Teleconverter Question - PhotoCamel

Tx_40d · 09-16-2009

Has anyone used a Tamron 1.4x AF TC on a canon EF 70-300mm f/4-5.6 IS USM, and if so were you still able to use the auto-focus feature?

thanks,
tx_40d

20DNewbie · 09-16-2009

I wouldn't bother, I'm not sure if the Tamron reports to the camera or not.

Reasons being if it did report to the body it should only AF up till the point in which the widest aperture changes to 5.6 when zooming, from that point on you would lose AF. Even if it doesn't report I imagine the AF would hunt heaps and be slow as heck anyhow.

swampler · 09-16-2009

I had an old Tamron 1.4x that didn't report and it would work on my 70-300 IS, but it was really slow focusing and the image quality was no good.

Tx_40d · 09-17-2009

Thanks for the input guys; I had a feeling it probably wasn't a good idea but had to ask

thanks,
Tx_40d

09-16-2009	#1
Tx_40d Alpaca Posts: 31 CamelKarma: 50 Gallery \| Blog	Teleconverter Question Has anyone used a Tamron 1.4x AF TC on a canon EF 70-300mm f/4-5.6 IS USM, and if so were you still able to use the auto-focus feature? thanks, tx_40d __________________ Members don't see ads in threads. Register your free account today and become a member on PhotoCamel - Your Friendly Photo Forum, gaining access to posting privileges, contests, free plug-ins and other downloads, unlimited online storage for your photographs, reviews, free marketplace listings, and much more.
Tx_40d Alpaca Posts: 31 CamelKarma: 50 Gallery \| Blog

09-16-2009	#2
20DNewbie Vicuna Location: Massachusetts Posts: 165 CamelKarma: 46 Gallery \| Blog	Re: Teleconverter Question I wouldn't bother, I'm not sure if the Tamron reports to the camera or not. Reasons being if it did report to the body it should only AF up till the point in which the widest aperture changes to 5.6 when zooming, from that point on you would lose AF. Even if it doesn't report I imagine the AF would hunt heaps and be slow as heck anyhow.
	__________________ Christian. 1D MkII N/1D/40D/20D and a couple bits of glass.

09-16-2009	#3
swampler Camel Breath Location: Lebanon, TN Posts: 11,801 CamelKarma: 18114 Editing OK?: Ask first Gallery \| Blog	Re: Teleconverter Question I had an old Tamron 1.4x that didn't report and it would work on my 70-300 IS, but it was really slow focusing and the image quality was no good.
	__________________ Steve Middle Tennessee Sports Photos

09-17-2009	#4
Tx_40d Alpaca Posts: 31 CamelKarma: 50 Gallery \| Blog	Re: Teleconverter Question Thanks for the input guys; I had a feeling it probably wasn't a good idea but had to ask thanks, Tx_40d __________________ Members don't see ads in threads. Register your free account today and become a member on PhotoCamel - Your Friendly Photo Forum, gaining access to posting privileges, contests, free plug-ins and other downloads, unlimited online storage for your photographs, reviews, free marketplace listings, and much more.
Tx_40d Alpaca Posts: 31 CamelKarma: 50 Gallery \| Blog

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