EOS_JD
TPF Noob!
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Fast lenses are considered to have apertures that are f2.8 and larger. the fastest zooms available in the Canon range are f2.8 and these are as you will see the most expensive also.
Cameras like the 350D and the 20D/30D (I have the 20D) have a number of AF points but the centre one is more sensitive when used with a lens that is f2.8 or faster (f2, 1.8, f1.4 etc) so AF can be faster when used with a good lens. The lower the fnumber the bigger the lens opening (aperure) the faster the shutter speed you can attain. So fast lenses are useful in lower light.
I would suggest you buy a book on "understanding exposure" by Bryan Petersen. Will give you an insight into fstops, shutter speeds and ISO so that you get the most from your camera and lens.
Also in that first image, did you have one AF point selected or do you still have all AF points active.
When they are all active you may be focusing on the wrong area. there doesn't look to be much sharpness on the first but that may be down to where the camera focussed.
Also when using a larger aperture (like f3.5 as you noted) the depth of field (amount of the image in focus) is smaller than if you had closed down the aperture (f5.6, f8 or smaller).
Learn what settings to use. Using any of the creative modes and the flash will not pop up. I use Av (aperture priority) 90% of the time as I mainly like to control the depth of field. the camera will select an appropriate shutter speed to give a correct exposure in most cases.
Read and Learn and you will benefit greatly with much better images.
Regards
Jim
Cameras like the 350D and the 20D/30D (I have the 20D) have a number of AF points but the centre one is more sensitive when used with a lens that is f2.8 or faster (f2, 1.8, f1.4 etc) so AF can be faster when used with a good lens. The lower the fnumber the bigger the lens opening (aperure) the faster the shutter speed you can attain. So fast lenses are useful in lower light.
I would suggest you buy a book on "understanding exposure" by Bryan Petersen. Will give you an insight into fstops, shutter speeds and ISO so that you get the most from your camera and lens.
Also in that first image, did you have one AF point selected or do you still have all AF points active.
When they are all active you may be focusing on the wrong area. there doesn't look to be much sharpness on the first but that may be down to where the camera focussed.
Also when using a larger aperture (like f3.5 as you noted) the depth of field (amount of the image in focus) is smaller than if you had closed down the aperture (f5.6, f8 or smaller).
Learn what settings to use. Using any of the creative modes and the flash will not pop up. I use Av (aperture priority) 90% of the time as I mainly like to control the depth of field. the camera will select an appropriate shutter speed to give a correct exposure in most cases.
Read and Learn and you will benefit greatly with much better images.
Regards
Jim