Time Exposures Greater Than 30 Seconds: How

Question

What I'm looking for may not exist but I thought I'd ask here first. I know product recommendations are kind of verboten, but I'm coming up empty when I look on the Google. The goal is to accomplish several disparate tasks (Canon 5DmIII):

• Time exposures in excess of 30 seconds
• Bracketed HDR exposures in groups greater than 3 (7 and 9?) at user-defined exposure variation (i.e., -3, -2, -1, -, +1, +2, +3)
• Exposures at preset intervals for a given duration (like, every 30 seconds for 6 hours)

I don't want to use my phone for this and there may not be a single simple device that fills the bill but it seemed these techniques are common enough that somebody would have come up with a commercial (not DIY) solution. Has anyone seen such a solution?

Answer 1

Your camera can take exposures that are longer than 30 seconds, this is called Bulb mode. In this mode the exposure lasts for as long as you keep the shutter button pressed. For this kind of photography you might want to use a remote shutter cable, so that you do not have to physically touch the camera and risk moving it during the exposure.

For your other requests, my recommendation is that you wait for Magic Lantern to become available on the Mark III. Magic Lantern is an add-on software that runs along side the Canon firmware and provides many additional features. At the time I'm writing this (October 2012) there is a public alpha release for the 5DmIII. Magic Lantern supports advanced bracketing with unlimited number of shots per bracketed set and also has a very flexible intervalometer module.

Answer 2

The Canon TC-80N3 Timer Remote Controller will provide items 1) and 3) of your question. 2) is more challenging, and I do not know of a solution

For item (3, Luminous Landscapes suggests:

A Special Technique

You would think that setting the TC-80N3 to be able to do a series of automated bracketed exposures would be straightforward, but it isn't. The trick is to set the camera itself to self timer mode (2 second is preferred to 10 second, if your camera model has it), and of course to auto bracketing. Then set the Interval on the TC-80N3 to how long you'd like the pauses to be between sets of exposures (say, 5 minutes). Next set Frames to the number of times that you'd like the series of bracketed exposures to be taken.

Note that mirror lock up can't be used if you use this method.

Answer 3

Cmason has indeed suggested the correct solution of using a timed remote controller (in bulb mode i might add) for points 1 and 3. I am inexperienced with HDR so i cannot assist with point two though unfortunately.

A word of warning on 30+ second exposures however (and this is based on experience with 7D's and 5D MKII's). If you set up a shot at ISO-100 and for say, 2-3 minutes, your image will generate a LOT of noise. This noise comes from the constant use of the sensor and I believe it is due to the heat that begins to build up. I'm unsure if extended periods of time (say several hours for example) will cause the sensor to fail completely however I would be reluctant to test that. It is rare to need to take exceptionally long exposures so i'd be curious to know what you are trying to achieve (and how long you're aiming to use it for).

I believe the 5DMKIII's have better noise reduction so it might not be so much of an issue but at some point it does effect all cameras.

Instead of spending $130+ bucks on a remote, check ebay for almost identical devices at a fraction of the cost...

Also, long exposures drain battery super quick!

Hope it all helps!