Andreas Bruckbauer

Low magnification lens, LED light and Lumina 520 phone. I used a cavity wall slide, added a few drops of pond water, covered with cover glass and sealed with nail varnish. Sealing is probably not a good idea as the little organisms won’t survive for long. I filtered the pond water and took the content of the filter with a bit of water to increase the chances to find something interesting. The fast moving organism is probably  a paramecium and the long twitching one the back end of an insect larvae. Once the foldscope was assembled, this was very simple and fun! In the future it would be good to have a little chamber like a dish on an inverted microscope to add more water.

<div class="wp-video" style="width: 640px;">
 
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 <source alt="pond_live_2.mp4" class="gcloudimg" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_5088/pond_live_2.mp4" type="video/mp4"/>
 <a alt="pond_live_2.mp4" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_5088/pond_live_2.mp4">
 https://microcosmos.foldscope.com/wp-content/uploads/old/pond_live_2.mp4
 </a>
 </video>
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 <video alt="pond_live_2.mp4" class="wp-video-shortcode gcloudimg" controls="controls" height="360" id="video-5088-2" preload="metadata" width="640">
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 <a alt="pond_live_3.mp4" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_5088/pond_live_3.mp4">
 https://microcosmos.foldscope.com/wp-content/uploads/old/pond_live_3.mp4
 </a>
 </video>
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Pond live movies with Foldscope

Taking photos and movies with a mobile phone or tablet attached to the foldscape works very well and is great fun. Here I am looking for a cheaper alternative, so that I can let everyone have a go without worrying about the phone. I tried one of these cheap 640×480 pixel webcams with 6 LEDs, which I bought for £4.60 from eBay, here I already removed the little stand (it is not a megapixel camera and has no zoom):


 <a alt="webcam_1.jpg" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/webcam_1.jpg">
 <img alt="webcam_1" class="alignnone size-full wp-image-6756 gcloudimg" data-attachment-id="6756" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}' data-image-title="webcam_1" data-recalc-dims="1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/webcam_1.jpg"/>
 </a>


 With the lens focused to infinity and the camera as close to the foldscope as possible the result was very disappointing:


 <a alt="webcam_before.jpg" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/webcam_before.jpg">
 <img alt="webcam_before" class="alignnone size-full wp-image-6763 gcloudimg" data-attachment-id="6763" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}' data-image-title="webcam_before" data-recalc-dims="1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/webcam_before.jpg"/>
 </a>


 The problem is that the actual lens is too far away from the ball lens of the foldscope so that the image fills only a tiny bit of the screen. First I tried to replace the webcam lens with a simple lens, but I found that the original lens design is actually quite clever and consists of several elements:


 <a alt="lens_webcam.jpg" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/lens_webcam.jpg">
 <img alt="lens_webcam" class="alignnone size-thumbnail wp-image-6767 gcloudimg" data-attachment-id="6767" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}' data-image-title="lens_webcam" data-recalc-dims="1" height="150" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/lens_webcam.jpg" width="150"/>
 </a>


 With the original lens now destroyed, I looked for an alternative and found this one on ebay for £4.80 (3.2mm Focal Length M12xP0.5 Camera Lens for Raspberry):


 <a alt="new_lens.jpg" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/new_lens.jpg">
 <img alt="new_lens" class="alignnone size-thumbnail wp-image-6758 gcloudimg" data-attachment-id="6758" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}' data-image-title="new_lens" data-recalc-dims="1" height="150" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/new_lens.jpg" width="150"/>
 </a>


 It can be screwed into the circuit board of the webcam. It is shown here without the casing, you can see the CCD chip, it is only about 1.5 mm x 1.1 mm)


 <a alt="webcam_2.jpg" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/webcam_2.jpg">
 <img alt="webcam_2" class="alignnone size-full wp-image-6757 gcloudimg" data-attachment-id="6757" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}' data-image-title="webcam_2" data-recalc-dims="1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/webcam_2.jpg"/>
 </a>
 
 I also removed the LEDs and a little bit off the plastic, putting everything back together with the lens focused to infinity it looks like this, the lens protrudes much less:


 <a alt="webcam_modyfied.jpg" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/webcam_modyfied.jpg">
 <img alt="webcam_modyfied" class="alignnone size-full wp-image-6759 gcloudimg" data-attachment-id="6759" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}' data-image-title="webcam_modyfied" data-recalc-dims="1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/webcam_modyfied.jpg"/>
 </a>


 I attached the magnetic stripe with a bit of blue tack and the double sided tape, adjusted so that the hole is centered on the image:


 <a alt="webcam_magnets.jpg" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/webcam_magnets.jpg">
 <img alt="webcam_magnets" class="alignnone size-full wp-image-6760 gcloudimg" data-attachment-id="6760" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}' data-image-title="webcam_magnets" data-recalc-dims="1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/webcam_magnets.jpg"/>
 </a>
 
 Attached to the foldscope it looks like this:
 
 <a alt="webcam_on_foldscope.jpg" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/webcam_on_foldscope.jpg">
 <img alt="webcam_on_foldscope" class="alignnone size-full wp-image-6761 gcloudimg" data-attachment-id="6761" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}' data-image-title="webcam_on_foldscope" data-recalc-dims="1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/webcam_on_foldscope.jpg"/>
 </a>


 Now I can record movies on the computer e.g. with the quicktime viewer:


 <a alt="screenshot2.jpg" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/screenshot2.jpg">
 <img alt="screenshot2" class="alignnone size-full wp-image-6762 gcloudimg" data-attachment-id="6762" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}' data-image-title="screenshot2" data-recalc-dims="1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/screenshot2.jpg"/>
 </a>
 
 Below is a still image with the low magnification foldscope and LED illumination. The object is a stem cross section from limewood (
 <a alt="prepared-slides.html" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/prepared-slides.html">
 http://www.brunelmicroscopes.co.uk/prepared-slides.html
 </a>
 ). One problem at the beginning was the saturation of the image, it was mostly white. Putting a piece of paper folded several times between the condenser lens and the stage to attenuate the LED light solved this problem. These cheap webcams also compress the images a lot, which cause artefacts. Anyhow the image is much improved compared to the one at the beginning.
 
 <a alt="webcam_modified-1.jpg" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/webcam_modified-1.jpg">
 <img alt="webcam_modified-1" class="alignnone size-full wp-image-6766 gcloudimg" data-attachment-id="6766" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}' data-image-title="webcam_modified-1" data-recalc-dims="1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/webcam_modified-1.jpg"/>
 </a>
 
 This is an image of the same sample taken with my Lumina 520 mobile phone:
 
 <a alt="mobile_phone.jpg" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/mobile_phone.jpg">
 <img alt="mobile_phone" class="alignnone size-full wp-image-6765 gcloudimg" data-attachment-id="6765" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}' data-image-title="mobile_phone" data-recalc-dims="1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/mobile_phone.jpg"/>
 </a>


 One can see the larger field of view showing more of the sample. The mobile phone has a 3.2 mm x 2.4 mm CCD chip, which is four times the size of the webcam chip. The phone has a focal length of about 2.6 mm, the focal length of the foldscope is 1.7 mm (large lens), which would mean the image is only magnified 1.4x on the CCD chip. In the case of the webcam we have 3.2 mm focal length which results in a little higher magnification of 1.8x. The reason both work so well with the foldscope is because of the small pixel size of the CCDs, 1.2 micrometers for the mobile phone and 2.2 micrometers for the webcam.


 When using the original webcam lens (I bought a new one), it is possible to unscrew the lens, so that it is quite far away from the CCD chip. This way it is possible to focus on very close objects. A computer screen is very good for testing. Below is the same sample viewed just with the webcam (no foldscope). The outer ring is about 4.5 mm diameter.


 <a alt="MAX_test.jpg" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/MAX_test.jpg">
 <img alt="MAX_test" class="alignnone size-full wp-image-6764 gcloudimg" data-attachment-id="6764" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}' data-image-title="MAX_test" data-recalc-dims="1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/MAX_test.jpg"/>
 </a>


 This is the same sample photographed through a simple 2x magnifying glass and with a ruler:


 <a alt="magnifying_glass.jpg" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/magnifying_glass.jpg">
 <img alt="magnifying_glass" class="alignnone size-full wp-image-6768 gcloudimg" data-attachment-id="6768" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}' data-image-title="magnifying_glass" data-recalc-dims="1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_6755/magnifying_glass.jpg"/>
 </a>


 It might have been easier just to cut of the front part of the original lens. Has anyone experience with a better webcam?

Andreas Bruckbauer

Earth

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Pond live movies with Foldscope

Fitting a cheap webcam to the foldscope

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Foldscope Lens Magnification