Sigma 28-300 F3.5?
Discussion
I haven't used one but it's what I call a one-size-fits-all lens. It may do everything you ever need, but it will compromise to do so. Note that the aperture at 300mm is only f6.3; fine for outdoor days but limiting in low light. Also note that it won't give you much wide-angle, and it doesn't have silent wave focusing (which I like but may not be a factor for you). Depending on your needs, you might find a 18-200mm more useful.
>> Edited by simpo two on Saturday 17th December 20:03
>> Edited by simpo two on Saturday 17th December 20:03
Bee_Jay said:
Dunno about the sensitivity of the AF sensor in the D50, but it most likely will not be able to autofocus at f/6.3 (certainly my 20D needs f/5.6 minimum, and the 1DsII can doo f/8). So you will be in manual focus mode at the long end...
Umm..nope.
The Sigma 50-500 is also f6.3 or so at the 500 end but will still autofocus on a 20D as the lens fools the camera into believing it's at f5.6.
As for the lens in question in this thread, go to fredmiranda.com and read the reviews there. I think "mixed" is the best way i can describe them
Mmmm - there's a lot of technical reasons why N go for a smaller sensor and C try and "Mix'n'match" for full frame! Maybe we'll all understand it one day 
I have a simple observation, though - and remember I'm a complete Luddite here!!!!
Why would something that produces a half decent image at 28mm be anywhere near any good at 300?
I have a simple observation, though - and remember I'm a complete Luddite here!!!!
Why would something that produces a half decent image at 28mm be anywhere near any good at 300?
beano500 said:
Mmmm - there's a lot of technical reasons why N go for a smaller sensor and C try and "Mix'n'match" for full frame! Maybe we'll all understand it one day
ATBE the 35mm sensor (it's not 'full frame' in the true sense) makes more sense - bigger pixels make for better sensitivity to light and lower noise. The benefits of DX are (1) if you use a lens designed from 35mm you're using the best part of it, not the edges, (2) if you use a lens designed for DX, it's lighter, smaller and theoretically cheaper as it doesn't need so much glass - though whether you then run into edge problems again is not clear... oh yes, and the smaller sensor means that light rays don't hit it at such extreme angles so tnat, according to the nice man at Nikon Expo, the rays don't fall into the wrong pit and bollox things up... but I got the distinct impression there that Nikon's explanations were 30% technical and 70% marketing....
simpo two said:I know what you mean. I favour the argument over lens mount size. Nikon never increased theirs, although Canon did when they moved to autofocus. And I'm intrigued by the Olympus change; just been reading about the need for an adaptor to fit the old Zuiko lenses onto the new digi-format!
... 30% technical and 70% marketing....
Anyhow, I'm left wondering if the full effect should mean that if you're on digital the best results will always be on the smallest aperture?
That way you get the "most parallel" rays of light! Does this override everything else???
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