Ok I have decided that this weekend I'm going to focus on f stops... One of the basics for using SLR's in the pre digital age, they are still just as important but with a lot of people only using full auto settings on there digi SLR's its easy to forget what they are used for... so lets all refresh on f stops.

Best we go back to pre digi SLR days when the lens was how we controlled our f stop setting...

f stops are a measure of the diameter of aperture ( or how far the shutter will open ) for a given setting this effects the amount of light that will be exposed to the film or in the case of digi cameras the image sensor...

The ' f ' stands for fraction so the number that follows denotes the actual fraction of opening of the lens eg. f 9 is 1/9 ... hence the lower the number the greater the opening the higher the number the smaller the opening eg. f4 - 1/4 , f16 - 1/16...

So from this we get the smaller the f stop the more light you allow to be exposed because of the greater aperture of the lens and the greater the f stop the reverse, less light will be exposed due to the smaller aperture of the lens...

f4.5 at 1/320 sec iso 400

f6.3 at 1/320 sec iso 400

f9 at 1/320 sec iso 400

Ok have we got that........ any questions????