Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Canon Lenses

Thread Tools Search this Thread
Old Apr 27, 2008, 9:52 AM   #1
Junior Member
janij00's Avatar
Join Date: Mar 2005
Posts: 9

I cannot get a maximum aperature of f/3.5 on my EF 28-135mm f/3.5-5.6 IS USM. Even having the ISO set at 1600 in direct sunlight I can only get a max of 5.6 Any ideas?
janij00 is offline   Reply With Quote
Sponsored Links
Old Apr 27, 2008, 9:56 AM   #2
Join Date: Aug 2004
Posts: 8,529

It's a variable aperture lens. It is only 3.5 when at it's widest zoom (28mm). As you start to zoom out the max aperture changes to 5.6. I never bothered to map out exactly what focal lengths the max aperture changed at though.
JohnG is offline   Reply With Quote
Old Apr 27, 2008, 12:38 PM   #3
Super Moderator
Mark1616's Avatar
Join Date: Oct 2005
Posts: 7,451

John is right and frommy experience with variable aperture lenses nearly all will change from their widest aperture almost the instant you start to zoom and at the long end you usually find that you have quite a lot that is at the long widest aperture.
Mark1616 is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -5. The time now is 4:33 AM.