Openflexure Microscope High Resolution vs Basic

Hello all. I’m a Biology teacher looking at building a Openflexure microscope for use in my school’s science classes, however I had a couple questions to help establish what configuration we need to prevent wasting money as schools are exactly fountains of wealth. We already have class sets of fairly budget microscopes that the kids can use but my thought was that the Openflexure microscope would be ideal for class demonstrations to complement the hands-on microscope work to allow for more complex microscopy to be carried out or to illustrate key features of cells etc. by connecting it to classroom projectors.

1 - Is there any significant advantages between using the Raspberry Pi 2 vs the Raspberry Pi 4? I’m aware the 4 has significantly more performance but will a Pi 2 hamper the usage of the Openflexure software? We can source a Pi 2 for free but would need to purchase a Pi 4.

2 - I’m terms of the image quality is the jump in image quality between the “High Resolution” configuration and the “Basic” configuration worth the jump in cost (around £40 by my estimate)? Our usage would focus on examination of pond water and various plant, animal, fungal cells and the larger organelles within them.

3 - I see there are developments on a next version of the OpenFlexure microscope is it worth holding off on printing and assembling the microscope to wait for this version to be released?

Thanks in advance for any help you folks can give me.

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Hi @Parzival I have not got a complete answer to your question, but some thoughts.

The Pi 2 will struggle. I use a Pi 3B+, and that is quite slow if you are using it as a standalone microscope, so that the Pi is operating the microscope and providing a desktop to a screen. It manages well if I don’t make it run the desktop and connect from another computer.

The basic Pi camera lens is very good indeed. You will easily be able to see larger cells and larger organelles. The field of view is large, so finding what you are looking for can be easier than a conventional microscope. If you need 100x objective on a conventional microscope, then you will need the high resolution optics with 100x on the Openflexure microscope. The Pi lens is better than a cheap conventional 20x objective in my opinion. I have not looked at anything in the 40x range in between. For the high resolution optics you will need a tube lens as well as the objective lens. The tube lenses are not so easy to get cheaply.

The good news on upgrades is that the expensive hardware is the same - Pi, Pi Camera, lenses etc, so you would only need to print the plastic parts. In the next release the optical performance will be the same, there will be improvements in robustness. I think it is probably not worth waiting for your build.

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Hi @WilliamW thanks for the quick reply and you’ve done a brilliant job answering my questions.

I’ll look into costing up adding the Pi 4 to the build as although we don’t need something exceptionally responsive, having slow downs with a class of kids in front of you is best avoided though.

For what we currently examine we typically use objectives in the range of 4x-40x (10x is our most commonly used lens) with a 10x eyepiece lens on our actual microscopes. I’m unsure how the optics of the Pi camera lens works given this replaces the eyepiece lens, so in a conventional microscope a 10x eyepiece and 10x objective lens will give a total magnification of 100x. Based on what you’ve said is the Pi camera lens by itself a 20x magnification? I’m just trying to determine if in a situation where we want a 100x-400x magnified image what objective lenses does that require?

That’s brilliant as I think the technical teacher that is assisting with the 3D printing side was thinking that before summer would be an ideal time to get it printed, so we can get started on that soon.

Thanks!

The ‘magnification’ of a microscope does not make a lot of sense when we have a digital microscope as the image ends up as big as the screen that you display it on. The resolution and field of view are the things that really tell you what the microscope is able to look at. However for what you describe I think the Pi lens will be a very good start.
Magnification, Resolution, and Field of View · Wiki · OpenFlexure / openflexure-microscope · GitLab and Resolution and Field of View · Wiki · OpenFlexure / openflexure-microscope · GitLab explain some of this.

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I figured it wouldn’t be directly comparable. Having read those links it does seem like a Pi lens by itself might be a good place to start. Thanks again for your help,

Do let us know how you get on if you do build a microscope.

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