TG users and prospective buyers should note that the TG series only has two f-stops: f2.0 and f2.8. It also has a 3x Neutral Density filter that gives the illumination equivalent of f8 (f2.8 to f4 is one stop, f4 to f5.6 is two stops. f5.6 to f8 is 3 stops, hence 3x). The two basic f-stops get smaller (the number gets larger) when the lens is zoomed in from its widest setting; so at the maximum full 4x optical-zoom setting, the effective stops are f4.9, f6.9, and (with the 3x ND filter) f19.5
There are two consequences to this:
(1) you do not get increased depth-of-field (DOF) if using (not zoomed) f8 compared to f2.8, just less light.
(2) you get slightly sharper pictures by the elimination of diffraction effects that are caused by putting light through a very small hole. The issue is that the sensor on a TG is very small; the corp factor relative to a full-frame camera is 5.6. This means that f2.8 has the DOF equivelent to f15.7 on a full-frame camera, and f2 is like f11 full-frame. So you have lots of DOF, especially if you zoom.
There are two consequences to this:
(1) you do not get increased depth-of-field (DOF) if using (not zoomed) f8 compared to f2.8, just less light.
(2) you get slightly sharper pictures by the elimination of diffraction effects that are caused by putting light through a very small hole. The issue is that the sensor on a TG is very small; the corp factor relative to a full-frame camera is 5.6. This means that f2.8 has the DOF equivelent to f15.7 on a full-frame camera, and f2 is like f11 full-frame. So you have lots of DOF, especially if you zoom.
