TAKO. INTERNET SEIT 1996.
Olympus-OM

Re: [OM] Inexpensive way to macrophotography

Subject: Re: [OM] Inexpensive way to macrophotography
From: Ken Norton <kenorton@xxxxxxxxxx>
Date: Fri, 16 Jan 1998 11:31:52 -0600
Oops, do we have a magnification ratio calculation error here?

>> I then used a 50mm f/1.4 reversed onto a 135mm f/3.5. This gives roughly
>> 2.7 times magnification (50/135).

Hmm.  Doesn't it go the other way?  50/135=.37  That's 1/3 magnification
not 2.7x. If I put a 50mm reversed on a 50mm, I get 1:1 magnification.  If
I put the 50mm on a 100mm I get a 1:2 magnification.  A 50 on a 200 would
give you 1:4 magnification.  You will only get greater than life size by
reversing a longer focal length on a shorter focal length.  For example, a
50mm reversed on a 35mm is 50/35=1.4x magnification.  A 200mm reversed on a
50mm will give you 4x magnification (and serious vigneting too).

...when in doubt, reference John Shaw's books...

Ken Norton
Quincy (400/5.6 doesn't reverse well on a 24mm) Illinois.


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