Long exposure

[James whaley]

I have a 7D and I want to Learn how to take long exposures.

[ohata0]

You didn't say how "long" of a long exposure you wanted. The 7D can be set to go up to 30 sec in M or Tv.

if you don't have anything else (and want > 30s exposures), use bulb mode. For that to work set to B, press and hold the shutter button down as long as you want the shutter to be open.

If you want it to be a bit more automated, you can either get a programmable remote shutter, or if you have a laptop, use the usb cable and the EOS Utility for remote shooting.

Other things you'd probably need is a tripod. You probably won't take many great pics handholding a long exposure, unless that's the effect you really want.

Although it's good to use a remote shutter so that you're not introducing camera shake while taking the picture, if you're doing shots < 30s, you can get away with pressing the shutter button if you use the 10s timer (2s may not be enough time for the camera/tripod to settle down). If you have to take longer than 30s, a remote shutter is pretty much necessary (using the laptop as a remote shutter works too).

If you're going to do astronomy stuff with it, I would suggest turning OFF all NR functions, especially LONG Exposure NR. I suppose it will be ok if you're just going to take one shot and would like the NR done and you're not familiar with or not going to do any stacking.

Hope that helps...

[tonylong]

A good "starter kit" would be a good, sturdy tripod, one that will withstand at least light breezes, and then for starters a standard cable release, on that you can lock the shutter with in the cameras Bulb mode. This will both let you trigger the shutter without "fingering" the camera, and will give you full control of the timing without needing to hold down the shutter button. Of course, for shorter exposures, you can set the exposure for whatever time you like within 30 seconds. The cable release will again give you "hands-free" control of the shutter release.

As you go you can look at other options for the remote shutter release. One "step up" would be a cable release that has a battery-powered set up options for everything from a very long timed exposure to having a built-in inervalometer for time-lapse shooting or with shorter intervals for taking a series of shots for stacking/blending.

And then, there are wireless remote shutter triggers that can be nice because you can be at a distance, unlike the cable releases. In fact, if you get "serious" in all this a wireless remote will likely become "standard equipment"!

Beyond that, well, for astrophotography "the sky is the limit"!