English Language Teaching in Japan
| ISO & Noise You can usually find this as a dedicated button on your camera, or in the main menu. |
 |
| ISO basically is the
sensitivity of film; or in our case, the sensor. ISO50 is great in snow
where there is lots of light; ISO 200 is a great general purpose outdoor
film, and so I got used to this with my film cameras; ISO 400 is great
general purpose film; and ISO800 is good in the evening. Sounds simple?
Well, yes and no. With digital we have a problem and in using higher ISO
settings, like ISO400, 800 and up: noise. It appears as coloured spots in
the darker areas of a picture, and even in some lighter areas. Compare the
different ISO settings below on the moon below (and the brightness, too). These were taken with a Sony A200, with 70-300mm G on a tripod, with remote shutter release. f5.6, 1/125 at varying iso's (see below). Also see How to photograph the moon.
As you maybe able to see there is a little bit of noise at iso100, but iso400 is getting a bit off. Usually for high quality work, you would only use iso100, even if it means you need to use a tripod. Consequently, about 90% of the time my camera is set on iso100 and prefer iso100 film. What causes it? Most digital cameras at the moment, and perhaps yours included, has a small sensor. Film is 35mm, the lenses were designed to land a circle of light on a 35mm area. However, our digital sensors are usually smaller, resulting in less light information falling onto the camera's sensor, so an incomplete picture is recorded, so the camera has to 'guess' to fill in the gaps, and that 'guessing' creates the noise you see below.
|
||||||||||||
 |
||||||||||||
 |
||||||||||||
| In good pictures, black should appear smooth, and not speckled like in these How can we prevent or reduce noise? Use ISO100 where possible, and cautiously move up to ISO200 and ISO400 if you really have to. Use a flash if it's dark. And there's some things in PhotoShop that you can do to reduce or get rid of noise, too, though options are still limited and are cosmetic at best. Review some pictures you've already taken, and see if you can spot any noise in them. If there was a picture that could've been great, but you couldn't work out why it wasn't: check that, too. Night Having discussed noise, well, I think you know now, use a flash where possible and appropriate. Some cameras have a special colour setting for nighttime portraits, check your camera manual to see if you have this. Also, refer to the White Balance section of these pages for other possible settings to use. Experiment with friends and family in the evening and see what you can do. Almost always, if you're using a flash, then you don't need a tripod. The pictures below were taken with the Shutter Speed set to 'slow' and a tripod was used. I usually use the timer, as just pushing the button with my finger puts a wobble in the picture, where as the timer won't.
|
||||||||||||
| Also see in the 'How to take photos' section: Fireworks. | ||||||||||||
 Konica Minolta Alpha Sweet, with 18-70mm, f10, 30sec, iso400, with tripod. Note the car trails. (No flash) |
 Very slow camera shutter speed, iso400 film, with tripod. Minolta 303si. (No flash) |
We proudly support:
Get a guided tour of Angkor Wat
We support
