Sometimes, in order to take stereo photos of larger objects, you need a bigger turntable. Also, a bigger turntable makes it easier to incorporate the lighting on its surface. It is always best to take a stereo pair in such a way that the lighting moves with the object thus preventing confusing changes in the shadows. This very short blog post explains how you can make a stereo turntable from a ‘Lazy-Susan’ bearing – a ‘Lazy-Susan’ being a thing you normally put food on in the centre of the dining table and that allows you turn the turntable to present the food to whomever you want.
The bearing I have used is readily available from Ebay suppliers. It is made in metal, is a high quality product, and comes in a variety of diameters. The one I chose is about 25cm across and supports a turntable about 60cms in diameter. The bearing cost about £15. You will need a bigger bearing for larger turntables. I cut the turntable from chipboard.
Manufacture is pretty simple. You need a piece of chipboard bigger than the circle you plan to cut from it. It is helpful if it is square or rectangular. Take a rule and draw two diagonals from each corner to the other. If the board is rectilinear, the diagonals will cross at the centre. Drill a 2mm hole at this point. Find a strip of wood longer than the radius of the turntable you want to make. Bang a nail trough it at one end – choose a nail the point of which will sit nicely in the 2mm hole – it’s going to be the pivot of a crude beam compass. Drill a hole in the other end of the strip of wood of such a size that you can push a pencil through it. The hole needs to sit at distance from the nail equivalent to the radius of the turntable you want to make. Fix the pencil in place with hot melt glue or tape. Place the point of the nail in the small hole in the chipboard and scribe a circle. An alternative way of doing this is to tape two pencils to long rule if you have one. Then drill a hole just outside the circumference of the circle that is big enough to take the blade of a jig-saw. Very carefully cut out the circle of chipboard. It doesn’t matter if the finished object is perfectly circular or not but it’s nice if you get as close as possible. You can finish the edge of the turntable with a rasp or sandpaper depending on how good the cut surface you left is. When you are happy, decide which surface is going to be the top and spray it with matte black paint – I guess you could choose white or gray or any other colour but black seemed best to me. Let it dry. Don’t throw the piece of board you cut the circle from away, you are going to need it later!
Take a sheet of tracing paper bigger than the bearing. Mark the centres of the holes in the bearing on the tracing paper. To find the geometric centre of the bearing, join the points you have marked with lines. Carefully position the tracing paper on the back of the chipboard turntable so that the bearing centre sits on the small hole – a light behind the board may aid in this. Now tape the tracing paper down and using a sharp stylus (a nail?) mark the fixing holes for the bearing. Using those marks as a guide, fix the bearing to the board. You will need to put some spacers behind the bearing to hold it away from turntable, otherwise it will bind on the turntable. I used two washers under the bearing at each screw point. To give you some ideas about how to centre the bearing, the photo below shows the bearing screwed to the chipboard rectangle marked with the turntable circumference and the lines to show how the holes in the bearing can be used to find its centre.
If you are going to use the turntable for stereo photography, calculate the circumference of the turntable (pi * D). Take that number and divide it by 360. That is the distance the edge of the turntable needs to rotate through to move 1 degree. For my 60cm turntable that is about 0.5cm. Take a piece of the board from which you cut the turntable and select a quadrant or a smaller section that is nice and ‘circular’. Spray it with black paint and using a fine brush, mark it with white 1 or 2 degree index marks. Also, place such marks at intervals on the turntable – I just put four marks at 90 degree intervals. Insert the little plastic feet that come with the bearing into the holes for them in the bearing and put the turntable on a flat surface and give it a spin! You are done!
There are plenty of instructions for taking turntable stereo pairs to be found elsewhere on the web. In short, place the object you want to photograph over the turntable’s centre. Set up your lighting on the turntable – I use Nikon’s twin macro flashes on suitable stands. Put you camera on a tripod and take a picture (left-eye image). Turn the turntable clockwise through about 3.5 degrees (you can experiment!) and take the second (right-eye) image. It’s that easy. Of course, the turntable can also be used to take pictures of objects at many angles; they can even be combined into movies and stereo movies.