Please help with CAD design

[anthony113]

wow you guys are hardcore. if i can get you guys the measurement around the cameras focus ring and some measurements of the base of the camera and all do you think you could CAD something like this? i have a few more facts to help you guys out.

the saddle bracket clamps on to two 15mm diameter rods that stick out of an aluminum base that mounts onto the camera. these parts would also need to be built to mount the follow focus system, however they are relatively simple to design.

its ok if the black knob turns infinitely in either direction, there is no stopper on the cameras focus ring. the ring is connected to a sensor which controls the cameras lenses. basically, the focus ring on the camera can be spun in either direction without causing any harm to the camera or lenses. the focus though is electronically limited.

there are two ways to approach the gear that interfaces with the cameras focus ring. you can either bore out a large aluminum gear and slide it onto the cameras focus ring, then use a gear on the follow focus to interface with it. or, you can design a more custom gear that would fit in the not so gearlike grooves of the cameras focus ring. heres a detailed picture http://www.frimu.nl/AG-DVX100.jpg the focus ring is the one to the left of the numbered ring. has little grooves in it. THERE ARE 30 "PEAKS" and 30 "VALLEYS" on the cameras focus ring. the distance around the focus ring is about 28.8mm.. not exactly sure though cause i took it with a crap tailors measure.

[Al Skierkiewicz]

Anthony,
You can manufacture this out of stock parts from almost any source. Check with Small Parts, Inc. though. I think your dimensions on the focus ring are off by a factor of 10 though, it looks more like 28 cm in circumference. The part is assembled from a right angle drive, (black knob is on the input shaft and the brass pulley is on the output shaft) two brass pulleys, belt and a mating gear for the larger gear. The part you show has a custom part to hold the right angle drive and the upper shaft (likely holding a bearing in the upper part of the housing.) The thumb screw on the bottom allows side adjustment to mate with the focus gear. You can buy the base plate from a camera store like B & H in New York and add you own arangement to hold it all in place. The rods are not a necessity but likely are used on other camera attachments from the same manufacturer. You might want to check with the manufacturer for a "studio kit" which might be cheaper and provide a remote focus knob that would be easier to use than this one.
A word of caution, messing with the lens of any camera is risky business. If you permanently distort the focus ring, or accidently over drive it, the cost for repairs is astronomical compared to the cost of the camera since this is not a removeable lens. It is possible to cause the lens to become a "fixed focus" if the ring or internal parts are damaged.

[anthony113]

Al, hmm i have very little experience when it comes to making things like this. if you would be able to recommend a list of parts i might need and a way to go about making the casing or structure to hold all this stuff in place and mount to the camera i would be very appreciative. thanks!

[Astronouth7303]

Interesting mechanism... I would agree that it looks like a focus tool (Most lens adjustors are). And you probably have more cad expierience than me.

[Aignam]

Maybe you could use emachineshop.com to manufacture your parts if you don't have access to a real machine shop? Anybody ever work with this website before?

[Al Skierkiewicz]

Originally Posted by anthony113

Al, hmm i have very little experience when it comes to making things like this. if you would be able to recommend a list of parts i might need and a way to go about making the casing or structure to hold all this stuff in place and mount to the camera i would be very appreciative. thanks!

Anthony,
I will look around but I am up to my eyeballs in a special project at the moment. This thing does not need to be that elaborate. A section of right angle aluminum, a few bevel gears for the right angle drive, some rod for the shafts, maybe a couple of small bearings, a small belt, (with pulleys for round belt you can use an o ring for this part) and a gear big enough to go around the the focus ring with a matching little drive gear, a hand full of set screws and other hardware, a plate to mount everything on that attaches to the bottom of the camera and a weekend ought to do it. There are little junk stores in most big cities that sell just what you are looking for or there are a lot of stores on line. Check out Small Parts, American Scientific or any of the online sources for RC car and robot parts and you should be able to pull it all together. You have a good start since you have seen a real one up close and you have plety of pictures. Just reverse engineer the parts, this should be fun. I know you can do it, don't be discouraged by the finished look of the part you have. It does not have to be designed that well to work for you. Remember the part you showed is engineered for constant professional use over years of service life with no failures and ease of movement from camera to camera throughout it's life. You can build a camera specific part for far less that will work great for you application and if it fails every so often, you fix what broke or slipped and reshoot.