what 1x4 teleconverter
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geoff1965
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sorry yes 1.4x
Hi Geoff.
The Canon 400D will only autofocus with a Canon 1.4x extender if the lens and the extender can achieve a maximum aperture of f/5.6 or less. A Canon 1.4x extender (or any other make) will add one f/ stop itself, so any lens must be f/4 or faster (eg f/2.8) for the 400D still to retain autofocus.
The Sigma 150-500mm is a f/5-6.3 lens i believe, so the widest aperture is f/5 at 150mm. Add another stop to f/5 and you get f.7.1 at 150mm, add 1 stop to f6.3 and you get f/9 at 500mm. Both exceed the 400D limit of f/5.6
You can try the old trick of taping the pins on the 1.4 extender, I tried that on my own 400D when I had it, and found autofocus with a 1.4x and a Canon 100-400 f/4.5-5.6 both erratic and very slow. However, I think the taping trick only works up to f/8 anyway, so wouldn't work at f/9 at 500mm. Some third party 1.4 extenders are also meant to work up to f/8 on some Canon models, but you would still have a f/9 problem.
You can of course try a 1.4 converter with the Sigma and just use manual focus, but if you want to use the combination for wildlife then, you might have to literally nail down your subject first
The Canon 400D will only autofocus with a Canon 1.4x extender if the lens and the extender can achieve a maximum aperture of f/5.6 or less. A Canon 1.4x extender (or any other make) will add one f/ stop itself, so any lens must be f/4 or faster (eg f/2.8) for the 400D still to retain autofocus.
The Sigma 150-500mm is a f/5-6.3 lens i believe, so the widest aperture is f/5 at 150mm. Add another stop to f/5 and you get f.7.1 at 150mm, add 1 stop to f6.3 and you get f/9 at 500mm. Both exceed the 400D limit of f/5.6
You can try the old trick of taping the pins on the 1.4 extender, I tried that on my own 400D when I had it, and found autofocus with a 1.4x and a Canon 100-400 f/4.5-5.6 both erratic and very slow. However, I think the taping trick only works up to f/8 anyway, so wouldn't work at f/9 at 500mm. Some third party 1.4 extenders are also meant to work up to f/8 on some Canon models, but you would still have a f/9 problem.
You can of course try a 1.4 converter with the Sigma and just use manual focus, but if you want to use the combination for wildlife then, you might have to literally nail down your subject first
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geoff1965
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Hi Geoff.
The Canon 400D will only autofocus with a Canon 1.4x extender if the lens and the extender can achieve a maximum aperture of f/5.6 or less. A Canon 1.4x extender (or any other make) will add one f/ stop itself, so any lens must be f/4 or faster (eg f/2.8) for the 400D still to retain autofocus.
The Sigma 150-500mm is a f/5-6.3 lens i believe, so the widest aperture is f/5 at 150mm. Add another stop to f/5 and you get f.7.1 at 150mm, add 1 stop to f6.3 and you get f/9 at 500mm. Both exceed the 400D limit of f/5.6
You can try the old trick of taping the pins on the 1.4 extender, I tried that on my own 400D when I had it, and found autofocus with a 1.4x and a Canon 100-400 f/4.5-5.6 both erratic and very slow. However, I think the taping trick only works up to f/8 anyway, so wouldn't work at f/9 at 500mm. Some third party 1.4 extenders are also meant to work up to f/8 on some Canon models, but you would still have a f/9 problem.
You can of course try a 1.4 converter with the Sigma and just use manual focus, but if you want to use the combination for wildlife then, you might have to literally nail down your subject first
thank you for the info i guess its not worth getting one just yet until i upgrade my 400d.
thanx
geoff
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The only bodies that can AF up to f8 is the 1D series and even then it will struggle to AF at the long end of a Sigma 150-500 with a 1.4x converter. I have a Kenko Pro300 DGX 1.4x and that enabled my 550D, 7D and 5D2 to retain AF when used with a maximum f5.6 lens, even though it registered on the camera and exif that it was up to f8.
I tried it on my Sigma 150-500 OS to see if it would AF on any of my bodies but at the long end I had to use manual focus. You 'might' get away with it if you get a 1D body and Kenko Pro300 DGX converter, but even if you do then I would think the AF speed would be slow and unreliable. I've used my 150-500 with the 1.4x and a 2x converter on manual focus on a tripod and you can get some great shots of the moon like that, but wildlife would be impossible.
I tried it on my Sigma 150-500 OS to see if it would AF on any of my bodies but at the long end I had to use manual focus. You 'might' get away with it if you get a 1D body and Kenko Pro300 DGX converter, but even if you do then I would think the AF speed would be slow and unreliable. I've used my 150-500 with the 1.4x and a 2x converter on manual focus on a tripod and you can get some great shots of the moon like that, but wildlife would be impossible.
DizMatt
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I have a 2x sigma TC on my f2.8 lens and that is fine
but I wouldn't want to do it on a non-f2.8 lens
Look for the DG version of the TC if you go for a sigma, which I would as it's more likely to be tested more.
double check compatibility on the sigma website of course.
also remember that if you stop down to get some extra sharpness. I think that this is accentuated with a TC.
so I will shoot f3.2 min if possible on my sigma f2.8 (can't justify L glass for what I do), then to get the maximum sharpness, I shoot at f8 with my 2xTC on.
it still focuses as is can acheive f5.6 but it's noticeably less sharp than f8-9 and then it drops off again afterwards iirc. Of course this is with the 2xTC which will have a more noticeable affect
but I wouldn't want to do it on a non-f2.8 lens
Look for the DG version of the TC if you go for a sigma, which I would as it's more likely to be tested more.
double check compatibility on the sigma website of course.
also remember that if you stop down to get some extra sharpness. I think that this is accentuated with a TC.
so I will shoot f3.2 min if possible on my sigma f2.8 (can't justify L glass for what I do), then to get the maximum sharpness, I shoot at f8 with my 2xTC on.
it still focuses as is can acheive f5.6 but it's noticeably less sharp than f8-9 and then it drops off again afterwards iirc. Of course this is with the 2xTC which will have a more noticeable affect