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Choose a way to make your camera take pictures continuously

by liz |

Reposted from https://publiclab.org/wiki/balloon-mapping-materials

Easiest:

Most complex -- difficult to set up, but perhaps more stable:

  • Use a Canon camera and the CHDK hacked firmware to trigger the camera at longer intervals (check compatibility on the CHDK website). This can save battery and memory for longer flights.

Browse all ways to trigger a camera remotely:

Adjust camera settings

  • Set everything on AUTO.
    • Why? Some grassroots mappers finesse manual settings based on how cloudy it is, etc, but I've had a few flights where the sun broke free of the cloud cover and overexposed my photos, so I tend to leave everything on auto -- full resolution, S quality (super, or minimal compression).
  • Take a first picture of the horizon to set the contrast and focal length.
  • OPTIONAL: Consider turning off the LCD to save battery, weighing the fact that it will then become hard to confirm that the camera is actually continuously shooting. It's unclear if leaving the "click" sound on saves battery vs. using the LCD, but with AA batteries it really hasn't been a problem... you run out of memory first.

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4 Comments

There are a few misleading things about these suggestions.

The "Easiest" approach to interval shooting might be to use a camera with that feature built in, e.g., the Mobius Actioncam or many other actioncam type cameras.

Using CHDK requires some attention, but "Most complex -- difficult to set up" does not do it justice. It can be very easy to install using STICK, and the rewards in photo quality will be worthwhile for many users trying to capture good aerial photos.

The advice to "Set everything on auto" is very misleading if you are using continuous mode and mashing the shutter button. When shooting a PowerShot in continuous mode, the focus and exposure for all the photos are the same as the first photo taken when the shutter button was depressed. I don't think automatic adjustments are made as subsequent photos are taken.

I'm not sure the phrase "set the contrast" applies here. The term "memory" is used here to refer to storage (on the SD card).

Chris


I have exclusively used the rubber band on a knot method in everything I have ever done that needed multiple images. Its simple and works but data can build up fast. Its perfect for those who don't have a camera with a specific function or don't want to change firmware.


I agree that the rubber band trick is a very clever hack and a critical way to lower the barriers to entry to remote interval shooting. This research note is apparently intended for those new to aerial photography, so it is very appropriate to include this technique.

It might also be appropriate to be open with those new users about the greater implications of deciding to use the technique. The material requirements are minimal: 1) a camera with continuous shooting feature, 2) a rubber band, 3) a lumpy thing.

The less friendly aspects of the technique include:

  1. it's not that easy to know whether a particular camera has a continuous shooting feature,
  2. continuous shooting on PowerShots does not work in "Auto" mode,
  3. focus, shutter speed, and aperture are determined by the camera on the initial shutter press and repeated for every subsequent shot,
  4. there is no way to ensure that a high shutter speed will be chosen by the camera,
  5. the interval between photos is about one second, so 5 or 10 times more photos are taken than are typically needed,
  6. at one photo per second, a 4GB SD card will fill up in about 20 minutes,
  7. there is a free alternative that eliminates all of these issues.

So some practice is required to get the camera settings correct and to ensure that the first photo taken sets the focus and exposure appropriately. There is no way to ensure that the shutter speed will be fast enough to minimize motion blur. Lots of redundant photos will be captured, so lots of photo sorting will be required after the flight.

If you use the continuous shooting feature on PowerShots with the standard Auto, P, Tv, Av, and M modes, you should be aware how those modes will affect the exposure decisions made by the camera when the shutter button is first pressed. The differences could be dramatic.

There are also issues involved with using CHDK. These should be described so people can make an informed decision.

Chris


I agree with Chris on many of these points. CHDK is great to have, and STICK has made things much better. a direct link to STICK would help: http://www.zenoshrdlu.com/stick/stick.html


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