Moose wrote:
>
> And then a bit more on how different film/sensor sizes interact with
> FOV, fl and magnification necessary for equal subject size and you've
> done it. ;-)
>
> Moose
And from Andrzej Wrotniak's site:
http://www.wrotniak.net/photo/tech/dof.html
"What's so special about digital cameras?"
"Actually, not much, except that most have sensors smaller (or much
smaller) than the 35-mm film frame. Therefore the CoC size used to
define "acceptably sharp" also has to be proportionally smaller."
"This would, seemingly, lead to less DoF in small-sensor cameras, if not
for one additional fact: for the same image angle (field of view) a
smaller sensor requires also a proportionally smaller lens focal length."
"For example, a 100 mm lens on a 35-mm film camera gives the same field
of view as a 25 mm (approximately) lens on a digital camera with a 2/3"
sensor. This is why we often say that the EFL (equivalent focal length,
implying the 35-mm film as a reference) of the latter lens is 100 mm.
The ratio before these two values (here: four) is often referred to as
focal length equivalence ratio, or focal length multiplier. In this
article I will denote this ratio as simply M."
I hope Ali is following all of this DOF stuff..
Dick
==============================================
List usage info: http://www.zuikoholic.com
List nannies: olympusadmin@xxxxxxxxxx
==============================================
|