i just bought a Sigma 50-500mm f4-6.3 and both the matched 1.4x and 2x extenders. i bought it with a Gitzo 1325 CF tripod and a 1377M ball head. so long as i use mirror lockup, 1000mm is a piece of cake. if i were to stack the extenders, i think it would still work OK. composing and locking the ballhead is no problem either. i have Arca-Swiss quick release system on my head now and that is the reason i bought into the system. no movement of the camera or lens once i lock the head.
Herb.... ----- Original Message ----- From: "Th. Stach" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Friday, September 12, 2003 4:07 AM Subject: Re: Fs on Friday: Pentax 2000mm f13.5 > I once was experimenting with three stacked converters: > > F*300/f4.5 x 2 x 2 x 1,7 turning into something like 2040/f32. > Well, that was an experience... :-) > > Mounted on a wooden Berlebach tripod with Manfrotto 2-inch ballhead, > camera-shake could be handled - but to compose a view and then fix it > with the ballhead was a pain. > Too much clearance ratio for that device... > > All the best,
