when to change appature setting on DSLR's

[darrenm]

have been playing around with my DSLR camera's for a few months now but mostly in auto settings and now wanting to get better depth of field and sharper images of the main focus of the image.

I understand this is down to a combination of appature settings and ISO speeds and having the subject behave how you predict it will but the more i try to experiment and the more i read when back at home the more confused i get. Anyone know of anywhere this can explianed to a total beginner. I also know that most good results are also down to good light.

F stops i also find very confusing and dont know what to set the camera to get the best results or when using a 1.4x converter to get best out of it. The cameras i have are Canon D60, D40 and a D500 and the lenses are a IS100-400 mm, a fixed IS 400mm and a 70-300mm.

Any help or links to a decent publication/s which will help will be very greatfully taken and i know i have asked a lot of inane questions.

[hank]

This link is called A Tedious Explanation of the f/stop

A Tedious Explanation of the f/stop

It is tedious! but take your time and study it a bit by bit, it will explain all you need to know !

[squishy]

Hi

Larger aperture = smaller f/number, so f/2.8 is a larger aperture than f/5.6.

Larger apertures give you a faster shutter speed (because it lets in more light), and a smaller depth of field.
Smaller apertures give you a larger DoF, but let less light in so you have to have a longer shutter speed (or increased ISO sensitivity).

So if you are trying to get a very blurred background, you should choose the largest aperture you can.
But if you want the DoF to cover a large area (i.e, you have more in focus), then you need a smaller aperture.

I also have a 100-400, and I generally use it between f/5.6 and f/8.
F/5.6 gets the fastest shutter speeds, but this lens (like a lot of lenses) gets a bit sharper when you stop it down, so when there is plenty of light you can get the optimum image quality by stopping down a bit.

However, when I'm doing macro, the aperture will be between f/8 and f/16, to maximise the DoF.

If you stop a lens down a lot (say, past f/11), image quality will start to degrade because of diffraction. This happens with all lenses, and it's a trade of for the larger DoF.

Generally, aperture priority mode