Click image to view
Location: Martin Down, Hampshire
I often start at f8 when photographing butterflies. Aperture controls depth of field but magnification has an even greater effect on depth of field. If you stand a fair distance back (eg low magnification) then everything looks in focus even at f4 but if you get very close then the higher magnification means that very little looks in focus, only a narrow band, and it can be difficult to get the whole of the insect within this sharp band. This is why trying to get your camera sensor parallel to a wing surface is important at higher magnifications. When trying to get the ‘goldilocks’ aperture so that the subject looks sharp but the background blurry you therefore need to factor in this magnification effect and also that full frame cameras have a shallower depth of field than a standard cropped sensor APS camera (eg the depth of field at f8 on a cropped sensor will be deeper than a a similar sized butterfly at f8 on a full frame camera).