Is this possible ???

AndySwinden

AndySwinden

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I was wondering if anyone knew of a way to change the focus position of a lens using a computer ?

I have seen a few different programs / API’s for tethered shooting – they allow you to change exposure related settings but nothing much to do with focus.

I am wanting to come up with something similar to ‘auto bracketing’ but for the focus position. I like macro photography and have experimented with stacking, but it’s very hard to move the focus ring on the lens in small enough, equally spaced increments.

If a computer could change the focus position, surely it would be very easy to write some code to shoot, change focus, shoot change focus etc. effectively automating the acquisition of the images for a stack at 5 fps (or whatever) without having to touch the camera.

Is there a good reason why this isn’t possible ??

Thanks !
 
The only answer I can come up with is no, because you would have to have 2 way comminication with the camera and I cant see the camera's software being set for that. Also you would need 2way cables that fitted your camera's ports and also whether the ports could be re-assigned for this purpose.

It would be brilliant if someone comes up with a solution.
 
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The cameras focus system is a closed loop between the focus sensor and the focus motor within the lens. The camera would need to be completely rewired to allow external control of the focus motor. The alternative would be a stepper motor attached to the manual focus ring on the lens. Not an easy thin to do.
 
Canons can do it. You can focus my 40D through a computer using EOS utility. You just plug the camera in, open up the remote shooting window, and click on a set of little arrows that move the focus in either direction in different increments, with the live view from the sensor up on the screen.

No idea if it's possible with other brands though.
 
squishy said:
Canons can do it. You can focus my 40D through a computer using EOS utility. You just plug the camera in, open up the remote shooting window, and click on a set of little arrows that move the focus in either direction in different increments, with the live view from the sensor up on the screen.

No idea if it's possible with other brands though.
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Damn - I'm a Nikon guy......and I've never said that before :lol:
 
AndySwinden said:
So if I was a Canon guy, could I get my hands on the API to write my own code to do that stuff ?
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Yes, looks like it. Support varies by model

http://www.usa.canon.com/cusa/suppo...09c&id=0901e02480057a74_1&fileURL=ps_sdk_form

http://blog.waynehartman.com/archive/2009/01/07/edsdk-to-remote-control-your-canon-camera.aspx

edit: The Canon one above is for the American developers,

European URL http://www.didp.canon-europa.com/

the odd thing is that the SDK seems to be supported on Mac OS X in the US, but not in Europe :thinking:
 
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I dont wanna change to Canon :bang:

Anyone got any ideas for doing the same thing with Nikon ?? I can get the APIs (well for a D200 anyway) buy cant see the fuctionality i need to manipulate the lens focus.
 
you can get rigs that change the focus by spinning the manual focus ring, using a toothed rubber ring you put round the focus wheel.
I can't remember where I saw it, but the price was in 4 figures.
 
squishy said:
you can get rigs that change the focus by spinning the manual focus ring, using a toothed rubber ring you put round the focus wheel.
I can't remember where I saw it, but the price was in 4 figures.
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lego mindstorms as a cheaper alternative? :D
 
AndySwinden said:
It will have to be if the alternative runs to 4 figures :D I just dont understand why its not in the Nikon API, just seems such a simple, useful thing to have given you can change pretty much anything else on the camera !
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It's possible it may be more difficult to implement given the history of f-mount lenses and with some of them having AF motors built into the lens and others relying on one in the camera?

Canon EF was designed from the ground up for the camera to control a motor-equipped lens.

Nikon also have a bit of a track record with proprietary encryption of their NEF formats - maybe they're a little less open to the idea of opening up control to other people.

This could be entirely spurious speculation, of course...

:shrug:
 
Denyerec said:
A rig and a stepper motor? :/
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Hmmmmm it might be a backup plan.....I liked the idea of the software solution as nothing would have to make physical contact with the camera to re-focus (potentially moving it between shots) and also, being able to shoot at a relatively high fps rate would reduce the chances of subject movement.
 
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