One of the smarter things I did was buy a used DSLR for a bit under 3 mil VND (~135$) to document my work better. I had been using a smartphone camera for years.
The thing is, most of the stakeholders I communicate with don't understand at a deep level what I build, so being able to document using photos that look OK is sort of important.
So I divide photos into 3 categories that use different strategies.
First, there are purely descriptive photos for internal use or for communicating with other engineers. For these, I still use a smartphone in macro mode, and a good ruler:
These don't have to look great, but need to clearly show the parts and something for scale.
Next, comes something which mainly to communicate with non-engineers. The message is probably related to size, the state of the project, cost, or function. These photos have to look halfway decent, but there's no specific need for it to provide exact dimensions or part numbers.
In this case, I take out the tripod and DSLR. I'll do one of two things -- either use an ancient manual 50mm lens with sharp focus plus lens extender rings, or more commonly, I'll use an ancient manual telemacro lens. The former is better for photographs at very high magnification and narrow depth of field -- when I want to highlight some specific part. The latter is better for medium magnification and deep depth of field, when I want an overall photo. In both cases, pretty long exposure times are required.
This is an example of the latter:
And this is an example of the former, with focus on the GPIO capability of the ATMEGA chip:
Finally, in the third case, I want to communicate to a mix of engineers and non-engineers. For this I use a cheap, new telemacro lens with autofocus, and a tripod. I usually set the aperture to enable a large depth of field, rather than a narrow focus. This is so every component is in focus, ideally with part numbers legible. These photos are pretty generic, the type you might see in a user manual. I won't waste space with an example!
One thing I found interesting is that ancient lenses outperform newer ones at a given price point -- by a significant margin. My best closeup shots are with lenses from the 1970s which I picked up for a very low price (even in junk heaps). I think I have a Nikon 50mm f/1.4 AI, and a ridiculously heavy all-metal Tamron 60-300mm telemacro.
However, they are more complicated to use, so in the 3rd case where I might need a lot of photos and don't want to spend too much time on it, a cheap modern telemacro lens with autofocus works well (I don't even remember the brand, I paid 50$ for it).
In summary, I am definitely not a professional photographer. However, spending a few hundred dollars and a little effort learning to use a camera helped me document projects much better, and land more work. Some images have even ended up in the final marketing materials!