Quick question regarding 7D, 70-200f4 and extenders

[Skyline On Fire]

Okay, would putting a 1.4x extender on my 7D with a 70-200f4 lens, lose me the excellent auto focus the 7D provides? I tried the 2x extender in jessops today, and lost autofocus completely. Would using the 1.4x result in the same thing? I understand that the f stop would narrow to 5.6.

Thanks in advance

 

[StewartR]

You'll be fine. All Canon DSLRs can autofocus when the lens (or lens plus Extender) has a maximum aperture of f/5.6 or better. Only 1D-series bodies retain AF at f/8, which is what you had with the 2x Extender fitted.

 

[Ziploc]

this good enough for you ?

 

[Skyline On Fire]

Excellent And image quality, stays great yes? Nice test shots btw ziploc. Worth getting this then?

 

[Ziploc]

Its a handy bit of kit for travelling light. Also works well on primes. theres a few around 2nd hand if you want to save money. You can notice a very slight lag to the focus locking on. The only other downsides the loss of f stop. What your main subject to shot ?