Motorized Zoom lens

Hey guys,

I'm hoping somebody with a lot more than I have can shed some light on this for me.

I purchased several motorized zoom lenses on eBay and I hope I can use them on my cameras.

My problem is how to control them. 1. is a Fuji with a 9 pin D plug. 2. is a Fuji with a 10 pin round plug.

3. is a Rainbow with a 20 pin plug but with only 11 wires. Can anybody tell me how these are controlled or

where I might find some info on them?

Thanks,

John

I built a system around one of those Rainbow lenses (or a very similar one) sometime around 1999. What a pain in the ass...

 

As I recall the zoom and focus are DC motors and you move them by applying a voltage and/or changing the voltage polarity. Like most lenses, any time you shift the zoom, the focus needs to be adjusted. Without some kind of auto-focus circuitry this quickly becomes an effort in frustration to operate.

 

Unless you are REALLY looking for an electronics engineering type of project challenge, you might want to not get too hung up on putting those lenses to work. You'll either need a camera that can auto-operate the focus portion (no idea where/if one exists), or you'll need a peak contrast detection circuit (the heart of most auto-focus systems).

Like most lenses, any time you shift the zoom, the focus needs to be adjusted.

Not true. Properly back-focused, the lenses will maintain focus while zooming in or out since they are true zoom lenses, not varifocals.

 

That said, there is a knack to getting the back focus locked in. First, you need to have the iris fully open (an ND filter or welding glass helps). Then you zoom fully to telephoto (on a distant object), adjust lens focus, pull all the way back to wide and adjust back focus. Repeat as necessary until focus stays sharp across the entire zoom range.

Like most lenses, any time you shift the zoom, the focus needs to be adjusted.

Not true. Properly back-focused, the lenses will maintain focus while zooming in or out since they are true zoom lenses, not varifocals.

 

That said, there is a knack to getting the back focus locked in. First, you need to have the iris fully open (an ND filter or welding glass helps). Then you zoom fully to telephoto (on a distant object), adjust lens focus, pull all the way back to wide and adjust back focus. Repeat as necessary until focus stays sharp across the entire zoom range.

 

You may be correct. It's been forever since I worked with these, but even so the focus point may stay constant, but if you're panning and tilting (which is likely, otherwise, what's the point?) you will most likely still need/want to shift the center focus point around quite a bit.

Thanks for the feedback guys,

Being a photographer, I understand about the zooming and back focus and all that (at least to some extent) but I guess my main question is weather or not I can get ahold of a controller (lets forget the rainbow) for the fuji lenses. Or is there anyone here willing to post a schematic for building one? I'm not against trying that.

Thanks again,

John

 

Computar CBZ-24 Lens Controller

 

 

Rainbow LCA-4 Zoom Lens Controller

For the wiring pinout for the Fujinon lenses, http://www.fujifilmusa.com/products/optical_devices/security/zoom-lenses/index.html#See_All

The Rainbow, http://www.rainbowcctv.com/specs/23_inch/s10m.html

 

If you want to roll your own controls, (the hard way, BTW) you pretty much just need to have a reversible polarity (for zoom, focus direction control) ~6 volt DC or so signal applied to each of the control motors through relays. There are RS422/485 controllers on fleabay, too, although I can't vouch for how well they work.