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Troutnut

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About Troutnut

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  1. Just an update on this for anyone who reads it with a similar question in the future. Steve's idea to use a microcontroller to simulate a "shutton button half pressed" (i.e. focus) signal every 29 minutes worked great to trick the 30-minute auto off timer. And the camera (Nikon D5300) had no overheating or other problems running a nonstop HDMI feed to the Atomos Ninja Blade for 3+ days. However, the battery powering my microcontroller died... and the thing still worked!! I still haven't figured out how, but I must have short-circuited it somehow with my amateur soldering or something else. It turns out that (at least with the camera in manual focus) one can just continuously send that focus signal (i.e. hook the green wire to the black wire within the remote shutter cable and leave it connected) and that keeps the live view running. It doesn't need to happen at regular intervals, so no microcontroller is required. I was a little bit concerned about eating up too much of the camera's battery this way, since I'm trying to squeeze every bit of life I can out of my power supply. A multimeter showed the connection using 0.5 to 0.9 mA current. I found that I could put a 1 kilo-Ohm resistor in line between the wires and it still kept the camera alive, but it didn't work with a 1 mega-Ohm resistor. So I'm using the 1k, which makes the power draw basically negligible. Now my final setup is just the black wire connected to the green wire via a 1k resistor, with things appropriately insulated from each other and protected under heat shrink tubing. So simple. At least the microcontroller thing was fun to learn about.
  2. Thanks, Steve. I just got all the parts to try this and it works great.
  3. Thanks Steve. Great idea on the shutter release button. I just checked, and it does keep the view alive. This would be my first time using a microcontroller, except for a couple days tinkering with an Arduino. I'm good with programming so I'm sure I can figure it out, but I very much appreciate any advice from someone with more experience. I don't have the ability to have a custom PCB made. My initial search for tiny programmable microcontrollers turned up the Adafruit Trinket (http://www.adafruit.com/product/1501). Do you suppose that would do the trick? Do you know how I can find out what kind of signal the controller has to send to simulate a shutter half-press? I'm getting the video out through an HDMI cable with a right-angle connector going into the camera, and a bulkhead and 66-foot HDMI cable made by diveandsee.
  4. Your business looks really interesting, Bill. I'll send you an email with some more details about this issue and some other things I'm trying to figure out for our system. I'm not using the strobe connectors. I'm in Fairbanks, Alaska.
  5. I'm using a stereo pair of Nikon D5300 DSLRs in Ikelite housings for fisheries research in small, shallow (< 2 m) streams. I'm recording via HDMI to Atomos Ninja Blades, and I'm trying to figure out how to power the cameras for much longer than their usual battery life via the external power supply connector: http://www.nikonusa.com/en/Nikon-Products/Product/Power-Packs/EP-5A-Power-Supply-Connector.html and corresponding AC adapter http://www.nikonusa.com/en/Nikon-Products/Product/Power-Adapters/EH-5b-AC-Adapter.html I'd like to find a waterproof way to run power from a portable AC generator to the cameras, through the housings, to keep them on indefinitely. The waterproof part of the system needs to run at least 6 feet or so (to an extension cord above the water's surface). Does anyone make any sort of generic bulkhead I could adapt for this? Is it possible to do this with some sort of epoxy instead? Does anyone know any resources or webpages that would be helpful for figuring out how to do this? (On a related note, I also have to figure out how to circumvent the 30 minute "live view auto off" limitation. I'm currently thinking of using a tiny microcontroller and linear actuator to press the exposure compensation button inside the housing every 29 minutes, which prevents the auto off but does nothing else. I'd welcome other suggestions.)
  6. Thanks for the advice so far, everyone. A few clarifications: I don't need autofocus or zoom. I'll be looking for a fixed focus setting with maximum depth of field. I'll be setting the cameras in a fixed position, as close as possible to the spot the fish feeds (to avoid the turbidity issues seen in Julian D's image), and then hiding back on the bank and waiting for the fish to come back and resume feeding. In my past experience with juvenile Chinook salmon, the fish return to normal behavior within 5-10 minutes after the cameras are placed, and they treat the cameras like just another log in the water. I'm hoping I can get similar proximity to the larger Arctic grayling and dolly varden I'll be studying (in addition to Chinook) in this new project. I understand there's a tradeoff between field of view and size of the subject on screen, but I have to resolve that in favor of field of view because it's important to capture almost 100% of the fish's activity on both cameras. The angular size of the fish in both Julian and Tom's images would probably be adequate for what I'm doing. The closer the better, as long as I'm getting all the activity on screen. The HDMI monitors should be a big help in framing the shots optimally. Tom, your work is excellent. I'm surprised we haven't crossed paths before -- where are you based in Alaska? I'm in Fairbanks. Do you ever go to the state AFS meetings?
  7. I'm getting ready to purchase a pair of cameras for scientific video analysis of freshwater fish behavior. I've done as much reading as I can to put together a suitable system, and would appreciate the opinions of some professional underwater photographers about my plan and anything I might have overlooked. I'm going to use a stereo pair of video cameras, placed side-by-side on a crossbar on the bottom of a small, shallow, clear, freshwater stream, pointed at a drift-feeding fish (that is, a fish that maintains one semi-stationary position in the river and darts back and forth from there to intercept potential prey from the current). I need to be as close to the fish as possible, with the best sharpness possible, to resolve subtle details (for example, to see whether it "spit out" an item it just captured), yet I also need to have a wide enough view that almost all the fish's prey capture attempts are on-screen in both cameras. The fish will be anywhere from a few inches to ten feet from the cameras. I'll be using the video from the two cameras to make precise 3-D measurements of the fish's activity using software I wrote (http://www.vidsync.org), but I don't need feedback on the 3-D part of things, just maximizing image quality. To assure adequate camera placement and maximize recording quality, I need to run clean HDMI output from the cameras to external recorders, which I'll be observing from dry land up on the stream bank. I'll be setting the exposure/focus/etc and starting the recording manually, placing the cameras in the stream, and then watching the fish through the monitors on the bank to make sure the camera placement is good. One important difference between my requirements and those of most videographers is that I don't want the "cinematic" look -- I need every frame of the video to give the sharpest possible view of every detail, including moving objects (like the tiny drifting items the fish are pursuing). This means going for the fastest shutter speed I can (widest aperture and highest ISO) while maintaining adequate DoF for sharp focus throughout the virtual image and avoiding losing important details to high ISO noise. Artificial lighting is not possible, and I expect to work in a range of natural midday lighting on sunny/cloudy days or in moderate shade from trees. My plan is to use a pair of the following: Camera body: Nikon D5300 Lens: Samyang/Rokinon/other brands 8mm f/3.5 Aspherical Fisheye for Nikon AE Second choice lens: Nikon AF DX 10.5mm f/2.8G ED Fisheye Housing: Ikelite #6801.53, with hole drilled for HDMI bulkhead Housing port: Zen Underwater DP-230 9" Superdome Housing port spacer: I don't know HDMI monitor/recorder: Atomos Ninja Blade HDMI bulkhead and cable: DiveAndSee It makes me nervous that Ken Rockwell's review of the Samyang/Rokinon lens says it can focus up to 12" from the image plane, which will hopefully allow it to focus on parts of the virtual image all the way up to the 9" dome, but I'm not sure. The Nikon lens could definitely focus close enough, but it's more expensive and based on reviews I've read seems like its projection and optical performance aren't quite as good. Also I assume it would have a very slightly narrower field of view and smaller depth of field given the longer focal length. Also, I don't know what kind of spacer (if any) will be needed to approximately align the nodal points of the dome and the lens. Does anyone have experience with this combination? I'd appreciate your thoughts on the likely performance of this system, things I might be overlooking, options that might be better, etc. Thanks in advance for any help!
  8. I'm using an Ikelite housing for my Sony SR-12 and recently tried the W-20 wide angle lens, and had the same problems. (Actually, I have two identical setups, and they both have that problem.) I was wondering if it was just some issue with the camera being misaligned with the lens, but this ghosting idea makes a lot more sense. I had a lot of fogging and other issues, too, under demanding conditions, so I'm switching up to a Zen Underwater WAVP80 Wide Angle port, which totally replaces the glass port in the front of the Ikelite housing. It seems to be a lot sharper around the edges than the W-20 was, but it's a lot more expensive, too. I haven't tested it under conditons where ghosting reflections might occur yet.
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