# Determining magnification for photographs taken with Bresser MikrOkular camera through Zeiss IM microscope

Rhys and I used a calibration slide to determine the on-screen magnification of images taken through the Zeiss IM microscope with different objectives using Bresser MikrOkular camera.

6×0.01mm horizontally = 0.06mm
4.5×0.01mm vertically = 0.045mm.
On my laptop (Dell M4800) one of my photos through the MikrOkular appears at 290mmx170mm in size.
Hence the magnification in this image = 290/0.06 = 4833 x magnification (calculated on basis horizontal size)
Or 170/0.045 = 3778 x magnification (calculation on basis vertical size).
The difference is probably explained by either unequal pixel sizes on screen or part photo cut off (probably vertically) on screen.
Taking an averge magnification = (4833+3778)/2 = 4300x magnification
Hence magnifications using MikrOkular camera are:
(i) 4x objective = 273x
(ii) 10x objective = 680x
(iii) 20x objective = 1360x
(iv) 32x objective = 2180x
(v) 40x objective = 2730x
(vi) 63x objective = 4300x

For future posts, the magnification using MikrOkular camera can be calculated using a magnification factor = Magnification calculated as MikrOkular camera & screen magnification factor 68 (=4300/63). To calculate magnification = magnification factor x objective magnification. For example, for 32x objective with MikrOkular camera, on screen magnification will be 68×32=2176 (approx).

Andy & Rhys

Calibration images taken using 63x objective – the lines are 0.01mm apart from each other:

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