When I first picked up a camera there was no magnification factor (actually cropping factor), and a 20 mm lens is really wide, with tremendous dof. Today my kit lens 18-70 is in mm count wider than my 20 mm, but in actual fact delivers only 27 mm wide equivalent.
Now comes the question - I seem to have read somewhere that the dof is dependent on the focal length. If this is correct, then the dof from my kit lens at 18 mm would be comparable to that of the 20 mm, more so than that of a 28 mm.
Is this correct?
That's with the DSLR, the question gets further complicated when we moved to PnS, tiny sensors. My S60 at the tele end is 20.7 mm (35 mm equivalent of 100 mm). Does that mean I get more dof using the PnS?
And I can only stop down to f8 on the PnS, as opposed to f22 on my DSLR.
Or put it another way, if I try to get macro shots on my PnS, with accessories lens, stopped down to f8 (sigh, back in those days there was a saying, f5.6 and be there), do I have enough depth of field? Like if I use my 100 mm equivalent at f8, do I get more dof than 105 micro Nikkor at f8?
20 mm on film is very wide, on DSLR is just starting to be wide, but a tele with PnS. What an animal of a term.
Any thoughts are much appreciated.