressed-raw-with-adobe-dng-converter

JimKasson wrote:

The reason to avoid compressed raw in some circ*mstances has nothing to do with precision in the case of the a9. 13 bits is plenty with the amount of noise the a9 has. The reason to convert some images is to avoid compression artifacts from the delta-modulation portion of the craw compression algorithm.

Jim

Thanks for the comment, Jim. If I shoot uncompressed RAW, is there a reason to convert to DNG?

2

vett93 wrote:

JimKasson wrote:

The reason to avoid compressed raw in some circ*mstances has nothing to do with precision in the case of the a9. 13 bits is plenty with the amount of noise the a9 has. The reason to convert some images is to avoid compression artifacts from the delta-modulation portion of the craw compression algorithm.

Jim

Thanks for the comment, Jim. If I shoot uncompressed RAW, is there a reason to convert to DNG?

Just to save disk space.

JimKasson wrote:

vett93 wrote:

JimKasson wrote:

The reason to avoid compressed raw in some circ*mstances has nothing to do with precision in the case of the a9. 13 bits is plenty with the amount of noise the a9 has. The reason to convert some images is to avoid compression artifacts from the delta-modulation portion of the craw compression algorithm.

Jim

Thanks for the comment, Jim. If I shoot uncompressed RAW, is there a reason to convert to DNG?

Just to save disk space.

Got it. Thanks again.

I went through this exact scenario/conundrum a while back, and really did some digging and pushing of files before ultimately deciding...

Our needs are likely different than most, as we're a high volume studio that has a system where the raw files are synced over the internet to three different locations, with sometimes up to 10 weddings in a weekend. For this reason, file size was an absolute priority. Most of us shoot on the A7III, but there's also some A9, A7RIV, and A7RIII, as well as a couple of Canons in the mix.
We use Lightroom for processing and output our processed files to 20mp JPEGs for delivery to the client.

After examining and comparing all combinations of compressed RAW and Uncompressed RAW as well as their resulting DNG conversions in both normal and lossy DNG, we settled on the following:

Shooting uncompressed RAW and converting to lossy DNG.

The reason for this is simple, and comes down to a few key factors
-Compressed RAW really looked bad in the shadows of pushed files
-Lossy DNG actually visually held up very closely to the uncompressed raw files even after pushing to extremes... To the point where we really couldn't tell the difference in a bind test
-Lossy DNG gave us the smallest file sizes
-Lossy DNG allowed us to downsize 61mp files to 20mp, which is amazing since we never output higher

Although in an ideal world we would be happy to keep the full RAW files and maintain 14 bit glory, in the real world we will never actually see the difference. We add a mild film look as a part of our processing and output mainly to black and white, so the lossy DNG is fine.
Having 125mb raw files down to 6 to 12mb is such a major deal for us.

In the end, everyone's priorities will differ, but for us having the most dynamic range with the smallest file sizes is the key.

The day we have a client complain that the files are too low res or not 14-bit is the day we reconsider... But I won't hold my breath