Here’s another in the series of articles of photographic uses for the Raspberry Pi SBC (Single Board Computer). This time, it’s re-purposing an old flatbed scanner as a macro rail for focus stacking images in macro photography.
Category Archives: Tutorial
This article shows howto send images to Adobe Lightroom from a wireless connected device.
I’ve had the idea of embedding a computer DSLR camera for a couple of years now, but for whatever reason I never got around to implementing it, mostly due to the cost of small single board computers. Until now, that is. With the release of the Raspberry Pi, embedded computing has all of a sudden become much more affordable. At €35 for the computer, it’s far cheaper than any of it’s rivals.
So what I’ve done is take an old (broken) battery grip that I had lying around (for my Canon 5D Mark II), and made a few modifications to it so I could fit the Raspberry Pi SBC (Single Board Computer) into it.
Here’s something that might be of interest, and will help speed up some parts of your workflow.
Get a faster memory card, and the means to get the images onto your PC as quick as possible.
I recently ordered a couple of 600x Duracell 8Gb Compact flash cards from 7DayShop.com….
They give a read speed of 90MB/sec. and are only £20.99 for 8Gigs. That’s great value.
Now USB 2.0 can’t go that fast, it can only manage about 45MB/sec if you’re lucky.
But USB 3.0 is getting much more popular, so you could get yourself a USB 3.0 card reader.
This one is about €19 from the UK.
USB 3.0 is rated at 5gbps, or in megabytes about 500MB/sec, More than enough for the fastest CF/SD card, so should be able to max out the 600x Compact Flash card.
If your PC doesnt have a USB 3.0 connection, you can always add one using a USB 3.0 PCIe adapter (about €20).
Or, for a laptop (about €20).
The Pretec card reader comes with a pretty short stubby adapter, so if you want to have the card reader on your desk, you’ll also need a cable (about €5).
So, you’ll have the added advantage that your camera will be able to keep going longer for those rapid-fire shots (by writing to the card faster), and you’ll also get your images off your card and onto your PC MUCH quicker, giving you more time to process, etc.
The following is a benchmark of the above setup.
As you can see, this card is really tuned to work with a block size of 64K or greater. The write speeds max out at is 30MB/sec, but the read speed jumps dramatically to 90MB/sec once the block size hits 64K.
(See edit below regarding DSLRBot. A slightly more expensive solution, but quite a bit better…)
Recently I was awe-struck by a Time-lapse video by Terje Sorgjerd I saw which was shot around El Teide on Gran Canaria early in 2011. Looking around on the internet, I saw various solutions for time-lapse, including some very fancy rigs for moving the camera as it’s shooting the images. What I needed was something that could trigger my dSLR camera to take an image at regular intervals over a few minutes up to a few hours. The camera already has a port for a remote switch, so I needed some way to trigger that at regular intervals. There are solutions available as cheap as €50 on e-bay, so I wanted to see if I could do it a lot cheaper than that.
I came up with the idea of using my smartphone’s camera flash to trigger an optical switch, and hook the optical switch into the remote trigger port on the camera. I could then write an app on the phone that would trigger the flash at intervals, thus triggering the dSLR to take an image. I happened to have an optical sensor for triggering flash heads (I use these sometimes for strobist work). This did not work. Maybe it needed a small voltage to operate. Anyway, I headed out to my local Maplin store, and got myself a phototransistor (SFH300-2) at about €2.49. I had a spare shutter release cable lying around that I got off ebay for about €5, so I took the switch off the end and replaced it with the photo-transistor. Nothing else, just the photo transistor directly wired to the shutter release port of the camera.
So, I plugged the phototransistor cable into the camera, and tried taking a picture with the smartphone while holding the phototransistor up to the flash of the phone, and it successfully triggered the dSLR. Yay!
So, the theory worked. One photo-transistor connected to the shutter release port of the dSLR was the hardware side sorted. Now for the software side.
Before investing in a few dozen hours getting the development kit for the iPhone, I took a quick look at any apps already out there for the iPhone that might do the job. Sure enough, there were a couple of apps that do just what I was looking for, and they were free. The one that I settled on was “Canopy Camera Tools” app, that had an intervalometer built in. It would take a picture at pre-defined intervals, and if I set the flash to be always on, this would trigger the dSLR, and I could then throw away the images taken on the iPhone, using the dSLR images for my time-lapse video.
So, with Canopy installed on the iPhone, I duck-taped the phototransistor in place on the back of the iphone, and took my very first time-lapse video.
I set the phone to take 160 images at intervals of 3 seconds. Because the flash duration on the phone would cause several shots to be taken for one shot on the iPhone, I set the dSLR to 2 second timer. Once I’d taken the shots, I loaded them onto my PC, re-sized them down, and used a free application called “PhotoLapse” to stitch them together into a video. The result is here. Very rough, long lens pointing out a dirty window. But you get the idea. 🙂
Once I proved that it all worked, I made an enclosure that would fit around the top of the iPhone, and hold the photo-transistor in the best position to be triggered by the phone’s flash.
So, I guess I could stretch the truth and say that this is an intervalometer solution for €2.49, but that’s assuming you have a dSLR shutter release cable that you can hack and a smart phone with suitable software. Even then, the shutter release will only cost you about €5. I believe it’s the cheapest solution around for time-lapse videos with a dSLR. 🙂
Here’s another slightly longer timelapse test video…
So, I found DSLR bot has a very similar solution, except that it uses a couple of IR-LEDs driven from the audio-out port of the iPhone. I found an old TV remote control and ripped out the two IR-LEDs from it, put them onto a 3.5mm stereo jac plug, and bought the DSLRBot app at €3.99. So, I’m sure you’ve got some old tv remote controls, and a stereo jac plug lying around, that’s all you need. For build instructions, check out the DSLRbot web page.
I was browsing around Woodies DIY today, and spotted the following clamps for sale in the bargain basement bin at €2.99 each. The spring was strong, and the plastic seemed like the good quality, hard wearing type. So I purchased a couple with some DIY strobist work in mind…
I noticed that the plastic jaws did not have a lot of grip:
so I super-glued some bits of bicycle inner tube to them:
Next, onto the real reason for the purchase, the double flash mount. This consisted of a simple tube bolted onto one of the handles of the clamp.
The copper tube has a bit of timber jammed into it so the tube would not collapse when brolly/strobe holders are screwed onto it. A simple drill hole in the clamp handle, and a drill hole throuhg the copper pipe, with a 30mm bolt and wingnut to hold them together. All done. The Result:
They’re probably not as strong as the Manfrotto clamps, and would struggle to hold a flash out horizontally, but the have no problem holding two strobes in the position of the image above, and would have no problem hanging from something. Not bad for under a fiver….