Hi all,

I have a new digital camera -- a Sony DSC W5 which I like very much -- and it offers a setting for picture quality: fine or standard. As far as I can tell (the manual doesn't indicate), the difference appears to be the latter uses JPEG compression (I estimate 75%), which saves a lot of space on the memory card (~50%). Is there any reason not to use JPEG compression? Can one see compression artefacts with the naked eye?

Thanks...

It all depends on what you are taking a picture of and your own eyes. Jpeg is a variable compression format so depending on what your camera is set to will make a difference (this is usually set by the maker).

Anyway if you took a picture of something like the sky at sunset when it is cloudy and you have lots of shades of oranges and reds. If you then use high compression jpeg it will take all of these different shades and do some stuff with them like take an area with some oranges in them and compare them to see how much they vary if there is not much difference in them it will make them all one shade then with some more calculations this will result in a smaller data size. So what affect will this have, well if you now look at the whole picture you will see little and sometimes big patches of one shade of colour, which will take some of the detail out of what you where taking a picture of. In a worst example I have seen of this the sky had distinct strips of colour when it should have had little differences.

Well I hope this helps you out a little bit.

Personal bias only......

Set the camera to the highest quality setting--memory is cheap, and you cannot ever increase the quality, resolution, etc. later.

Exception--when you KNOW that all you'll be doing is 4X6 snaps, then you might go a bit lower.

I completely agree. I don't know how many times I took pics at lower resolutions to save memory and regretted it.

It also depends on what you are taking the photo for - if you intend to getting it developed and mounted go for the highest setting.

If you are just taking happy snaps on holiday, a standard setting will be fine.

Having said that, flash memory cards are very cheap, so if you don't mind transfering the pictures to your computer regularly or changing cards often, go for better quality. You can never increase the quality of a picture once it is taken.

--Ian

I've seen this kind of distortion in poor-quality DivX rips of videos, especially in dark patches, where the "quilting" effect can be quite noticeable, but I have never seen it in JPEG stills. Prior to buying a digital camera, I used to scan 35mm prints and save them with 75% JPEG commpression, and I never noticed this problem. Maybe it only becomes visible if you enlarge a compressed image to 20 x 30cm on paper. I guess I need to experiment further.