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Magnification ratio equation


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#1 Daniel Miler

Daniel Miler
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Posted 30 April 2016 - 08:20 AM

Hello all

 

Beware, a hardcore technical question ahead....

 

I know that by having the focal length and minimum focus distance of a given lens, plus the sensor size, one can calculate the magnification ratio of that lens, such as with this very useful online calculator.

 

However, I don't want to have to rely on an online calculator, and have been frantically searching for the equation that will enable me to calculate this on my own, to no avail. 

 

I have been spending the last day drowning in technical terminology and trying to make sense of it, just to understand how very simply focal length + minimum focus + sensor size = magnification ratio...

Shouldn't be that complicated...

 

Any Ideas fellow geekster cinematographers?

 

Thanks 

 

 

 


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#2 David Mullen ASC

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Posted 30 April 2016 - 10:48 AM

The same site you listed gives you the math behind the calculations for magnification here:

http://www.kielia.de.../magnification/

 

As it points out, sensor size has no bearing on magnification ratio of a lens.


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#3 Daniel Miler

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Posted 02 May 2016 - 03:17 PM

Hi David thanks for your quick reply

 

However, there is still way too much algebra in there for me to figure out, as in all the equations I see online they go into image distance and object distance and other comlex terms. 

 

Im trying to find a straightforward formula where I only need to put in focal lenght and focusing distance...


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