Tethering to Control Zoom on Nikon DSLR

Question

Most Nikon DSLR have a tethered capture option, however I haven't come across any of them that controls the zoom of the DSLR.

I guess the zoom is controlled manually by rotating the ring on the lens.
On the web I have come across several attempts of controlling the zoom by mounting a motor on the camera with a belt that wraps across the zoom ring.

Something like this.

My first question
Are there any off the shelf solutions for auto zoom control ?

Additionally I tend to shoot a lot of objects that are static but different in sizes. Second question
Is there a zoom to fit option available for DSLR's where I can autocompose and the object fits in the frame with the proper zoom level?

Answer 1

There are a couple of factors that come into play here:

Regarding "off the shelf options", I'd be surprised if there were any, as different lenses have differing dimensions, so you would need a different controller per lens. The other option would be for SLR lens to incorporate motors for zooming, but I'm not aware of any manufacturer with this feature at present.

Zoom to fit would require that the camera communicates with the zoom controller (admittedly, relatively straightforward, although there is currently no such connection point), but more importantly, the camera would need to decide whether it had recomposed to include the complete object; a task that with today's technologies, would only be possible with simple scenes with plain backgrounds - whilst composition seems like a simple task, computer science isn't able to offer that level of decision making just yet.

Answer 2

A lot of people who do filming with DSLR cameras, use some sort of follow focus system, maybe it's possible to use some of this stuff.

Here's a link to some examples: http://www.lightsfilmschool.com/blog/dslr-follow-focus/597/