Lens Extenders

[bradrjames]

Hi

I am thinking of purchasing a lens extender. Is there any sacrifice of picture quality?

Thanks

Brad

[coffee]

Hi

I am thinking of purchasing a lens extender. Is there any sacrifice of picture quality?

Thanks

Brad

Are you referring to a teleconverter(TC)?

[bradrjames]

Hi Joseph

I am looking at the Extender EF 2x II, as seen on this website http://www.canon.com.au/products/cameras_lenses_accessories/extenders.html

I have a few different lenses but was mainly thinking of this for my 75-300 and my 17-85. I also have a 50mm macro and was thinking that this would be hany for this too.

I realise that this effectivly means that I can not use these lenses at their lowest Fstop, but I don't want to loose picture quality.

Thanks for your help.

Brad

[coffee]

Ok, well do your research. I have a 40d, 1.4 TC and a series of L lenses. If your lenses don't open up to 5.6 or bigger your lens won't auto-focus. And consider that you lose 1 stop I beleave due to the TC. So with a aperture of 5.6, the TC brings it to 8.0. You probably won't be able to auto focus. It's hit and miss with my 100-400L because at 400mm I'm at 8.0. Plus even to be able to attempt to auto focus, a series of 3/4 contact pins have to be taped to keep the lens from reporting back to the camera.

Because of this, I rarely use it, and will probably sell it.

But if you have a 1d series Canon, auto focus is no problem so I read.

[bradrjames]

Thanks for your help :-)

I may hold on to my dollars for now.

[jonrayner]

Just catching up on the forum.....

By using these TC's you lose a slight bit of image quality, but you probably won't notice it unless you are printing out large sized images orperforming heavy cropping. You lose 1 F Stop on the 1.4x convertor and 2 stops on the 2.0x convertor. However before you buy you need to know that they are only compatible with certain lenses; all 4 variants of the 70-200mm L lenses, the 100-400 L lens, any fixed focal length L series lens or DO lens of 135mm or higher. They will not fit any other EF lenses as the front elements of the extenders get in the way of the rear element of the lenses.