a proposed system for capturing wildlife: your opinion ple..

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Hello,

I originally posted this in the astro.amateur group as I am an amateur
astronomer, but am seeking opinions on the following:

Recently, I have become somewhat interested in trying to capture daytime
images of wildlife and landscapes. However, I am having difficulty deciding
what direction to take. After browsing the archives of this group, entering
the wildlife realm looks like it might be an expensive
proposition, but I have an idea and I wonder if it would work:

For astronomy, I have been using an ETX-90/ webcam combination for nearly 3
years now with success (for photo.digital group: The ETX-90 is a telescope
of the Maksutov-Cassegrain design with a 90mm aperture and 1250mm focal
length). Why couldn't I just afocally couple (this means to attach a
standard digital camera to the eyepiece of the telescope) a digicam to
the ETX-90 ota (optical tube assembly), with the combination mounted on a
tripod? If the digicam I
use has a zoom, I would have a range of magnification just like I would with
a telephoto lens. Does anyone use a similar combination to image wildlife?
I'd be interested in seeing your results, so share your website if
appropriate.

I realize that there are some DSLRs, like the Canon Digital Rebel, that
could directly couple to the ETX or even a telephoto lens, but the price is
beyond my budget. The afocal method I could already do since I have the ETX
and a Scopetronics wide angle eyepiece- the only thing I would have to add
would be a digicam and would appreciate recommendations for a suitable, low
cost camera.

Like I said, the aforementioned is just an idea and wouldn't cost me much-
that is, if it would work.

Thanks, in advance, for your response.

Ian Robelot
 
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Paul

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Ian Robelot wrote:

> digicam
> ETX-90 telescope
> 90mm aperture
> 1250mm focal length


Take the telescope to a store & try it on for size with various
digicams. What sort of f/stop would this be capable of?
 
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Darrell

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"paul" <paul@not.net> wrote in message
news:0uednd75b-99JsffRVn-hg@speakeasy.net...
> Ian Robelot wrote:
>
> > digicam
> > ETX-90 telescope
> > 90mm aperture
> > 1250mm focal length
>
>
> Take the telescope to a store & try it on for size with various
> digicams. What sort of f/stop would this be capable of?

The math says 1250/90+ f:13.8 mirror lens, so actual T:stop is closer to
f:16
 
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Paul

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Darrell wrote:

> "paul" <paul@not.net> wrote in message
> news:0uednd75b-99JsffRVn-hg@speakeasy.net...
>
>>Ian Robelot wrote:
>>
>> > digicam
>> > ETX-90 telescope
>> > 90mm aperture
>> > 1250mm focal length
>>
>>
>>Take the telescope to a store & try it on for size with various
>>digicams. What sort of f/stop would this be capable of?
>
>
> The math says 1250/90+ f:13.8 mirror lens, so actual T:stop is closer to
> f:16


Thanks I wasn't sure if that was the right way to calculate. I don't
know how you'd add on whatever the attached digicam starts at. Anyways I
guess this won't be a fast lens for moving wildlife at dusk.
 
J

Jim

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"Ian Robelot" <ianrebo@tigs.nets> wrote in message
news:ZKy6e.5201$sp3.8@newsread3.news.atl.earthlink.net...
> Hello,
>
> I originally posted this in the astro.amateur group as I am an amateur
> astronomer, but am seeking opinions on the following:
>
> Recently, I have become somewhat interested in trying to capture daytime
> images of wildlife and landscapes. However, I am having difficulty
deciding
> what direction to take. After browsing the archives of this group,
entering
> the wildlife realm looks like it might be an expensive
> proposition, but I have an idea and I wonder if it would work:
>
> For astronomy, I have been using an ETX-90/ webcam combination for nearly
3
> years now with success (for photo.digital group: The ETX-90 is a telescope
> of the Maksutov-Cassegrain design with a 90mm aperture and 1250mm focal
> length). Why couldn't I just afocally couple (this means to attach a
> standard digital camera to the eyepiece of the telescope) a digicam to
> the ETX-90 ota (optical tube assembly), with the combination mounted on a
> tripod? If the digicam I
> use has a zoom, I would have a range of magnification just like I would
with
> a telephoto lens. Does anyone use a similar combination to image
wildlife?
> I'd be interested in seeing your results, so share your website if
> appropriate.
The problems that you will have with this telescope and any camera is that
the focal length is too long and that the out of focus highlights look like
doughnuts. Some people aren't bothered by this strange look, but most are.

You must be a very long way from the beast to get much of a shot. In
addition, the atmospheric heat waves wreak havoc with the images. So, if
you really want good wildlife shots, you should think of no longer that
600mm, and it should be a refractor.
Jim
 
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Guest

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Archived from groups: rec.photo.digital (More info?)

In message <kfz6e.33760$vd.26097@tornado.tampabay.rr.com>,
"Mark Lauter" <available_upon_request@just_ask_in_a_post.com> wrote:

>> Recently, I have become somewhat interested in trying to capture daytime
>> images of wildlife and landscapes.

>Less to do with your equipment choice, but a good intro article for wildlife
>photography none the less:
>http://www.wildflorida.net/whenandwhere_article.html

I don't shoot in Florida, but the idea translates well to New York. I
have taken most of my best bird photos in Central Park, in the heart of
NYC. The birds literally let me get up to 15x closer than I could get
in suburban or rural woods. I've been within 10 feet of herons and
egrets. In the suburbs, they will fly away as soon as they see me get
within 150 of them, most of the time.
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS@no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
 
G

Guest

Guest
Archived from groups: rec.photo.digital (More info?)

> >Less to do with your equipment choice, but a good intro article for
wildlife
> >photography none the less:
> >http://www.wildflorida.net/whenandwhere_article.html
>
> I don't shoot in Florida, but the idea translates well to New York. I
> have taken most of my best bird photos in Central Park, in the heart of
> NYC. The birds literally let me get up to 15x closer than I could get
> in suburban or rural woods. I've been within 10 feet of herons and
> egrets. In the suburbs, they will fly away as soon as they see me get
> within 150 of them, most of the time.

Yup. I "met" James Shaddle on photosig.com a couple years ago and when he
pointed me to this article of his it was like a whole new world opened up to
me. One does not need to trek to the most remote parts of the planet to find
wildlife. :)

--
Mark Lauter

Photos, Ideas & Opinions
http://www.marklauter.com
 
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On Mon, 11 Apr 2005 17:47:37 GMT, in rec.photo.digital "Ian Robelot"
<ianrebo@tigs.nets> wrote:

>For astronomy, I have been using an ETX-90/ webcam combination for nearly 3
>years now with success (for photo.digital group: The ETX-90 is a telescope
>of the Maksutov-Cassegrain design with a 90mm aperture and 1250mm focal
>length). Why couldn't I just afocally couple (this means to attach a
>standard digital camera to the eyepiece of the telescope) a digicam to
>the ETX-90 ota (optical tube assembly), with the combination mounted on a
>tripod? If the digicam I
>use has a zoom, I would have a range of magnification just like I would with
>a telephoto lens. Does anyone use a similar combination to image wildlife?
>I'd be interested in seeing your results, so share your website if
>appropriate.

Google Digiscoping for a bunch of useful links. The Nikon 99x/4500 with
their 28mm objective are well known choices.
----------
Ed Ruf Lifetime AMA# 344007 (Usenet@EdwardG.Ruf.com)
See images taken with my CP-990/5700 & D70 at
http://edwardgruf.com/Digital_Photography/General/index.html
 
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"Ed Ruf" <egruf_usenet@cox.net> wrote in message
news:725n515rppel6oiu2dsssq9rtj7e0d6ttp@4ax.com...
> On Mon, 11 Apr 2005 17:47:37 GMT, in rec.photo.digital "Ian Robelot"
> <ianrebo@tigs.nets> wrote:
>
> >For astronomy, I have been using an ETX-90/ webcam combination for nearly
3
> >years now with success (for photo.digital group: The ETX-90 is a
telescope
> >of the Maksutov-Cassegrain design with a 90mm aperture and 1250mm focal
> >length). Why couldn't I just afocally couple (this means to attach a
> >standard digital camera to the eyepiece of the telescope) a digicam to
> >the ETX-90 ota (optical tube assembly), with the combination mounted on a
> >tripod? If the digicam I
> >use has a zoom, I would have a range of magnification just like I would
with
> >a telephoto lens. Does anyone use a similar combination to image
wildlife?
> >I'd be interested in seeing your results, so share your website if
> >appropriate.
>
> Google Digiscoping for a bunch of useful links. The Nikon 99x/4500 with
> their 28mm objective are well known choices.

Yes, I did that yesterday, thanks. I actually used to own a Coolpix 4500
and, to my surprise, I see they're still available. I also have a custom
18mm eyepiece that couples directly to the 4500. The Coolpix/ 18mm combo
was going to be my imaging setup for the grand Mars opposition of 2003. I
ended up using a simple webcam instead, and the Coolpix was returned before
the 30 day period expired. The only question in my mind that remains is
what the field of view is going to look like. Say if I see a bird at 100
yards and were to target it with the ETX-90/ 18 mm eyepiece/ and Coolpix
4500, what range of magnification would I have and would this amount of
magnification be an overkill? It runs in my mind that there used to be an
on-line calculator somewhere, where I input parameters, such as the
aforementioned, and an approximate result (bird size, whether it fits in the
field of view) is produced.

Ian

> ----------
> Ed Ruf Lifetime AMA# 344007 (Usenet@EdwardG.Ruf.com)
> See images taken with my CP-990/5700 & D70 at
> http://edwardgruf.com/Digital_Photography/General/index.html
 
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Archived from groups: rec.photo.digital (More info?)

In article <bqS6e.4495$go4.1282@newsread2.news.atl.earthlink.net>,
Ian Robelot <ianrebo@tigs.nets> wrote:
>
>"Ed Ruf" <egruf_usenet@cox.net> wrote in message
>news:725n515rppel6oiu2dsssq9rtj7e0d6ttp@4ax.com...
>> On Mon, 11 Apr 2005 17:47:37 GMT, in rec.photo.digital "Ian Robelot"
>> <ianrebo@tigs.nets> wrote:
>>
>> >For astronomy, I have been using an ETX-90/ webcam combination for nearly
>3
>>
>> Google Digiscoping for a bunch of useful links. The Nikon 99x/4500 with
>> their 28mm objective are well known choices.
>
>Yes, I did that yesterday, thanks. I actually used to own a Coolpix 4500
>and, to my surprise, I see they're still available. I also have a custom
>18mm eyepiece that couples directly to the 4500. The Coolpix/ 18mm combo
>was going to be my imaging setup for the grand Mars opposition of 2003. I
>ended up using a simple webcam instead, and the Coolpix was returned before
>the 30 day period expired. The only question in my mind that remains is
>what the field of view is going to look like. Say if I see a bird at 100
>yards and were to target it with the ETX-90/ 18 mm eyepiece/ and Coolpix
>4500, what range of magnification would I have and would this amount of
>magnification be an overkill? It runs in my mind that there used to be an
>on-line calculator somewhere, where I input parameters, such as the
>aforementioned, and an approximate result (bird size, whether it fits in the
>field of view) is produced.
>

The actual focal length of CP 4500 is from 8 - 32 mm. In digiscoping,
you are most likely to use the longer focal range of the lense. So
if you use 18 to 32 mm range, the additional magnification is 1 to 1.77
for the 18 mm eyepiece. The size of the sensor is about 6 x 8 mm (the
diagonal is about 11 mm).

I have found that the Nikon 3X teleconverter is more compact and easier
to handle in the field (with a monopod). The effective focal length is
465 mm. If you use a moderate digital zoon (1.41, still a 2 MP picture),
the effective focal length is 655 mm. If you use a digital zoom of 2
(still an 1 MP picture), the effective focal length is 930. The whole
package is very sturdy and relative light and a monopod is quite
adequate.

Charles S. Ih
 
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