35mm lens / spotting scope equivalent
Davebudnick
has magnification equivalent to spotting scopes. Is there a formula or a
standard conversion for 35mm lenses?
For instance, how many "X" magnification is a 600mm lens?
Or, what 35mm lens would be comparable to a 20X spotting scope?
Just to let you know up front, I'm not interested in purchasing a spotting
scope and using an adaptor to attach a camera body.
I would like a fixed focal length lens for my Nikon FE that falls somewhere in
the range of spotting scopes that I've used (20X to 60X, generally).
Anyhelp would be much appreciated.
David Dyer-Bennet
> I'm interested in purchasing a fixed focal length lens for my 35mm camera that
> has magnification equivalent to spotting scopes. Is there a formula or a
> standard conversion for 35mm lenses?
>
> For instance, how many "X" magnification is a 600mm lens?
Conventionally, people would say 12x.
> Or, what 35mm lens would be comparable to a 20X spotting scope?
By similar convention, 1000mm.
These are both based on considering 50mm a "normal" lens. If 50mm is
"normal", then 600mm is 12 times that. Same thing in reverse to get
1000mm for a 20X
> I would like a fixed focal length lens for my Nikon FE that falls
> somewhere in the range of spotting scopes that I've used (20X to
> 60X, generally).
As you can see, it's going to be expensive and difficult to get up
much above 20x. That's "easy" with a 500mm mirror lens plus a 2x
converter. Of course, that combination is likely to be f16, too.
You'll also need a really solid tripod for this sort of focal length.
--
David Dyer-Bennet, dd...@dd-b.net / http://www.dd-b.net/dd-b/
John Dyer-Bennet 1915-2002 Memorial Site http://john.dyer-bennet.net
Dragaera mailing lists, see http://dragaera.info
columbotrek
So to get your 60X lens you will need about 2600mm lens.
Davebudnick wrote:
> I'm interested in purchasing a fixed focal length lens for my 35mm camera that
> has magnification equivalent to spotting scopes. Is there a formula or a
> standard conversion for 35mm lenses?
>
Malcolm Stewart
news:m2wuk3k...@gw.dd-b.net...
> daveb...@aol.com (Davebudnick) writes:
>
> > I'm interested in purchasing a fixed focal length lens for my 35mm camera
that
> > has magnification equivalent to spotting scopes. Is there a formula or a
> > standard conversion for 35mm lenses?
> These are both based on considering 50mm a "normal" lens. If 50mm is
> "normal", then 600mm is 12 times that. Same thing in reverse to get
> 1000mm for a 20X
The problem I've found is that no matter what focal length camera lens you use,
you always feel that you saw more through the telescope than you capture on
film. I guess there's a clarity to the central image in a good ED 'scope that
is easily lost on 400 ISO film or whatever needed to give you a shake reducing
shutter speed - particularly in the UK most of the year.
--
M Stewart
Milton Keynes, UK
Hemi4268
A spotting scope or telescope is somewhat different then a telephoto lens. The
reason is, the spotting scope has an eyepiece that magnifies the image to the
eye.
The eyepiece can be someplace between 5x to 50x with most being about 20x.
Example, a 50mm lens with a 20x eyepiece is exactly the same as looking at a
slide taken with a 50mm lens using a 20x lupe.
You can more or less get an idea of the focal length of the spoting scope by
measuring the front element. Most of these run about f-4 so a 2 inch front
element means about an 8 inch focal length or 200mm.
Now look at the eyepiece. If it says 20 x then the whole system is like
looking at a slide taken with a 200 mm lens using a 20x lupe.
Larry
Paddy
scope is simply the focal length of the objective divided by the f.l.
of the eyepiece. For example, my Nikkor telescope adapter unit has a
10mm f.l., so the power of a 1000mm lens is 100X.