On my 70D, why is 250mm by Canon a larger zoom than 250mm by Sigma?

Started Jul 26, 2014 | Questions thread
Shop cameras & lenses ▾
Sir Atfus OP Forum Member • Posts: 77
Re: On my 70D, why is 250mm by Canon a larger zoom than 250mm by Sigma?

Thanks Howard.. I think Focus Breathing is the lingo. I've never heard of this.

http://www.bobatkins.com/photography/technical/focus_breathing_focal_length_changes.html

Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow