Canon 1.4x Extender

[greekspy2001]

Guys and Gals

Just trying out this extender with my 30D and 40D with the 100-400L lens. The blurb says it supports this lens. However when ever I put the extender on to either body the Auto focus is disabled. Any help in where I'm going wrong? Seems pointless if the AF does work.

Any ideas?

Thanks

Graham

[Virgin777]

Hi , it should be ok ..

Which extender is it by the way ?
white or black & model ?

regards

[arnie]

Yes, it works but without auto focus. The AF on your 30D and 40D is only specified to work until f/5.6 and the 100-400 + extender has f/8 (you lose a stop of light with an extender!). Only the Canon 1D(s) have an auto focus sensor that works until f/8.

You can of course tape the pins or use a non reporting extender, but the auto focus will then be quite unreliable and need a lot of light to function.

[greekspy2001]

Thanks Arnie

So I guess with these bodies I would need something like the 2.8 70-200?

Graham

[arnie]

Thanks Arnie

So I guess with these bodies I would need something like the 2.8 70-200?

Graham

What kind of range do you need? You better work that out first and then see how you can cover the needed range with lenses and/or extenders.

BTW: A 70-200 2.8 with an 2x extender will yield a 140-400 5.6 with questionable quality. Your 100-400 5.6 is much likely much better in picture quality anyway. Please remember that an extender WILL cost light and quality!

[Virgin777]

Yes, it works but without auto focus. The AF on your 30D and 40D is only specified to work until f/5.6 and the 100-400 + extender has f/8 (you lose a stop of light with an extender!). Only the Canon 1D(s) have an auto focus sensor that works until f/8.

You can of course tape the pins or use a non reporting extender, but the auto focus will then be quite unreliable and need a lot of light to function.

Odd one that ... i heard the same however i had one working with no taping pins or anything once !

Besides you dont really want to go extending the 100-400mm anyway at it will become F8 as mentiones and you will loose a sharpness , best to stick it on an F4 or F2.8 where possible ( F stop x 1.4 )


cheers

[chris78cpr]

A 70-200F4 will still AF with a 1.4x on the 40/50D.

To get AF on the 100-400 with a 1.4x you will have to use one of Canon's 1series bodies as they AF to F8.

With the 100-400 i would not recoomend using the 1.4x, i've used it on my 100-400 and 1D2 and the quality isn't great even in perfect light.

Chris

[ecapdeville]

Went to find a canon extender and is hard to find it here, the man at the store offered me a SIGMA 1.4 converter for canon almost half the price...do you think the SIGMA version is good enough?

[saupatel]

Just curious. Based on this discussion can the 1D autofocus on a 600mm F4 with a 2X Extender ? (i guess the min will be F8 ).