how do connect an isight camera to Mac mini (2018)

You will need to use a Firewire 400 to 800 adapter and two Apple adapters to connect an old Firewire iSight Camera to your new Mac Mini. You need a > Apple Thunderbolt to FireWire Adapter - Apple to plug the Firewire 400 to 800 adapter into and then a > Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter - Apple to plug into the Mac Mini. Then you need to do a lot of hoping and praying that it will work.

Instead of forking out cash on expensive adapters to connect an obsolete iSight Camera, that may not work....?

Your best bet, is to just purchase a new (mac compatible) Logitech Web Cam.

for example > https://www.logitech.com/en-us/product/hd-pro-webcam-c920s?crid=34

Whilst it might theoretically be possible to connect and use an old iSight FireWire camera as den.thed says there is not a lot of point. Buying all the necessary adapters would be more expensive than buying a new USB webcam.

There are some esoteric features of the old iSight camera that are still more advanced than newer cameras e.g. true auto-focus but for most people it is not worth the cost or hassle. It does also have significantly lower resolution than current cameras.

I did it as I had the connectors anyway, so just to see how it worked. But as mentioned, the iSight is only a 640x480 pixel resolution camera, so looks horrid relative to anything of recent vintage. For a viewer using a modern high resolution monitor. And it does a much poorer job of light and color balancing than modern cameras are capable of.

I actually use a Logitech c925-e as my regular cam with my mini, and it works excellently with FaceTime, MS TEAMs, FCC, GoToMeeting etc.

Not sure how that would work. Any cylindrical web cam has a large front lens. But the actual aperture to the CCD sensor is no bigger than most flat faced web cam housings. It’s that bare basic VGA resolution that would still be a limit on the resolution of what you could capture in a telescope image. A single pixel on a 1080p camera is equal to 6.75 pixels on the iSight (or one iSight pixel = 27 pixels on a 4K camera).

The iSight has a much larger lens than a typical modern webcam and therefore might still have better light gathering capabilities. It is certainly true its resolution would still be limited. For night time dim objects as in astronomy this might be a help.

The iSight at the time it was launched was massively over engineered. I did manage to find some ancient articles via Google circa 2004 and 2005 from people who had fitted it to telescopes.

I suspect that a modern webcam would still likely beat an iSight but it might be closer than you would think.

These days a more common approach is to fit a DSLR camera and such cameras could be linked to computers. These have vastly superior capabilities to webcams but a corresponding price tag.

@Michael Black @Benalman

It might have a use for connecting to a telescope although I am not an expert in this area. With its large lens it might have better light gather capability.