Here´s a sketch of the homemade softbox I´ve used for all my tabletop studio model car photos. The cardboard softbox sits on top of a 45 x 45 cm wooden frame with four legs. Any filters and diffusers I want to use also rest on the top of the wooden frame, and can be easily changed by lifting off the softbox. For some shots I´ve covered most of the softbox front with black gobos, leaving a 11cm (or whatever I want to try) window to give a strip light effect. I make black doors to control the light further.
The only thing that really cost any money on this was a €5 desk lamp fitted with a €20 daylight low energy (23w = 120w) bulb. Because I still use film cameras I needed a bulb that would give me a good white light. Perhaps with a digital camera that lets you adjust the light balance a cheaper bulb would do. Low energy is great because the bulb doesn´t get hot and has a really long and reliable life. I know many tabletop studio setups use flash, but I don´t have a flash, and also I like the WYSIWYG that a continuous light gives me.
The base card is swept up vertically into a backdrop. I have great fun with different colour sheets of card, as you can see on my photostream. To get a gradually darkening background I extend the backdrop out beyond the softbox and cover it with the black extension card that I show in dotted lines on the sketch. If I want a blacker graduated background I either lengthen this extension card to push the backdrop even further back, or I raise the base to get it closer to the softbox.
Over the months I´ve added a few extra whizz-bang refinements. Now I can strap the softbox down onto the wooden frame so I can turn the box on an angle or on it´s side without the whole assembly falling apart. I´ve also added extensions to the legs so that if I want to I can raise the softbox another 20cms. It´s good for taller subjects, or if I want to get a higher camera angle. But actually the best softbox light (big and soft) is when it is as close to the subject as possible.
I´m no softbox or studio lighting expert, and there are plenty of good sources on the net and here on flickr for advice on making your own softbox and other studio lighting tips, but I have been asked how I do my car shots, so I thought I´d share this with you. I´ve had so much fun from this softbox...I´ve shot almost nothing else in the past six months!
If anyone else is inspired to try this feel free to ask any questions....
All the best, Andy