Question for owners of Canon's 28-300L IS

[Joe Austin]

I just bought this lens and was comparing it to my 28-70, 70-200 and 300f4. I noticed that the 28-300 shot wider than the other lenses for a given focal length. This occured at 28, 200, and 300, being most noticeable at 200 and 300. A 1DmkIII was used for the testing.

Has anyone else noticed this? Is this normal?

[Chris Korman]

I do not personally own this lens, however what is common among zoom lenses and even some primes is a term called "focus breathing" i.e. at close focus distances the actual focal length is reduced in order compensate for focusing closer. However, focusing a zoom at infinity and a prime at infinity you would see both recording similar fields of view. Have you tried your experiment at close range or at subject far into the distance?

[Joe Austin]

Thanks. Yes, I did discover this yesterday. Was not aware of he phenomenon before. The field of view between the lenses is identical at infinity focus for a given focal length.