09/21/14

Low cost laser barrier Photography

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After trying to capture an exploding water balloon with a very rudimentary method (see here), I dedided to try again but using a low cost laser barrier and a LDR (Light-dependent Resistor) to get more accurate results.

Materials:

  • 1 Laser diode (5v, a pack of 10 is very cheap on eBay).
  • 5v Power supply (or 4xAA batteries) for powering the laser.
  • 1 small LDR (Light-dependant Resistor)
  • 100K variable resistor
  • N3 camera connector (Canon 5D) or minijack depending on camera model.
  • Bag of water balloons
  • Also a flash is necessary to freeze the motion, and also using it at the minimum power possible.

Circuit:
 
Knowing that to shoot the camera with an external cable we need to short-circuit two wires (Shutter and Ground), I put a 100K variable resistor between the two wires and saw that the camera shoot when I set the resistance lower than 25K.
Once we know that resistance, we know that if the sum of the variable resistor + LDR is < 25K, the camera will shoot.
To build the circuit I just put the LDR and the variable resistor in serial and then connected them to the shutter and ground cables of the camera. The variable resistor serves to callibrate the initial status and set the camera to a point that almost shoots. Then, when we point the laser to the LDR, its resistance lowers and the overall resistance between the Shutter and Ground cables will be < 25k, so the camera will shoot. In normal conditions, when the water balloon is in front of the LDR, the camera won’t shoot because the LDR resistance is too high to trigger the camera. When the water balloon explodes, the laser beam will illuminate the LDR.

Camera and flash settings:

  •  Shutter: 1/125 (if there’s ambient light it should be faster).
  •  Lens focus set to manual.
  •  ISO 400
  • Apperture: f/8-f/12 to get enough DOF.
  • Flash power set to 1/64 and zoom at 105, about 60cm from the water balloon (on the left). Also, the flash is triggered from a remote emitter in the camera.

Once all is prepared, we just have to tie a water ballon to the rope so that it is placed between the laser and the LDR, and when we make the balloon explode with a needle the camera will automatically shoot.

Original idea:

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Setup and circuit:

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Results:

_MG_9912_MG_9918

 

 

 

 

 

 

 

 

 

 

 

 

Notes:

  • I built the same circuit with a LDR of a greater size and it didn’t work so well, so I recommend using a LDR of the same size as the laser point if possible.
  • I noticed a significant delay between the balloon exploding and the camera shooting, which I didn’t find so slow in my old Canon 40D. To solve this I recommend setting the water balloon higher than the camera frame, so that the balloon doesn’t appear in the frame until the water balloon falls.
06/12/14

Making of “Ephemeral dreams”

To create this work, I mixed a 3D rendered labyrinth with some photos. The final photo is composed by these three kinds of images, created in this order:

Hands: I used a Canon 17-40L lens at 17mm, f/20 to get a lot of dof and flash on the right with a small softbox.

hands_setuphands

 Sand falling:

I needed to get some photos of sand falling and merge them together to create the parts where the labyrinth was melting. My photoshop skills are very limited so I had to get a good perspective and shoot at 17mm too in order to facilitate the edition. I did some tries using a shutter speed of 1/30, also f/20 and natural light to get a kind of “silk effect”, but when I joined the captures with the 3D labyrinth, the result looked like plastic. I repeated the sand captures using flash to get the opposite appearance (freeze the motion), and I stuck with that setup for the rest of the photos I needed (just 3 or 4).

sand_setup

sand

 

 

 

 

 

 

 

 

 

Labyrinth: Modeled with 3D Max 2014 with iray. First I created in Photoshop a 2D image in black and white with the labyrinth I wanted, until I got this:

plantilla_laberint2

I added some layers and used the gradient tool to darken the corners so that the labyrinth appeared that was melting when applying later the “displace” modifier in 3D Max (depending on the shade of gray, the height of each wall will differ).

Then in 3D Max, applying the modifier “displace” I used the displace map created to get the 3D appearance. With the modifiers melt, noise, wave and bend I added some imperfections, and also edited the mesh of the labyrinth to melt much drastically the middle part and the sides. Result:

laberint_high_low_mid_fused

Each part was processed with Lightroom to add some dramatism by using clarity and blacks, and changing the temperature of the captures, and also desaturating to have a similar appearance in all of them and facilitate the Photoshop part.

Final photo:

04/8/14

Making of “Captivity”

In this one, I wanted to create an mood similar to a jail by projecting the light through something like “metal bars”.
I used a cutter and cardboard to create my bars and set a flash behind it on the right of the camera to project the shadows of the bars onto the composition.

I could have created shadows with a more defined borders by placing the flash farther from the cardboard, so that the relative size of the flash would be smaller, but for me it was ok this way, because it can be interpreted as an office curtain too, which I also found appropiate.

To emphasize the highlights and textures of my hand and give the impression that the person was in tension and sweating, I used a dropper with water to wet my hand. I used an old keyboard I had at home because by combining it with the b/w processing seemed more adequate to me than a modern keyboard.

Before:

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After:

04/3/14

Making of “Drowning”

To create this photo, I used my computer screen again as a softbox. I wanted to get the silhouette of the glass so I didn’t need a flash, and using a tripod I could choose the dof I wanted and then the necessary exposure time to get a white background.
I placed the razor blade very carefully before filling the glass until it held in the position I wanted, and then I started to fill the glass with water using a dropper, and also doing some photos of the composition while I was filling it, just in case the razor blade changed its position, in which case I could loose the shot.

Also, in the first attempts I noticed that the edges of the glass weren’t as defined as I wanted due to unwanted light coming from the screen, so I placed a couple of books as flags to reduce the amount of light on the sides of the glass to get a more defined silhouette.

Finally, I used photoshop to create the silhouette of a face and then its symmetry with a copy of the layer.

Before:

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After:

04/1/14

Making of “Pens and Swords”

Today I’m going to start a little project about how I make some of my photos or build my light tools, usually using materials that can be found at home, because sometimes there’s no need to have an amazing studio to create decent photos. I won’t describe the details in each case, and the making of photos will probably be made with the smartphone, but feel free to ask if you have any doubts ;)

The idea was suggested by my friend and photographer Xavier Carol, check his blog if you want: lalquimista.com

For this first photo, I used a feather I found on the street. With a cutter, I carefully cutted the feather to the point I wanted, and then I placed a decoration sword I had at home inside the feather. I wanted a dark background but also emphasize the details of the sword and feather, so I used my computer screen and a polarizing filter in the lens, rotating the filter to a point where I saw a black background.

With some exposure time, I could illuminate the objects and also keeping a dark background. Also, although I knew the final capture would be vertical, it was much easier to make the photo horizontally due to the working area of my “soft box”.

Before:

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After: