Camera question

[Mildlyamused]

I have a digital rebel that I bought a few years ago and was wondering about one particular feature. One of the features is to let the shutter be continously open for up to 30 secs which can be useful if you want a high quality picture and or a "smear" effect. But as I was thinking of this feature, I recall a coversation I had with some one a while back about cameras stating how analog cameras are better because of the fact that you can have the shutter open for hours if you want to take pictures of lightening. They also mentioned that if you were to keep the shutter on for too long in the day time that it would become over exposed so now I ask, why doesn't my camera become "over exposed" if I leave the shutter open for 30secs?

 

[GTaudiophile]

Originally posted by: Mildlyamused
I have a digital rebel that I bought a few years ago and was wondering about one particular feature. One of the features is to let the shutter be continously open for up to 30 secs which can be useful if you want a high quality picture and or a "smear" effect. But as I was thinking of this feature, I recall a coversation I had with some one a while back about cameras stating how analog cameras are better because of the fact that you can have the shutter open for hours if you want to take pictures of lightening. They also mentioned that if you were to keep the shutter on for too long in the day time that it would become over exposed so now I ask, why doesn't my camera become "over exposed" if I leave the shutter open for 30secs?

You might be confusing shutter speed with mirror lock up? And you may not overexpose if you're shooting in the dark with low ISO and high aperature.

But you might want to ask over at DPreview.com.

 

[Anubis]

i can set up a shot where i expose for 30 seconds and get pure black or pure white, or anything inbetween, it depends on what you are shooting


ive done 2 min exposures with my D70 and had them come out fine, with DSLRs you run the risk of hot pixels at longer lengths tho, doesnt happen with film, longest film exposure ive done in recent memory was 48 minutes, came out perfect as well, shot it at f/64

if you have a more specific question about this ill be glad to answer it