Episode 437: DIY Motorized Zoom for Your DSLR

I never rule out revisiting a project.

I chose to use gears for a simple reason . friction does not work. I tried.

To have friction working(every lens has a different surface which makes things more difficult and wear on the zoom/focus ring is absolutelly intolerable) any slack in the system has to be removed, that requires to lok the lens and camera tightly to the system and makes lens changing or other setup changes a nightmare.

I make videos for companies mostly. On a set you usually have 10-30 seconds to set up a shot. so locking it tightly up is not an option in most cases.

the gear sleeve is just fixed with a zip tie so it fits on almost any lens. slack is not as much an issue but still present if you want to move zoom shots, but for reframing it is a non issue.

On universatility I deam the friction approach much less universdal than a gerasystem (the sleeve remains on the lenses, when they are excahnged and protect the rings from wear, they also slip in case the device overrotates

of course I'm aware of the features of the tmc2130 and other TMC drivers, I worked at a 3d printing filament company and built quite a few machines from scratch.

The reason i did not use a stepper for this application is the power to wait ratio and time constraints.

to get enough force towith a stepper to move my lenses, I need a lot of gearing (the servo already has some internal gearing so the stepper ration might be somewhat around 30/1)
it  adds alot of weight (like 20 times as much on estimation) and more power delivery requirement that would make it a lot more complicated.

I want to make my videos revolve around a central component or aspect and in this case the focus was on makeing two esp8266 devices talk remotely.

And I need tog et the device idea fleshed out, parts determined and sourced, constructed, sometimes multiple times until it works, built, tested filmed and edited withing a given time. So i need to choose a route that leads me to sucess asap and delivers on the central topic, which is electronics in general.

Ok I can see your point behind the route you have taken, but as a few pointers, to make attachment a little on the universal side, instead of using gears, try using a friction grip on the zoom and focusing ring, as this would avoid having to allow for varying diameters, plus a friction grip with slide on the ring, when it reaches the end, some rollers with a rockwell hardness round the 40 or lower mark would be good for this, I will admit the friction approach is not as positive move as direct gears, but it allows the adapter to be a bit more on the universal side.  Also if you did look into stepper motors you could use the TMC2130 and the SPI interface to know when you have reached the limit of the ring, I assume you have had experience with the sensor less end stop ability of the TMC2130.

I'll be curious if you revisit this in the future.

Hi, thanks for your comment!

I have taken the specific route to make my specific equipment work differently and enable many others to do the same regardles of lens used or brand.

Secondly, what my system does is motorize not the FOCUS but Zoom. To my knowledge there is no DSLR lens that has inbuilt motorized zoom at a reasonable prizepoint.

Canon themselves sell basically the same thing I have built (but without remote and no openness ) https://www.e-infin.com/eu/item/3248/canon_pz-e1_power_zoom_adapter_pze1?gclid=CjwKCAjw4KD0BRBUEiwA7MFNTX3V69Xk5zaZs6ouR…

to motorize zooms on their lenses.

While using the SPI interface is a great way to expand capability and control lthe features of the lens it does not give you a way to actuate the zoom as those lenses do not have a motor for the zoom built in.
And on some camera systems the motor is in the camera not the lens.

I wanted to build a system that works on any camera with any lens, so as many people as possible can take advantage of it.

Your SPI -idea is a very good option to gain follow focus on older models or unsupported lenses, but I had a different goal, faster reframing through remotely controlling the zoom.

Hi Clem,

Great concept but way over complicated, there is a much simpler way to do this, and keep the 3D printing to a minimum, Why put attachments on the camera lens when there is lenses available that are cheap, that can do this, but also the protocol it uses was hacked out over 10 years ago.

Canon EF lenses use a variation of the SPI protocol that needs to be bit banged but are easy to talk to, there are hundreds available on the second hand market, and all you need if you don't own a canon camera, is a Canon EF lens adapter that permits connection to the pins that control the lens, the lens can be connected to any Micro Controller or SBC that has an SPI interface, and a detailed document on the lens protocol can be found here https://gist.github.com/marcan/858c242db2fc595da1e0bb70a05192fc

Here is another example of someone hacking an EF lens to get a similar facility https://pickandplace.wordpress.com/2011/10/05/canon-ef-s-protocol-and-electronic-follow-focus/

But if you use a Canon camera its a little more of challenge as you need to allow the camera to still speak to the lens whilst sending commands from a 3rd party device

Ok I will admit you have to buy a Canon EF lens but cause the EF lens has been around for so long there are plenty on the market especially in the second hand market, so they are cheap to come by, even as cheap as $50 AUD.  A logic level shifter as EF lenses are 5V logic levels, and a Micro Controler or SBC. and a 3D printed lens adapter, to connect to the pins.

Regards

Celcius1

Looks like something I could use for my cameras! I like the independent control settings, too!

thanks DAB

Good project Clem.

DAB

Hi. Once the lens reaches the max rotation the ring should slip, or the gears skip. There is no electronic endstops as the lenses can be very different. In case you ant to have a non reversal endpodition you can line up the end of the belt with that position and the gears won't engage past that point but, thst also means you can not go back once that position is surpassed.

That way a much bigger feat back 10years ago. Today it's so much easier to pull of, thanks for sharing your story.

You can use it for focus, just need to reposition the device to your focus ring. No alterations needed