Finally got into the world of DSLRs recently and wanted a lens with some reach.  Camera I got is just a basic (used) Nikon d3100 with a standard 18-55 vr lens (which quickly went to crap, auto focus quit working, and then a ring inside broke while camping and the zoom began binding while the end lens tube flops around a little).  While camping I was trying to get pictures of a mountain goat through my friends spotting scope, and was thinking "man I could sure use a higher powered lens about now"
I was looking at the Sigma 150-500 lens, and was having a hard time bringing myself to spend around $750 for a used one.  
Ended up getting a Nikon 55-300 VR lens, and started noticing some other cheap high-powered lenses.  Read some of the reviews, and finally decided to spend $200 on this behemoth, the Opteka 650-1300mm lens.  It comes with a 2x tele-converter for a total of 2600mm, but the supplied ring has to be switched back and forth, so I ended up using a different 2x tele-converter that my dad gave me from his old nikon.  
As for packing it around, it's a tad over 2 feet long at max power, with the weight to match, and a tripod is a must as it takes some longer exposure times (it's f-8/f-16).  I made a mount to use it on my spare equatorial mount I got for $20 at the goodwill.

Here's a shot looking across the road and field at a sign (1/2 mile away) using the 55-300mm lens at max power.




And here's the same sign at 2600mm.  Picture quality starts to suffer at this high of a power, and I need to try some comparisons with cropped images at a lower power, but one can't expect the best at $200.  The brush didn't help.  I've also noticed a spot of bluish lens flare in the middle with this tele-converter, so I'll have to try the other one again, or see if it goes away at lower power.






 

Fuckin hell.

Point it at the moon. 3/4 full is best moon.

Tag for interest

D3100 owner here.

FWIW I keep a couple of spare 18-55 lenses laying around.
Same with the 55-200mm lenses.

Murphy's law says if you have spares, nothing bad will happen.

And point that lens at the moon.  You might see the lunar rover.

More D3100 goodness
55-300 DX VR
1/20 sec
400 ISO
handheld
freezin' ass cold in the middle of winter

Moon was disappearing behind clouds, and I won't have a chance to do any more photos over the next 2-3 weeks, so here's a shot of the moon when testing the other 2x converter several weeks ago.  I need to try the one it came with along side it to see if I get that blue spot again.  



'shutter shake' was an issue when I took the following three shots.  It's just like a telescope.  the slightest touch and things jump around a lot.  I realized when I took the picture of the sign that bumping the iso up to 800 made it much better.



Focus is manual, and quite sensitive.  I'll do some more practicing with focus, steadying, and exposure levels the more I mess with it.  The deer pics were re-sized down, but I was getting added graininess when I converted them from RAW and opened in photoshop, so the moon shot is still a big file because it was far more noticeable with that one.



2600mm





1300mm





2600mm (did about 4 more with nose and mouth in shot, but lighting was getting too weak, and she wouldn't hold still for the longer exposures.  Just managed this one)

Nice.  Here's another I did at 1300mm I forgot to post.





 

Yeah, shooting this thing at the higher powers on that equatorial mount kinda feels like that.  The perspective I shot it at with my other camera makes it seem even bigger.  at the lower 650-900ish range it's much more maneuverable.  



Another problem that I read about in the reviews before I bought it was that at higher power, the outer tube sags just a tad.  The mount I built with the wooden spacer under the camera cures that issue.  Not how much it really affected the pictures.



 

I like that shot!