Hi Niles,
For best results, you want a large sensor with a high resolution and a good prime lens.
The choice of camera and focal length of your prime lens will depend on what you are trying to model/capture in 3D.
If the budget allows it, get a digital camera with a full frame sensor because bigger sensors can capture more light and have better signal-to-noise ratios. To sum it up, a bigger sensor will give you higher quality pictures. Better pictures will give you better photogrammetric modelling results.
Get at least a camera with an APS-C sized sensor (unless you are planning to capture pictures by drone and have weight restrictions).
Last but not least, higher resolution sensors will give you higher resolution models for the same survey setup (same distance to the object, same lens, same sensor size).
Here are my favourites:
- Sony A7 series
- Sony A6000, A6300, A6500
- Canon 6D
- Canon 5D Mark IV
There might be other cameras out there which are great too, but these are the ones I myself would get.
Pro Canon: User friendly, ergonomic and great battery life
Pro Sony: Picture quality and lower price
Note: All Nikon cameras use sensors from Sony, so it is probable better (and cheaper) to just buy a Sony instead ;-)
Finally, get a prime lens with a focal length that suits your purpose (e.g., for taking pictures in confined spaces such as the interior of a house; in such a case you would need a wide angle lens to achieve a proper image overlap).
I hope that makes your decision easier.
Regards
SAV