The Holga is a cheap medium format film camera that has achieved cult status for its inconsistent, truly unique photographs featuring blur, light leaks, vignetting, and distortion. Poor quality digital photos aren’t nearly as interesting and [Joachim Guanzon] wanted to achieve the Holga effect without using robotic Photoshop filters. He constructed this lens for his Canon 20D. The base is an EOS body cap with the center drilled out. A tube is constructed from a white film canister and the Holga lens is mounted inside. The tube length increases the usable distance of the camera and the white body lets some light leak in. A lens cap with a 3/16th inch hole is snapped over the top. The hole creates a vignette and since it isn’t permanently attached the pattern will be more random. Check out Joachim’s sample photos.

Continue reading “Holga Style Digital Camera Lens” →

I know the camera pictured looks kind of wonky, “They just glued a peephole to a digicam, right?” The fisheye camera guide from Aggregate.org goes much further than that. They’ve tried out the $4 peephole lens on almost every camera in the office and have built dedicated ones using $15 pen cameras. I don’t plan on building one of these, but I did find their guide for removing “dark noise” from images really interesting. Sensor noise can be fairly consistent from shot to shot. So with some smart subtraction of a black frame from an image you can remove noise without blurring the image. They have information on masking and projection conversion as well.

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[Jan-Erik Skata] recently had to perform surgery on his Canon 300D since the secondary mirror would not raise up (and if manually locked wouldn’t autofocus). His repair guide is good; you may remember his focus screen replacement. The thing I found really interesting was the site he referenced for his disassembly: Gary Honis’s Canon Digital Rebel (300D) Modification. Gary removes the IR cut glass from inside the camera and replaces it with a piece of clear glass. He then shows how to setup color correction and confirm that autofocus is still working correctly. He’s even got a mockup for how to add peltier cooling to the CMOS chip.

Continue reading “Canon 300D Mod For Astrophotography And IR Imaging” →

[MM] has built a simple lighting adapter for analyzing skin lesions. Different layers of the skin absorb different parts of the light spectrum. By shining those particular wave lengths on the skin you can get an image of the lesion in various layers. This camera adapter is designed for a Nikon Coolpix E3100 digital camera. The ring of LEDs contains blue, green, red, and IR. White is included as well for taking normal pictures. A polarized filter is used to cut down on light reflections from the skin surface. The device does have some calibration issues since it was soldered by hand, but the preliminary results look very promising.

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[Greg Lipscomb] was working on this disposable camera based slave flash when he stumbled into his macro photography project. Slave flashes are used as fill lighting and can be triggered by several different methods. Greg’s project uses a photocell and a microcontroller for trigger and timing. It also makes sure the flash stays charged. He concedes that this design is a bit complicated, but he went with it because he didn’t have any silicon controlled rectifiers available. The microcontroller would be too slow, but his Canon 10D uses a pre-flash before the actual photo, so the slave has a built in delay from that first flash.

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Most modern digital SLR cameras use matte focus screens with their autofocus systems instead of the split circle manual focus screens found in non-digital SLR cameras. Although not factory endorsed, there are replacement manual focus screens which can be very expensive. Reader [Jan-Erik Skata] decided to save some money by salvaging the focus screen from a Miranda dx-3 film camera. Removing the screen proved extremely difficult and the Miranda would have been a total loss if it had been functional. Once out, the screen was sanded down, cleaned and then placed in a Canon EOS 300D. It’s hard to take a picture of the screen through the view finder to prove that it works, but I’m sure Jan-Erik is taking some great photographs having completed this upgrade.

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