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Bulb Exposure
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Hi
With regard to long exposures, I want to try some night time star shots. Is there any special care I should take while using the bulb option for timing the shutter speed, ie is there a maximum time I should keep it open for? Am I likely to risk any damage to the shutter or sensor?
Thanks
Dwhen I’ve done this in the past I have wrapped the camera body in waterproofing, it shouldn’t damage the camera in any way but take a look at your manual just in case, if you don’t have manual check here you should find it http://www.pdfgeni.com/” onclick=”window.open(this.href);return false;
Something I might add is to use the eyepiece cover to prevent light from getting in through the eyepiece and changing exposure. It is said it does not do much difference at night, and I’ve personally shot 30second exposures with no covering, but longer exposures might be affected more, I don’t know.
Hope this helps!
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this is a cool shot but rather than bulb it is done with many exposures.
I got a cable release on ebay which is very handy for Bulb exposures. You can set it and walk away rather than stand there with your finger on the shutter release button.
Bulb is for any exposure that is longer than 30 seconds. So the main problem with bulb exposures is that you really should use a shutter release cable to keep the exposure ‘triggered’ if you dont have one of these you will have to stand there and hold down the shutter release button for how ever long you want which is just silly and will lead to lots of camera movement even on a tripod. Ebay is a good cheap place, you really dont need a decent branded one cause you dont need them to do much ;)
For start photos you will be able to get some decent shots with just a 30 second exposure. After 30 seconds you normally start getting the blurred light streaks as the earth rotates. So if you are wanting these streaks then the bulb exposure is one option. It is also possible to take a number of, lets say 30 second exposures and use some star stacking software to put them together. http://www.startrails.de/html/software.html The benefit of stacking is that you get less noise(normally). Depending on the camera you might have to manually trigger each shot or you might be able to set up some interval shooting to take a series of photos for you.
There is no risk with how long you can keep the shutter open for, the only limit is the battery since it has to physically hold the shutter open for this period of time. I remember that with some older cameras it was possible to get some artefacts or strange colours from the sensor getting warm/hot, this wont cause damage but just effects the image, but i dont think it is very common these days and im talking about on maybe 40 minutes + exposures.
One useful tip that I can give, is that if you are unsure of the exposure to use turn up the ISO to its MAX, 3200 or higer, set the aperture to its widest, F/3.5 or lower. and then experiment with the shutter speed to see which one ‘looks’ right. Ok I know the image will look terrible, but its just a test, which means you dont have to wait around as long to see if the longer exposure of 30 seconds + is right or wrong. – If that makes sense ;) And if it seems right, then you can work backwards. reduce the ISO to lets say, ISO 100 but then INCREASE the shutter speed by 5 stops, and do the same with the aperture. So that you have the exact same exposure, but now your shutter speed is longer.
But all long exposures are pure trial and error, so good luck ;)
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