Still camera recommendation

Phil Pilgrim (PhiPi)

My robotics class needs a recommendation for a digital still camera with the following specs:

1. High resolution: 10M pixels or more.
2. Inexpensive underwater housing: to 1 meter only, though.
3. IR shutter release.
4. Normal (not wide-angle) lens. (IOW not a GoPro.)
5. Good sensitivity in low light.
6. Photos saved to SD or micro-SD card.
7. Economical. (We're really strapped for cash.)

We have to be able to identify sea stars at a depth of 2 meters from the sea surface in natural light from a slow-moving craft and classify the extent of their wasting disease.

Any and all ideas are welcome!

Thanks!
-Phil

xanadu

I think that Canon camera's CHDK http://chdk.wikia.com/wiki/CHDK is a great feature for a robot based still camera. I have a Canon S100 which I though was a good deal for $250. It is pretty light and also has GPS geotagging of images which could come in handy. You need a $40 battery replacement kit to use external power, but I think for stills the battery should be good for a lot of pics. Video isn't much, maybe 35 minutes at 1080.

You would have to add external circuitry to the camera's USB port and script CHDK to snap the shutter. The camera doesn't have an IR remote built in.

Edit: I just noticed the underwater housing part, that is another $250. Sounds like a waterproof camera may be cheaper. There are a lot of inexpensive waterproof cameras but I'm not sure about the IR port.

W9GFO

Both Canon and Nikon make waterproof still cameras. I have no experience with them. How big are the stars?

GoPros do have a "narrow" view option. I think a GoPro Hero 3 or 4 would meet all but #3 and #7 unless the stars were real small.

If this is meant to be attached to the boat and pictures snapped at regular intervals, then I think that you may be better off taking HD video than individual snapshots.

Can you mount the camera to a pole and lower it a meter or so into the water? If so then a GoPro should work great.

Phil Pilgrim (PhiPi)

xanadu,

Thanks for the input. I tried an inexpensive Chinese underwater camera. It wasn't bad, watertightness was superb, and it had an IR shutter release; but it had a wide-angle lens, and the image quality suffered. $250 just for a housing would break the bank, I'm afraid.

Rich,

Thanks for the suggestions.

I have a GoPro Hero 3 with a submersible housing. The still image quality is really poor, IMO. I was not aware that it has a "narrow" option, but I suspect this is not due to a mechanical zoom, but the result of confining the image to the center pixels and mathematically enlarging them. I've also noticed that the image sensor has a plethora of dead pixels (both black and white), futher compromising the image quality.

Regarding video, as opposed to still images: yes: video looks great as video. But when you freeze frame, you notice how much your eyes and brain have filled in details that do not really exist in the individual images. That's the reason that quality still images seem more appealing at first blush.

BTW, the IR shutter-release spec is to enable the camera to be housed separately from the other electronics without needing a thru-hull cable fitting. The idea is to trigger it with a powerful, down-facing, coded IR beam that relies on backscatter to reach the front of the camera.

-Phil

CuriousOne

#5 directly suggests DSLR/mirrorless camera with APS-C or larger sensor.

I had a similar task, so I boiught used Sony NEX5 on keh.com (w/o lens) for $133, and then bought some aftermarket lens and adapter on ebay for $20. Since I have CNC, making custom polycarbonate case was not that hard.

W9GFO

Phil Pilgrim (PhiPi) wrote: »

I was not aware that it has a "narrow" option, but I suspect this is not due to a mechanical zoom, but the result of confining the image to the center pixels and mathematically enlarging them.

The narrow option is for video, it does not enlarge the pixels but uses only the center pixels of the 4K sensor. Likewise the 7MP still option does the same while the 11MP uses the entire sensor.

You should be able to make your own housing pretty easily using PVC pipe and acrylic. I made one years ago that worked as deep as 230 ft.

Phil Pilgrim (PhiPi)

Rich,

Maybe I should give the GoPro another chance. 'Next nice day, I'll take it out in the kayak and snap some shots of the bottom.

Thanks,
-Phil

W9GFO

You can also find underwater camera bags for far less than $250. This one is $40.

Tor

I saw somebody with what looked like a perfectly ordinary small compact camera in a public outdoor bath. He said it was waterproof down to some depth I don't remember. But it looked just like a normal small Canon or Casio camera to me. No special housing as far as I could tell.

W9GFO

Another idea, use a clear pelican case. Only about $15, should be fine for the meager 1 meter depth requirement - actually rated for 1 meter submersion for 30 minutes.

http://www.amazon.com/Pelican-Micro-Snorkelers-Kayakers-clear/dp/B001CNNEXE

ajward

Interesting project Phil. I can't help with the camera, but I wanted to wish you luck.

Amanda

W9GFO

Phil Pilgrim (PhiPi) wrote: »

Regarding video, as opposed to still images: yes: video looks great as video. But when you freeze frame, you notice how much your eyes and brain have filled in details that do not really exist in the individual images.

Not sure I agree with that. When we were using aerial video to peer into eagles' nests looking for eggs it was about impossible to tell if or how many eggs there were using still images, but watching the video playback made the difference. Sort of like trying to see what's on the other side of a wood fence by looking through the gaps. Stand still and you can't see anything, move side to side and the brain can stitch together an accurate image.

LoopyByteloose

CANON will allow you to DIY an IR shutter release via its USB port. You do need the CHDK firmware. A BasicStamp or Propeller can easily decode the IR.

I have an SX-150 and have built my own shutter release for use with the CHDK. Acutally buying one will cost $30 USD or more and may not be what you desire. A DIY is less than $5 USD.

mindrobots

Phil, contact BH Photo Video in NY (bhphotovideo.com). They have any extensive line of underwater products and know their cameras. I bet if you explain what you need, they can come up with something. Most camera manufacturers seem to have some version of a waterproof compact camera but finding your feature set is a challenge unless you know all the products. There are also 3rd party remotes but knowing which works with what camera is another challenge.

I've always had good results with BH, if there is (still) a large camera store in Seattle, they could probably help too. REAL camera stores are getting hard to find. :0 (

Phil Pilgrim (PhiPi)

The CHDK stuff looks pretty interesting, and the Canon ELPH cameras are relatively inexpensive. I like the idea of using a hard case, such as the Pelican 1050. Thanks for all the suggestions! And I'll definitely be checking with B&H.

-Phil

LoopyByteloose

CHDK combined with locating a clearance sale of an older Canon might be optimal. CHDK usually has better support for the older cameras as the software has an established test base and support group.

I got an SX-150 that uses AA NiMH cells and it is quite delightful. The reviews did complain of the zoom failing to move, but it appears that the problem was simply due to not using NiMH batteries. It works horribly with alkaline AA cells. This also happened to be the last to support a NTSC interface... newer cameras are all a high density TV video interface, HDMI.

I love Canon for supporting so much hacking.... very affordable and open to creativity.