ISO
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Dan Leach
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ISO is the sensitivity of the film or digital CCD.
A high ISO is more sensitive to light and will allow for faster shutter speeds, the downside is the picture will be more degraded and 'noisy'. Better quality images come from low ISO settings, but these require longer shutter speeds and camera shake might become a problem
A high ISO is more sensitive to light and will allow for faster shutter speeds, the downside is the picture will be more degraded and 'noisy'. Better quality images come from low ISO settings, but these require longer shutter speeds and camera shake might become a problem
chuckles
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International Standards Organisation (ISO), was American Standards Association (ASA) and Deutches Industrie Norm (DIN). I think there is another the Russians invented, GOST but I don't know the Acronym words and it was also one third "notch" away from the others! 
Basically it a controlled way of stating sensitivities of film or light densities. The lower the number the 'slower' the sensitivity. You need a long or slow exposure (aperture depedent of course). The higher numbers give shorter or 'faster' exposures.
Low numbers tended to give finer grain as well due to the fact the emulsion or sensor would be bathed in image forming light. Conversely, faster films/sensors received a briefer exposure to light thereby, usually, giving grainier images.
It is a strange way giving a sensitivity rating like this but there you go :shrug:
Just a rating system of either film or sensor.......
Basically it a controlled way of stating sensitivities of film or light densities. The lower the number the 'slower' the sensitivity. You need a long or slow exposure (aperture depedent of course). The higher numbers give shorter or 'faster' exposures.
Low numbers tended to give finer grain as well due to the fact the emulsion or sensor would be bathed in image forming light. Conversely, faster films/sensors received a briefer exposure to light thereby, usually, giving grainier images.
It is a strange way giving a sensitivity rating like this but there you go :shrug:
Just a rating system of either film or sensor.......
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It stands for International Standards Oranisation which sets the standard these days for all sorts of things. As far as us togs are concerned it refers to the speed of film we buy, 100 ISO, 200 ISO, 400 ISO etc. Each doubling of the ISO number indicates that the film becomes twice as fast.
Obviously with digital cameras, we don't buy film so we have to set the ISO which we want our sensors to use. For best image quality use the lowest ISO number you can, but the prevailing light isn't always strong enough to allow this and we often have to increase ISO.
As we increase the ISO with digital cameras, the images become more susceptable to image noise, which is the grainy, pitty appearance in shots which you've no doubt seen, which looks rather similar to grain in film.
It sounds fantastic doesn't it doubling the ISO but don't forget it will only give you either one step faster with your shutter speed or one aperture smaller.
Hope that helps.
Obviously with digital cameras, we don't buy film so we have to set the ISO which we want our sensors to use. For best image quality use the lowest ISO number you can, but the prevailing light isn't always strong enough to allow this and we often have to increase ISO.
As we increase the ISO with digital cameras, the images become more susceptable to image noise, which is the grainy, pitty appearance in shots which you've no doubt seen, which looks rather similar to grain in film.
It sounds fantastic doesn't it doubling the ISO but don't forget it will only give you either one step faster with your shutter speed or one aperture smaller.
Hope that helps.
K
kinchy
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Dont know if you have it, but if you are stuck on ISO then maybe you are stuck on other things, so i would suggest buying :
http://www.amazon.co.uk/Understanding-Exposure-Photographs-Digital-Camera/dp/0817463003/ref=pd_bbs_sr_1/202-3271813-5176626?ie=UTF8&s=books&qid=1183048764&sr=8-1
Its very good for beginners and helps in understanding the basics of ISO, Aperture, shutter speed etc etc. And for £13 you cant go wrong. I found it very usefull when starting off.
http://www.amazon.co.uk/Understanding-Exposure-Photographs-Digital-Camera/dp/0817463003/ref=pd_bbs_sr_1/202-3271813-5176626?ie=UTF8&s=books&qid=1183048764&sr=8-1
Its very good for beginners and helps in understanding the basics of ISO, Aperture, shutter speed etc etc. And for £13 you cant go wrong. I found it very usefull when starting off.
Sisteron
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I was having a problem with way to much light and was adviced to get:
Understanding Exposure by Bryan Peterson and Now I know much more about ISO, Aperture, shutter speed and managing all three to get the correct exposure
Here's a link:
http://digital-photography-school.com/blog/understanding-exposure-by-brian-peterson-a-reader-review/
Understanding Exposure by Bryan Peterson and Now I know much more about ISO, Aperture, shutter speed and managing all three to get the correct exposure
Here's a link:
http://digital-photography-school.com/blog/understanding-exposure-by-brian-peterson-a-reader-review/
K
kinchy
Guest
Its a bit like what i said, but in a different order
I would also recomend this months Practical Photography for £3.70.
It has a small colour supplement and has loads of useful beginners tips on ISO, aperture etc etc.
Its very concise, but fdoes advertise the doomed Jessops a bit too much.