bago100 wrote:Thanks for that Jed and Aussie Dave
What you said is a huge help. Thank you both very much. I've printed it out and will be taking what you said with me now!
Moreover, I understand what you said!
One further question if I may?
If ISO is also put into the equation, is the rule "the more light the lower the ISO and the less light, the higher the ISO?"
and will ISO settings affect what shutter speed and F stop one uses?
Cheers and thanks again gentlemen
Graham
Hi Graham
using ISO is basically like using an amplifier (but for the sensor). At ISO200, the sensor is working at it's usual 100%. Going one stop up in ISO (which would be ISO400) now doubles the amount of sensitivity - similar to going one stop in aperture from f8 to f5.6, or shutter speed from 1/200sec to 1/100sec (sort of like letting more light in, but not).
ISO doesn't let more light in, but actually boosts the sensitivity (and noise) of the sensor, allowing you to use faster shutter speeds/slower apertures to obtain the desired exposure (that was otherwise underexposed at ISO200)
This may be useful, for example, when trying to shoot indoors at a party, where the lighting is "just" a little too dim. You want to shoot at least 1/60sec. so you don't get blur from handholding the camera, but 1/60sec. is giving you an underexposed reading. This is where you could bump your ISO from 200 to 400, or maybe even 640, and this would allow the camera to now expose correctly and let you attain your desired shutter speed of 1/60sec.
Clear as mud ???
I usually try to leave it on ISO200 whenever I can, but if I cannot get enough exposure, then I work my way up the ISO levels until I can (hopefully) find a middle ground.
Once you reach about ISO800, noise levels can sometimes be a concern, especially in shadow or darker areas of an image.....however, sometimes it's better to get the shot and contend with some noise than to not have the shot at all !
Hope this helps....