Bulb Exposure


Status
Not open for further replies.
#1
Ok so this is a truly Newb-ish question but for some reason in all my days as a photography (maybe 2 years tops haha) I've yet to come across an explanation for this.

If you shoot using the Bulb Exposure setting, which if I'm correct lets you hold the shutter open for as long as you hold the shutter release in, how do you know when to release it to get the best exposure?:confused:
 

Goldenstars08

Senior Member
Nov 21, 2004
1,511
2
38
Singapore
#2
Rmh159 said:
If you shoot using the Bulb Exposure setting, which if I'm correct lets you hold the shutter open for as long as you hold the shutter release in, how do you know when to release it to get the best exposure?:confused:
If you are using a DSLR try exp for 5 second too bright try a shorter time or under try a longer exp .
Because every situation exp time is different...;)
 

student

Senior Member
Jul 26, 2004
3,078
0
0
#3
Rmh159 said:
If you shoot using the Bulb Exposure setting, which if I'm correct lets you hold the shutter open for as long as you hold the shutter release in, how do you know when to release it to get the best exposure?:confused:
Simple.

Just use a meter, usually a handheld meter to determine amount of light you need. And then based on the selection of aperture, the amount of time is calculated.

BTW, from my limited understanding, the "B" mode in most DSLRs do not allow one to keep the shutter open for a "long" time. My understanding is that the sensor generates too much heat during exposure, and the camera is therefore programmed to shut down after a while. I think probably about 30 secs +/-.

In comparison, film camera, and even better, cameras with no electronics, can have the shutter opened for hours!!

Correct me if I am wrong.
 

Snoweagle

Senior Member
Jan 26, 2005
14,002
0
0
Pasir Ris, Singapore
#4
Rmh159 said:
Ok so this is a truly Newb-ish question but for some reason in all my days as a photography (maybe 2 years tops haha) I've yet to come across an explanation for this.

If you shoot using the Bulb Exposure setting, which if I'm correct lets you hold the shutter open for as long as you hold the shutter release in, how do you know when to release it to get the best exposure?:confused:
Not very sure abt DSLRs but SLRs can expose until the battery runs flat. But usually an exposure (depending on what u're taking) around 1 min or so is enough, unless u want to make the night sky like daylight. :)
 

Dennis

Senior Member
Jan 24, 2002
3,881
0
0
Singapore
8dennis8.fotki.com
#5
I find the bulb mode not useful now (especially DSLR).
There is not much advantage in using super long exposure with DSLR unless you are trying to take circular star trails that requires hours of exposure. You could use the metered (now most metered to 30s) ones which is more than enough for normal photo.
Bulb on film is a different story because once you put in the film you can't change any other stuff, i.e. pushing the ISO etc in mid roll and bulb are mostly used for compensating reciprocity failure for film in which you can use the metered exposure and add the required timing using your watch etc.
 

Snoweagle

Senior Member
Jan 26, 2005
14,002
0
0
Pasir Ris, Singapore
#6
Sometimes a timer remote can be very useful for doing blub shots as u don't have to time yourself while exposing the shot.
 

yanyewkay

Senior Member
Sep 22, 2004
3,924
0
0
Cons digger.
#7
yes, you are wrong about the 30secs thing

the D70 and some other Nikon bodies can only open up to 30mins each "bulb" exposure ( dunno if this is still called true 'bulb mode').

Canon's 300D and some (if not all) models can hold for just about until the battery is flat. :D

if you use film you have to take note of reprocity (is this how you spell it?) I'm not an expert with flim but it is something that you have to expose the metered value longer than theory else it will turn out under exposed.

No experience with other brands.
 

yanyewkay

Senior Member
Sep 22, 2004
3,924
0
0
Cons digger.
#8
Snoweagle said:
Not very sure abt DSLRs but SLRs can expose until the battery runs flat. But usually an exposure (depending on what u're taking) around 1 min or so is enough, unless u want to make the night sky like daylight. :)
I don't think you can quite make night skies into daylight.. else there wun be anything called star trails and 1 minute is definitely not sufficient.


 

yanyewkay

Senior Member
Sep 22, 2004
3,924
0
0
Cons digger.
#9
Dennis said:
I find the bulb mode not useful now (especially DSLR).
There is not much advantage in using super long exposure with DSLR unless you are trying to take circular star trails that requires hours of exposure. You could use the metered (now most metered to 30s) ones which is more than enough for normal photo.
Bulb on film is a different story because once you put in the film you can't change any other stuff, i.e. pushing the ISO etc in mid roll and bulb are mostly used for compensating reciprocity failure for film in which you can use the metered exposure and add the required timing using your watch etc.
i still remember some CSers who love to go on 'bulbing' outings :bsmilie:
 

Snoweagle

Senior Member
Jan 26, 2005
14,002
0
0
Pasir Ris, Singapore
#10
yanyewkay said:
I don't think you can quite make night skies into daylight.. else there wun be anything called star trails and 1 minute is definitely not sufficient.


Yes...i've heard that people do expose up to 8 hrs for star trails. But also depend on ISO and aperture.

As for night sky turning into daylight it's true. I once used my previous SLR, set it to f/8 and expose it for a full 5mins. Results, the sky turned very very light and the green grass all can be seen. These are all done in pitch darkness with a clear sky.
 

yyD70S

Senior Member
Dec 25, 2005
2,454
0
0
Singapore
#11
Indeed it's true that DSLR can accommodate bulb exposure up to 30 minutes (and longer perhaps)... so I guess there's no reason to think that there'll be any sensor burnout.

Having said that, I won't volunteer trying consecutive 30-minutes exposure on a DSLR !!!

Interested to know if anyone has actually attempted that.
 

yanyewkay

Senior Member
Sep 22, 2004
3,924
0
0
Cons digger.
#12
yyD70S said:
Indeed it's true that DSLR can accommodate bulb exposure up to 30 minutes (and longer perhaps)... so I guess there's no reason to think that there'll be any sensor burnout.

Having said that, I won't volunteer trying consecutive 30-minutes exposure on a DSLR !!!

Interested to know if anyone has actually attempted that.
read my post again.

to summarise again:
D70 only has 30minutes exposure maximum, i've done that already
and I've done continuous 30mins exposure and posted a picture which says 4830seconds exposure which works out to be 80+ mins.

the sensor did not burn out and the D70 I know which did this multiple long exposure is still well and alive. It is still under warranty.

The Canon 300D has unlimited bulb mode which will only stop capturing when the battery runs out.

Snoweagle said:
As for night sky turning into daylight it's true. I once used my previous SLR, set it to f/8 and expose it for a full 5mins. Results, the sky turned very very light and the green grass all can be seen. These are all done in pitch darkness with a clear sky.
with only 5min in pitch darkness?
 

Snoweagle

Senior Member
Jan 26, 2005
14,002
0
0
Pasir Ris, Singapore
#14
yanyewkay said:
read my post again.

to summarise again:
D70 only has 30minutes exposure maximum, i've done that already
and I've done continuous 30mins exposure and posted a picture which says 4830seconds exposure which works out to be 80+ mins.

the sensor did not burn out and the D70 I know which did this multiple long exposure is still well and alive. It is still under warranty.

The Canon 300D has unlimited bulb mode which will only stop capturing when the battery runs out.

with only 5min in pitch darkness?
Yes...maybe it's becos i was using ASA400 film bah...
 

student

Senior Member
Jul 26, 2004
3,078
0
0
#15
yanyewkay said:
yes, you are wrong about the 30secs thing

the D70 and some other Nikon bodies can only open up to 30mins each "bulb" exposure ( dunno if this is still called true 'bulb mode').

Canon's 300D and some (if not all) models can hold for just about until the battery is flat. :D

if you use film you have to take note of reprocity (is this how you spell it?) I'm not an expert with flim but it is something that you have to expose the metered value longer than theory else it will turn out under exposed.

No experience with other brands.
Thanking you for pointing that out.

I had first heard of the exposure limit of 30 secs at a Leica seminar when Leica introduced the digital back for the R. They do not recommend exposure of more than 30 seconds citing heat as the problem.

I had since checked the web, and indeed the D70 can take exposure of up to 30 minutes. This is only for my information. But there are things which are not clear to me.

Is the 30 minutes exposure continuous? Or is it repeated exposures of a smaller quantum? I ask this because in Thom Hogan's report, he said that he did not expose for more than 1 minute because of unacceptable noise.
 

yanyewkay

Senior Member
Sep 22, 2004
3,924
0
0
Cons digger.
#19
student said:
Thanking you for pointing that out.

I had first heard of the exposure limit of 30 secs at a Leica seminar when Leica introduced the digital back for the R. They do not recommend exposure of more than 30 seconds citing heat as the problem.

I had since checked the web, and indeed the D70 can take exposure of up to 30 minutes. This is only for my information. But there are things which are not clear to me.

Is the 30 minutes exposure continuous? Or is it repeated exposures of a smaller quantum? I ask this because in Thom Hogan's report, he said that he did not expose for more than 1 minute because of unacceptable noise.
i do not really know if the camera has internal processing that chops up the 30mins into smaller time frames but the end result is a single file with 30min worth of exposure. This means that I had to find a means of holding the shutter button down (by means of diy "button presser") I set to low ISO (200 IIRC).

Erm.. am I answering your question?
 

lsisaxon

Senior Member
Nov 29, 2004
11,941
0
0
#20
yanyewkay said:
i do not really know if the camera has internal processing that chops up the 30mins into smaller time frames but the end result is a single file with 30min worth of exposure. This means that I had to find a means of holding the shutter button down (by means of diy "button presser") I set to low ISO (200 IIRC).

Erm.. am I answering your question?
No, I don't think the exposure is split up. You don't have to use a button pusher with D70/D70s, you need the IR remote control, when you set to the RC mode, the B-mode becomes T-mode, push once to open, push again to close. Care need to be taken not to fog your exposure with the IR beam.
 

Status
Not open for further replies.
Top Bottom