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Old Jan 7, 2004, 6:09 PM   #1
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Default ISO's

Since I am a newbie with digital cameras, I'm not sure how to ask this question, but here goes.

My film camera has ISO 100-800 available to me, with ISO 100 being the clearest speed. I am looking at a Nikon D100 now which starts at ISO 200, but goes way up to ISO 6400. Is the lack of the ISO 100 setting a disadvantage?

My inexperience is showing, but I'd appreciate any discussion of ISO film vs digital.....

Thanks
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Old Jan 7, 2004, 6:48 PM   #2
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Hi Hangloose!
I'm probably a little less of a newbie than you, but one just the same . I have the D100 and from my experience with it the ISO 200 is just fine. The pro's might notice a difference between 100 & 200. But to my untrained eye, I can't. Now on to the other end of the spectrum, the ISO also goes to 1600 and I believe you can "push" it thru the camera up to 3200 or 6400. I've never had an occasion to go past 800. My problem is I have to remember to change the ISO when I take night shots and back again when in daylight!! :lol:

Chris
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Old Jan 7, 2004, 9:02 PM   #3
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The lowest "film speed" setting (ISO number) that is supported by any digicam is the setting that yields the lowest image noise that is possible with that camera. A camera like the D100 will exhibit its highest quality images (lowest noise) at ISO 200. This is good since it means that at the lowest noise level you still get quite respectable light sensitivity.

A lesser quality camera might have its lowest noise sensitivity at ISO 64, which would mean that its best quality images would require longer exposure times, or larger aperature settings (or flash) compared with the D100.

Note however, that the image noise at one camera's lowest ISO setting may still be greater than the image noise of another camera at its lowest ISO setting.
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Old Jan 7, 2004, 9:02 PM   #4
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The lowest "film speed" setting (ISO number) that is supported by any digicam is the setting that yields the lowest image noise that is possible with that camera. A camera like the D100 will exhibit its highest quality images (lowest noise) at ISO 200. This is good since it means that at the lowest noise level you still get quite respectable light sensitivity.

A lesser quality camera might have its lowest noise sensitivity at ISO 64, which would mean that its best quality images would require longer exposure times, or larger aperature settings (or flash) compared with the D100.

Note however, that the image noise at one camera's lowest ISO setting may still be greater than the image noise of another camera at its lowest ISO setting.
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Old Jan 8, 2004, 6:43 AM   #5
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From "blue sky" tests I've done with the D100 the noise begins to come in more significantly at about the ISO 800 mark. This seem to tie in with the noise reduction profile supplied as part of Nikon Capture Editor. As I recall that goes up a step from ISO 640 to 800.

In practice I can't tell the difference between my ISO 200 and 400 shots in terms of noise, and I've recently started to experiment with ISO 640 on these gloomy Scottish days.

Regards,
Graham.
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Old Jan 8, 2004, 8:00 AM   #6
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I don't know if its true on the D100, but on some cameras the lower the light the more noise. So if you need the higher shutter speeds on a well lit day any ways (really fast moving subject) you might get less noise than if it were sunset.

Eric
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Old Jan 8, 2004, 9:13 AM   #7
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The ISO rating is a measure of the amount of light required to create a properly exposed image.

a 200 speed film needs half the light that a 100 speed film does and a 400 speed film requires a quarter of the light that a 100 speed film requires. In simply terms for a fixed apeture you would use 1/30 at 100 1/60 at 200 and 1/125 at 400 and so on. Or you can leave the speed the same and change the aperture f8 f11 f16.

With film slower films have finer grain (the particles of chemical that actually record the light). With digital the grain is always the same because it is the number and size of the sensors on the CCD (1mp 2mp 3mp ....).

As others have explained a new problem enters the equation with digital and that is noise. This is roughly equivalent to the coarser grain on faster film but it's cause is entirely different.

So in terms of image quality which is the main reason for using slow film in cameras there is no loss in not having 100 ASA setting on the D100 you are getting the best quality the camera can produce at 200.

What you do lose is the ability to use slower shutter speeds or wider apertures in very bright conditions. However I wouldn't expect this to be a major problem.
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Old Jan 8, 2004, 10:20 AM   #8
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Quote:
Originally Posted by eric s
I don't know if its true on the D100, but on some cameras the lower the light the more noise. So if you need the higher shutter speeds on a well lit day any ways (really fast moving subject) you might get less noise than if it were sunset.Eric
I think this may apply with the D100 as Nikon recommend their in-camera noise reduction be switched on for long exposures. I suspect that low light = longer exposures at the same ISO = more chance of circuit noise ?
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Old Jan 16, 2004, 3:32 PM   #9
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What about the Olympus C-750. What is a good ISO for indoors and outdoors. My camera ISO is 50-400. I hope I worded this right for a newbie.
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Old Jan 16, 2004, 4:10 PM   #10
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Quote:
Originally Posted by Imacer
What about the Olympus C-750. What is a good ISO for indoors and outdoors. My camera ISO is 50-400. I hope I worded this right for a newbie.
Check your manual to see what the default ISO is. This is the one that will give the best results in most situations. You can set up a test subject--say, a still life with various types of objects of various colors, then place it in front of a window where full light is coming in. Try different ISO's. Then move the still life away from the window or draw the drapes or whatever it takes to block out the strong light, and take the same pictures using the same settings as you did for the first group of pictures. Make sure you jot down your settings for each shot so that you can evaluate them later.

It's a pain in the neck to do, but you'll learn a huge amount about your camera by performing tests like this one.
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