I have just started building a microscope. I apologize for annoying noob questions. Perhaps over time I will be able to answer them…until then…
I wanted to order a Tube Lens. Note: My knowledge of optics is close to non-existence. It is recommended to buy Thorlab’s AC127-050-A
Unfortunately, this lens is not available and there is no date on the site for when it will be available.
If I understood optics better, I would just think…that’s ok, I got this…I just need to look at… but I don’t.
Can you please help me with links to Tube Lenses that work?
Thank you very much.
Hi @happyday. The important parameters are that this is a 50mm focal length lens. The diameter is 1/2" or 12.7mm. This is not important for the optical performance, but just to make it fit. It is an achromatic doublet lens, this means that it is corrected for colour aberrations, so colour images will be clearer. It is also anti-reflection coated for visible light. Lenses with those parameter should be quite widely available. For example Edmund Optics have Magnesium Fluoride Coated Achromatic Lenses, they are a little more expensive and don’t quite match - either 1/2" diameter and 2" (50.8mm) focal length, or 50mm focal length and 12.5mm diameter. Either should I think work.
You may not actually need the high resolution optics with the tube lens. The low cost optics with the Raspberry Pi camera lens is remarkably good ( Comparison of a pi-camera and a 20x optical lens - Contributions - OpenFlexure Forum. Although looking at your other thread you have previously used a 40x objective.
Thank you @WilliamW. Especially for your clear explanation. Breaking out the pieces and their function sure made it understandable.
I found this lens on Alibaba. Will this lens be a good fit?
Again, thank you.
Ordered. Thank you very much @WilliamW
I’ve used similar lenses from AliExpress with good results - though probably not from exactly the same seller. I have never been ordering large enough quantities to have an ongoing relationship with a specific supplier, but my experience is that most of them seem fine, we’ve certainly never decided that a batch of lenses was not usable. However, that means any links we put in the documentation will go out of date very quickly, which is why we only link to the ThorLabs part.
I hope ThorLabs stock them again soon - they are normally pretty good at keeping that kind of thing in stock for next day delivery, but I guess supply chains everywhere are a bit strained at the moment.
I wish I could click on a link within DigiKey and my shopping cart was full with the items from the BoM. 
You and me both! kitspace.org more or less does this for electronic components, but I’ve not found anything equivalent for mechanical hardware. McMaster Carr stock more or less everything you’d need if you’re US based, but that’s not much help if you’re outside the US (and as we’re outside the US, we’ve not found the time to figure it out).
LabMaker.com do now sell kits of the non-printed parts for v6.1.5, and hopefully will stock v7 once it’s released, though they are more geared up for high-value items and so their fasteners kit is more expensive than they’d like…
I am a HUGE fan of Adafruit. I see them as a perfect kit partner. Digikey probably too since they really embrace Makers. McMaster Carr is at the high end…I use their 3D models all the time in Fusion 360. While we are on the subject of parts, I was going to wait to ask after I made the microscope, but why can’t the raspberry pi also control the motors? You could look at it the way Tasmota looked at putting together the pieces - as one mqtt message away. I use mqtt in my home to turn stuff on/off measure stuff all the time.
In principle, I think the Pi could probably control the motors directly, but you’d need to do some fairly low level programming to get them to move smoothly without timing jitter (the pulses need to be very reliably 1kHz), and I’ve not actually checked there are 12 suitable GPIO pins. Largely, we made something based on a Nano and it worked nicely - the additional expense of another board (which can be picked up pretty cheaply) is, for me, a reasonable compromise to have very simple real-time control of the motor timing.
I’ve always thought of Adafruit as dealing primarily with electronics - but if there’s someone there who’d be interested in a chat, I’d be very happy to talk to them. I think LabMaker is much better set up to supply full systems than low-cost kits of components, so I suspect they’d be very happy if someone else wanted to sell the kits!