Posts tagged “Photography

[Engineering] – Bullet Flight Sensor, Systems Integration

Quick status update on the bullet flight sensor. This is heading into systems integration testing next, where I’ll be firing up each section of the circuit and making sure it all works. Missing is the break beam sensor that I put a air rifle round through by accident :-)

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Note the “unusual” arrangement with the pocket wizard. The “hot shoe adapter” is actually plugged into the sensor to simulate a camera’s hotshoe firing the pocket wizard.


[DIY] – 3D Camera Rig

I’ve really been lagging on my blogging. Here’s a quick update.

I’ve recently found myself working out of the Beaverton office again, so late one night after finishing up I hopped onto the company’s aging, crusty lathe:

Machining stainless

These are custom captive screws for the Benro quick-release plates I picked up in Hong Kong. I’m mounting the Benro plates to a piece of 8020 1010 extrusion, and the T-slots are a little bit deeper than an ISO standard camera mount. So, for my application, a custom screw would be needed.

I’m actually pretty happy with how this turned out; the machine is old and the hand-ground parting tool isn’t the best for cutting stainless steel.

To chuck the screw into the chuck without damaging it, I took a page from an old machinist trick of slotting a nut with a hacksaw and clamping it in a 3-Jaw chuck. I started with a 1/4-20 x 0.5″ SAE button head socket cap screw.

(Note: Yes, I am aware that the standard tripod thread is a 1/4-20 British Standard Whitworth – cut with a 55 deg angle instead of a 60 deg angle. I challenge the reader to find one here in a hardware store in the good ol’ USA. A 60 deg SAE thread is “close enough” for this application with some very minor interference)

The resultant screw is a bit too long, so I trimmed it down a little bit with my motor tool.

Trimming the screws

The tool is a Taiwanese made version of the Foredom – a 600W motor on a flex shaft and a foot pedal for actuation. It takes all the standard Dremel accessories and it’ll slice through stainless pretty easily. I lined the jaws of my Wilton vice with some engineering paper scrap, and used my pano clamp as a clamping base for the tripod plate. Then, using another machinist’s trick, I put a nut on each of the screws to be cut. When removing the nut, the nut acts as a tap and cleans out any debris on the screw threads and restores the proper thread form. :-)

And BTW – at 20,000+ RPM and with 600W of power behind the disc – any slip up is … painful. Warning: somewhat graphic picture ahead:

Ouch

The wound looks A LOT worse than it actually is. I think the heat from the abrasive blade cauterized the wound – it didn’t bleed much. Digging all the abrasive grit out under running water was a different story – good reminder to be more careful the next time.

And here’s the finished rig! Now, I need to order some 3D glasses…

3D Camera rig

[Photography] – The great Hybrid-DSLR Meetup

Work had me in Southern California this week, performing some first article inspections on some SLA master patterns and cast urethane molds. I took advantage of the plane ticket to visit family and friends in the area, and found out that Phillip Bloom and Mitch from Planet5D.com are hosting a Hybrid DSLR meetup in Venice Beach.

Hybrid DSLRs, for those unfamiliar with them, are the latest evolution in photojournalistic tools. They allow the filming of video, often in hi-def, on a digital SLR body. Because of the large sensor size, large pixel site, and often resolution reduction employed to generate the 1080p frames, the image quality on the video is often much less noisier than what can be squeezed out of a high end video camera. Also, inherent with the use of a DSLR body for shooting video is the ability for these bodies to change lenses and maintain good control over depth of field.

This means that for the first time, indy film-makers can chase that shallow DOF film look without the use of expensive lighting trucks and 35mm film cameras. Although the movement is in its infancy, a small industry is springing up around this class of cameras (and as an enterprising engineer, I am wondering what I can do to grab a slice of that pie). There is also a very strong DIY movement too for the less affluent film makers.

Here are some of the rigs present at the meetup:

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Here’s your most basic HDSLR rig. Virtually everyone shooting video does so by manually pulling focus, so an LCD hood is pretty essential. This is a Zacuto Z-Finder hood – and quite frankly after playing with all the options out there, you really get what you pay for. These retail for $299 – not cheap – about the cost of an inexpensive prime – but the magnified LCD fills one’s field of view and really allows one to pull focus.

The Zacuto comes with a die-cut VHB adhesive backed mounting flange that sticks onto the back of the LCD. Once stuck there, it can be removed, at the expense of breaking the flange. New flanges are $20.00.

As much of a fan as I am in DIYing; this is something that I’ll have to buy if I choose to go this route. I simply do not possess the optical engineering skills to design something like this.

In this particular case, some sort of directional mic with a windsock is attached to the hotshoe.

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Moving onto looking at pull-focuses: here’s the DFocus pull focus system is designed by aerospace engineer David Aldrich in his free time. My kinda guy! :-). At about $150.00 it’s the cheapest pull-focus system out there. Since I don’t have regular access to a mill, I will have to buy one of these systems as well. Might as well support the little guy. Jag35.com carries these.

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Here’s another option for focus monitoring while pulling focus. This gentlemen is mounting a portable LCD monitor to a hotshoe to miniball head adapter. There are modifications out there to put a sunscreen on the LCD as well so that it is daylight readable. This particular LCD monitor was purchased on Planet 5D forum group buys and comes from some generic factory in China.

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On the other extreme end, ViewFinder LLC demonstrated their fly-by-wire radio controlled pull focus system. A RF link between the control module here drives a servo-motor setup. If you have to ask, you probably can’t afford it. That system costs more than my 5D Mk II – for the pull focus alone.

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The rest of ViewFinder LLC’s stuff is equally … well crafted. See those silver connectors? Those are LEMO connectors. Swiss made, precision medical grade connectors. Idenitfy those as such publicly, and the engineer who designed that system will size you up and see how good our engineering skillz are. These guys also build accessories for the Red Camera folks – so they are doing some very high end work. All their support cages are billet CNC machined.

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A really cool feature of ViewFinderLLC is their remote video start switch, positioned near the user’s thumb in the grip setup above. Apparently, on the 5Dii, putting it in 2 second timer mode, and configuring the live view screen to video only will start the video recording if the “shutter release” IR signal is received from a Canon RC1 remote unit. Now I’ll have to find a RC1 and a way to reverse engineer that IR signal…

Here are a few more of the big boy rigs:

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Most of these rigs consists of a pair of rails, onto which the camera body, lens adapter / DOF adapter, lens, pull focus system, and a matt box system to control flare mounted on a pair of 15mm rails. Stainless and carbon fiber are the material of choice here for building these rigs. Kinda like expensive Legos, I imagine. Actually, the only thing expensive about these rigs is the machining. Everyone is billet CNCing the clamps, when an extrusion tool would be cheaper. No one thinks that an extrusion tool is worth the effort to do, and the MOQ on an extrusion is high. On the other hand – by CNC machining the parts, the costs are kept high, so it locks out the more budget-conscious folks. Talk about a Catch-22 situation.

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Closeup of the battery reveals it to be a generic Li-Ion pack. That I certainly can build…

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Here’s a home-made camera stabilizer, using copper pipes, washers for weight, and a Traxx monster truck universal joint for the swivel. It’s very twitchy, as far as stabilization goes. I am not sure if this is a design path that I want to go down; I’m going to try a silicone grease dampened design first.

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Another great rig, featuring a rifle stock and a Zacuto finder again. These Zacuto units are quite popular.

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Here’s Hunter’s slide rail system. This allows the camera to slide laterally during a shot. This particular system uses TGP (Turned Ground and Polished) steel rails with an oil filled bronze linear bearing. It slides really smoothly.

Slider rail

Here’s Yaro’s version of the same thing. I asked him if it was DIYed and he gave me a strange look. Turns out someone online builds them and sells ‘em. I pointed out that they were all stock 8020 extrusion parts.

For those interested; the parts in questions are:

1020 extrusion piece (base rail – avail up to 140+” long)

Slider (linear bearing) appears to be part # 6535.
This section of the 8020 catalog has all the linear slider components, along with the replacement UHMW inserts for the bearing slides, for those of you going the DIY route.

While we are on the subject of camera slides and camera dollies, here’s a hack to convert an IKEA shelf piece into a camera dolly track system:

In the DIY spirit, here’s a 3D photo / video system, rocking twin 7Ds with nifty fifties. Note the use of the 80/20 profiles for spacing the cameras:

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There as so much gear floating around, even carrying my “full combat load” I honestly felt like an iPhone shooter at a UW garage shoot. So it was refreshing to finally see someone with *JUST* a 5D Mk II :-)

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And finally, the overhead cam group shot:

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A big thanks to Phillip Bloom for putting it together and Planet5D for helping to spread the word!


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