aperture on canon powershot S3IS digital camera

[QUOTE=Kidrobot]Hi Im relatively new to shooting digital and i was wondering if there are any other powershot users out there who can help me. I love the camera its got some pretty cool features on it but one thing that i am confused on, the highest aperture setting on the manual mode is F8.0 [quote]

Well, this is pretty typical of Point and Shoot cameras, even the advanced ones. The aperture is a function of the lens of course.

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im alittle confused on this. so first question why is the highest 8.0 and not something like F22, I've messed around with and the 2.7 is there and it looks to me that when i want foreground or background out of focus and the 8.0 works pretty well on giving me a greater depth of field ok so we're all fine there

Basically, there are a few things influencing the depth of field here. One is the aperture, but the more important ones are the image sensor format and the lens.

On the S3 IS, the lens is actually a 6.0-72mm lens. At 6mm focal length, ƒ/8.0 will be more than enough to get everything in focus at or even remotely near the hyperfocal distance (particularly since the focus throw to infinity is almost nil). Short focal length translates to greater depth of field for a given aperture. There is very little need for anything beyond that technically.

The format of the sensor is a 1/2.5" size, so there is another group of factors here: pixel size, circle of confusion, and so on. The issue it brings up is diffraction. Diffraction is the worst enemy of small apertures on digital. Depending on the viewing size, sensor size, aperture used, lens, viewing distance, and so on, diffraction can absolutely destroy the detail in the images. On DSLRs, depending on pixel size, diffraction can start to kick in around f/16, on some as low as f/13 or f/11. On the S3, the sensor size is a mere fraction of that of a DSLR, so the pixel size is much smaller at the same pixel count.

Simultaneously, due to the much greater crop, the lens sort of backtracks on the diffraction issue, but not as much. therefore, even around f/8, diffraction can already cause some major loss of detail. Beyond that, it is very obvious so they save time, money, reputation etc. and just don't let you go beyond that. There is very little need for it at the wider focal lengths, and by the time you zoom in very much, what it does isn't much different than an equivalent effective focal length lens on 35mm film at that aperture, so there's no real loss.

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however.......what is the translation from 35.mm F8("who cares" aperture) and F22(Foreground to Background focus) brought into the digital realm F2.7 F3.2 F3.5 F4.0 F4.5 F5.0 F5.6 F6.3 F7.1 F8.0

if anyone can answer this for me it would be greatly appreciated

If you still have any questions, I'll try to answer them.

P.S. I'm moving this post to the general digital cameras forum as the S3 is not an SLR :thumbsup: