My own Celestron is a 2000mm f/10. Focusing on celestial objects is
easy but, as a spotting scope or telephoto lens... I remember (just
once) trying to focus on a squirrel in the back yard at about 50 feet
(15 meters). Fuggetaboutit!
Actually, I just thought about calculating the DOF of that arrangement
and the reason is obvious. DOF is about 1.4 inches (36mm) at 50 feet.
If I could have actually focused on the squirrel I think he'd have been
laughing. :-)
On a semi-related note: Seeing the shots of the vultures reminded me
that yesterday I was out shooting when I noticed an osprey in a very
bare but also very tall tree just ahead of me. It would have made a
great shot if I'd had a 500mm lens with me instead of the Tamron 20-40. :-)
Chuck Norcutt
On 2/15/2011 5:54 PM, usher99@xxxxxxx wrote:
> I think with ease of PP, likely better to have resolution over
> contrast. As I recall the Sigma 600/8 has quite good res.
> I remember trying Moose's on a OM-2 and it was a bit tricky to focus
> but not impossible in good light with the 1-13 screen. I suspect
> with Mag live view on a tripod, would be a piece of cake. Might be a
> nice travel long tele for shots otherwise written off.
> I recall a few of Moose's shots during a visit a year ago or so to the
> North Shore of Boston with the Sigma 600/8 CAT. I doubt he would mind
> a re-post.
>
> http://tinyurl.com/45brl7d Not sure how he processed that.
>
> The Celestron 750 F6 is relatively easy to focus (thanks Jeff!!)
>
> Mike
>
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