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09/15/2003 10:00:06 PM · #1 |
Sorry if this has been asked before, I can't seem to find a way to search the forums (please let me know if I have been absolutely blind and missed it, it has been known).
With the recently aquired EOS 10D I can change the ISO between shots (wooohooo!!!!!!!!!!).
Uh, but hang on, I am now spoiled for choice, d'oh!
Can anyone point me to a decent guide, more than just a "bright and sunny use ISO 100, dark and gloomy use ISO 98,463,764" so I can try and get it better while I learn the intricacies.
Yes, I know lower ISO, slower film, less grainy etc .. but to be honest, that's about where my knowledge stops.
I am looking for a nice easy answer .... but have little doubt it will be highly complicated ... such is the joy of learning *laugh* |
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09/15/2003 10:04:38 PM · #2 |
I'll give you my only slightly educated opinion, but keep in mind I don't have as sophisticated a camera as you've upgraded to (yet!), so there may be more to it than this. :)
I always keep my ISO setting at the lowest, because that will always give me the least noise. I only increase ISO when all other adjustments (aperature, shutter speed, focal length) lead to the possibility of camera shake and/or too dark an image. (Well, that is, when I remember.) |
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09/15/2003 10:09:26 PM · #3 |
ISO Stands for International Standards Organization.
Here is an artical on understanding film speeds
//planetanimals.com/logue/Film-sp.html |
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09/15/2003 10:21:23 PM · #4 |
Oops, I responded before I read the last bit asking for an explanation. OSS's link looks good, but here's a quick and dirty definition: Every time you double the ISO, you double the sensitivity of the camera to light. So, a picture taken with the ISO set to 200 will be twice as bright (which is a bit hard to quantify) as one taken at ISO 100 (all other parameters being equal). Where this comes in handy is when the light is so dim that you have to set a slow shutter speed to get a good exposure. Say your ISO is set to 100 and, to get a bright enough picture, you have to set your shutter speed to 1/30 of a second. But then you risk capturing motion blur. You can compensate by increasing your ISO and cutting your shutter speed. If you double your ISO from 100 to 200, then cut your shutter speed in half to 1/60 of a second, you will get the same exposure (brightness) with a faster shutter. 1/60 may still be slow, so you can again double and half to ISO 400 and 1/120 of a second, and now you'll probably be able to avoid motion blur. (There are other variables and considerations, namely aperature and focal length, but it all comes down to how much light you capture.)
The price to pay for achieving the faster shutter speed is noise in your final picture. But there are techniques for dealing with that later, and if it's a question of stopping the motion, that's usually an OK trade-off. |
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09/15/2003 10:21:48 PM · #5 |
Nice easy answer? Always shoot at ISO 100 when you can. This produces less grain. But you'll notice that the 10D is still very usable up to ISO 1600 for those low light situations.
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09/15/2003 10:24:13 PM · #6 |
| ISO has been around since film and is more a film thing. even though it has been adapted by digital cameras there is more info out there through looking at film ISO, which is not really any different, other than the fact there is no longer film of course. |
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09/15/2003 10:33:04 PM · #7 |
| The other thing you might notice that the higher ISO shots are punchier, typically more contrasty and have a different look to the cleaner, low ISO shots. This can also be used creatively. |
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09/15/2003 10:37:29 PM · #8 |
| Good point. Here's a shot where the noise definitely adds to the atmosphere of the image: //dpchallenge.com/image.php?IMAGE_ID=27349 |
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09/15/2003 10:43:57 PM · #9 |
You'll always want to shoot at ISO 100 if light allows. Digital noise is rarely as pleasing as analog film grain; besides, if you want to add grain for effect, it can be done later in software.
That said, you'll find lots of instances where ISO of 200, 400 or greater is useful. I've used ISO 800 for existing light macro work and had great results, especially with a bit of judicious NeatImage work.
If you don't have exclusively "fast" L lenses, your max aperture of F3.5, F4.0 or even F11 (my Canon 28-200 3.5-5.6 at full zoom with a 2x teleconverter) can require faster ISO settings under even moderately challenging conditions.
I find I shoot most often in aperture preferred mode when using existing light, and letting shutter speed fall where it may. If shutter speed falls belwo what I deem to be appropriate, then I bump up ISO to compensate. |
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09/15/2003 10:58:54 PM · #10 |
| i agree with kirbic and do basically the same thing. he gives some good advice. |
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09/16/2003 08:56:41 PM · #11 |
Thanks everyone. Great discussion and very helpful indeed.
I'd been messing around with the ISO and had come up with my own basic rule of "I'll just leave it at 200 for day, 400 for night, and then occasionally mess around for other reasons.
Seems like the "Go for 100 whenever possible and only up it when there is not enough light (unless for a special effect MAYBE)" seems to definately be the way to go.
Thanks muchly :) |
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09/16/2003 10:55:30 PM · #12 |
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