Depth of field question

Started 11 months ago | Discussions thread
ForumParentFirstPreviousNextNext unread
Flat view
Senior MemberPosts: 1,045Gear list
Depth of field question
11 months ago

I am a bit confused about portrait lenses. In particular comparing the DoF of an 85 and a 135. My question is simple, but the answer may be complex.

If I have exactly the same framing, ie, a human head filling the exact same portion of the frame, and if I have set the apeture of each lens the same so as to have the front of the nose and the back of the ear in focus, will the amount of background blur also be the same?

To use a worked example, I assume it is possible for two lenses to have both the nose and ears in focus, because each lens, has say 2ft of "field", yet one of the lenses loses focus after say only another 1 ft whereas the other loses it only after 3 more feet.?

The reason for this question is that I see shots on the internet with massive out of focus backgrounds, but a lot in focus on the person, whereas, for example, if I try to get a lovely out of focus amount where I obliterate the background with my D5200, I cannot also get my dogs nose in focus, so I am wondering if using, say a 300mm lens would do this whereas a 85mm cannot? Any help much appreciated!

 zenpmd's gear list:zenpmd's gear list
Canon EOS 5D Mark III Canon EF 70-200mm f/2.8L IS II USM Canon EF 24-70mm f/2.8L II USM Canon EF 40mm f/2.8 STM
Nikon D5200
If you believe there are incorrect tags, please send us this post using our feedback form.
ForumParentFirstPreviousNextNext unread
Flat view
Post (hide subjects)Posted by
ForumParentFirstPreviousNextNext unread
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow