Canon 100-400L IS w/ 1.4x TC -- How sharp?

[Dave_J]

I'm thinking of buying a Canon 1.4x TC to use now with my 100-400 IS lens, with the plan that it will be nice to have later when I can afford a longer f4 lens. (Yes -- I know it will not autofocus with my 100-400 on my 10d). The 100-400 is obviously not as sharp as some other 400 primes, but not too bad either, but what about with 1.4x TC? I have looked at other threads from the last couple of years on this topic, but most of the discussion migrates toward whether or not AF works. I did have the chance to spend a morning shooting birds with a borrowed 300 f4 w/ 2x TC (MF on my 10D) and the results got me interested in adding a 1.4x to my kit. Any opinions based on actual results?

Thanks,
Dave Jones

[Francis_Specker]

The new 1.4 tc version II is very sharp. I think it is a must have tool in your camera bag. Buy it and cherish it. ( P.S. I don't own Canon stock or have an investment banking relationship with them.)

[budjames]

Starting with a soft lens and adding the Canon 1.4x extender won't make images sharper. The 100-400 is a nice lens for the price, but it is not the sharpest available from Canon. I just can't afford the others.

I own the 100-400IS lens and have been using it for about 1-1/2 years on my Canon EOS 1VHS and for the last few weeks on my new Canon 10D.

The 1.4x/100-400IS combo only auto focuses on the center focusing spot on my 1VHS. On the 10D, auto focus doesn't work so I have to manual focus. Fortunately, on the 10D with a 1.6X magnification factor, I don't have to use the 1.4x extender to get the same results as I would on the 1VHS.

I think that the 1.4x/100-400 combo is noticably softer than the 100-400 by itself, even when using a solid tripod.

Just MHO.

Bud

[Alexander_Dydula]

I am thinking of buying the 100-400 for my 10D, why doesnt autofocus work????

Thanks
Alex

[Dave_J]

10D autofocus works only for lenses f5.6 or faster. With 1.4x the 100-400 is an f8. Autofocus works great on the lens by itself, and the 1.6x crop factor yields 640mm effective length at f5.6.

[Alexander_Dydula]

Thanks, I understand this f5.6 requirement now. I am about to order via Canoga Camera. I am also looking at the 500D close up up lens. I have used a friends 100-400 the other day and fell in love with it...its an amazing piece of technology. Never thought that you would be able to do any good macro work with such a long lens. I was surprised.

Alex

[StevenCharles]

The autofocus will work on the 100-400IS and 1.4x convertor very well infact. All you have to do is tape the last 2 pins so they wont contact. Works great!