p.3 #1 · Compression vs Lossless Compression vs No Compression
AmbientMike wrote:
I shoot Canon, raw and jpeg. Raw is supposed to be lossless, but I don't really believe it. File sizes change and it's compressed so it's difficult to believe lossless compressed isn't losing any data. But I'm not really willing to go bigger than lossless compressed file size. C-raw and HEIF look interesting instead of jpeg but my body doesn't shoot those
Lossless compression is no different from a ZIP file (in fact LZW compression is commonly used for both applications). It very much is lossless and when uncompressed you get exactly the same data as prior to compression.
p.3 #2 · Compression vs Lossless Compression vs No Compression
I use 14 bit lossless compression as that has no IQ loss while creating a somewhat smaller file with my D850 and Z50. I see no point in the other settings for my uses.
Mar 07, 2021 at 12:59 PM
LeifGoodwin Offline • • [X]
p.3 #3 · Compression vs Lossless Compression vs No Compression
mawz wrote:
14 bit benefits the shadows, not the highlights (this is common across all systems, as there is always more highlight resolution than shadow resolution, so any increase in resolution benefits the shadows more than the highlights. With current sensor designs 12bit really captures all the available highlight data already, but not all available shadow detail at low ISO's). The only thing that affects highlight detail is compression type, because that tends to discard highlight data.
Current FF sensors show no benefit to 14bit at ISO's of 400 or up. On Nikon PDAF banding is also only ever present on 14bit files.
There's really little reason to shoot 14 bit unless you care a lot about shadow detail and shoot in the ISO 64-320 range much of the time. But there's also no downside for landscape/studio use unless you're card space limited. ...Show more →
Thanks. I shoot at 100 ISO most of the time, and don’t care about shadows, just maintaining detail in the highlights.
p.3 #5 · Compression vs Lossless Compression vs No Compression
Eruditass wrote:
Dynamic range is fungible. Losing detail in your shadows is the same as losing detail in your highlights with some exposure compensation.
Lossy compression affects highlights; 12- vs 14-bit affects shadows / shadow recovery. Both are described by Nikon as "visually lossless", which I agree applies if the dynamic range is modest and/or we aren't trying to recover highlights or shadow detail.
And I meant to say that I'm not so sure about 'fungible'; I think that lost highlight detail is gone, while shadow details are recoverable with some noise.
p.3 #6 · Compression vs Lossless Compression vs No Compression
kaplah wrote:
Lossy compression affects highlights; 12- vs 14-bit affects shadows / shadow recovery. Both are described by Nikon as "visually lossless", which I agree applies if the dynamic range is modest and/or we aren't trying to recover highlights or shadow detail.
And I meant to say that I'm not so sure about 'fungible'; I think that lost highlight detail is gone, while shadow details are recoverable with some noise.
You misunderstood me. By lowering exposure, shadow recovery headroom from going to 14 bit can be turned into highlight headroom. That's what I mean by fungible.
p.3 #9 · Compression vs Lossless Compression vs No Compression
I shoot compressed because I'm usually so far up in iso the quality difference is a moot point by then. Compression isn't a big deal at iso 6400+, right?
Mar 09, 2021 at 09:57 AM
AmbientMike Offline • • • • • • [X]
p.3 #10 · Compression vs Lossless Compression vs No Compression
mawz wrote:
Lossless compression is no different from a ZIP file (in fact LZW compression is commonly used for both applications). It very much is lossless and when uncompressed you get exactly the same data as prior to compression.
That is a great point, I'll give you that. Zip files often contain installation files so it's hard to believe that you are losing anything. Anyhow I'm happy with lossless compression on Canon. I'm just not that willing to shoot tif at this point. Raw files are big enough, often even shoot jpeg.
p.3 #11 · Compression vs Lossless Compression vs No Compression
kaplah wrote:
Lossy compression affects highlights; 12- vs 14-bit affects shadows / shadow recovery. Both are described by Nikon as "visually lossless", which I agree applies if the dynamic range is modest and/or we aren't trying to recover highlights or shadow detail.
And I meant to say that I'm not so sure about 'fungible'; I think that lost highlight detail is gone, while shadow details are recoverable with some noise.
Measurements by Kasson showed until now, that in single shot mode compressed files only minimally differ in DR. It is different when doing in AFC compressed, as the cameras went to 12 bit, here for the A7riv:
The A1 seems to differ, as DPreview claims there is only a minimal difference, which would be good news.
"Furthermore, although 30 fps bursts require you switch to lossy compressed Raw, we measured no additional dynamic range cost (there may still be potentially distracting local compression artifacts around high contrast edges of deep shadows in low ISO files)."
"Uncompressed and lossless compressed files retain the largest dynamic range, while lossy Raw files pay a slight 0.11 EV dynamic range cost. 0.11 EV is within our margin of error, so you're more likely to notice the local compression artifacts around high contrast edges of deep shadows than you are to notice this slight drop in measured dynamic range. Furthermore, if you're switching to lossy compressed Raw to achieve the camera's 30 fps burst rate, there's already a 0.2 EV drop in dynamic range due to the use of a fully electronic shutter, which makes this 0.11 EV cost typically irrelevant."
