Depth of Field

Just a thought regarding depth of field :-

Say I use a 55mm lens and a tube extension and fill the AF frame in the viewfinder with a ladybird.

The alternative is a 300mm macro lens also with appropriate tube to get the same sized image.

Which setup would give the greatest depth of field (focus) [I don't really want to get into the technicalities of which is the correct term - I'm told they're different]

Sorry I should have added - given the same aperture- as I realise that f22 gives a much greater dof than f3.5

Bernard

Depth of field is what we are talking about. Depth of focus refers to the allowable error in the position of the film/sensor.

If you have the same magnification you will have the same DOF regardless of lens. Of course, the perspective will be different as you will be a different distance from the subject.

It's the image size and aperture that control DOF.
Focal length doesn't matter, so use 50mm or 300mm
at say f/11 and the DOF for the same image will be the
same.

Thanks John/Algenon

I had a suspicion that was the case, but couldn't quite prove it to my self with the kit I have available. It's also almost 50 years since I did optics in physics at school so the formulae are somewhat vague.

You may have noticed that my last few posts have a similar theme - One of the things I'm investigating is what I might need in trying to improve the photographs I take of my grand-daughter. This one varies in that I had been looking at the bugs and flowers that are appearing in my garden.

regards
Bernard