Hacklet #11- Cameras

11

We preempt this week’s Hacklet to bring you an important announcement.

Hackaday.io got some major upgrades this week. Have you checked out The Feed lately? The Feed has been tweaked, tuned, and optimized, to show you activity on your projects, and from the hackers and projects you follow.

We’ve also rolled out Lists! Lists give you quick links to some of .io’s most exciting projects. The lists are curated by Hackaday staff. We’re just getting started on this feature, so there are only a few categories so far. Expect to see more in the coming days.

Have a suggestion for a list category? Want to see a new feature?  Let us know!

Now back to your regularly scheduled Hacklet

There are plenty of cameras on Hackaday.io, from complex machine vision systems to pinhole cameras. We’re concentrating on the cameras whose primary mission is to create an image. It might be for art, for social documentation, or just a snapshot with friends.

pinstax[theschlem] starts us off with Pinstax, a 3D Printed Instant Pinhole Camera. [theschlem] is using a commercial instant film camera back (the back for a cheap Diana F+) and 3D printing his own pinhole and shutter. He’s run into some trouble as Fuji’s instant film is fast, like ISO 800 fast. 3 stops of neutral density have come to the rescue in the form of an ND8 filter. Pinstax’s pinhole is currently 0.30mm in diameter. That translates to just about f/167. Nice!

largeformat

Next up is [Jimmy C Alzen] and his Large Format Camera. Like many large format professional cameras, [Jimmy's] camera is designed around a mechanically scanned linear sensor. In this case, a TAOS TSL1412S. An Arduino Due runs the show, converting the analog output from the sensor to digital values, stepping the motor, and displaying images in progress on an LCD. Similar to other mechanically scanned cameras, this is no speed demon. Images in full sunlight take 2 minutes. Low light images can take up to an hour to acquire.

democracy[Jason's] Democracycam aims to use open source hardware to document protests – even if the camera is confiscated. A Raspberry Pi, Pi Cam module, and a 2.8″ LCD touchscreen make up the brunt of the hardware of the camera. Snapping an image saves it to the SD card, and uses forban to upload the images to any local peers. The code is in python, and easy to work with. [Jason] hopes to add a “panic mode” which causes the camera to constantly take and upload images – just in case the owner can’t.

digiholgaThe venerable Raspberry Pi also helps out in [Kimondo's] Digital Holga 120d. [Kimondo's] fit a Raspberry Pi model A, and a Pi camera, into a Holga 120D case. He used the Slice of pi prototype board to add a GPIO for the shutter release button, a 4 position mode switch, and an optocoupler for a remote release. [Kimondo] even added a filter ring so he can replicate all those instagram-terrific filters in hardware. All he needs is to add a LiPo battery cell or two, a voltage regulator, and a micro USB socket for a fully portable solution.

openreflex

Finally, we have [LeoM's] OpenReflex rework. OpenReflex is an open source 3D printed Single Lens Reflex (SLR) 35mm film camera. Ok, not every part is 3D printed. You still need a lens, a ground glass screen, and some other assorted parts. OpenReflex avoids the use of a pentaprism by utilizing a top screen, similar to many classic twin lens reflex cameras. OpenReflex is pretty good now, but [Leo] is working to make it easier to build and use. We may just have to break out those rolls of Kodachrome we’ve been saving for a sunny day.

That’s it for this week’s Hacklet! Until next week keep that film rolling and those solid state image sensors acquiring. We’ll keep bringing you the best of Hackaday.io!

Retrotechtacular: Tube Amplifiers

retrotechtacular-how-tube-amps-work

It’s hard to beat this vintage reel for learning about how vacuum tube amplifiers work. It was put together by the US Army in 1963 (if we’re reading the MCMLXIII in the title slide correctly). If you have a basic understanding of electronics you’ll appreciate at least the first half of the video, but even the most learned of radio enthusiasts will find something of interest as they make their way through the 30-minute presentation.

The instruction begins with a description of how a carbon microphone works, how that is fed to a transformer, and then into the amplifier. The first stage of the tube amp is a voltage amplifier and you’ll get a very thorough demo of the input voltage swing and how that affects the output. We really like it that the reel discusses getting data from the tube manual, but also shows how to measure cut-off and saturation voltage for yourself. From there it’s off to the races with the different tube applications used to make class A, B, and C amplifiers. This quickly moves onto a discussion of the pros and cons of each amplifier type. See for yourself after the jump.

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Retrotechtacular: Films Used to Be Recorded on Film

retrotechtacular-movie-film-photo-finishing

We’re sure that this title makes some readers itch because there are still a number of well-respected directors who insist on shooting with film rather than digital, but the subject of this week’s Retrotechtacular shows a portion of the movie industry that has surely been relegated to life-support in the past few decades. Photo finishing, once the stronghold of chemical processes used by all to develop their photographs, has become virtually non-existent. This is the story of how film and photo finishing drove cinema for much of its life.

The reels seen above are negative and positive film. The negative film goes in the camera and captures the images. After developing and fixing the negative film, the process is repeated. Light shines through the fixed negative in order to expose a fresh reel of film. That film is finished and fixed to create the reel which can be used in a projector. This simple process is covered near the beginning of the clip found below. The 1940 presentation moves on to discuss the in-depth chemistry techniques used in the process. But you’re really in for a treat starting about half-way through when the old manual methods are shown, which have been replaced by the “modern laboratory”. We love those huge analog dials! The video concludes by showing the true industrialization of the film developing process.

We’re running out of Retrotechtacular topics. If you know of something that might be worth a feature please send in a tip!

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Retrotechtacular: World’s First Color Movie

world's-first-color-movie

It’s surprising how often a brilliant idea is missed out on until years after the fact. In this case the concept was seen publicly within ten years, but the brilliance of the inventor has been appreciated once again after 110 years. It’s a color movie which was filmed around 1901 or 1902 but it sounds like the reel wasn’t shown in its full color grandeur until 2012 when the National Media Museum in the UK started looking into the history of one particular film.

The story is well told by the curators in this video which is also embedded after the break. The reel has been in their collection for years. It’s black and white film that’s labeled as color. It just needed a clever and curious team to put three frames together with the help of color filters. It seems that [Edward Turner] patented a process in 1899 which used red, green, and blue filters to capture consecutive frames of film. The patent description helped researchers put image those frames — also using filters — to produce full color images like the one seen above.

The press release on the project shares a bit more information, like how they determined the age of the film using genealogical research and the fact that [Turner] himself died in 1904. The process didn’t die with him, but actual evolved and was exhibited publicly in 1909. This, however, is the oldest known color movie ever found.

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A beautiful pinhole camera takes wonderful photos

With digital cameras in everything and film slowly disappearing from shelves, everyone loses an awesome way to learn about photography. Pinhole cameras allow anyone to build a camera from scratch and also learn about those crazy f-stops, exposure times, and focal planes that Instagram just won’t teach you. [Matt] put up a great tutorial for building your own pinhole camera, and the project looks easy enough for even those who are still playing around with their cell phone cameras.

For film, [Matt] used 120 film, a medium-format medium that is sill available for purchase and processing in some areas. Because [Matt]‘s pinhole is relatively large and made out of very thin material, the camera could take very large pictures – much larger than standard 35mm fare. If you’re using a smaller camera projecting a smaller image onto the film, 35mm would be the way to go as it greatly decreases the difficulty of finding film and a processing center.

[Matt]‘s camera is constructed out of laser-cut plywood. Because he’s producing extremely wide images with his camera (6 x 17cm), [Matt] needed to curve the film around the focal plane of the camera to keep the entire image in focus.

The mechanics of the camera are simple – just a pair of knobs to wind the film and a small metal shutter. [Matt] added a shutter release cable to open and close the aperture without moving the camera and had a wonderful camera perfect for capturing either sirs and madams or Civil War battlefields.

Camera dollies hacked together by stop motion filmmakers

A little bit of technology goes a long way when it comes to stop motion animation. In this case it’s a trio of simple camera dollies built during production of a short film called The Maker.

A Dolly is a method of mounting the camera so that it can be moved smoothly during a shot. Of course with stop motion the movement actually happens between the shots so it’s even more important that the camera be moved accurately. The video after the break shows off how they added CNC control for the camera. The first dolly was built from a pair of PVC pipes with a sled that moves along them. A motor moves a loop of 35mm film which is attached to the dolly. This is a great choice of materials since it doesn’t stretch and it’s free (one of the filmmakers is a projectionist). The next dolly is made from a flatbed scanner, and the final offering is seen above. Built from a bicycle wheel it provides a stationary platform above the hub for the models, while the camera rotates on an arm attached to the wheel. You can watch the complete film here.

If you’re looking for more inspiration check out this dual-axis PVC dolly project.

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F/stop printer for analog printing black and white photos

This beautifully crafted device is a timer used for getting the perfect exposure when making film prints of photos. But in addition to keeping time, it also does logarithmic calculations that are based on the f-stop values used for each exposure. It does this in 1/100th of a stop increments. While he was at it, [William] also decided to pack in a bunch of other features like dry down correction, and support for making test strips. This is a little hard to understand when discussed in the abstract, but just take a look at his video after the break where [William] walks us through an example exposure and all will become clear.

You can see from the construction page that the device is basically an Arduino shield. It provides a relay for controlling the exposure lamp, a keypad, rotary encoder, and character LCD. Slap it in a fancy case, connect it to the equipment you’re using, and you’ll be creating perfect prints in no time flat!

[Read more...]

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