Compatible converter.

[John N]

I am using a canon100-400is lens on a canon 10d and find I need more reach, especially for bird photography. I am thinking about a 1.4 or 2 x converters, probably 1.4.I like the sigma 1.4 converter, but I do not know if it is compatible with this set up. Any advice would be very much appreciated. Thanks John.

[rin]

I was discussing the very same thing yesterday and was advised that I would lose too much DOF with the 2x tc and should stick to 1.4x tc.

I am going to borrow a tc later this week to experiment with so will decide after that.

Let me know how you get on.

Rin x

[hollis_f]

Originally Posted by John N

I am using a canon100-400is lens on a canon 10d and find I need more reach, especially for bird photography. I am thinking about a 1.4 or 2 x converters, probably 1.4.I like the sigma 1.4 converter, but I do not know if it is compatible with this set up. Any advice would be very much appreciated. Thanks John.

Yup, the Sigma 1.4x does work with the 100-400L.

You will lose autofocus unless you do the trick of taping the pins (do a Google on 'autofocus pins taping' to find the details of this trick). However, AF will be very slow. Yesterday I tried it with a friend's 100-400L and Canon 2x converter. AF was terrible, requiring a bright, contrasty subject at 100mm and not working at all (in fairly dim conditions) at 400mm.

[jammie*dodger]

If it is f4 max then AF is usually retained. Above that it's all manual :-(

Rob.

[Christine]

a reasonable image can be obtained using a 2x with the 100-400 but good light is needed and a tripod is recommended.But I find it is difficult to judge if one has the mf spot when viewing through the viewfinder esp on the 20d

[hollis_f]

Originally Posted by Christine

a reasonable image can be obtained using a 2x with the 100-400 but good light is needed and a tripod is recommended.But I find it is difficult to judge if one has the mf spot when viewing through the viewfinder esp on the 20d

With the 2x on a 100-400 it's going to be vital that the dioptre adjustment on the viewfinder is set perfectly for your eye. Otherwise it'll look as if it's in focus when it ain't.

[John N]

Thanks everyone. It looks like I will settle on the 1.4 converter and practice with manual focus. I managed to borrow one this week and although the weather was totally unsuitable I managed a couple of shots good enough for identification purpose. The only thing I have to decide is if the canon extender is worth the extra cash.

[rin]

Wow, how educated you all are. I am watching this thread and learning all the time.

I have gone off the idea of a 500mm lens as all the feedback I am receiving states that it is way too heavy for and held photography and I am not a lover of wandering about with my tripod.

I am interested in the 100-400 lens though. But wonder if a 400 prime lens would be better. I am keen on birdwatching and am looking for a lens to take bird photographs bearing in mind how far away they can be.

I am somewhat confused and as you suggest would love to try diffent lens' but we live in the very north highlands and don't have that option.

Keep the advice coming.

Rin x

[John N]

Hi Rin.The converter I borrowed I used on a 100-400is,it was a sigma1.4 and was hand held,it would have been better on a tripd,especially using manual focus but the shots were good enough to id the birds.