Here's a Great Project. Using a Raspberry Pi to control a Nikon Camera, via USB and capture bracketed images...

Don

23rd
Aug

HDR photography with Raspberry Pi and gPhoto2

This entry was posted in How To and tagged gphoto2, HDR, Photography, raspberrypi on August 23, 2012 by Khürt Williams.

UPDATE: See my new blog post where I rewrote the code in Perl and added a trigger for the Pi.

I bought my Nikon D40 in 2006. The D40 is my first and only DSLR camera and I’ve loved using it every day that I’ve had it. At the time, it was Nikon’s entry-level DSLR and it suited my budget and photography skills. Over the last 6 years that I’ve owned the device my photography skills have improved but not my budget¹. I’d had to make do with the limitations of the D40 — 6 megapixel DX sensor, 200-3200 ISO range, no auto-bracketing — but the lack of auto-bracketing has been the most limiting.

I love making high dynamic range (HDR)² photographs. I love how my photographs come alive with the expanded range offered by HDR. HDR photography involves taking multiple photographs at varying exposure levels and combining the photos into a single final image. HDR photography requires a good tripod and a camera that can shoot bracketed photos. Having a camera body with auto-bracketing makes this easy. On the D40 I can manually adjust the exposure values (EV) between each capture but I risk moving the camera. A slight movement can make aligning the images much harder.

I’ve researched various solutions for my problem. I used a Mac app, Sofortbild, to tether my D40 to my MacBook via USB. Sofortbild provides complete remote control of a Nikon DSLR camera — like shutter speed, aperture, exposure, white balance, iso, image format — and automatically transfers captures images to the Mac hard drive. It can also auto import images into iPhoto, Aperture or Adobe Lightroom. However I was interested in it’s use for HDR photography.

Perform bracketing with an arbitrary number of different exposure values by defining minimum and maximum shutter speed and step. After bracketing high dynamic range images can automatically be calculated including auto image alignment and saved in all major high dynamic range image file formats. Filenames will get same index including incrementing suffix for easier workflows with external high dynamic range applications.

Sofortbild is easy to use and fully functional but … the setup wasn’t only practical in a studio or controlled set. I just didn’t see myself lugging a laptop, tripod, camera and lenses around. With a MacBook Air, maybe. A 7 lb MacBook. No. I wanted something lighter.

I started researching options to control the brackets using my iPhone. Searching the web I found a project called DSLR.bot. The creator wrote an iPhone/iPad (iOS) app that could trigger an IR LED to send the correct binary sequence to trigger the IR on the Nikon. The creator sells a pre-built IR remote but I built one myself. However, he author of the app limited the fastest shutter speed to 3/10 second. This was too slow for my daylight HDR. Most of my test shots were completely blown out in the highlights.

When the Raspberry Pi single board computer was announced I could immediately see the usefulness of such a small. I ordered one and four months later I could starting working on my first project. I planned to used the Raspberry Pi to control my Nikon via USB and capture bracketed images.

After much research and trial and error I think I have a working solution.