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bcgeo

Joined: 15 Oct 2013
Posts: 3

 Posted: Wed Oct 16, 2013 7:14 pm    Post subject: Total Magnification with DSLR and Trinocular Microscope ? I am new and unsure how to properly know the magnification of the digital photo I have taken The Camera is a Nikon D7000 with 23.6 x 15.7 mm CMOS sensor 4928 x 3264 photo size 1.5x Focal Length ? an Old Meiji Trinocular 2.5x Camera Coupler for this photo the microscope is at 1x this is a mm ruler that is all I have right now Any Help would be appreciated, Thanks in Advance !
Chris S.

Joined: 05 Apr 2009
Posts: 3202
Location: Ohio, USA

 Posted: Wed Oct 16, 2013 8:20 pm    Post subject: Bcgeo, welcome to the forum! Direct measurement, such as you have done here, is a really good way to determine magnification on sensor. In this instance, we are seeing slightly over 11mm of the ruler. (So we can say that the horizontal "field of view" or "subject field" is about 11mm.) Your camera has a 23.6mm horizontal width. So your magnification on sensor is slightly over 2x (which can also be written as 2:1). You could use this formula: M=S/F Where M=magnification on sensor; S=sensor size, and F=field of view. It may be worth noting that these days, "magnification on sensor" is what we commonly mean when we say "magnification." But if you are looking at printed photographs, particularly in older sources, "magnification" might have meant "magnification in the final print." Your 11mm field of view, if printed on a piece of 8x10 inch photographic paper, could be accurately labeled as "Shown approximately 23 times life-size." (Magnification in print=254mm print width/11mm subject width.) (BTW, should this thread be moved to another section of the forum?) Cheers, --Chris
rjlittlefield

Joined: 01 Aug 2006
Posts: 19710
Location: Richland, Washington State, USA