Front attaching 2x telephoto lenses

[nathanie.ramanaden]

I would like members comments on the 2x telephoto lenses that screw on to the front of zoom lenses. We are all used to 2x extenders which are fitted to the camera body but not all zoom lenses will function with such extenders. However, the 2x telephoto lenses that screw into the front of the lens appear to over come this problem, and this might be the way forward for convertors.

As an ageing photographer I like to travel light on safari trips and the front element convertors seem fit the bill- gives my present 75mm- 300mm zoom lens a capacity to extend it to 600mm at the top end.

I am not sure of the picture quality of these convertors.

[collywobbles]

Re: Front attaching 2x telephoto lenses

I've never seen such a beast. However, if you double the focal length ( by whatever method ) you will halve the aperture size! i.e. f/5.6 becomes f/11.
Focal length / aperture value = diameter of aperture.

[nathanie.ramanaden]

Re: Front attaching 2x telephoto lenses

I agree with what you say; its the same with the normal extenders with which we are familiar with.

You can see such beasts advertised on Ebay under "telephoto lenses". These are advertised as "new" and many of the sellers are USA based. You can also see these advertised when you click on (Ebay) under Canon 450d cameras or 450 body. The seller usually say " with 3 lenses" and then you get with it a standard lens, and a wide and telephoto front fitting "extenders"!

The advantage with this type of extender is that it does away with the problems encountered with normal rear extenders which do not operate with many ZOOM lenses.

I would like to know whether any EOS member has used these lenses and the quality of the pictures- which is the predominant factor.