[Argee]

Originally Posted by greenwing

Geoff, the Back Button is AF-ON on Nikons. Don't know what it's called on other brands. You disconnect AF from the shutter button & use AF-ON to focus.

Also on the Canon it is the same.

Edit: Oh, I see... focus on something, anything, anywhere, at the right distance, before recomposing.

Yes it is confusing. But now I realise the actual hyperfocal distance on a chosen aperture doesn't change. Only your choice of lens focal length will affect it, then work out your depth of field accordingly.