Tutorial Long exposures

Jaffster

Jaffster

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Jaffster submitted a new resource:

Long exposures - Long exposures

I seem to get alot of questions on Flickr regarding my long exposures. I thought that there would be no better place than here to write about them.

From the outside it looks easy, plonk the camera down on it's tripod, point it towards your subject then hold the shutter open with your remote shutter. Wrong.

I first got into Long exposures after seeing some of Edinburgh Garys work, he was the best - answered my questions via PM and really gave me some inspiration!

What you'll need:

-...
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Read more about this resource...
 
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"Bulb mode"? I think someone answered this before but what is bulb mode on the Sony A350 or A700?
 
BalSanghera said:
"Bulb mode"? I think someone answered this before but what is bulb mode on the Sony A350 or A700?
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Switching to Manual mode gives you control over both shutter speed and aperture, with a Bulb setting available for longer exposures. Exposure time in Bulb mode is determined by how long you hold down the Shutter button. There doesn't appear to be any limit to the duration of Bulb exposures, but it appears that the dark-frame subtraction will only compensate for exposures up to 30 seconds long.
 
Great tutorial, thank you. I have digested and will be trying out these tips! I have always tried using loads of filters and suddenly I realise this is not neccessary!

Rob
 
Very informative Jaffster, thanks for sharing.
 
Thanks Jaffster, will really have to have a go at this..... great shots :thumbs:


John
 
Thanks very much for the great pics and advice. I was looking at the Xmas lights recently and thinking of trying a couple of long exps to try to get static xmas lights with/without movement of car lights below. Your instructions came at just the right time. Any particular hints when using long exps with brightish lights in the frame? I have to wait for my tripod to arrive - so won't be until the w/end at earliest. Can't wait to try.
 
thanks very much for the tutorial...i'm sure it will be invaluable

at the risk of sounding stupid could anyone explain what "dark frame substraction" is and what does it compensate for

Maggie
 
Maggie... Dark Frame Subtraction... the camera takes a second shot, of exactly the same duration, but doesn't open the shutter. The dark frame is subtracted from the light frame to remove the noise etc captured. This subtracts, temperature related noise (on some cameras, for instance, the amplifier remains on, and this will show up as a blotch in one corner), hot and cold pixels etc. leaving a much cleaner and less noisy image.
 
Short, simple and easy to understand, even for a numpty like me. Thanks
 
Blimey, I wish I was as clever as my camera. Thanks for the de-numptying John.
 
:D... You're welcome... Astrophotography uses the concept of Darks, not with the in camera processing though (and Lights, Bias and Flats too... that's getting way way into the depths of image processing though... and a very dark art it is indeed...). So I've had plenty of opportunity to play with the concept... you can take your own dark frame, if you want to see what your cameras noise responses are like for a certain exposure length... just put your lens cap on (make sure ICNR is turned off) and shoot a frame. This will show up amp glow, hot and cold pixels etc.
 
a couple of other things i have found useful:
-if you dont have a remote, use a 2 second timer delay to avoid shake.
-take a test shot on a higher iso so you can meter the scene, eg 1 second at iso 3200 then if that proves right you can take the proper shot eg 30 seconds at iso 100, otherwise you have to wait an age for each 'experiment'.
 
A nice guide!

I love your examples as well!
 
Thanks for sharing your technique, I love#1
Must give it a go and get a remote.
Dave
 
very helpful guide
 
How did you know that the exposure should have been 58 seconds. I am a complete novice but when shooting in manual I choose the aperture and shutter speed so the meter on my camera is in the middle. Obviously I cant do this when its over 30 seconds.
 
Hysteria_UK said:
How did you know that the exposure should have been 58 seconds. I am a complete novice but when shooting in manual I choose the aperture and shutter speed so the meter on my camera is in the middle. Obviously I cant do this when its over 30 seconds.
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ah, but you can! if the meter says its a stop under at 30 seconds then you need 60! likewise if your @ 30 seconds @ ISO 200 but your camera is native 100ISO so you want 100 to get less noise (else it soon accumulates on a long exposure) then do 60 secs @ iso 100, same applies to lens aperture value etc.

same logic (ie reciprocity) as when i said:
B3R said:
-take a test shot on a higher iso so you can meter the scene, eg 1 second at iso 3200 then if that proves right you can take the proper shot eg 30 seconds at iso 100, otherwise you have to wait an age for each 'experiment'.
Click to expand...

also you dont have to be 100% accurate on the guess work on long exposures. 1 stop is a long time on a 1 minute exposure! when shooting film night shots I started using my digital compact to meter but half the time I just guessed as you get a couple of stops leeway on film.
 
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u8myufo said:
Exposure time in Bulb mode is determined by how long you hold down the Shutter button.
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That's why I love my MC-20 remote. I can set any duration exposure with it I want up to 99hrs, 99mins, 59 seconds. May seem like laziness or a luxury to some, but it definitely helps me out with longer exposures. If it's really that dark, I don't want to be pointing a flashlight at a stopwatch or risk my finger going numb and slacking off a shutter release before the exposure is done.

So I can meter the scene at f/1.8, f/2.8, f/4 or whatever the lens maxes out at, ISO3200 to get a reading from the camera and a rough idea, then go from there. From a basic quick shot that exposes it approximately how you want, you can start to work out what shutter speed you'd need to switch to ISO200 @ f/16, and then program that duration into the MC-20 (or laptop if you're able to shoot tethered and the software you're shooting allows you to enter a custom duration).

From there you can just experiment and allow a few more or less seconds each time til you have your desired result.

They don't make the MC-20 any more, but you can pick them up cheap used if you're a Nikon shooter. I believe the replacement model now is the MC-36.

u8myufo said:
There doesn't appear to be any limit to the duration of Bulb exposures, but it appears that the dark-frame subtraction will only compensate for exposures up to 30 seconds long.
Click to expand...
That might just be a Canon thing. I never had issues with it on my old Nikon D100s. Whatever duration exposure, that's what it did for the noise reduction. My D200 was good enough @ ISO100 that I never bothered turning on the NR for long exposures, but I only ever did up to about 30 seconds on those, so it wasn't that big a deal. I've not tried exposures longer than 15 seconds on the D300s yet.

Great shots and info Jaffster :)
 
B3R said:
ah, but you can! if the meter says its a stop under at 30 seconds then you need 60! likewise if your @ 30 seconds @ ISO 200 but your camera is native 100ISO so you want 100 to get less noise (else it soon accumulates on a long exposure) then do 60 secs @ iso 100, same applies to lens aperture value etc.

same logic (ie reciprocity) as when i said:


also you dont have to be 100% accurate on the guess work on long exposures. 1 stop is a long time on a 1 minute exposure! when shooting film night shots I started using my digital compact to meter but half the time I just guessed as you get a couple of stops leeway on film.
Click to expand...

Ahhhhhh.....thanks a lot. Another thing off my 'I dont know diddly about this subject' list. Time to go and play I think
 
u8myufo said:
There doesn't appear to be any limit to the duration of Bulb exposures, but it appears that the dark-frame subtraction will only compensate for exposures up to 30 seconds long.
Click to expand...
put the lens cap on, crank the aperture right down to make sure, and take your own dark frame, subtract it in photoshop (or UFRAW has a dark frame function) and your winning. I do that anyway to avoid having to wait for the dark frame after every shot (especially annoying if hte shot was a long one and is a dud)
 
Nice pictures and very helpful guide, thanks:thumbs:. I will be giving this a go.
 
Kaouthia said:
That's why I love my MC-20 remote. I can set any duration exposure with it I want up to 99hrs, 99mins, 59 seconds. May seem like laziness or a luxury to some, but it definitely helps me out with longer exposures. If it's really that dark, I don't want to be pointing a flashlight at a stopwatch or risk my finger going numb and slacking off a shutter release before the exposure is done.
QUOTE]

Definately added one to my wish list after playing with welding glass filter, trying to use my IR remote for 500 secs and losing the shutter half way, then having to wait the same length for the in camera noise reduction, very frustrating and as you say sore thumb. If this is the one I am thinking off, it also has interval timer so you can take star trails while sitting inside watching telly with a beer :naughty::thumbs:
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Very useful, thanks gonna start saving for a remote and a tripod now:D
 
Thanks for the advice :) I will be shopping for a remote flash trigger on fleabay in the next couple of days! Gone are the days that i'm stuck with my Point and Shoot could manage a whole 8 seconds of exposure time!
 
James306 said:
Thanks for the advice :) I will be shopping for a remote flash trigger on fleabay in the next couple of days! Gone are the days that i'm stuck with my Point and Shoot could manage a whole 8 seconds of exposure time!
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It's not a remote flash trigger you want for something like this it's a remote shutter release, although some flash triggers can be used as remote releases as well :bonk:

There are lots of different ones, some of which just act as a shutter release so you're limited to the max exposure time of your camera, others allow a bulb mode which basically opens the shutter for as long as you hold the button down for (or lock it, or have a built-in timer do it for you).

I've got a couple - basic IR remotes, a wired remote which can lock and a battery grip which has a built in timed shutter release and intervalometer.
 
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