Added: 3 years ago
From: NightRunner417
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  • I've watched all your videos with your microscope and noticed you've been estimating the magnification due to using your camera. I found a good way to find the magnification was to take a photo of something you know has a fixed size like a red blood cell. Using the guide in the Microbehunter magazine of June 2011 about measuring sizes under the microscope, you can find the magnification. see my next reply

  • @MrCrowley45 - If 0.7 pixels = 1 micron at 10x and a red blood cell is 300 pixels in diameter in a photo taken at unknown magnification, divide 0.7 by estimated magnification (2400x would be 24) and then calculate 0.7/24 = 0.0291. Then calculate 300 x 0.0291 = 8.73 which is the diameter is microns. If this is too large/small for a red blood cell, adjust the magnification and calculate again until it fits. Read the June 2011 online microbehunter magazine, it describes most of this process

  • @MrCrowley45 That's an excellent solution, and brilliant but ONLY if you never divert from one fixed setup both in camera and display. The very second you upload your results to Youtube, your figures change dramatically for each separate person that views, based on their display setup which you can never hope to know. Therefore, if I do all this, say at full screen on my current setup, then commit a mag figure to the video, it will still be way wrong at the viewer end.

  • Having said that, however, it occurs to me that it would be possible to post a sort of a "magnification key" with or in the video. Say if my magnification on MY end worked out to be 1500x with a real image format of 18.5"x11.75", then I could submit that information and the end user could do some simple ratio based math to figure out what magnification they are seeing on THEIR end when they watch the video on YouTube. This would work for everyone despite great differences in setups.

  • surprised that bacteria can be seen. at micron size it's close to light wavelength. are you using UV light?

  • @DanFrederiksen Nope, not UV. That would require a UV sensitive imager btw which would be quite hard to find. I'm pretty sure that back when I did this one i was still using the stock incandescent bulb illuminator, nothing special. Nowadays, I have modified the illuminator so that it uses a single high power white LED, and removed the blue glass filter from the condenser as well. It works GREAT, its even a little more clear than the stock was, and almost no heat at all.

  • @NightRunner417 I believe cmos sensors will respond down to 300nm UV. not sure about glass and lenses though

  • Thanks for the information! Too bad my oil is solid... Do you know how this could have possibly happened?

  • Mine smells strongly of pine tar or some similar volatile odor. The Wiki page on Immersion Oil states that cedar tree oil has a refractive index of 1.516, and the obvious insinuation is that cedar tree oil is one type used for oil immersion microscopy. Such oil would be prone to drying out, and that is probably what happened to you. My own bottle of it leaked during shipping, and the outside has a sticky coating rather like half cured lacquer. In time, it would probably harden to a solid.

  • An addtional note... Online stores like Online Science Mall and Home Science Tools have multiple types of immersion oil for purchase and the prices are great. Possibly you could try out the high viscosity type, which I believe is supposed to have a longer useful life.

  • Argh, last minute addition... I just opened my new immersion oil I bought from Online Science Mall (type b high viscosity), and on the bottle it says odorless (it's true!) and stable, non drying. The results are lovely, I'll be posting a new video of a microorganism with and without the oil so you can see how badass it really is. :-)

  • How do you put oil on the 100x lens? Is the oil supposed to be almost solid so that it doesn't even flow?

  • What you do is you place a small drop on TOP of the cover glass (carefully so as not to muck up your slide), and then bring the oil immersion objective into focus in that spot. If you did it right, the drop of oil will contact the objective lens tip and connect it via the oil to the cover glass, greatly enhancing the clarity of the image. As you move the slide, the drop of oil will cling to the objective and keep the drop in place. It's thick, like castor oil, but NOT solid, it MUST flow.

  • Wonder what swam by at around 3:40!

  • Hey Rob! That's most likely a bacterium drifting by, the reason it appears like a "swarm" is that it is at a different focus. At these magnifications, just the distance between slide and cover glass is HUGE, and while objects at the slide level can be in sharp focus, at the same time an object closer to the cover glass can be so out of focus as to be totally missed.

  • Yes, I remember way way back when I had a decent scope. It was very cool discovering the different "levels" of existence. I would watch things swim up into focus, then dive down out of focus. The micro world, the same as the macro one, is fascinating.

    Please, make and post more vids! They are interesting and educational.

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