So, i have a rebel XS and a completely manual 8mm fisheye, which is perfectly ok for surface work, im more used to old film cameras than pushing buttons to switch settings, but since i will have to borrow an homemade housing for underwater and i will have no way to work focus and aperture i will have to just set it beforehand and leave it like that.
The depth of field of the lens is huge and i was thinking that if i focus for the virtual image distance that could be taken care of, but not sure thats right, i have no idea what to do for the aperture either, is there a "best setting" i should use or i should leave it at its best performance aperture (which is around F8) ?
Will the housing have a dome port? For a typical 8" port set the focus at about 2' for subjects between the lens and 3'-4' away, or at about 3' to be in focus from about 18" to infinity and use f8 or thereabouts. You're basically right: set the hyperfocal distance to the virtual image for close-focus and a little further out for landscape shots.
Tim
Focus on your fin, underwater and attached to your foot, and then lock the focus.
If your 8mm fisheye is of the rokinon/samyang/pro optic variety I would suggest checking, and calibrating if needed, the distance scale. The following website outlines how to adjust the distance scale : http://www.versacorp.com/vlink/jcreview/sy8rv9jc.pdf
