# dslt with 2x converter



## cadwr (Jan 16, 2013)

I've bought a used Jessops 2x converter with autofocus for my sony a33 dslt.  On all l enses [ 18-200/75-300/30mm macro] the autofocus hunts & then settles on a point quite a way from correct focus.  In manual focus, the converter works & results are sharp, good colour & no chromatic aberation, but of course there is so little depth of field it is a pain to focus manually.  Can anyone suggest a fix?  { yes I know it's cheap kit at under £50 but the image quality is fine !!!
Cadwr:x


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## CouncilmanDoug (Jan 16, 2013)

I don't know anything about sony lenses, but I'm assuming those zooms are f5.6 or f6.3 at the long end, I think a 2x teleconverter takes at at least 2 stops away, turning them into f11 lenses, so the camera has a hard time focusing. That's why most people use 2.8 lenses on teleconverters, so to get your £50 teleconverter to autofocus properly you'll need to get a much more expensive lens, or you could just focus manually.


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## gsgary (Jan 16, 2013)

The fix is dont use it your lenses are not good enough to use a 2x converter, most makes will not auto focus after F5.6, i would think your 18-200 is a F5.6 but as soon as you fit the 2X it turns into aN F11 lens


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## Kolia (Jan 16, 2013)

Is the converter affecting the resulting aperture ?  AF hunting is sometime caused by not enough light.


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## gsgary (Jan 16, 2013)

Kolia said:


> Is the converter affecting the resulting aperture ?  AF hunting is sometime caused by not enough light.




There will be no where near enough light because his lowest F stop will be around F8


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## jfrabat (Jan 16, 2013)

I guess that's why the sony teleconverters state that they only work with specific lenses...


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## cosmonaut (Jan 16, 2013)

Well for one no x2 converter is going to AF well and a none Sony knock off will be worse. Save up and get the lens for the focal length you need.


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## gsgary (Jan 17, 2013)

cosmonaut said:


> Well for one no x2 converter is going to AF well and a none Sony knock off will be worse. Save up and get the lens for the focal length you need.



Kenko 2X pro does on my Canon


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