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guild Dec 7, 2003 6:49 AM

General Easy Questions (but i'm still confused)
This may sound like an easy exam or something, but I have no clue what these means. Please help me out...

1) what is ISO? Is that related to film speed somehow?
2) Zoom wide and tele
3) Lens aperture - is that the f2.0 / f8.0?
4) CCD size

I'm basing it a lot on digital .. But if it could be related to film or film SLRs, please include some info.

Thanks a bunch!

bcoultry Dec 7, 2003 7:49 AM

I'm not all that technically minded, so maybe, in a way, it would be good if I were to be the first to answer your questions, allowing others who are more knowledgable to elaborate.

1) what is ISO? Is that related to film speed somehow?

Yes, it's very much related to film speed. Just as higher ISO's in film mean the film is more sensitive to light--quicker to pick it up--so it is with digital. And just as there's a trade-off with film, so there is in digital. The higher the ISO in film, the larger and more apparent the grain; in digital, the grain shows up as "noise."

2) Zoom wide and tele

I'm not exactly sure whether you're referring to two or three lenses here. A wide-angle lens does just as its name implies: affords a wider view of the subject. For instance, if you have a person standing between two trees in the middle of a field, the wide-angle lens will see the person, the trees, and the field. If you "zoom" in with a telephoto lens, the angle of view is progressively reduced, first cutting out the field, then, zooming in closer yet, cutting out the trees and showing just the person. With a powerful telephoto, you might even be able to zoom right in on just the person's face. Think binoculars.

3) Lens aperture - is that the f2.0 / f8.0?

You've pretty much got it on this one. The higher the number, the smaller the opening of the shutter when you take the picture.

4) CCD size

I'm not able to answer this one unless what you mean is the resolution of the CCD, which refers to how much information it can pick up. A five megapixel CCD will be capable of picking up far and away more pictorial information than a CCD of 2.5 megapixels.

Okay, there are my simple explanations. It's now time for the experts, the people who actually know what they're talking about, to chime in.

Mathilde uP Dec 7, 2003 8:08 AM

A quick shot;
1)Iso is the film speed/ sensitivity. It is adapted by digital cameras to nominate the sensitivity settings for various light values.

2)Zoom tele and wide is the lens ability to capture a wide shot (for instance at 28mm) of a scene. Or a remote part of the scene (for instance at 100mm). The human eye sees roughly at 50mm.

A bit more on lens mm. Iimaging aunt Betha standing in a field of corn with a scare crow at the end of a field. At wide angle you get a photo of the complete field and aunt Bertha a bit smaller than your eyes saw her on the photo.
Now imaging you want aunt Bertha as you see her, you zoom at 50mm. Next you hear her comment on your lifestyle, and you rather have her face with the scarecrow at the back, so you zoom at 120mm. The mentioned zoom mm numbers are just examples. If you like to capture a deer far remote in the mountains, you might like a 380mm or more zoom lens. Going for max zoom aint sacred. It is mentioned at this forum you will need a minumum shutterspeed 1/zoom mm to prevent blur. Or use a tripod. 300mm will require a shutterspeed of 1/300 which might not be practicle if you are bird chasing in a Scandinavian forest.

3)Lens aperture is the F number indeed. It refers to lens opening size. F2 means a large opening and little depth of field. F11 is a tiny lens opening with large depth of field. Depth of field is the range of photo that is in focus. It also depends on subject distance.

4)CCD size is the physical size of the cameras image capturing sensor. Bigger is better, but no guarantee on camera performance. Numbers are quite confusing, here is some guideline;
number mm size aspect ratio
1/2.7".=5.27 x 3.96 mm.......4:3
1/1.8".=7.18 x 5.32 mm.......4:3
1/1.7".=...............................4:3 Fuji camera's
2/3.....=8.80 x 6.60 mm.......4:3 dslr en Nikon 5000 enzo
4/3.....=18.00 x 13.50 mm...4:3 Olympus E-1
..........=22.7 x 15.1 mm.......3:2 Canon 10D, 300D
..........=36 x 24 mm.............3:2 = 35mm film

See also

There are also numerous tutorials on-line about photography, but I can't find it 123 back at my computer.

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