telescope lens?

[jessicalynn]

I was just looking through random lenses on ebay and came across a few that looked interesting and were cheap (well as lenses go!). I was wondering if this would be worth it? I'm not a professional or expecting anything spectacular but would want decent moon pics. Anyone have any ideas? I see that it says no electronical parts and you use manual and focus manually. which is perfect as I only use manual on my camera anyways. so thoughts?

2000mm Telescope for Canon Rebel XS XSi XTi T1i 5D 50D - eBay (item 220421717268 end time Sep-22-09 14:00:00 PDT)

15-30x 2500mm telescope for Nikon D40 D60 D70 D90 D5000 - eBay (item 320375930112 end time Sep-22-09 09:51:16 PDT)

[Aegea]

It looks like the first one is a catadioptric (mirror) lens. It has a fixed aperture of f/13.3 (90mm aperture, 1200mm focal length). That's very slow, and it will be hard to focus because the viewfinder image will be dim. I have no idea how good either of the lenses would be optically, but you don't generally get something for nothing ... if you buy either let us know how good it is!

[jessicalynn]

actually I just realized the first is 300-something dollars, so really more just the second link i'm curious about.

[ressalg]

Based on price alone, my biggest concern would be the optical quality of the glass. You could be looking at images with ALOT of colour distortion. I would also be leary of their claims about "taking impressive pictures of the planets and other celestial objects". If you can afford to spend $140 on this scope then go ahead. But I wouldn't hold out hope that it's going to do all it claims. However, basic daytime shots, like they show in their ad, might be ok.

[Digidave]

The second one, with the Nikon mount, has a maximum aperture of f/16. That's really slow! You would most likely have it on a tripod, but that is still really slow. I could see it working on a static(not moving) subject, on a cloudless day(very bright). As previously mentioned, I would think it would be very difficult to focus. For that kind of money though, it may be worth a shot.

[m.c.adams]

I have a Sigma 600mm lens that I use for super long shot, such as moon pics, etc. If thats what you are looking for, check these out. Heres a link to one on Ebay.

Sigma Mirror-Telephoto Multi-Coated 1:8 f=600mm Lens - eBay (item 160358719577 end time Sep-01-09 18:38:12 PDT)

Mark

[Aegea]

The Sigma is probably a better deal if you want to try a mirror lens - Sigma is a reputable manufacturer and f/8 is a lot better than f/13. 600mm is also a lot easier to manage than 1200mm. Camera shake will be your enemy and you will probably need a tripod for anything but perfect sunny conditions ... also on anything out of focus (background, foreground) mirror lenses produce wierd doughnut-shaped effects.

[sk66]

I can't imagine trying to shoot with a 2500mm lens....I can barely control camera shake at 1000mm (500mm F4.5 w/ 2x) using a wireless remote and a sturdy tripod at minimal extensions...even a slight breeze is a PITA!