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Camera lens microfocuser


tooth_dr

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1 minute ago, tooth_dr said:

Does this need fixed to a base plate or could it be entirely mounted on the lens?

I suppose that would depend on how you designed it. However, you'd need something to mount the knob end of the pulley on. Maybe a tube ring? Else, yeah, some sort of separate mounting plate.

Louise

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I have wondered why there is no option to manually focus in camera with plus and minus arrows rather than by physically moving the focus ring, the feature is obviously included in the camera software because it is used by manufacturers and third party apps.

The next best thing would be phone with OTG cable running an app for this purpose or like a lot of modern cameras doing it all over wi fi to the phone/tablet.

Alan

P.S. Not checked but I wonder if Magic Lantern has this feature enabled?

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4 hours ago, Alien 13 said:

I have wondered why there is no option to manually focus in camera with plus and minus arrows rather than by physically moving the focus ring, the feature is obviously included in the camera software because it is used by manufacturers and third party apps.

The next best thing would be phone with OTG cable running an app for this purpose or like a lot of modern cameras doing it all over wi fi to the phone/tablet.

Alan

P.S. Not checked but I wonder if Magic Lantern has this feature enabled?

I think you can only use on-lens electronic focus if both camera and lens support it. So not possible if using an astro cam or a vintage or other lens without the facility.

Louise

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1 hour ago, Thalestris24 said:

I think you can only use on-lens electronic focus if both camera and lens support it. So not possible if using an astro cam or a vintage or other lens without the facility.

Louise

Agreed, was under the assumption that the OP was talking about a DSLR with new lens.

Alan

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3 hours ago, Alien 13 said:

Agreed, was under the assumption that the OP was talking about a DSLR with new lens.

Alan

Did you edit your earlier post. I’m near 100% sure you said Canon, and now it says Nikon? Or am I doting?!

@Thalestris24 Hi Louise. My lens does have AF but how can I check if it can be controlled by the computer? 

 

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Do you have some sort of remote control software for the camera, e.g. Canon has as part of its utilities suite EOSUtilities, a remote shoot & control system, which includes an auto\manual focus control.

Other than that, you could use the BackyardEOS ~ Canon \ BackyardNikon for control.

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As an avid fan of DIY have been looking around at off the shelf solutions that could be adapted and found this range of kit.

https://www.amazon.co.uk/Adjustbale-Camcorder-Shoulder-Supports-Stabilizers/dp/B01FM50SKO/ref=sr_1_3?ie=UTF8&qid=1553154991&sr=8-3&keywords=neewer+follow+focus

Now this kit is not suitable as it stands as the ratio is 1:1 and requires a rail mount but it might have modding potential.

I also found these which could be the basis of a full DIY version for those that dont have 3D printers.

https://www.amazon.co.uk/gp/product/B01DEZIIP6/ref=ox_sc_act_title_1?smid=A30NVO4VNPCTDI&psc=1

https://www.amazon.co.uk/Fotga-flexible-DP500II-DP500IIS-DP500III/dp/B078QYL2M8/ref=sr_1_8?s=electronics&ie=UTF8&qid=1553155272&sr=1-8&keywords=follow+focus+ring

There are lots of similar versions out there with varying gear ratios so might be worth a look around.

Found this video to give an idea how they work..

Alan

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18 minutes ago, Gina said:

I like that - very clever.

I agree, from what I can gather all the gears etc use a standardized pitch so it shouldn't be difficult to swap the ratios around, I am also thinking the single rail mount wouldn't be difficult to fix to a standard dovetail with a few bits and bobs and it does have advantages for swapping out lenses.

Alan

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2 minutes ago, JamesF said:

It does look quite neat.  I wonder how much backlash there is in the gearing though?  That could be quite irritating for astrophotography.

James

I have the same thoughts on that, I expect it would be a project to fettle rather than an off the shelf solution.

Alan

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The KStars/Ekos software and INDI driver I use on the Raspberry Pi control board has compensation for backlash in the autofocus routine.  It does a better job than I could do manually.  Anyway, for most of my imaging I'm a fair distance away from the imaging rig in the comfort of my living room whist the imaging rig sits on a concrete post in the funny looking green shed in the corner of the plot that forms my property.

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6 hours ago, JamesF said:

It does look quite neat.  I wonder how much backlash there is in the gearing though?  That could be quite irritating for astrophotography.

James

I don't think backlash would matter too much since you're just turning a knob one way or the other. Having said that, it's hard to tell how much focus movement you get from a slight turn of the knob.

Louise

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8 minutes ago, Stub Mandrel said:

If the bar was slightly flexible with a threaded hole and the two opposing screws could be replaced by a single adjusting screw (in an opened up hole, with a c-washer or similar to keep it in place).

I was thinkng of this, and integrating a nut into the bar instead of threading it.

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34 minutes ago, Thalestris24 said:

I don't think backlash would matter too much since you're just turning a knob one way or the other. Having said that, it's hard to tell how much focus movement you get from a slight turn of the knob.

Louise

I think the overall ratio is 1:1 with the std gearing, I am tempted using it for macro work as well as astro if I can find alternative gears.

I think any backlash could be reduced by slightly stretching the rubber lens ring when fitting it.

Alan

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