Why so small?

Most of the time, i as many other photographers i know do, use smaller apertures over smaller ones, like 2.0 - 3.0. For their DSLRs, they only tend to buy lenses that go to 5.6. My G6 goes up to 8.0. Why do they put such high values on the camera? What's the kind of photography you can take w/ this aperture?

I assume you mean that you use larger apertures (f/2.0 is large, f/8.0 is small) because you can get more light into the lens, so you get a faster shutter speed etc.

You normally stop down the lens (use a smaller aperture) if you have enough light and want to get as much as possible of the image in focus.

For DSLR's, most photographers try to buy lenses with larger apertures as well, but those are very expensive, because they must have a lot of glass inside to to cover the larger sensor of the DSLR. E.g., a 70-200/2.8 lens for a DSLR is much larger, heavier and more expensive than most compact digicams

The smaller sensor of the P&S, however, has the negative effect that refraction starts to impact image quality at something like f/6.3 ... for that reason, most compact digicams are limited to f/8.0 as smallest aperture. Because of the different sensor size, this is roughly comparable to f/22 on a DSLR.

PS ... a 70-200/2.8 lens can be used at f/2.8, 4.0,5.6, ... 22. The 'real' limitation is the f/2.8.

Best regards,
Andy

I'm not absolutely sure I understand what you're asking but I'll give it a shot. If you are using a DSLR, there are times you are going to want to use apertures of f/8.0 or f/11.0 to increase the depth of field.

This is necessary with the larger size sensor and a telephoto or zoom lens. (Especially, if you are using a 5d or other full-frame 35mm sensor.)

Lenses have a "sweet spot" where the lens performs best at certain apertures. Typically, this is somewhere in the middle range of the f/stops available for a lens. On the G6, I tend to use it between f/3.0 and f/4.0 most of the time.

When I was using 35mm film cameras, I typically shot with the aperture set to about f/8.0 on a telephoto lens to get the best image and a decent amount of depth of field. If I wanted to isolate the subject from the background, I would drop it down to about f/4.0.

Now, it sounds like you're asking why the G6 will go up to f/8.0 when most people never use them at that setting and even DSLR users tend to use larger apertures. (By the way, I checked the specifications on a couple of Canon DSLR lenses and the range is usually from f/3.5 to f/22 for their zoom lenses.)

There are times when you need maximum depth of field at the telephoto end of the lens, especially if you are using a teleconverter on the lens. That's when you would use f/8.0. Other times, you might be in a situation where you want to keep the shutter speed down (to show motion) and the lighting is very bright. The built-in neutral density filters can help but, in bright sunlight, it still might not be enough so you would use f/5.6 or f/8.0.

I hope I interpreted your question correctly. If not, let me know and I'll give it another shot.

Michael

Thanks both of you, you nailed my question very well. I have one question though. When shooting sports in broad daylight, would using the f/stop 8.0 be a good idea w/ 1/2000? Or a larger aperture be better suited?

I think it depends on your composition. Some people like the focal point to be the subject and like the backgorund to not "interfere" with thier subjuct so they use a low depth of field. Some pictures look better to some people with a wide depth of field so they will bump up their f/stop...

The beauty of the small sensors (like that on the G6) is you get tremendous depth even at wide apertures; this can be a good or bad thing, depending on what you're trying to do. The smaller the format, the more inherent DOF you have. f/8 is all we need for a compact, whereas DSLR's use the same range of apertures as 35mm film SLR's. On an 8x10 view camera, even f/64 has limitations for DOF control.

I used f/5.6 most of the time on my G2, because I read on this fine forum here, that this is the 'sweet spot' of the lens. Also, because of diffraction, the image will get fuzzier if you stop down after f/5.6 (f/5.6 will yield the sharper image than f/8.0 on a compact digicam)

Also, you have to keep the ISO sensitivity in mind. In 95% of my images, I used ISO 50, because everything more than that is pretty unusable on the G-series without noise removal.

Best regards,
Andy

The aperture setting is an adjustment. Along with ISO, it controls the shutter speed for a given amount of light. To reduce the amount of light, go to a larger number (smaller aperture). To increase the amount of light go to a larger aperture.

While it is true that the aperture setting affects the depth of field and the sharpness of the lens, my advice is to ignore those effects until you are completely comfortable with the settings. Just open her up to let more light in and vice versa. Don't worry about "sweet spots" and "one setting fits all" for now.

I usually use f/5.0 (the middle of the f/stop range) unless I need to open up.