On Dec 24, 1:41 pm, kfj <_...
> What macros do you do?
Not sure I know just yet; I'm just starting out. I'm thinking still
life of any sort would be a good starting point with the gear I've
described earlier. The DOF is very shallow and the working distances
> If you want to make focus stacks, the HFOV doesn't matter much: you go
> in and out rectilinear and no transformation takes place. Use a rule-
> of-thumb value.
I see. Good to know, and thanks again.
> On the other hand, if you were making macro panoramas, which is a bit
> more unusual, you can do a 360 degree panorama, start with some
> estimate for the HFOV and optimize for fov, then take the value you
> get after optimizing. It doesn't sound like your setup is for
> panoramas, though...
Too true, though I suppose one could slap together a circular subject
of an appropriate diameter to allow the gear to focus, and suspend it
around the camera in some fashion. If the HFOV was a critical
parameter, this might provide the most precise estimate.
> You can also measure the value, if you know where your NPP is. Take a
> picture of, say, a horizontal ruler and take a reading of how many cm
> of the ruler fits in your image. Let that be w, and d the distance of
> the ruler from your NPP. If v is your horizontal field of view, you
> have w / ( 2 * d ) = tan ( v / 2 ), so v = 2 atan ( w / ( 2 * d ) )
Great information, Kay. I'll search around for how to find the NPP in
a reversed lens and then give this a try.