EDITORS NOTE: i will be adding pics slowly, and maybe last thing… slowly working on laying out the project. I mean, its easy and clear to ME, i have to stop and remember what someone new to this wont think of that i take for granted.
Step 1 - Basic description of the project
AT first blush, this would seem to be a complicated project, indeed, it really isnt. It would also appear to be a little time consuming or even expensive? It isnt. Also, this project is goin to open your eyes to a whole HOST of other projects you will then take on and tackle easily, and projects you will dream up yourself.
at the HEART of this project, are mainly 2 things…
1) a USB webcam
2) nearly any lens you get your hands on
Lets start with the USB webcam. Almost everyone has one laying around. Even if you dont? they can be had cheap. VGA webcams on the slow boat are price-bottomed-out on EBAY for somethng like 2 dollars new. When WARHAWK got his unit in? He was dismayed to find that he could take high resolution PICTURES, but, soldering requires a live video feed… whereupon his unit went to VGA (640x480).
To make my first unit, I decided to stay “budget” and get myself a VGA USB webcam… I ripped myself off by going to discount stores until i found one for ten dollars… because i was too excited to wait on a 2 dollar identical unit from china. You likely have one laying around, or its a whole 2 bucks.
I would RECOMMEND you get the “little square: CAM… its a little easier to work with. (the ”original” project online? started out with a 70 dollar webcam.) I am comfortable ripping into a 70 dollar webcam? But, you might not be, and, why not do a “2 dollar dry run” to get your feet wet. Works, and you can upgrade later.
carefully and slowly take the thing apart. A small #0 screwdriver will probably do fine. You will be left with a small square circuit board with what security camera guys call a “board lens”, and a rats tail that is a USB line. you will find that a couple more screws will remove the “board lens” and the “lens holder”… you want to be holding a BARE circuit board with a USB dangling off of it.
Go ahead and “touch” the glass covered sensor… if you dont scratch it? you really wont hurt it. You can just wipe it off with the edge of your tshirt. If you dont scratch it? You cant hurt it. I regularly do this with 100 dollar security cams. Dont fear. The only thing to really watch out for in my opinion? Is not to rip out any of the several wires soldered onto the board attaching the USB line… so what you really want to “watch out for” is the USB wires, not the sensor itself.
NOW? you need a lens. You can use almost ANYTHING. I started off with a chunk of glass, and my second unit I used a “real” camera lens. Both work fine. My first glass lens? Was just an old gun scope main objective… they screw right off. If i hadnt used that? i have old binoculars torn apart; you want the “big main lens” off of something.
EUREKA MOMENT time! to convince yourself how easy this is? simply take a sheet of white paper, and hold a magnifying lens over the paper, and “aim it” at one of those cheap “twisty” lights in your house… the humble CFL. They are easy to focus up. When the light, the lens and the paper are all in a line? move the lens in and out carefully, and you will see the twisty light focus up in amazing detail on the white paper!
if you HAVE a real camera lens? do the same trick… works the same.
ALL we are going to do now? is the SAME thing… except we are going to replace the PAPER with the CAM SENSOR. You probably cant hold the lens steady enough, but, we already know this works, so, take the square board cam, and put it on somethng, I used a piece of PVC pipe. I taped the corners down.
Take a larger piece of PVC pipe? and fix your lens or camera lens on the end of the larger PVC tube. You will want to “shim” the smaller pipe with some winds of electrical tape, or weatherstripping, or duct tape wrapped around paper towel. You are going for a “loose sliding fit”.
in the home built telescope world? This is called “slide focus”, and it exists for a reason… it works and its bulletproof.
=
you are more or less “done” at this point with your “mock up” unit, which could ave been made out of electrical tape and paper towel tubes. PVC pipe is cheap and works better.
you want “long” pieces of tube to start out with? because as the distance to the subject gets closer to the lens? the distance between SENSOR and LENS starts to grow exponentially long. Real photography guys call this “macro photography”, and they use special long tubes to mount their camera lens further and further out from the camera.
You dont NEED special photographic mounts and accessories, heck, you dont even need a real camera lens.
==
I “c-clamped” my PVC telescope device, to the edge of my computer desk… it “aims” down at the desk surface. The only HARD PART, is its initially frustrating to watch the webcam on the computer screen, sliding the tube in and out to “focus”. The trick is, going real slow? you will see a “flash” on the dark screen?? THAT was the focus!
if you cant do it? you are either not patient enough, or, your tubes are not long enough. And, the closer you get to the work surface with the lens? the LONGER back the sensor needs to be.
=
Once you focus up a “twisty” CFL onto a piece of white paper across the room? You will be “hooked”… the rest? is nothing more than patience and arts and crafts time… real telescope builders? Use cardboard mailer tubes to good effect, and we can too.
=
to “hold” focus? i temporarily jammed a piece of cotton between the tubes and wedged it in fairly tight with a fingernail sanding board. simply drill and tap a hole in the PVC, and use a bolt to hold focus with friction.Works fine for a mock up, later on you can refine your “arts and crafts” any way your imagination lets you.
==
so… where does the magnification come from? several places…
1) the focal length (FL) of your glass lens, or camera lens. A 135mm lens? is a 135mm lens… doesnt matter if its a 135mm “cannon EOS lens” or a 4 dollar “surplus shed” 135mm FL “objective lens”. Both will work identically here.
because we are using any length of PVC pipe we need to? anything works. (2 feet “plus” is a good starting point, you can cut off later when you know what you will need. I’d leave the extra on though… the closer you mount to the work surface? the LONGER the focus will get, and it grows in length QUICK
the HIGHER the FL of whatever lens you picked? will give you higher magnification.
2) the size of your sensor on your CAM… theres a camera rule called “crop factor”. When you draw your first image up with white paper? you will notice that the “image” is way bigger then the sensor,most of it is “wasted”… the smaller the sensor, the higher effective magnification you will get. I use 1/3” sensors in my OTHER projects all the time, i would get LESS magnification than when i use my cheapie USB webcam… cheap wencam sensors will tend to be tiny. If you THINK about it, thisd makes sense from a photography viewpoint. the SAME lens on 2 different camera? will give drastically different magnification… if the cameras have different size film or sensor.
so… the SMALLER your CAM sensor is? the HIGHER the magnification will be. Ironically for us, the cheaper webcams? have TINY sensors, which will yield high magnification… which is great for us, free extra magnification.
3) distance to the work surface., the CLOSER you can focus up (assuming you have the extra tube length, lol)the HIGHER the magnification will be. This is easy logic… take a picture of your cat 1t 100 yards, then take a picture of your CAT from 6 inches away… which one has more magnification?
for your TRIAL RUN? focus on somethng across the ROOM, it will be slightlyless “demanding” to focus up. Choose “2 feet” as a working distance to start out on the work surface… you can practice “coming in” and focusing longer as you go. I keep ending up somewhere around 12 inches or so on both of my units, and i have too much magnification (a good problem to have, lol)
=
i will continue this, by adding pictures of various stages of my “build” to make it easier… and some tips and tricks i have picked up, because i do this all the time for other stuff, i am used to it.
but, if all you DO, is focus up a “twisty CFL” with a few lenses around your junk bin onto a piece of white paper? You know all you need to know, to succeed at this.
