For the past month or so, I’ve been working on a project to modify an existing Logitech C920 webcam to accept modular lenses and allow for greater working distances but still have high magnification. I’ve got inspiration and parts from a few different sources.
The goal of this project is like many others: to have fun and learn! I already had a C920 web camera, and could really use more magnification when soldering. I also am a photo buff and own several Nikon lenses which I’m thrilled to be able to attach to this! I will probably buy a real microscope, but this was fun to do!
Sources and References
- This site at Operational Smoke blog talks about modifying a Logitech C270 to create a DIY USB Soldering microscope. This idea is fantastic, but the plastic case while being done in true hacker fashion just feels less polished than it could be if we just had a well-designed metal case. See next bullet point.
- This blog out of Lithuania details someone, Saulius Lukšė, who did exactly this. He created a custom black anodized aluminum case for basically accepting the guts from a dismantled Logitech C920. The case is SUPER high quality. Cost $70 USD + $1 2-week shipping from Lithuania. Don’t forget to order the IR-blocking filter and the C->CS mount adapter.
- Here is Saulius’ personal site where you can actually order items.
- Besides ordering from Kurokesu, I also ordered a few items from Amazon Prime:
- A ring light to get focused light on our subject: Fomito 48 Marco LED Ring Light with 8 Adapter Rings
- The adapter to convert CS mount to Nikon: Fotodiox Pro Lens Mount Adapter – Nikon G (FX, DX) Lens to C-Mount Cine & CCTV Camera Body w/Lens Aperture Control Dial
- A sensor loop to clean the dirt which is now on your C920 sensor: Carson SensorMag 4.5x30mm Camera Sensor Magnifier
- Small wire for the USB connections. You obviously don’t need 1000ft. PCB Solder Green Flexible 0.25mm Dia Copper Wire 30AWG Wrapping Wrap 1000Ft
- Really great wire strippers here that support 30awg: Klein Tools 11057 Klein Tools-Kurve Wire Stripper/Cutter, Blue with Red Stripe, 20 – 32 ga
- A cheap 50mm lens. This lens stopped focusing the day after I bought it. It feels like a high quality lens, but there’s definitely problems with it. I’m not linking to it because I really don’t want you to buy it. It was the Fotasy L5014 50MM F1.4 TV one.
- I also used this video on youtube to help figure out the initial screw locations: https://www.youtube.com/watch?v=94lDYZgihT4
Disassembling and rebuilding the C920
First, we start off with the essentially unmodified original Logitech C920 webcam.
Then we remove some (4) screws hid underneath TWO stickers on the bottom of the unit.
And then it looks something like this:
In the above right picture, you can see the existing autofocus lens in the center, with the two microphones on either the extreme left or right of the board.
And then, after removing the USB cable, removing the autofocus lens, and soldering (5) USB wires onto the circuit board in different places, this is what it looked like.
Between the video and the rework instructions provided at Kurokesu, I found it relatively straight forward to do this.
The tricky parts are:
- Making sure you have small enough wires. You probably can’t tell but these wires are 30 gauge. They really need to be somewhere around there for the case to close properly. I linked the exact wire I purchased up in the Amazon list. You of course need a way to strip those wires, too.
- There is a manufacturing defect with the screw-hole that accepts the screw to hold the USB connector in the case. I fought with this b*tch for an hour or so, and while I got it mostly tight, it’s a real pain in the butt. Outside of trying a small screw or something from the hardware store, I have no idea how to make this easier to do.
- You need to scrape the soldermask off the top layer of the PCB to expose a (ground plane?) from the layer underneath, and you need to solder a wire to that plane. This requires a sharp xacto knife and some steady hands. Accidentally cut a trace, and you’ll be fixing your PCB.
- If you haven’t done stuff like this before, this project might be on the edge of a beginner’s skillset. I’ve got moderate skills.
Some finished pictures of the unit with and without lenses are below.
Notice the sensor is visible inside. The sensor is 4.8mm x 3.6mm, or 6mm diagonal. This is normally referred to as a 1/3″ sensor and likely has a crop factor of around 7.2.
You can also see the double-faced duct taped IR blocking filter which is clear above.
Below shows the Fotodiox adapter which allows me to connect my existing Nikon Lenses. The adapter is reasonable quality and works exactly as it should.
Below you’ll see what the setup looks like with my Nikon 50mm F/1.8D lens.
I think this image below is badass with my Nikon 18-200mm lens attached. Now we’re cooking with gas!
Images through the C920
I’m still trying to figure out and optimize this setup for the best image quality. This is a work in progress, but here are a couple to start with
The image below is at 18mm and a working distance of 10 inches(25cm). I’m using the definition of working distance to mean from the front of lens. (Farthest from the body of the camera)
To give you an idea of magnification, the hynix memory chip you see pictured is 22mm wide.
This image below is at 100mm and a working distance of 15″(38cm).
The image below is at 200mm and a working distance of 15″(38cm). I could actually reduce the working distance here and achieve higher magnification levels. This lens focuses closer than spec (spec = 1.6m) with this camera setup than with my Nikon D300.
(A video coming soon)
I’m currently using a half broken tripod that I bought years ago. I have to buy a new tripod, but I have to come up with a better mounting solution. I’d like the camera more or less directly over the subject, but how do I manage to mount and still be flexible enough to move the camera around?
Saulius recommended a 7/11″ Magic Arm and a C clamp. I still need to investigate this.
Practicality, image quality, results
Because I already have the lenses, I might be an exception here. Maybe this project only makes good financial sense if you can find cheap, quality lenses. But the Fotasy 50mm that I tried from Amazon was pure junk. It’s not lost on me that I’m using a $600+ lens here for this project. This was a fun project. I’m still trying to analyze the results. Due to the magnification on the monitor, I can have this 22mm chip appear to be the full width of a 24″ monitor, or even bigger without exceeding the initial image resolution. The overall magnification of the system seems huge!