Canon XSi ISO Test

ISO:

ISO is the third component of the Aperture / Shutter Speed / ISO equation of creating an exposure.

ISO is a technical term that carries over from the film world, when higher speed ISO film was used to capture images in lower light settings.

Low ISO is desirable, the less “sensitive” a sensor has to be, the less noise is generated in the image.

The images with low ISO will have lower “noise” on the image, as you make your sensor more sensitive to light the noise will increase. ISO on the XSi between 100 – 400 is very acceptable and not overly noticable. ISO 800 is pretty good too, it would be appropriate for indoor sport shooting. ISO 1600 is to be used only for necessary times, when its very dark out and the image can’t be obtained any other way.

As you will see below, ISO 100 – 1600 when viewed at reasonable sizes work, but if you scroll further you will see whats really going on at a higher detailed viewing.

Higher ISO options are there to help achieve faster shutter speeds when there is insufficient light. Typically you would use higher ISO when shooting indoors, at dusk, or without a tripod. Higher ISO does perform well on the Canon XSi, however the excellent IQ does not come without any loss of image detail. As you can see the introduction of noise will remove some details, which will be noticeable when making larger prints. All in all the Canon XSi delivers outstanding noise performance from ISO 100 – 1600.

Again, only use higher ISO when you need to. If you can choose a wider aperture to let more light in, do so before increasing ISO.