Introduction: How to Make a Variable Zoom Head Lens From a Photocamera's Telescopic Lens
For all magnifying glass enthousiasts, precision art workers, investigators, biologists, micro electrotechnicians, jewel repairmen, Borg, and many more, improve life and joy, build a Variable Zoom Head Lens !
Having both hands free for your expert work and at the same time having eye for crystal clear magnified details of any spot you point your head to is now within everyone's reach if you build a Variable Zoom Head Lens. If you take the lens from a discarded good or even high quality photocamera, it gives an impressive and adjustable magnification, mounted techie-wise on a head band, covering one eye and easy to flip up. If you build it smart and simple, you'll have adjustable left- right turning, flipping up to return to normal vision, fix-click vertical tilt angles in between and variable zoom (optionally: fixed zoom).
Soon enough you’ll also find that by turning the lens a little to the left or right and a little training you can have both eyes looking at the same spot with one eye bringing great magnification in overlap with the other eye. So from now on you can have visionary overview, an eye for detail and two hands free.
Here is how I did the thing (version 1.02)
- a discarded compact photo camera with telescopic zoom lens with magnification as you desire (70mm I used)
- head band LED light with removable and adjustable bracket
- small and very small screwdrivers, perhaps also Torx
- 4 or 6 mm bolts and self fastening nuts
- cutter and pliers
- glue, soft padding like rubber foam washers
- electric drill
Step 1: Find a Photocamera With Telescopic Lens and Disassemble It
Find a discarded compact photo camera with a built-in telescopic zoom lens, for instance a 60 or 70 millimeter lens. As long as the lenses are in line and undamaged and the ‘telescopic’ part I call cylinders are not cracked or stuck, go for it. Some cameras have a zoom lens with just one cylinder. Others, often larger telescopic lenses have 3 or more cylinders in the telescope.
For the rest in this step you must go your own way. I disassembled several cameras and many differ a lot on the inside so I figured it didn’t seem beneficial to make photos of the disassembling process. When you go ahead, disassemble the camera with your best skills and knowledge. You’ll need steady hands and sharp vision to find and unscrew the many tiny screws. Also you need to have a little patience, don’t give up when you get frustrated working in the miniature, complex inside of a camera.
CAUTION: be careful to not touch the coils and capacitors used for the built-in photoflash. If you recently have used the flash on that camera, the capacitor is likely still charged. If you happen to touch the wrong wires or connections during disassembly you may get a very nasty bite in the hands. Typically these capacitors are fairly large compared to the other components. Often they are cylindrical shaped, colored black, yellow, red or blue. Also be careful with the flashlight itself because it could contain chemicals and the little glass tube inside may splinter when handled roughly.
Step 2: Understand the Working of the Telescopic Lens and Prepare It
When you succeeded removing the zoom lens from the camera, spend some time to understand how the parts move, slide and turn, interact with each other. Avoid applying strong ‘single force’, like turning or pulling. Many lenses use helix grooves, meaning that gentle simultaneous turning AND pulling/pushing is the way to smoothly manually operate your lens.
Furthermore, you can remove small motors and sprockets driving the lens, electronic connections (thin plastic circuitry or tiny wires), sensors and switches.
Also, the shutter, diaphragm and any automatic lens ‘cap’ at the end of the lens is to be removed in a delicate manner to prevent damaging lens or telescopic parts.
The rim and sides of the lower end of your telescopic lens needs padding. It is probably the kind of hard plastic with notches and irregular shapes making it uncomfortable because it will be close to your eye, likely resting on your cheekbone or eye brow. Either cut out a ring out of foam rubber or filt and glue it to the backside of the lens. Or use a filt o-rings. Spread glue evenly on the ring and put the lens on it. Don’t use too much glue and to be save let it dry with the lens on top of the padding to prevent glue dripping in the sliding telescope parts of your lens.
Step 3: Try and Play With the Lens and Determine Your Desired Magnification
Try the lens in minimum and maximum focal length and get a feeling for your most comfortable eye, lens and object distances. With the telescope at full magnification it requires you to be very close at your object, perhaps too close for comfort, in my case less than 2cm. Find the most comfortable magnification for you and your future working preference.
Now, you decide if you plan to make a Fixed or Variable Zoom Head Lens. My original built was a fixed one, making it easy to mount the whole thing to a head band . Last week I changed the mounting to make it a Variable one, see photos.
A) for a Fixed Zoom Head Lens , find and mark with pencil your optimal zoom by changing the lens length (remember that simultaneous twist and turn does the trick) and put a tape alongside to prevent it from changing while you work. Then, find a spot at the lower part of the lens through which you can drill. Note that you may need to reach the drilled hole from the inside of the lens to tighten a nut or screw. Mounting of the lens on the LED/light bracket is a matter of drilling the right side hole so the bolt can fit through. Measure the distance between your eye and the centre of the (still empty) bracket on the head band, and measure the distance between your eye and the view hole of your lens. Drill the hole in the right places to have your lens at those desired distances.
B) for a Variable Zoom Head Lens the telescopic cylinders must move smooth and freely. Putting a bolt through the cylinders as in option A) will prevent the cylinders to move. Instead of a nut and bold as in option A) I used the metal strip from a handle of a broken coffee can to use it as wrap tightened. See photos. From a hole through the cylinder bodies you can stick the bolt through the hole and also hold it when working on the other end. As you tighten it the bolthead will be pulled accordingly through the hole outwards and leaves the hole clear enough for the telescope to rotate.
When finished drilling, you may may notice that zooming the telescopic lens may be a little hard, feeling like it is stuck. This is because of the drilling hole's ragged edges or perhaps dirt in between the still standing cylinders. Try to release it gently.
Also, don't forget there are other smart ways to mount it, for instance with large duct clamps and axial thightening screws or what have you.
Step 4: Find a LED-light Head Band or Similar and Modify It
Obtain or purchase a LED light head band – for instance, the head band lights in this Instructable were a mere few Euros / Dollars and serve our purpose well. Try to find one with click-removable socket and changeable angle. The bracket that holds the light typically use clickers or rattles to change and keep the angle of the LED casing.
The lens you want to attach to the head band is probably heavier than the head LED light or at least bigger and unbalanced. The elastic cord of my head band was too long (or too weak) to keep it tightly and steadt around my head. The cord can be strengthened by doubling the slack cord and laying it over the rest of the cord and stapling it together. But a new problem arose. The cord was much tighter than before and now slipped off of the mounting pins on the head plate due to the extra force. This I solved as follows: strip 5 centimeter (2 inches) of 3 wire electricity cord with a sturdy mantle. Cut and keep the stripped off mantle into 2 pieces of 2 centimeter. Warm them in hot water until they are flexible enough, stick one in each of the elastic cord’s end and you can slide the whole over the 1 pin first, then you need to feel how to and in what order to shift and shuffle the cord with the piece of wire mantle over the 2 pins.
Step 5: Modify the Adjustable Bracket and Plate
The original L-shaped adjustable LED light bracket (see photo) would prevent the lens to tilt upwards enough to remove if out of sight , against your forehead. I found out that the bracket rotated just enough farther when it points the other way. To achieve that, remove the rubber padding, unscrew 4 tiny screws underneath it, then wiggle and pull out the assembly containing 2 springs and small plastic pins that rattles over the grooves of the inside of the L-bracket. Make sure you remember the order and position of all parts. In general, any adjusting mechanism with springs never seizes to surprise me when disassembling it, finding myself puzzling how to re-assemble it after searching my livingroom for the catapulted spring..
Take out the L-bracket and just flip it 180 degrees and reassemble the whole thing.
I added a little extra padding on the inside of the headband plate because the existing padding was flimsy, especially after adding the weight of the lens.
Step 6: Create Mounting Point on the Lens and Attach It to the Head Bracket
A) For a Fixed Zoom setup, like I did my first time: drill a hole in the lenshousing (aka telescope) and measure how close to your eye you want it to be. It also depends how the head light bracket is positioned in relation to the lens and your eye. Measure and double check your measures, do this carefully to fit a bolt and a self-fastening nut. For the FIXED setup I used a 6 mm thick 12 mm long bolt, sticking through the hole from -outside- , through the LED/light bracket into the telescope . Hold the head of the bolt with pliers while tightening the nut from inside the telescope
B) History: I modified my ‘Fixed zoom head lens’ into ‘Variable Zoom’ one as I mentioned earlier, so I had to remove the above mentioned bolt because it blocked rotation of the cylinders. I decided to use a metal flex strip from a coffeecan/teapot grip. I cut it to roughly the desired length and marked where a hole for the bolt would come.
The bolt I used for this modification is a 4mm bolt with a Philips (+) head, indeed, a bit smaller than the 6 mm hole so it ‘sinks’ a little in the previous hole without blocking cylinder rotation or cause a weird hump in the metal strip.
This Philips head bolt I stuck through hole in in the telescopic lens (from the –inside- this time) and through both ends of the metal strip from the coffeecan. When steadied, put the bolt through the headband bracket and tightened with a nut.
My intention for this method was to clear the bolt out of the telescope cylinders, which worked fine: the head of the philips bolt was smaller than the original hole so the bolt moved outwards and therefore out of the telescope cylinder when I tightened the nut and bolt.
To hold the bolt/screw whilst tightening the nut use pliers to hold a Philips (+) drill/screwdriver bit and stick it from inside the telescope through the hole, into the Philips bolt head.
Fasten it firmly, but you should ofcourse be able to the entire telescope left to right for adjusting to your eye.
Finally, clean the lenses and make the interior of the lens free of grains and sawdust. Keep your Variable Zoom Head Lens away from dust, put it in a small pouch.
...well, how does it look?
Qwertypat, February 5th, 2016