How does the bulb function work?

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GerryD

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How does the bulb function work on my camera? What is it for? :shrug:

I seen it this afternoon messing about with the camera. No idea what it means.
 
In t'olden days (well over 100 years ago) you took a flash photo by opening the shutter fully, then firing your bulb (a sort of light emitting thing, basically a bulb that blew up so was a once only affair) then closed your shutter afterwards

It worked because the film was so insensitive it didn't record anything for the extra time the shutter was open

Now we still have it for things like night-time fireworks - you press the shutter on bulb and it opens, you see a flash from the fireworks or two, then you close the shutter several seconds later - with luck you've got something

So basically, the shutter speed is as long as you have the shutter open

HTH?
 
taxi said:
How does the bulb function work on my camera? What is it for? :shrug:

I seen it this afternoon messing about with the camera. No idea what it means.
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Hi taxi, i think bulb is for very long exposures, im sure some will tell us more.:thumbs:
 
DiddyDave said:
In t'olden days (well over 100 years ago) you took a flash photo by opening the shutter fully, then firing your bulb (a sort of light emitting thing, basically a bulb that blew up so was a once only affair) then closed your shutter afterwards

It worked because the film was so insensitive it didn't record anything for the extra time the shutter was open

Now we still have it for things like night-time fireworks - you press the shutter on bulb and it opens, you see a flash from the fireworks or two, then you close the shutter several seconds later - with luck you've got something

So basically, the shutter speed is as long as you have the shutter open

HTH?
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Thanks Diddydave for the history lesson and instructions. :thumbs: So if I understand this correctly, the bulb function gives you control of the shutter speed, rather than using one of the presets.

Cheers
 
Yep - but it's only any use on 'long' exposures of usually several seconds - night-time or seaside motion of waves after/before the sun's about, etc.

Interestingly perhaps, modern flash sync speeds work on the same premise - only much faster, they are all double-exposures; but the open-shutter one is usually so under-exposed nothing records - unless you want it to - but that's another story:D
 
DiddyDave, I understood the first sentence perfectly, the second sentence went so far over my head I didn't even see it. :eek: Newbie to photography. As you said thats another story.
 
Okay - try this then...

Olden days - open shutter for 3 seconds, flash goes off for 1 second, close shutter - okay? That was on 'Bulb' setting

Modern cameras can open the shutter, trigger the flash, and close again in about 1/160th up to 1/500th of a second, the flash goes off in maybe 1/1000th of a second - so the principle is the same, it just all works much much quicker

Why it's a double-exposure is that the camera shutter is open trying to record an image even in 1/160th second, but often it's too dark for much or anything to record - so only the flash firing records an image as it's so much brighter - hence 2 exposures (a double-exposure) but only 1 records anything

Often in dim light a Wedding photographer will expose for the sunset (getting a nice sky but silhouetted bride & groom), but fire a flash too to light the couple correctly - hence using 2 exposures at the same time - thus a double-exposure where both exposures record = nice effect - try it outdoors in the early evening (night is too dark) and you'll see what I mean
 
Cheers DiddyDave, thats well explained and I understand it now :)

Thanks chouglez for the extra info
 
Google is my best friend [Now only if those 2 blokes can pass few of their billions to me] :lol::lol::lol:
 
WHOA!

There's so much misinformation in this thread! :D

The 'Bulb 'setting is an old fashioned term which has no place on a modern camera. The 'B' setting shouldn't be referred to as 'Bulb' at tall, it is commonly referred to as 'Brief' which is the best way to think about it if you need to call it anything other than 'B'.

On the 'B' setting, one press of the shutter button opens the shutter and it stays open as long as you keep your finger on the button. The best way to use it is with a lockable cable release so that you can lock the shutter open, leave the camera exposing the subject for as long as you wish, then close it using the release mechanism on the cable release.

The term 'Bulb' never had anything to do with flash bulbs , it was a reference to the remote release used in those days which was operated by squeezing a large rubber bulb which activated the mechanical shutter by air pressure.

Dave, the flash duration of a modern electronic flashgun is more in the order of 1/50,000th of a second to 1/500,000th of a second, considerably faster than any shutter speed available on our cameras.




 
I use studio flashes CT and they say nothing like those speeds. The manual on one still says 1/1000th sec as it's slowest up to 1/10,000th at its fastest - either way the principle is correct as they are all above the camera's synch speed and a double-exposure results

As for bulb settings, an old boy taught me such many many years ago - seemed to make sense at the time (and since), so if he talked bol**cks I stand corrected - he's dead now so I can't kick him

My current D2Xs has the B setting as 'Bulb' - so feel free to complain to Nikon - LOL
 
CT said:
WHOA!

There's so much misinformation in this thread! :D
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Well I got the irony CT so it wasn't totally lost :D
 
My current D2Xs has the B setting as 'Bulb
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As does the only camera I have within arms reach right now, a 5D. Which is odd as apart from anything else, it must be very hard to say if you're japenese. :shrug:
 
may make some see that as an insult, which is inappropriate from CT???
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Hell, I'd pay good money to see CT throw an insult on this board. :lol: I know the money is gonna stay safely in my pocket though. ;)
 
DiddyDave said:
I use studio flashes CT and they say nothing like those speeds. The manual on one still says 1/1000th sec as it's slowest up to 1/10,000th at its fastest - either way the principle is correct as they are all above the camera's synch speed and a double-exposure results

As for bulb settings, an old boy taught me such many many years ago - seemed to make sense at the time (and since), so if he talked bol**cks I stand corrected - he's dead now so I can't kick him

My current D2Xs has the B setting as 'Bulb' - so feel free to complain to Nikon - LOL
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LOL. Sorry mate, Cobra picked up on my dig at mho's mysterious thread. :D

Studio flashes are purely manual, so they will put out a consistent flash burst every time. The dedicated electronic guns which are fitted to modern cameras, will vary their output, depending on how close you are to the subject, the ISO set, and numerous other factors, like just being used for fill, and will produce incredibly brief speeds in the order of those I quoted. I know you know this Dave, I'm just stating it for those who may not, and flash is one of the things which causes people the most problems on these forums.

I'm not quite dead yet, but I used to get through loads of flashbulbs when I was a lad, and bloody awful things they were too - everyone should be made to use them for a while and then they'd appreciate the fantastic guns we get nowadays. ;)
 
I didn't mean he did - just some sensitive types (:cuckoo:) hereabouts may think he did

Anyway, here's a quote from a website explaining the fab modern SB600 Nikon flash unit, which I also have...

Flash duration (approx.):- 1/900 sec. at M1/1 (full) output; 1/1600 sec. at M1/2 output; 1/3400 sec. at M1/4 output; 1/6600 sec. at M1/8 output; 1/11100 sec. at M1/16 output; 1/20000 sec. at M1/32 output; 1/25000 sec. at M1/64 output

So I can only wonder at the amazing Canon gear CT uses - :D we Nikon types obviously pale by comparison :lol:

Seriously though, does Canon flash gear really work at between 1/50,000th - 1/500,000th of a sec? And if so, why? So much power so briefly must be absolutely blinding
 
No probs Dave, and honest mate, no insult intended, that's not my style at all. :wave:
 
Ahhhhhhhhhhhh NOW i understand what its for!!


well thats the main thing
 
Thinking about this 'Bulb' thing - for as far back as I can remember, it was represented just by 'B' on the shutter speed dial. When the shutter speed dial was replaced by LCD displays, I suppose 'B' didn't display that well and could easily be mistaken for 8, so 'bulb' seems to have been re-adopted around that time as the best way to display the setting. No wonder though that people scratch their heads! :D
 
aha
but Time also had a meaning
Bulb - shutter open all the time you hold the button
Time - one press to open - one press to close

all with a cable release, of course

and don't forget to lick the flashbulb to make sure you ge ta good contact!
 
True, forgot that one - but few coming into photography now would ever know about that 'Time' function and at least it'd be less confusing than 'Bulb'

Could always call it Guess - cos you never know what you're getting; or Tampax - for an awkward period of time with often unpleasant results
 
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