Does the focal length change while AF ?

[Vaibhav]

Hi

Recently got my 55-250IS Canon zoom lens. Noticed that while the lens is autofocusing the focal length also changes, I mean the zoom also changes, and as a result the frame also changes a bit. Is this normal ? Or something wrong with my lens ?

Thanks !

 

[yamcake]

hmm strangely yes...
its normal..

i was shooting a very long time before i knew this.. i thought like u something is wrong with the lens..

 

[rapier84]

;p Ken Rockwell actually comes in useful here
http://www.kenrockwell.com/nikon/2485afs.htm

Look @ the section on 'Focus Breathing', it seems to me to be the case

 

[Vaibhav]

thanks very much all !