The Term "Bulb"???????

[reg]

Sorry, reg, close but no cigar.
What you describe is the "T" mode (for "Time"). A setting you won't find on cameras younger than, say, 30 or 40 years.
In "B" mode (for "Bulb") you press the shutter release to open the shutter, and you keep it pressed down for the duration of the exposure. You release it again to close the shutter.

Good thing I described both, then, huh?

:roll:

 

[kdabbagh]

is there a link someone can share that explains how long to hold down the bulb depending on your aperture?

 

[reg]

^ That's not really possible.

 

[Garbz]

Indeed. This is what your light metre is for. Bulb has two purposes for me:

- Capturing self illuminating subjects like lightning or fireworks where the length of the shutter doesn't determine the brightness of the subject.
- Capturing scenes which require longer than 30second exposures.

The latter is hit and miss kdabbagh unless you have a light metre that works in such difficult conditions. I take a test shot at 30seconds and go from there. If it looks 2 stops under exposed I jump up to 2 minutes.

 

[Ejazzle]

how do you "focus" for shooting lightning?

 

[reg]

hyperfocal or infinity focus.

your choice.

 

[Ejazzle]

a whatson? whts hyperfocal?

 

[reg]

http://www.google.com/

 

[Ejazzle]

thanks. still dont get it. i'm dumb. no worries though!

 

[TamiyaGuy]

There's no way to tell how long to hold the shutter open in Bulb mode, because you might be shooting in bright daylight (but for the love of god, don't do that with bulb ) or complete darkness, it all depends on the situation.

Garbz, I'm sure you're right, but I read somewhere that DSLRs have a built-in failsafe that stops bulb exposures at 30 secs to stop the sensor overheating. If that's the case, what's the point of Bulb?

 

[Josh66]

Garbz, I'm sure you're right, but I read somewhere that DSLRs have a built-in failsafe that stops bulb exposures at 30 secs to stop the sensor overheating. If that's the case, what's the point of Bulb?

That's not the case (on no camera I've seen anyway). The longest exposure I've personally done (on digital) was around 15 minutes, but you could go as long as you want. I guess if you left it on too long the camera might just shut down...I don't know - never tried it before (don't plan on it either).

 

[TamiyaGuy]

Thanks, O|||||||O. I thought it was rubbish, I mean, if that was the case, then a Bulb mode would be pointless. I do agree with you, though, I should be careful if I try to do a long-time exposure. I have a dreadful habit of forgetting things...

 

[Garbz]

Actually it's not rubbish but not true either. No camera would blow the sensor in 30seconds (unless taking a photo during the day).

I have seen a canon 350D with a dead sensor. The exposure apparently went for 40 minutes. But different cameras have different breaking points. Before I saw this (while picking up my lens from a repair place) I had previously done a 1 hour exposure to test how star trails go on a digital camera. Well never again! The image was useless due to thermal bleeding and the number of dead pixels could probably be measured in percentages.

But the most alarming thing is my camera was HOT, and I mean very hot. The lens mount and the base of the camera both of which are metal was uncomfortable to touch. But you'd never get there in 30 seconds

If I had to hazard an educated guess I would say the 30second limit is to do with the digital light metre. I haven't seen a digital meter that voluntarily goes beyond 30 seconds (digital or film). Only the old ones with a mechanical readout that goes literally off the scale are known to be able to go for long exposures, but typically they get very non-linear too after a few minutes.

 

[AndrewG]

The term 'bulb' derives from the time when photographers used an air release for the shutter which was basically a rubber tube with a rubber bulb on the end; you attached it to your shutter release button, set the camera on 'B' and depressed the bulb which then depressed the shutter button for as long as you needed it.

 

[Helen B]

There are plenty of shutters that are still manufactured with the T setting, it's just that you guys don't use medium and large format cameras.

Best,
Helen