2x converter

Author
Discussion

Michael30

Original Poster:

78 posts

264 months

Saturday 10th January 2004
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My dad has a 10D with a 28-200 lens and is looking at this Jessops 2x converter
JES2XCCAF
hes been told that it will make the picture darker but are there any other dissadvantages and will we still be able to use autofocus
Thanks
Michael

getcarter

29,630 posts

286 months

Saturday 10th January 2004
quotequote all
well it won't exactly make it darker... but you'll need better lighting conditions to take photos. It's a trade off... you get closer to the subject, but it'll need to be a sunny day, or the subject will be out of focus (if it's moving) or indeed too dark.

2x converters are worth the money (IMHO) if you understand that you need good light to use them.

Steve

malc350

1,035 posts

253 months

Saturday 10th January 2004
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The teleconvertor (ask in the shop to make sure it's compatible withyour camera / lens - they usually are) will appear to darken the image because it reduces the amount of light entering the camera by 2 stops, i.e. if your lens' max aperture is f4, it will become effectively f8. If you have a variable max aperture that reduces as focal length increases, which I'd imagine you have, you could find that the aperture at the telephoto (200mm) end becomes too dim for comfort, i.e. effectively becomes f11, if it was originally f5.6.

Also the teleconvertor reduces image quality slightly, and coupled with a zoom that probably doesn't perform at its best at max aperture (sharpness) you could find it's too much of a compromise. Probably best to buy a longer lens if budget allows. Convertors are best used IMHO if there's no alternative or if the lens you use it with is a high quality item.

mxdi

13,993 posts

256 months

Sunday 11th January 2004
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I have a jessups x2 convertor, got it years ago for my minolta dynax. I use it with my 70-300 sigma zoom. The only thing I noticed apart from what the others above have said is you will have to use manual focussing on it as the auto focus wont work when it is extended right out.

simpo two

87,066 posts

272 months

Sunday 11th January 2004
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mxdi said:
I have a jessups x2 convertor, got it years ago for my minolta dynax. I use it with my 70-300 sigma zoom. The only thing I noticed apart from what the others above have said is you will have to use manual focussing on it as the auto focus wont work when it is extended right out.

The product in question is a Canon AF unit and intended for use on a Canon camera - so I don't see why it shouldn't maintain AF function regardless of zoom setting. Or am I missing some subtlety?

nighthawkEP3

1,757 posts

251 months

Sunday 11th January 2004
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srider

709 posts

289 months

Sunday 11th January 2004
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simpo two said:

mxdi said:
I have a jessups x2 convertor, got it years ago for my minolta dynax. I use it with my 70-300 sigma zoom. The only thing I noticed apart from what the others above have said is you will have to use manual focussing on it as the auto focus wont work when it is extended right out.


The product in question is a Canon AF unit and intended for use on a Canon camera - so I don't see why it shouldn't maintain AF function regardless of zoom setting. Or am I missing some subtlety?


The AF systems in SLRs have a limit on the minium aperture. Above this minimum they won't work. On most cameras it's f5.6, but the Eos 3/1v/1D/1Ds can go to F8. As 2x converters take 2 stops, you're usually above the AF limit.

simpo two

87,066 posts

272 months

Sunday 11th January 2004
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Cheers Stuart, haven't hit that problem before. I do have a 2x convertor but as it doesn't support AF, that might explain why!

Still, as long as you've got the time to focus manually, losing AF for a bit isn't the end of the world.

Michael30

Original Poster:

78 posts

264 months

Sunday 11th January 2004
quotequote all
Thanks all very usefull information

simpo two

87,066 posts

272 months

Sunday 11th January 2004
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Michael30 said:
Thanks all very usefull information

Just one other thing - as the effective aperture is smaller, you'll be using longer shutter speeds to compensate which means you'll hit the camera-shake threshold sooner as well, doh!

ehasler

8,567 posts

290 months

Monday 12th January 2004
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I've got a Canon 1.4x and 2.0x converter, which are both very useful and give good results, although I do have a very sharp lens (Canon 300mm f2.8) to begin with.

It is generally acknowledged that the 2x converter loses sharpness, however I'm willing to sacrifice this to save spending over £6k on a pukka 600mm lens!

There is also a tip here which explains how to enable AF with lens speeds of greater than f5.6 (Canon only I believe).

DustyC

12,820 posts

261 months

Monday 12th January 2004
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Ed, bring the converters, I want to play with them!