Teleconvertors

The canon ones wouldn't fit, due to a protruding front element. 3rd party ones would, but you'd lose autofocussing ability, and the quality would be less than good. TC's are mostly designed for primes, and f/2.8 zooms, but on the zooms they can still lead to a noticeable degradation of image quality. :)
 
Ok thanks Chris321.I guess i will have to keep saving for a decent lens.
 
I don't know much about Canon lenses, but when I asked why could I not use a teleconverter on my Nikon 70-300 I was told it is because of the fact that you lose at least two stops with a converter meaning that as the lens was f4.5/5.6 to start with you would probably have a maximum aperture of f8 which makes sense I suppose. It would be the same for Canon I assume.
 
madmardle said:
... when I asked why could I not use a teleconverter on my Nikon 70-300 I was told it is because of the fact that you lose at least two stops with a converter meaning that as the lens was f4.5/5.6 to start with you would probably have a maximum aperture of f8 ...
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Not quite.

A 1.4x teleconverter loses 1 stop of light, so a lens which is f/4.5-5.6 becomes f/6.3-8.

A 2x teleconverter loses 2 stops of light, so a lens which is f/4.5-5.6 becomes f/9-11.
 
caddie152 said:
Would teleconvertors work on my 75-300mm EF 1:4-5.6?.Thanks.
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As well as magnifying the image a TC will magnify flaws in that image. The 75-300 is geneerally recognised to be the worst lens Canon ever made. So, even if a TC would work, you'd probably not be pleased with the results.
 
hollis_f said:
As well as magnifying the image a TC will magnify flaws in that image. The 75-300 is geneerally recognised to be the worst lens Canon ever made. So, even if a TC would work, you'd probably not be pleased with the results.
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There is no way the 75-300 was the worst made. That honour should go to the 28-200, an *utter* dog of a lens.
 
dentedshed said:
Use a 2x TC and you will lose AF at about 120mm.

Use a 1.4x or even a 1.5x, they retain AF all the way through.
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That's on a 1D body only isn't it? A x2 TC would make it f/8 at 70mm, meaning only a 1d would AF, the x1.4 would probably af (or try to at least) till about 120mm, but after then it would be MF only :)
 
chris321 said:
That's on a 1D body only isn't it? A x2 TC would make it f/8 at 70mm, meaning only a 1d would AF, the x1.4 would probably af (or try to at least) till about 120mm, but after then it would be MF only :)
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The 75-300 has a max of 4 so add 2 stops and that makes it 5.6 at 75mm.

A 1D I can only dream of but I have tested on both a 400D & a 40D.

75-300mm with 2x loses AF after 120mm, with a 1.4x or 1.5x AF is retained all the way to 300mm.
 
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