Just get yourself a basic body of any sorts. Canon or Nikon or even Sony will work and spend a little extra on a good lens for your purpose. Nice thing with sonys like A5000 (can find them for like $200) is they sell adapters and in camera focus aids to use any of the old school 35mm manual lenses of all sorts from Canon to Nikon, Pentax... and other camera makers. You can buy these used lenses and adapters on Ebay or even amazon like this...
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This might be manual focus but its way better lens than the standard plastic f1.8 kit lens. Perfect for your application since you can dial in the focus, then snap away, rinse and repeat. This is made for the FD mount so you will need an adapter. But you can get adapters of all sorts from one make to another, just look it up.
You dont really need any fancy features other than basics. Get a good tripod and a dongle for the camera to take remote shots. Some bodies do this by remote and others need a wired remote but make sure you investigate that. Of course you can always do the delayed timed shot option too so youre not shaking the camera by pressing the shutter release.
That 50mm will equate to about 75mm on a Nikon crop sensor and about an 80mm for Canon crop. So this will prob suite your needs well since youre probably going to do some post shot cropping and processing in lightroom or whatever.