If shooting at f/22, is a fast 1.8 lens still considered fast?

Started Apr 17, 2011 | Discussions thread
SteveL54
Senior MemberPosts: 2,613
Like?
Re: tell me Steve
In reply to edwardaneal, Apr 22, 2011

edwardaneal wrote:

So tell me - why does the test I posted above show that AF is more accurate between F/2.8 and F/4 and why does Canon specifically state the following

"The final advantage concerns the focusing. More light can be gathered by these lenses because of the larger maximum aperture making it easier for the autofocus sensors within the camera to find contrast even in low light or low contrast situations. Lenses with smaller maximum apertures may struggle to focus in such low light conditions as they cannot allow enough light into the autofocus sensors."

are they all lying?

The person doing the test doesn't understand the fundamentals of PDAF. Explain the f/1.4 test results. He is assumming a certain cause and effect.

The Canon marketing source you quote is refering to the f/2.8 advantage designed into their AF system.

Steve

Reply   Reply with quote   Complain
Post (hide subjects)Posted by
f16New
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow