Control the focus motor on Canon lenses

Sequence Generator Feature Requests
1

What would it take to use the focus motor on a Canon lenses as your autofocusers? For those using a Canon camera and lense with SGP, I am envisioning that the camera will take a picture, FWHM or HFR are calculated in SGP, then SGP sends a signal to the focuser to tweak the focus as necessary.

I originally posted this in the general help forum because I wasn’t sure it existed.

Thanks!

Gilbert

1 Like
2

Hey folks,

If you come across this and it’s something you’d like to see, can you “me too” or “+1” on this? Just trying to determine popularity on this with respect to a hundred other things on the backlog.

We have a bunch of code written to test this stuff and it’s definitely possible, but will require a good amount of work to be releasable.

3

Yes, would be very helpful.

4

I sometimes use a Canon EF 200mm f/2.8 II USM. The advantages of such a feature would be manyfold:

  • no need to touch the lense,
  • shortening of the focusing procedure and
  • probably higher accuracy of the focus result.

+1

5

I’d +1 this too

:grin:

6

I would like this too. However I wonder if the lens focus control would be accurate/repeatable enough. Would this work for “USM” lens? Or only “STM” lens?

DaveNL

7

We’ve looked into this multiple times and, unfortunately, we don’t think it’s a viable option. To be able to move the lens you must be in live view and you must have the lens set to Auto Focus.

So this means we’d need to do something like:

  • enable live view
  • move lens
  • disable live view
  • take normal frame
  • evaluate frame
  • rinse and repeat…
  • once focus is found attempt to move to that position
  • realize you’re likely out of focus as the method to focus a lens is not accurate.

I think the best we’d be able to do is to allow you to move the lens focus when live view is enabled but I don’t think we could support auto focus with any success.

Thanks,
Jared

8

This seems to depend on the lens also. I was in the US photographing the solar eclipse in August, and noticed that I could control my 300/4L focus with Eclipse Orchestrator even if I turned AF off using the switch on the lens. Live view is always required, though.

9

That’s too bad. I figured it probably was too good to be true - especially since it hadn’t been done yet. :slight_smile:

Thanks!

Gilbert

10

“We’ve looked into this multiple times and, unfortunately, we don’t think it’s a viable option. To be able to move the lens you must be in live view and you must have the lens set to Auto Focus”

Jared BYEOS does this. You do need to be in live view, but not autofocus. I focus with BYEOS then switch to SGP. The process is semi-manual in that the focus controls are on the screen, but I don’t have to touch the lens for good focus.

Regards,

Charlie