Which compression should I use?

[Chrisku13]

Hi, I've been reading around these forums for a while, and have enjoyed learning a lot about how to take good photos from all of the knowledgeable users. I recently bought the Powershot A630, and I was just wondering if anyone knew how the JPEG compression affects the pictures. I don't know if it's the same with other Canon digitals, but mine has normal, fine, and superfine compression modes. I took three photos of the same subject with all of the same settings, except the compression used, and couldn't notice any difference between them. Is this normal? The superfine images are almost 4 times the size of the normal compression, so I want to save as much space on my computer as possible, but I also want high quality shots. Thank you in advance for any information.

[Jon]

Compression affects areas where there's very little difference between adjoining pixels; the more compression, the more similar colour levels are replaced by one colour. In extreme cases this'll lead to noticeable banding. Same thing happens when you open and re-save a JPEG so it's re-compressed. Cards are cheap; use Large Superfine. You won't find yourself regretting it when you want a large print.

[283CID]

Yup... Jon has it nailed... again.. [grin]. *I* got tired of being led down the Rosey Path so one day I set up my El Cheapo tripod and got in good and close for some 'tight' pictures of an unpainted piece of lumber... Lots of variation in the grain, etc. Even a knot hole. I took a slew of pictures, various resolutions, various compressions, etc. Looking at the .JPGs on the screen here.. side by side.. it was *just* visible, the differences. In fact, I now only run in Super-Fine, 'cuz I know it is supposed to be The Best. With a 2 GB memory, I can easily crank down the compression to Fine for a long trip, with no need to download and empty the memory...nice touch.

Try it for yourself; as usual, there is no Right/Wrong.. there's only what YOU like...

[Chrisku13]

Alright, thank you both for the advice. I searched and found a bit more about the compression (suppose I should have done that before), but your answers have helped me. I will probably just use the best quality that I can get, although I plan on purchasing an SLR sometime in the future so I can really dive into photography and make better prints.

[283CID]

There is no 'magic' to SLRs...I'm quite happy to leave that thing in the closet and use my S3 ! The only thing *I* know special about getting those Good Pictures is to zoom all you can, so that all those pixels you paid for are concentrated where you want 'picture information'. Not much good to have a bunch of pixels wasted in sideground, and be cropped away...

Have fun...

[Thomas S.]

There is no 'magic' to SLRs...I'm quite happy to leave that thing in the closet and use my S3 ! The only thing *I* know special about getting those Good Pictures is to zoom all you can, so that all those pixels you paid for are concentrated where you want 'picture information'. Not much good to have a bunch of pixels wasted in sideground, and be cropped away...

Have fun...

This is true, however with the S3 set to large size, there is still plenty of room to crop down to a regular printable size even 8x10. Sometimes I get in too tight and wish I had a little room around the subject later when I edit in PS. getting in too tight really makes the subject look constrained. But that is 100% my preference.

[Robukincan]

Never take my A630 off superfine!

[283CID]

I'll drink a La Batt's to that... especially if you can see the difference ?

[Robukincan]

I'll drink a La Batt's to that... especially if you can see the difference ?

Nothing is worth drinking North American beer for ;)

[jrobert]

The thing I find most distracting about .jpg compression is fringing around contrasty edges. More compression leads to more fringing.
Both of these pictures are 230x240; the left picture is 45Kb, the right one is 8Kb. Look at the edges of the candle and of the bear's ears:

[283CID]

Pretty dramatic, alright. I guess you pays yo' money and yo' takes yo' chances? As someone else commented, *mine* is now glued to Superfine as well. [with a 2GB memory....720 top quality JPGs]

[Jon]

As I've said before; memory's cheap. Especially if you compare it to film. And you won't pay any more for a Large Superfine print than for a Small Normal one of the same size, but in larger prints you'll see the difference.