The Butterfly Bracket

- J. F. Tremitiere

Click HERE for Butterfly Bracket diagram.

A 2-foot length of 1/8" x 1" aluminum strap is needed for construction.

Base Arm:

1. Cut a length of aluminum 12" long. Drill a 1/4" hole one inch from the end. Locate the hole to line up with the hole in the camera base, which may not be centered, front-to-back.
   
   
2. At the other end, drill a 1/4" hole 1/2" in from the end and centered. This hole is for a 1/4-20 bolt that attaches the ball and socket head.
   
   
3. To form the tab that holds the ball and socket head, place the aluminum in a vise and make a right-angle bend 1/2" from this second hole. Striking with a hammer close to the vise will make for a tighter angle.
   
   
4. Make a right-angle bend in the camera-holding end of the aluminum. Position this bend so that the arm clears the left side of your camera by about 1/2".
   Note: Both bends must be in the same direction.
   
   
5. Place the short arm of this bend in a vise and bend the long arm so that it will be at a 45° angle. (See sketch)
   CAUTION: There is much stress on the aluminum during this operation and it can snap off. You might want to pre-heat the metal with a propane torch just prior to making the bend.
   
   
6. I added a small bracket to the short arm to prevent the entire assembly from rotating on the camera. Position it closer to the end of the camera than the diagram indicates.
   
   
7. I also added felt to all parts of the bracket that make contact with the camera body, to minimize camera wear.

Adjustable Arm:

1. Cut this piece (the adjustable arm) of aluminum strap 7" long.
   
   
2. If the threaded stud atop your ball and socket is long enough for it to pass through the metal and allow for a nut to be fitted over it, drill a centered 1/4" hole 1/2" in from one end.
   If not, you will have to drill and tap for the 1/4-20 stud. I used a #8 bit for the hole and a 1/4-20 tap to form the threads. Kerosene can be used as a lubricant if needed. Make a 90° bend 1/2" from the hole.
   
   
3. Making the slot in this bracket is probably the most difficult part of the entire procedure. I drilled a series of 1/4" holes down the center of the arm close to each other but not touching. I then used a small round file to connect the holes and a flat file on the sides of the slot.
   CAUTION: Make sure that the metal is sell secured when drilling, since the bit may grab, causing the metal to rotate dangerously. Avoid overlapping the holes, since the drill bit can bind and break very easily.
   
   
4. To hold the flash adapter shoe, I fitted an old radio knob with a 1/4-20 bolt. A manual flash with a guide number of 40-50 at ISO100 will do nicely.
   
   
5. I did the same thing in order to hold the entire assembly to the camera base.
   CAUTION: Carefully measure the depth of the threaded hole in the camera base and make sure that the length of the 1/4-20 stud from the knob, that extends above the aluminum arm, is slightly less than the depth of the hole. A bolt that is too long can puncture the camera base.

Using The Butterfly Bracket

1. Since I use the bracket in conjunction with the Calhoun Formula (for determining flash distances), I made a series of reference lines alongside the slot.

   The Calhoun Formula can only be used with pure macro lenses, extension tubes, and bellows:

   

2. After determining and recording flash distances for various magnifications, using the Calhoun Formula, you need to know the position of the flash on the adjustable arm and the angle of the arm that will give you these distances.
   
   
3. This is my method:
   1. Set your lens for the desired magnification and place the camera on the table. Move a focusing target in front of the lens until you get the sharpest image.
      
      
   2. Change the position of the flash in the slot and the angle of the adjustable arm until you obtain the recorded Calhoun distance for this magnification. Record the positions of the flash and the angle of the arm. A metal measuring tape is best for determining these positions.
      
      
   3. Repeat this procedure for other magnifications.
      
      
   4. I record the results on a small card which I carry in my wallet. I also attach a card, containing this information, onto the flash for instant reference. (See sample chart below)
      
      
   5. If I am going to photograph a Monarch butterfly (3 1/2-4" size) at 1:3 magnification, a quick reference to my chart indicates that the adjustable arm should be located approximately 40° forward and the flash at the bottom of the slot.

      These adjustments take just a moment to do and they can be modified according to the reflectivity of the subject. For very dark subjects, move the flash forward 1-2"; for very light subjects, move it back 1-2".

   6. Be prepared to waste some film, since these are very "flighty" subjects.