Comparison of digiscoping hardware

The most important features of digital telephoto
photography hardware are the minimum field of
view (the smaller the better) and the resolution
(the bigger the better). The field of view
(sometimes call angle) conveys info about
the magnification of the image. Human eyes see
a horizontal field of view of 120 angle degrees.

Olympus SP-550UZ (expected to come out in March 2007)
field of view in angle degrees: 4.8 to 72
field of view with conversion lenses: 2.8 to 103
close focus: 1 centimeter
resolution: 7.1 megapixels
advanced image stabilization
ISO sensitivity: 50 to 5000
batteries: 4 x AA
planned price $499.99

Canon Powershot S3 IS
field of view in angle degrees: 5.6 to 56
field of view with conversion lenses: 3.7 to 75
close focus: zero centimeters
resolution: 6.0 megapixels
image stabilization
ISO sensitivity: 80 to 800
batteries: 4 x AA
street price: $480

ZEISS Diascope 65 T* FL with Camera-Eyepiece DC4:
field of view in angle degrees: about 22
close focus: 4.0 meters
resolution: 4 megapixels
no image stabilization
ISO sensitivity: 50 to 800
batteries: 2 x AA

Kowa Prominar TD-1
field of view in angle degrees: 1.8 to 5.4
close focus: 5.0 meters
resolution: 3.14 megapixels
no image stabilization
ISO sensitivity: 100 to 200
batteries: 4 x AA
suggested price: $2100

wrote:
The most important features of digital telephoto
photography hardware are the minimum field of
view ...

I won't argue, but that's an odd way to put the matter. I'm assuming
that the image fills at least the shortest dimension of the picture area
and preferably more. Field of view, as you wrote in what I snipped is
inverse to magnification; magnification is limited in practice by the
quality of the optics and in particular by diameter of the objective. A
narrow enough field could capture perhaps just a sparrow's eye at 50
yards. I want a wider view than that.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

M-M wrote:
In article ,
Jerry Avins wrote:

wrote:
The most important features of digital telephoto
photography hardware are the minimum field of
view ...
I won't argue, but that's an odd way to put the matter. I'm assuming
that the image fills at least the shortest dimension of the picture area
and preferably more. Field of view, as you wrote in what I snipped is
inverse to magnification; magnification is limited in practice by the
quality of the optics and in particular by diameter of the objective. A
narrow enough field could capture perhaps just a sparrow's eye at 50
yards. I want a wider view than that.

Jerry


I think he means minimum depth of field. Often less than an inch.

Shallow depth of field is a usually unwelcome consequence of optical
magnification. Both for microscopes and telescopes, longitudinal
magnification is the square of the lateral magnification. The
accommodation range of your eye is reduced 50 fold when using 7-power
binoculars. it is reduced 360,000-fold when using a microscope at 600 X.

There are other considerations when capturing an image on film or other
recording medium, but the conclusions turn out to be pretty much the same.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

" wrote:

The most important features of digital telephoto
photography hardware are the minimum field of
view (the smaller the better) and the resolution
(the bigger the better). The field of view
(sometimes call angle) conveys info about
the magnification of the image. Human eyes see
a horizontal field of view of 120 angle degrees.

edited, for brevity

Kowa Prominar TD-1
field of view in angle degrees: 1.8 to 5.4
close focus: 5.0 meters
resolution: 3.14 megapixels
no image stabilization
ISO sensitivity: 100 to 200
batteries: 4 x AA
suggested price: $2100


Hello,

$2100, for a camera of such (seemingly) modest specifications? Is that a
misprint, or is there far more to the "Kowa Prominar TD-1" than you've
revealed, above?

Oh, wait a moment; the answer is he

Digital Photography Review - Kowa Prominar TD-1, 3mp, 1350 mm zoom
http://www.dpreview.com/news/0406/04...rominartd1.asp

The TD-1 is a big (15" long) and heavy (5.1 lb) "digital spotting
scope," instead of a mere digicam.


Cordially,
John Turco