Finally was able to use this lens last night.. last week , the skies were not clear and i had trouble focusing .
the lens is solidly built and gives clear photos..
Of course, you will need to spend some time getting used to the focusing ( Manual).
I am quite pleased with this purchase.
I wanted to take pictures of the moon and I was certainly able to do so .
a sample of a photo taken by this lens.. I Used a 2X teleconverter to bump it up to 1600 MM and still got good results...