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Old Jul 1, 2003, 3:55 PM   #1
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Default ISO settings on a digital camera? Why?

Just got a Canon A70 and like having manual control over shutter speed. But why are there ISO settings on a digicam? I always thought (from my film days) that lower speed films gave better 'resolution' and more color saturation (loved Kodak 50) at the cost of shutter speed and higher speed films allowed faster shutter speeds but gave grainier results when blown up and less snap in the color.

Does my A70 automatically pick an ISO or is it preset? If I have to pick I suppose I'd go with 200 or 400 since, in theory, there's no downside (ie grainy pics, poor color saturation) to allow for faster shutter speeds.

What would you all recommend for vacations shots on a cruise? I'm leaving Saturday and don't have enough time to master this thing!

Thanks for the help,
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Old Jul 1, 2003, 5:48 PM   #2
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Your camera will default to the AUTO ISO setting.

The higher the ISO the more "noise" will be created for shots. Higher ISOs are good for night shots.

I honastly just leave mine on AUTO for ISO and the images seem to be good. I should play around more with this. I've taken indoor(dimly lit) shots with an ISO of 400 and YIKES it look like to took the images in a resolution of like 100x100 that was blown up to 1600x1200

The outdoor shots were a bit better, but too much noise for my tastes.

If you have no time to play with it.. Set the camera to mode 'P' which is Auto apeture and shutter, yet lets you play with the White Balance, shooting modes, exposure compensation and stuff

Hope that helps some
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Old Jul 1, 2003, 6:00 PM   #3
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Not sure about the A-70, however, my Powershot Pro90 has a selection for ISO numbers from 50 to 400 plus AUTO. The AUTO position chooses between 50 and 100, depending on the lighting conditions. You can't set ISO numbers in the camera's automatic mode. Choose "P", Tv, Av or manual modes to set ISO numbers.

From what I understand, digital camera ISO settings just control the voltage output of the sensor chip...

Higher ISO settings in your digicam let you squeeze out some shots you couldn't otherwise get at a lower ISO number. The price is noise in your pictures.

I use higher ISO numbers after everything else fails, including using my tripod, flash, lens stabilization (yours doesn't have this option), etc.
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Old Jul 1, 2003, 8:22 PM   #4
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Check out this current thread:

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Old Jul 1, 2003, 9:12 PM   #5
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With the A70, you can let the camera pick the ISO for you as Gimli stated. I like to keep it on ISO 50 for most shots and you can set that manually in the P, TV, AV or M settings.
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Old Jul 2, 2003, 1:09 PM   #6
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Ah...at least a big WHY question...but I can tell you this: there are a lot ov BECAUSE answers. The photography system has been exist outhere for a long time, on film, and now digital. To make is more practical, the digital photography system need be consistent with the film system to make everything in order and simple. The ISO rating is the sensivity of film or the digital chip subject to light, the higher ISO rating, the more grainy result in picture (for film) and noise (for digital), but it will allow you to shoot picture in low light in some instance without using tripod (hopefully) and utilize the high speed shutter in sport photography or other applications . The most important thing is to allow you to use many existing photographic tools available outhere for digital photography. For an expample, if you decide to buy a studio light system, or you decide to shoot in manual mode, but using a handheld meter for exposure, if you camera doesn't have the ISO system built in, you are completely out of luck since the meter is calibrated base on ISO as well. You can also shoot picture in film and make a comparison to digital base on the same exposure you set on the camera. I hope you see the points...Cheers
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Old Jul 2, 2003, 1:24 PM   #7
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I too use mainly 50 ISO setting to keep the pics as noise free as poss

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