The ZS20 used as a “Microscope” - 2

 


Results on Some Test Subjects


A Desktop Computer Display

The image below was taken of my iMac LCD screen using the ZS20 alone, in macro mode, held near the screen at a FL of 30mm.  The width of the captured field, which was 12 point black text on a white background, was 3.85cm.


12 point text on iMac display using ZS20 alone at 30mm FL


A 100% crop of the above image is shown below.  The crop clearly shows the array of red, green and blue pixels but does not show any detailed structure within the pixels.


100% crop from above image


Using the setup as previously described with the camera at max zoom I took shots of the screen, and this time the structure of the individual pixels could be seen, as shown in the image below.


12 point text on iMac display using the “microscope” setup


The width of the captured field in this image was just 1.7mm.  This meant that the magnification factor obtained with this setup was about 22.  The measured factor was somewhat less than the calculated value of 24.5 because at close distances the TCs give a lower magnification factor than their power values.


A 100% crop of a green pixel near the centre of the above image is shown below.


                            100% crop of a green pixel


I calculated that the pixels are about 67 micrometres wide and 223 micrometeres high.  The small rounded structures in the green pixel are about 7 micrometres in diameter, and the narrow horizontal black gap in the centre of the pixel is about 1.5-2 micrometres wide.


To give a comparison, the diameter of human hair varies, but ranges from 17 to 180 micrometres (that is, 0.017-0.180mm).  Therefore the setup provides a magnification somewhat equivalent to that of a low power microscope.


An Audio CD

I tested the printed side of an audio CD with grey printed text over a pale grey background, as shown in this shot taken with the camera alone:


Printed CD used in the test


I first looked at the grey background with my setup, as shown below:


Printed grey background using the setup


It is interesting that the inkjet droplets are scattered and don't generally overlap each other.  Each colour is printed in distinct straight lines, but the lines are at a different angle for each colour.  The droplets vary in size and shape but are roughly 20-65 micrometers across.


I then used the setup to look at the letter "u" in "Gudrun", which was about 0.9mm wide on the CD:


Top part of the letter “u” on the CD


Only the two arms are shown, as the base of the "u" is out of the field.  The arms show heavy overlapping ink droplets, and from the way the light is reflecting, the dried ink seems to have formed little "peaks", rising above the disk surface.


Unfortunately I had no success with the CD grooves on the recorded side, as I was unable to get a focus.


I then tested the setup using an insect and a plant as the subjects, as shown in the following section.




Continue to Two Further Examples


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