Thanks for your thoughts.
I have had a number of "cheap" 500mm mirror lenses, and didn't like the
quality of them.
As you both remark, it is quite difficult to get sharp images.
I also thought about a true telescope (do you suggest a cassegrain type or
something else?).
But since I need the carry the thing with me, a heavy tripod is not really
an option.
The Yashica lens is quite expensive (I think) almost 600 euro's including
the adapter to fit my e510. I might be able to talk it down a bit. But it
remains (especially in these credit stress times) a significant amount.
I'm curious what type of telescope, you would suggest.
I have had a close look at the Celestron c90 Mak spotting scope.
Any ideas are welcome.
Maarten
-----Oorspronkelijk bericht-----
Van: olympus-owner@xxxxxxxxxx [mailto:olympus-owner@xxxxxxxxxx] Namens Moose
Verzonden: woensdag 22 oktober 2008 11:28
Aan: olympus@xxxxxxxxxx
Onderwerp: [OM] Re: Yashica 1000mm lens
I agree with what Chuck has to say.
I would add that actual lens performance is usually not the limiting
factor at greater distances. Atmospheric contamination, thermal movement
and subject movement all have an effect and the donut OOF highlights are
a constant bother.
I have a Meade telescope that is also a 1000/11 lens. With the proper
scope to T and T to OM mount adapters, it makes a nice, solid
connection. The finder scope is a real help. Focusing is not bad in
bright light with standard 1-13 screen. I found the 1-7 and 1-8 screens
both helped. I liked the 1-8 better.
Taking pictures of nesting hawks, I found the swaying of the trees in
even tiny breezes was a real problem.
I think you may have a problem with focusing on any of the E-thingies,
alhough the E-3 should be best. Maximum aperture of F11 is really
outside their design criteria.
Moose
Chuck Norcutt wrote:
> I checked the old Modern Photo tests of mirror lenses and there's no
Yashica of any focal length and the only 1000mm tested was a Meade. But
Yashica generally made good stuff so I wouldn't be too concerned about
purchasing it if it's in good condition and you get a good price.
>
> But some other thoughts. There's a reason why you only see Meade listed
> in the 1000mm range. At 1000mm you are basically in telescope
> territory. Given the narrower angle of view of the e-camera it will be
> more like using a 2000mm lens on a 35mm camera. Been there, done that
> with my 2000mm Celestron 8. When you get that long and with that narrow
> a field of view it is extremely important to have
> 1) a massive tripod and sturdy head
> 2) a wider field finder to be able to locate your viewing target.
>
> If you're intent on 1000mm or above I think I'd skip the "lens"
designation and go straight to a true telescope which is designed to resolve
points 1) and 2) above. Meade and Celestron are the principal
> and low cost purveyors of same.
>
> Chuck Norcutt
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