Two Infinities

Mon, 03 Apr 2006

Halogen light stand for studio photos
Getting accurate colors of the products I photograph for my website has been a constant struggle for a novice photographer like me. I feel I've made real progress for a modest investment following a wonderful article over at

Figure 3 in this article plots the spectral power distributions of special "daylight" fluorescent lamps and of filtered halogen lamps against the D50 referent. I found that using "natural sunshine" fluorescent bulbs and calibrating the white balance of my Nikon D-50 to a gray card solved the problem I was having representing various olive greens. Needing directional lighting and seeing how filtered halogen achieves a color rendering index of 98 or 99, I decided to try making my own halogen fixture. The parts I have bought are

Smith-Victor 1/4 x 20 screw adapter for light stand
Provides a screw stud for attaching a light assembly to one of their light stands.
2 3" corner braces
From the hardware store, these "L" brackets provide two vertical mounts as well as horizontal angle adjustment. They're tightened down with thumbscrews for convenient adjustment.
2 3/8" conduit hangers with speed thread
Instead of conduit, the hanger holds a halogen light socket. I used a 1/4" x 3/4" serrated flange bolt to attach the hanger to the "L" bracket and tightened it with washers and thumbscrew to facilitate vertical angle adjustment.
2 2" mending plates
These are attached to the hanger clamp bolt by two hex nuts and provide a handle for vertical adjustment of the lights--I expect the clamp to get too hot to handle comfortably.
2 MR-16 sockets
The filtered halogen bulbs (Solux) I need have an MR-16 base--one reason I couldn't use off-the-shelf fixtures I saw at the hardware store.
1 120VAC to 12VDC transformer
Halogen lights use DC current. I'm expecting to use 2 50 watt bulbs but I spent an extra $10 for the 150 watt transformer just in case I need more wattage later.
1 6' cord set with switch
This one came with a socket at the end, but I cut it off and spliced the cord to the transformer.
7' 12 gauge wire
I'm planning to let the transformer rest on the floor, so I need a length of heavy guage wire (because of the high amperage) to run from the floor to the top of the light stand.
The total cost has been $68 for the assembly and $14 for two 50 watt filtered halogen bulbs with most the assembly cost due to the transformer ($39). This does not include the cost of the light stand, but it does include the cost of various 1/4" nuts, washers and bolts as well as electrical connectors which one might already have lying about the shop.

Here is a photograph (click to enlarge):

posted at: 09:41 | path: | permanent link to this entry