Close-up math

Started May 3, 2014 | Questions thread
Shop cameras & lenses ▾
ForumParentFirstPreviousNextNext unread
Flat view
Senior MemberPosts: 2,979Gear list
Close-up math
May 3, 2014

The Olympus 12-50 specs include a maximum magnification of 0.72x. Given that a m43 sensor is 17.3mm x 13mm, I would have thought the minimum field width would be 24mm (17.3/0.72). However, the smallest I can get in focus is about 33mm across (macro mode, manual focus with ring spun clockwise).

What am I doing wrong?

I'm asking because I'm trying to figure out the diopter strength or extension tube length to get a minimum field width of about 35mm with the Olympus 40-150. With a max magnification of 0.16x and a MFD of 900mm, I would have thought I'd need 4-5 diopters or 60mm of extension. Of those two, I'd choose 4-5 diopters (60mm of extension would lose too much light). That's assuming my math and understanding are correct.

Close-up calculator at

-- hide signature --
 richarddd's gear list:richarddd's gear list
Olympus OM-D E-M5 Panasonic Lumix G Vario 7-14mm F4 ASPH Olympus M.Zuiko Digital ED 40-150mm 1:4-5.6 R Olympus M.Zuiko Digital 45mm F1.8 Samyang 7.5mm F3.5 UMC Fisheye MFT +3 more
This question has not been answered yet.
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