Introduction: Diffused Illumination With Dimmable LED Strips, for Macrophotography and Photomicrography

See also my other instructable: dark background for diffused light illuminator.

Compared to using a flash, a constant, continuous, indirect illumination means the possibility to mitigate undesired reflections, to rely on your camera's electronics to find the best exposure time, and to force, if desired, shutter speed and diaphragm combinations that would be unavailable if using a flash.

As a second step after my first attempt of indirect illumination based on the coordinated use of microscope LED illuminators, in this instructable I'll illustrate the use of dimmable LED strips to build a self contained and easier to manage indirect light illuminator for taking pictures of small objects via a small table stand.

This isn't actually a step-by-step tutorial. The two parts will respectively describe a simpler and a more advanced version of the same illuminator, and provide some self-explaining images.

Basic version

  1. a couple of short (25-30cm) pieces of dimmable LED strip
  2. adhesive tape
  3. a dimmer for LED strip
  4. a power supply for LED strips (obviously these three items should be compatible with each other, and the power supply should provide an amperage suitable for the LED strip length)
  5. a soldering iron (soldering won't be illustrated here, but may be needed to connect the stripes to the power connector)
  6. two plastic cans+lids of suitable diameter (here I used a 500g yogurt can)
  7. a compass to mark the circular area to be removed at the center of one of the lids
  8. a blade to cut the hole in one of the lids
  9. some foam rubber to keep centered the LED strip ring (LED's will be pointing towards the center)
  10. a white cardboard disc as wide as the internal part of a lid
  11. also this version may benefit of some cardboard discs with central holes of decreasing diameters, suitable for each photographic objective and subject size

Advanced version

  1. a continuous 1 meter of dimmable LED strip, adhesive (if not adhesive, bi adhesive tape may be needed)
  2. a dimmer for LED strip
  3. a power supply for LED strips (obviously these three items should be compatible with each other, and the power supply should provide an amperage suitable for the LED strip length)
  4. a plastic flowerpot holder or any cylindrical or subcylindrical plastic container, 18 - 20 cm in diameter
  5. a compass to mark the circular area to be removed at the center of the flowerpot holder bottom
  6. a blade strong enough to cut easily through the flowerpot holder
  7. some metal wire to keep the internal loop of the LED strip at mid-heigth
  8. adhesive mirror paper
  9. pure white cardboard
  10. scissors to cut the cardboard
  11. stapler to stitch the cardboard strip in a cylinder
  12. some cardboard discs with central holes of decreasing diameters, suitable for each photographic objective and subject size

Step 1: A Self-contained, Diffused Light Illuminator

The first, simpler attempt with LED strips, over-simplified, and with direct illumination of the subject (LED's pointing at the subject), is based on two short strips composing a cylinder, with the subject surrounded by the cylinder on a white cardboard background, and enclosed between the upper part and the lid of a yogurt can.

For the sake of clarity: from one can I took the upper part, with the lid snapped on. This part reversed, with the lid facing the table, will constitute the base of the set - a white cardboard disc is placed at the bottom.

Adhesive tape keeps the strips in a cylindrical shape (LED's facing inwards), while small pieces of rubber foam are used to keep the LED strip cylinder centered.

From another can, I took just the lid where I made a central hole as wide as than biggest subject I intended to photograph (in my case, some insects). The lid, coming from a can of the same diameter, sits snugly and firmly on the base.

This set allows the elimination of the shadows at the base of the subject, without having the drawbacks of transmitted light illuminators.

Ideally, this device anyway needs to be complemented by the "rain of indirect light" that, as an example, may be obtained by an annular illuminator pointing upwards, surrounded by a cylinder of reflecting "mirror" paper, and topped by a disc of white cardboard, as illustrated here.

Step 2: A More Advanced Version

The second solution, decidedly more ambitious and performing, is self-contained (no other illuminator is needed) and is based exclusively on indirect/diffused light.

The main novelty, if compared to the simpler version, is that this illuminator can be put above the subject almost like a hat, and provides at the same time indirect illumination from the sides and from above, thus minimizing shadows and avoiding reflections.

A continuous dimmable LED strip, 1 meter long, is positioned to form a double loop, the inner ring with the LED's pointing outside, and the outer ring with the LED's pointing inside: both the rings illuminate from the two sides a white cardboard cylinder.

In other words, no LED is directly pointed at the subject. Everything is contained in the bottom of a plastic vase holder, with the "ceiling" coated by reflective adhesive paper.

In the ceiling, a central hole is made for the camera lens to peek in.

This illuminator is to be positioned like an hat over the subject, that obviously must be small enough to be entirely framed through the top hole.

The pictures show how the connector for the power supply and the dimmer is positoned externally.

With this set of illuminators I obtained the photo attached here as Figure 8 - please check also these six pictures of insects in diffused light, quite acceptable in terms of diffused illumination and reflections control.

Comments

author
DIY Hacks and How Tos (author)2017-02-04

Cool photography trick. Getting good diffuse lighting is always one of my biggest problems when I am out of my studio.