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View Full Version : MkIIn: Which JPEG do you use?


Doc Nickel
26th of April 2006 (Wed), 14:36
First, yes, I know about RAW. I'm working towards it, but I need a faster PC first. :D

So at the moment, I'm shooting large JPEG. One of the first things I did was set the JPG "quality" up to 10- minimum compression. But, interestingly enough, that cut the card capacity down to about half over the default 8.

So I took some experimental shots, shooting the same scene at the same distance with the same area in focus, in settings 4, 7 and 10. Obviously there's a major difference in actual file size, because I'd have 500+ shots at 4, and only 150 at 10.

One of the main projects I have in mind involves printing photos at poster size- I've had "large JPEG" shots from the XT blown up to 18" x 24" and they look great. Though the printer did do a bit of upsampling and sharpening. But I still want the best image I can get to start with- which is why I bought the N in the first place. :D

I'm not all that worried about running out of space. I have four gigs of cards now and six more on the way- typical, I can now buy a 2Gb Ultra II for what a 1Gb cost me a year ago. :)

But in my experimental shots, even at 200% I can't tell the difference between JPG settings 4, 7 and 10. Obviously some data is lost since the file sizes change so radically, but I'm having a hard time spotting any artifacting or other image degradation.

Dropping from 10 down to the default 8 gives me a solid 25% more space in the cards, and doesn't seem to visibly affect the image.

So, to those of you who shoot JPEG with a MkII or N, what setting do you use? Have you tested the various compression levels? How would I quantify the difference, is there is any?

Doc.

Jon
26th of April 2006 (Wed), 14:43
The difference will be most evident if you shoot something with a very gradual tonal gradation. At higher amounts of compression you're going to see more "banding" in the colours.

René Damkot
26th of April 2006 (Wed), 14:45
Well, I did a similiar test with my 1D2, and was just able to see a difference between 7 and 10 (2 layers in PS, clicking the top on and off.... Holding the files next to each other is *not* gonna work ;)
8 thru 10 looked the same. (or near enough) So I use 8. Sometimes I do see a bit of jpg artefacts, but if I want optimum detail, I'll use RAW.
Try this test with something that has *a lot* of fine detail. A newspaper at so small a size it's barely readable at 100%. Might help. Using higher ISO might also make differences more visible (I presume: I tested at ISO 800)

Doc Nickel
26th of April 2006 (Wed), 14:52
Hmm, good point. I'd been looking for objects with high contrast, since I usually noticed artifacting at hard edges with the older digitals. But I suppose I wouldn't see that kind of thing until very high compressions

Wonder what I can find with a smooth gradient...

Doc.

Jon
26th of April 2006 (Wed), 14:53
Hmm, good point. I'd been looking for objects with high contrast, since I usually noticed artifacting at hard edges with the older digitals. But I suppose I wouldn't see that kind of thing until very high compressions

Wonder what I can find with a smooth gradient...

Doc.There's always the sky, or shine a light across a stretch of wall.

Double Negative
26th of April 2006 (Wed), 15:07
10, or the max setting is practically no compression at all. If you plan to edit your photos after shooting, I'd set it for this - and do the compression part on the final save.

JPEG compresses large areas of similar color the most. You'll see the artifacting here first, like skies. Detailed vegetation and the like compress the least, because the algorithm can't compress the details as much as flat color.

I shoot RAW on my 1D2N though. :)