Home made heater for dslr lens
What is the common point between
a bike brake cable and astrophotography ?
An anti-dew heater for dslr's lens !
Finaly, a clear night to make a star trail.
Unfortunately, the last experience was disappointing : the dew arrived earlier than expected and ruined most of the shots.
Only one hour to find a solution ?
One of the 0.3mm diameter x 1.2m long wire of the brake cable is used : it is the resistor that will produce the heat.
The wire is made of stainless steel, that is known for its electric resistance.
It will be connected directly to a 12V powertank. A preliminary with such a wire (same length : 1.2m) produced a soft heat, arround 30°C. A shorter wire produced an excessive heat.
As my pultimeter is out of order, I couldn't measure the resistance of the wire. I will as soon as I purchase a new multimeter.
I sewed the heating wire on the "soft" side of a 50mm x 300mm double-sided Velcro tape (passing the wire in the loops).
A second double-sided Velcro tape sandwiches the heating wire and helps hold it in place.
As the stainless steel can't be soldered on a copper wire, I made a mechanical connection with a domino.
The domino is sewed and glued on the tape.
Overview of the heater, with a 1.5m long power cable and a ON/OFF switch :
Views of the heater in place on the Samyang 8mm fisheye lens :
On these pictures, one can see the difference between
- star trail without heater : short sequence and blur due to the dew,
- star trail with heater : long sequence,without blur.
Manufacturing in a very short time (1 hour) of an efficient and safe heater (around 30°C).
This solution makes possible the manufacturing of different size heaters.
Tags : anti-dew heater, dslr, lens, astrophotography, leca philippe, philippe leca, diy