The ZS20 as a “Microscope”

 


The Setup


A lens from an interchangeable lens camera can be used as a closeup lens by reversing it and placing it in front of the lens of the test camera.  I used a 50mm f/2.0 lens from an old Pentax film camera for this purpose.  Views of the front and rear of the lens are shown below:



When reversed, the power of this lens when used as a closeup lens is given by: 1000/50 = 20 dioptres.


Teleconverters (TCs) can be used to increase the effective focal length of the test camera, in this case the ZS20.  I have shown here how a DIY adapter can enable TCs and and stacked TCs to be used on the ZS20.  I have also described various alternative options for adapters for the ZS/TZ series here.


By combining the two systems it is possible to achieve a very high degree of magnification.  I tested the ZS20 with the Nikon E15ED stacked with the Olympus C180 in front.  I attached the reversed 50mm Pentax lens in front of the C180, with the aperture blades of the 50mm lens held fully open by inserting a small wedge of cardboard into the spring mechanism.


As the housing of the front of the 50mm lens was very similar in diameter to the front of the C180, I simply used tape to attach the lens for test purposes.  The setup is shown in the image below:


The ZS20 set up with stacked TCs plus reversed 50mm lens in front.


I used the ring clamp which was provided with my Nikon E17ED around the E15ED to attach the setup to my tripod.  Since the camera is the smallest and lighest component it does not require any other support.

  

I used a CD case as a “microscope slide”, which facilitated the very small movements needed to align the subject in the field of the reversed lens.  The CD case also conveniently provided either a white or a black background for the subjects. 


When focussed on a subject, the front reversed lens is about 50mm (the FL of the lens) from the subject, which allows a reasonable amount of light to reach the subject but there can be shadows.  For additional lighting I used an LED flashlight, shown at the left above.   I simply held the flashlight in one hand and moved the beam until it gave the best lighting of the subject when viewed on the camera LCD.  I then held the flashlight in that position during the exposure, for which I used the 2 second timer.


The predicted magnification provided by such a setup is given by: 


(FL of camera x power of TCs) / FL of reversed lens


which in this case, with the camera set to maximum zoom, is (480 x 1.5 x 1.7) / 50 = 24.5.


The results on some different types of test subjects are given in the following section.





Continue to Results on Some Test Subjects


Return to Testing of the ZS20/TZ30


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