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DPChallenge Forums >> Tips, Tricks, and Q&A >> What is ISO?
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 05/15/2004 12:36:26 AM · #1
What exactly is ISO? What does changing the ISO number change in the pictures taken? My camera can have 100, 200, 400, or auto (the default).

Also.. how might I go about changing the shutter speed? I know that many cameras are different.. and I've looked through the menus but I'm not exactly sure what I'm looking for.

(Yes, I am lame when it comes to anything about cameras. Isn't it obvious?)

Edit: I may as well add some more here while I'm at it:

I sort of kind of understand what depth of field is. I know that you can change depth of field by changing where the lighting is, though I don't really know how. How else can you change depth of field?

How do you focus besides using auto-focus? Someone said that one of my current entries is sort of blurry.. but.. I just let the camera do the focusing for me. How could I do it manually?

Message edited by author 2004-05-15 00:38:57.
 05/15/2004 12:38:45 AM · #2
Best suggestion...read your camera's manual. That should be your first step.
 05/15/2004 12:39:56 AM · #3
Originally posted by cbeller:
Best suggestion...read your camera's manual. That should be your first step.


I wish that I had it! I got the camera passed down from my dad, since he got a fancy new one. I really doubt that he has any idea where the manual to this one is.
 05/15/2004 12:44:52 AM · #4
It's not the manual, but has pretty much the same info. Quick Google search for "coolpix 800 owner manual".

//www.imaging-resource.com/PRODS/C800/C800A.HTM

That should help you answer a lot of your questions about your camera. If you Google some more you can probably find a PDF version of the actual manual to download, as well.
 05/15/2004 12:51:18 AM · #5
Thanks, cbeller. I'll definitely try that.
 05/15/2004 02:34:28 AM · #6
ISO a.k.a. International Standards Organization, formerly ASA (American Standards Organization), refers to the sensitivity to light.* The smaller the number, the less sensitive to light the camera will be. Also, lower ISO/ASA numbers are less grainy than the higher numbers.

Generally, when choosing a film speed, consider how large you plan to print the image. Lower sensitivity is better, with smaller grain, but requires more light. This necessitates either increasing the duration of the exposure or using additional light sources. The ISO/ASA numbers lose one stop of light for each doubling of the number, and film graininess generally increases proportionally as the number increases.

* European camera manufacturers also used another method of referring to light sensitivity, DIN, which stood for Deutsche Industrie Norm. (The German method is very precise but is not quite as easily calculated. 100 ASA/ISO = 21 DIN but 200 ASA/ISO is 24 DIN, 400 ASA/ISO is 27 DIN. It̢۪s all fairly complicated, and thank Goodness we now have the ISO that seems pretty well universally accepted.

I believe that the Japanese played with the concept of their own rating, and THAT was when ASA became ISO and we quit quibbling. (Now only old photographers know or care about this trivia).

I found a chart about ASA/ISO/DIN at //www.rit.edu/~rckpph/faq/28.17.html.

05/15/2004 04:40:20 AM · #7
ISO - What the jerk should call himself after cutting me off on the freeway.
 05/15/2004 05:41:42 AM · #8
Try this. Maybe helps
dpreview in depth review

or this

//www.steves-digicams.com/nikon800.html

Ups! Took me 1h but I got it. I know hoe is it without a manual!!!

//www.nikonusa.com:80/pdf/CP800man.pdf

Enjoy

Message edited by author 2004-05-15 06:05:14.
 05/15/2004 01:00:21 PM · #9
Thanks everyone!

f-32, it's nice to know all of that stuff, even if it's only "old-timer" trivia. Calling me an amateur is being kind. The best title would be "an idiot with a camera" - hehe. I'm really trying to learn everything I can.. and even history is fine in my book.

fadoi, very funny!

Tiberius, you didn't have to spend so much time on that! Thanks so much. Hm. Now I just need to find a little time for some reading!

Thanks again!
 05/15/2004 01:14:30 PM · #10
In simplest terms, from what I have read and found with my camera is the Higher the ISO the more noise you introduce into the picture. Use higher ISO for faster shutter speeds, use lower ISO for less noise. I found saturation better at lower ISOs (my blues are bluer etc.) I never use auto and stay at 50 or 100 for almost all my shots. I have been lucky enough to take (handheld) low light pics at ISO 50. If I want the grainy film effect I will go higher.
 05/15/2004 02:12:37 PM · #11
Originally posted by awpollard:
In simplest terms, from what I have read and found with my camera is the Higher the ISO the more noise you introduce into the picture. Use higher ISO for faster shutter speeds, use lower ISO for less noise.

Uh, I think it's the other way; that at a given aperture, if you raise the ISO number, you can use a slower shutter speed to achieve the same exposure.

To answer the main question, ISO is the acronym for the International Standards Organization. The numbers used to rate cameras were originally a set of ratings applied to film by the American Standards Association (now the American National Standards Institute or ANSI); I believe European films used a different rating scale. At some point, the ISO aparrently adopted the ASA scale to be the international standard.
 05/15/2004 03:15:18 PM · #12
Originally posted by GeneralE:
[quote=awpollard] In simplest terms, from what I have read and found with my camera is the Higher the ISO the more noise you introduce into the picture. Use higher ISO for faster shutter speeds, use lower ISO for less noise.

Uh, I think it's the other way; that at a given aperture, if you raise the ISO number, you can use a slower shutter speed to achieve the same exposure.

text

Now General, let's not confuse anyone with inaccurate information. We all know that higher ISO settings mean higher sensitivity, permitting faster shutter speeds and smaller apertures. The higher sensitivity also means higher noise levels.
 05/15/2004 05:32:40 PM · #13
ISO is an organization that publishes standards, not just related to photography. For example, as a project in grad school, I built a piece test equipment that measured acoustic absorption per an ISO standard.
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