Re: "That's a REALLY nice 1500mm lens you have there"

dennis@home wrote:
"ASAAR" <caught@xxxxxx> wrote in message
news:2mct139pgc1lvteh2c8pgeumeebv4go0mu@xxxxxxxxxx

So now you're down to 366mm from 500mm, both of which are
significantly less than Nikon's 1000mm scope which (with its
adapter) is designed to interface with and provide data to a digital
camera. Anodized and plated could indicate a flimsy aluminum tube.
Maybe we could tell more about it, but you weren't proud enough of
your feeble telescope to have mentioned the name of the company that
manufactured it. Was it on sale at Radio Shack? :)

For what it's worth, what kind of image quality can we expect from
that 366mm telescope? As good as the images you'd get from one of
Nikon's 300mm lenses?

A well made astronomical telescope is way better than a camera lens.

Define "way better".

I have never seen a *diffraction limited* optic for a camera.. do they
exist?

There are few photographic lenses tht are _not_ diffraction limited at
apertures typical of astronomical telescopes. The difference is that
they open up to apertures far wider than any but a few very, very
expensive (not talking _house_ money here, I'm talking the whole
subdivision) professional telescopes, and wide open they are sacrificing
some resolution to gain light gathering.

It is the norm for telescopes (excluding the toy ones).

As for the Nikon one adding exif info its not going to make the
decision for me.
I can always add the fixed apature and focal length manually.
I'm not sure about which way up the image is on the Nikkon as the 45
degree mirror is an erecting prism which makes a spotting scope image
the correct way up.
So it will be inverted with respect to a proper lens/ telescope prime
image. Unless they are using the eypiece to do image projection which
adds a focal length multiplier and introduces optical defects.
If they are you can just hold a pair of binocculars infront of you
lens to take pictures (yes I have done that with my Optio WP where
the lens doesn't move).

The difference in focal length isn't very
significant and you can get an AF 70-300mm f/4-5.6G for as little as
$129.95 & $139.00 from B&H, or $294.95 & $319.95 for the better AF
70-300mmD ED version. You can pay as much as $479.95, but that's a
VR lens. They all have several advantages over your anodized
aluminum scope. All of the normal lens features, AF, metering and
passing lens data to the camera. They may also include the 5 year
extended warranty often included with some of Nikon's lenses. Do
you actually own that $299 lens and know how it performs, or do you
just know of it as a web surfer?


I bet my Meade 900mm F9 telescope out performs them, but its not
going to win in a usability trial.

If you investigate I believe that you will find that at F/9 most
photographic lenses _are_ diffraction limited.

As for your 900mm, if you need a 900 f/9 then yes, it will outperform a
300mm photographic lens. It will also be a lot cheaper than a 900mm
photographic lens.

Camera lenses compromise performance for usability and costs IMO.
They don't actually need much performance as neither film nor digital
is as good as the human eye.

So why do telescopes, which also normally use film or digital sensors
(only hobbyists actually _look_ through telescopes other than when
trying to troubleshoot a problem), need such high performance?

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)


.

Relevant Pages

  • Re: Advice please for a newbie
    ... Again, I have no digiscoping experience, so ... Is 12x optical zoom ona 10 mp digital camera good enough ... on the spotting scope is not very useful, ... less expensive than a standalone 3000 mm telephoto lens. ...
    (rec.photo.digital)
  • Re: TDS360 -- any good?
    ... A regular 35mm film camera can be used as a scope camera provided you ... A 50mm or 100 mm macro lens is perfect - since the ... part of it is that a screenshot would go right in my occasional article I ...
    (sci.electronics.design)
  • Re: Why does older CoolPix-995 work with scopes, and DSLRs will not?
    ... remove eyepiece and camera lens, ... Use special relay optics designed to couple the scope to the camera, ...
    (rec.photo.digital)
  • Re: Lens choice recommendations
    ... camera components to make them work together, they don't come with a camera ... scope) eyepiece and the proper spacing and focusing hardware. ... Due to the longer focal-lengths and fewer lens elements in use the ... objective lens design of the spotting scope is much simpler to be precisely ...
    (rec.photo.digital)
  • Re: Why does older CoolPix-995 work with scopes, and DSLRs will not?
    ... remove eyepiece and camera lens, ... Use special relay optics designed to couple the scope to the camera, ...
    (rec.photo.digital)
Loading