A80 Resolution suggestions

[kph100]

Hi
My question relates to what resolution I should set the A80 at.
I currently have it at M1 and Fine compression. Can you confirm that this will produce good quality 6x4 inch prints.

What would this setting look like at enlarged size ?

primarily my prints will be 6x4 occasionally 7x5 but if a great pic maybe get enlarged.

If Im looking to enlarged print will it mean changing to L ( Large) setting prior to taking print or will M1 go to larger than 6x4.

Also whats the difference between fine and superfine for a 6x4 print ?

Thks.

[CowboySlim]

Well, KPH,

I was hoping that someone would come along and answer your question as I wondering about the compression levels, normal, fine and superfine. However, perhaps if I toss some speculation in, someone will correct me I'm wrong.

Firstly, I have a Canon A40, which is much the same as the A80 but with only 2Mb on pixels and lacking some other features. I generally shoot at the maximum resolution, which for me is 1600 x 1200 and save them at the superfine compression level. I have no reservations with respect to the quality of 4 x 6" prints and have blown some up to 8 x 10" with quite acceptable results. With the Compact Flash cards so cheap now, I just don't bother with a lesser resolution of more compression.

Now, I'm really clueless with respect to the effects of the compression. I don't know if more compression is "lossless" like "Zip" compression but just takes battery charge and processor time to compress. Or, maybe it is like the MP3 compression used for songs that saves a lot of space but also is somewhat "lossy" in that it tosses out data that it considers insignificant. The A40 guide indicates that the storage requirements are in approximately the ratio of 1:2:3 for normal, fine and superfine, respectively. So, this is where I'm really guessing that 1/3 of the pixels are dicsarded going from superfine to fine and 2/3 are discarded if the photo is saved at normal.

Looking at the guide again, the resolutions large, medium and small are basically in the ratio 10:5:3 for Mb required per photo. So what to make of this? If one is memory limited, is one better off at superfine compression and medium resolution or large resolution and fine compression? I'm clueless.

Anybody?

Slim

[Oleg]

JPEG compression is more like MP3 compression. It does lose data, although it doesn't discard any pixels. As far as I know, it works with color fields. The best compression is achieved with the pics which have large uniform color fields (like Malevitch's 'The Square' ) - you'll get a very small JPEG file with very little loss in quality. On the contrary, pics with many tiny details (like tree leaves, grass), smooth gradients, or just really noisy ones will give you rather big JPEG files. As the result, if you try to apply a high JPEG compression to the second kind, you'll get very distorted colors - where you had smooth gradients, you'll see color stripes, the details' edges will have parasitic "waves", etc. In brief, if you're taking pics of the second kind, you'd better go with the least compression possible. The higher resolution compensates the compression effects to some extent, because the compression distortions being of the same size in pixels look smaller in respect to the whole image, so there has to be the golden mean, but it probably depends on the characteristics of a particular camera - try different combinations and see what works best for your camera. In my A70 I usually set M1/S - 1600x1200 at the superfine quality.

[CowboySlim]

Thanks, Oleg,

That is a good, understandable answer.

Slim