Forums
New posts
Search forums
What's new
New posts
New media
New media comments
New profile posts
Latest activity
Media
New media
New comments
Search media
Members
Current visitors
New profile posts
Search profile posts
Log in
Register
What's new
Search
Search
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Lenses
General Lenses
Is 120mm really 120mm on the 24-120mm f/4?
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="aroy" data-source="post: 292865" data-attributes="member: 16090"><p>From what I have read, the problem is the IF (internal focusing) mechanism. For maintaining constant focal length the barrel has to increase and decrease its length while focusing. In case of IF one group of lenses moves back and forth, and this changes the focal length.</p><p></p><p><a href="http://en.wikipedia.org/wiki/Breathing_%28lens%29" target="_blank">Breathing (lens) - Wikipedia, the free encyclopedia</a></p><p><a href="http://www.bobatkins.com/photography/technical/focus_breathing_focal_length_changes.html" target="_blank">Focus Breathing (Focal length variation with focus distance)- Bob Atkins Photography</a></p></blockquote><p></p>
[QUOTE="aroy, post: 292865, member: 16090"] From what I have read, the problem is the IF (internal focusing) mechanism. For maintaining constant focal length the barrel has to increase and decrease its length while focusing. In case of IF one group of lenses moves back and forth, and this changes the focal length. [url=http://en.wikipedia.org/wiki/Breathing_%28lens%29]Breathing (lens) - Wikipedia, the free encyclopedia[/url] [url=http://www.bobatkins.com/photography/technical/focus_breathing_focal_length_changes.html]Focus Breathing (Focal length variation with focus distance)- Bob Atkins Photography[/url] [/QUOTE]
Verification
Post reply
Forums
Lenses
General Lenses
Is 120mm really 120mm on the 24-120mm f/4?
Top
