# Bulb (long exposure) night photography



## benjyman345 (Sep 26, 2006)

hello,
I want to take a long exposure photo of the night sky and stars so that you can see the movement of the stars in the photo. 

What is the best settings to use to achieve this?
Shutter time? (30mins, hour etc?)
Appeture?
What film? (100, 200, 400?)
What ISO should i set the camera to? (the same as the film or diffferent)

Anything else i should know or consider? 
(I have a remote shutter release button and lock and tripod)

thanks


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## Big Mike (Sep 26, 2006)

Welcome to the forum.

I haven't done much of this really long exposure stuff...but I seem to remember that low ISO film works best.  After a minute or so...it's actually more sensitive than faster film.  As for aperture, I don't think that matters too much...your DOF will be at infinity anyway.

I think that trial and error seemed to be the way in which people found the right exposure time...you may be able to find a starting point if you search around.

Good luck.


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## fightheheathens (Sep 26, 2006)

well....I like to use the Lowest ISO film possible.
like 50 or so
i would say for starters, go f/8 and then what ever you want for your shutter.
you would get good stuff after 30 min. but i personally have done 4+ hours with my camera.


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## JDP (Sep 26, 2006)

There's someone on this forum who has taken a LOT of space pictures, I can't remember who - but he did a wonderful job and has plenty of info on his site - I *hope* he sees this and lets us all know!


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## benjyman345 (Sep 26, 2006)

if I use 100 film should i leave the ISO setting at 100 or set it to a lower setting such as 50?

If i do change the ISO setting for one or two photos out of the roll of film do i need to notify the people processing the film?

thanks for all your responses so far.


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## astrostu (Sep 26, 2006)

I doubt I'm the person that JDP is referring to, but I've done a lot of astrophotography (and I have some star trails on my photosite in my signature).  The exposure time will depend upon how long you want the trails to be.  One hour will give you arcs that are 15° long (2 hrs will be 30°, 20 minutes will be 5°, etc.).

One issue in exposure length, however, is how much light pollution there is where you are.  Near a city, if you expose too long (even for a half hour), the sky is bright enough that it could wash out all of the stars.  Hence, really trial and error is the only way to really figure out what's best for you.


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## Big Mike (Sep 27, 2006)

benjyman345 said:
			
		

> if I use 100 film should i leave the ISO setting at 100 or set it to a lower setting such as 50?
> 
> If i do change the ISO setting for one or two photos out of the roll of film do i need to notify the people processing the film?
> 
> thanks for all your responses so far.



Don't worry about over-riding the ISO setting...just leave it the same as the film.


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## JDP (Sep 27, 2006)

astrostu said:
			
		

> I doubt I'm the person that JDP is referring to, but I've done a lot of astrophotography (and I have some star trails on my photosite in my signature).  The exposure time will depend upon how long you want the trails to be.  One hour will give you arcs that are 15° long (2 hrs will be 30°, 20 minutes will be 5°, etc.).
> 
> One issue in exposure length, however, is how much light pollution there is where you are.  Near a city, if you expose too long (even for a half hour), the sky is bright enough that it could wash out all of the stars.  Hence, really trial and error is the only way to really figure out what's best for you.



Wrong! It WAS you I was responding too! I have an odd love for space, though I let other people to the dirty work - you have some wonderful pictures Stu, you should be proud!


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## astrostu (Sep 27, 2006)

JDP said:
			
		

> Wrong! It WAS you I was responding too! I have an odd love for space, though I let other people to the dirty work - you have some wonderful pictures Stu, you should be proud!



Alright, I just figured it was someone else since I've only been on this forum for under a month ... but I'm glad that I'm already making a good impression - thanks! :blushing:


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## rmh159 (Sep 27, 2006)

How about a lens for these shots?  I have a 18 - 55mm... would that do it or would it work better with a telephoto?


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## astrostu (Sep 27, 2006)

rmh159 said:
			
		

> How about a lens for these shots?  I have a 18 - 55mm... would that do it or would it work better with a telephoto?



It depends upon the effect that you're going for, but I would think you'd want a pretty wide-angle lens in order to capture more stars.  All of the trails on my site were done with an 18 mm lens.


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## mortallis288 (Sep 27, 2006)

somone did this in the AP art class at school. they did it for an hour and a half exposure time, im not sure about the other settins


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## Torus34 (Sep 28, 2006)

It's not possible to give you exact information as the exposures you will use will depend on your night skies -- light pollution, haze, scattered light from the Moon, etc.

An ISO 100 film will do the job. Very grainy films do not give satisfactory images. Color slide film is best as there is no loss of contrast/sharpness in a printing process. Set lens at infinity and use one stop down from your widest aperture. Then try a range of time exposures. You will find, when you examine the results, that stars have different colors. Your first roll of film, if you take notes of the exposures, will tell you lots of things. Exposure is a trade-off. If you stop down, you can expose for a longer period of time before the background sky light will fog the image. This will provide longer star trails, but you'll lose the fainter stars. The choice of focal length, aperture and exposure time depends on just what sort of an image you're after. 

Learn your sky. Free download-able star maps are available from several sites. The 2.7 Meg Basic Program from this site will get the dog walked, and then some:

http://www.stargazing.net/astropc/download.html

Pick out stars of various magnitudes [1 through 4] as references. Some nights, all you can see are mag 2 and brighter. Other nights, mag 3 and brighter, etc. By knowing the magnitudes of a few reference stars, you can accurately judge the photo conditions. There's a nice series to be found in Ursa Minor and the stars are visible at all times of the year. For brighter stars, either Ursa Major or Cassiopeia are visible each night. Right now, Cygnus and Lyra are overhead in the early evening. All five are easily-recognizable constellations. 

Try including an Iridium satellite flash in a photo. They can be very bright -- up to mag -8. There are other satellites visible almost every night with various magnitudes. Here's a site with information on them -- just log onto it and enter your longitude and latitude. It will provide nightly predictions. [It's a freebee, too!]

http://heavens-above.com/

As a side note to anyone reading this: catching an Iridium flare or seeing the space station or shuttle is worth the effort, IMHO. About all you need is your longitude and latitude, a decent view of the night sky, a timepiece and the above site. The nature of satellite viewing is such that you don't even have to stay up late. Binoculars of not more than 7X are a nice aid.


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## astrostu (Sep 29, 2006)

Torus34 said:
			
		

> As a side note to anyone reading this: catching an Iridium flare or seeing the space station or shuttle is worth the effort, IMHO. About all you need is your longitude and latitude, a decent view of the night sky, a timepiece and the above site. The nature of satellite viewing is such that you don't even have to stay up late. Binoculars of not more than 7X are a nice aid.



True, but they're somewhat difficult if you have a lot of obstruction around your observing site.  And an *accurate* timepiece is necessary, since passes usually last only 1-3 minutes, and most watches/computer clocks will disagree up to 10 minutes from each other.

The space station is especially neat to see since it's usually quite bright (mag -3 when I saw it).

For those non-astro people here, the magnitude scale is really weird, where brighter objects are smaller numbers.  Naked eye at a dark site has a limiting magnitude around 6, cities closer to 2-3, with NYC closer to 0 or -1 (I saw one star, Sirius, when I was there last, and Sirius is the brightest star in the sky (other than the Sun)).  The Moon is usually around -12 by comparison, the Sun -26.  "Standard" bright stars, such as Vega, are defined to be 0, and the magnitude scale is a logarithmic scale where every _increase_ of 2.5 in magnitude is a _decrease_ of a factor of 10 in brightness.


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## Torus34 (Sep 29, 2006)

Quite correct about the time.  For US folks, you can check your timepiece here:

http://www.time.gov/


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## fmw (Sep 30, 2006)

What you want to do is very simple.  Mount the camera with slow film on a tripod, point it, choose a small aperture and open the shutter for as long as you like.

As long as no artificial light and no moon is in the frame you can get different effects with different exposure times.

Anything other than starlight, however, will quickly overexpose.


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## benjyman345 (Sep 30, 2006)

fmw said:
			
		

> choose a small aperture.
> 
> I thought i had to use a large aperture (small number)?


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## usayit (Sep 30, 2006)

small aperture for maximum depth of field but at the sacrifice of very slow shutter speeds which is not a problem since you will be using a tripod.

BTW.. for really long exposures... a very stable support is extremely important.  Even wind blowing at your camera can cause blurring.  May I suggest a bag full of rocks attached to your tripod to weigh it down.... removing the camera strap.. using Mirror lock up if available on your camera.... using a remote/timer.


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## astrostu (Oct 1, 2006)

usayit said:
			
		

> small aperture for maximum depth of field ...



Depth of field isn't important because everything you're looking at is at "infinity."


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## uberben (Oct 5, 2006)

Not sure if this applies to you at all...I shoot star trails with my 20d and 300D and have found that if I shoot a series of 30-40 minute shots and then layer them in photoshop that I get amazing results. This reduces the noise commonly found with long exposures.  

~Ben


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## astrostu (Oct 5, 2006)

uberben said:
			
		

> Not sure if this applies to you at all...I shoot star trails with my 20d and 300D and have found that if I shoot a series of 30-40 minute shots and then layer them in photoshop that I get amazing results. This reduces the noise commonly found with long exposures.
> 
> ~Ben



Not to say Ben's wrong, because theoretically this will work.  However, you have to be careful and make sure that you start the next exposure _immediately_ after you end one, otherwise you will get small gaps in your star trails (speaking from experience here).


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## W.Smith (Oct 12, 2006)

benjyman345 said:
			
		

> hello,
> I want to take a long exposure photo of the night sky and stars so that you can see the movement of the stars in the photo.
> 
> What is the best settings to use to achieve this?
> Shutter time? (30mins, hour etc?)


The length of the exposure determines the length of the arcs in degrees.


> Appeture?


f5.6 or f8.0.


> What film? (100, 200, 400?)


100 or 200


> What ISO should i set the camera to? (the same as the film or diffferent)


The same.


> Anything else i should know or consider?
> (I have a remote shutter release button and lock and tripod)


You can also use the selftimer: if you set it to long (ca. 10 sec.) the camera/tripod combo will have enough time to stop swaying/moving before the exposure starts.
Minimal movements are not visible in long exposure shots anyway.


> How about a lens for these shots? I have a 18 - 55mm... would that do it or would it work better with a telephoto


The exposure time will determine the length of the arcs IN DEGREES. The focal length will influence the size/visibility of the arcs in-photo. Wide angle lenses will give you many, many stars/arcs, but they'll be so small that it looks like the picture is a very grainy black. Better use a short telephoto lens, imo.

Dunno the exposure time of these Leonids, but looking at the arcs of the stars I'd guess between 5 and 10 minutes:


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## benjyman345 (Jan 4, 2007)

hello,

Would ISO 200, F5.6, and 30 minute exposure in a suburbarn area with the moon out (but not in the picture) be adequete exposure for star trails or would it be over exposed?........

thanks


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## CMan (Jan 4, 2007)

A suburban enviroment is not really a good place to take pictures like these, honestly. On a long exposure, light pollution will creep into the picture.


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## astrostu (Jan 4, 2007)

What CMan said.  And, unless the moon is a crescent, then even if it's not in your field, it will severely limit how many stars you can see.  The moon is over 10,000x brighter than any star (other than the Sun).



benjyman345 said:


> Would ISO 200, F5.6, and 30 minute exposure in a suburbarn area with the moon out (but not in the picture) be adequete exposure for star trails or would it be over exposed?........


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## RacePhoto (Jan 11, 2007)

benjyman345 said:


> hello,
> I want to take a long exposure photo of the night sky and stars so that you can see the movement of the stars in the photo.
> 
> What is the best settings to use to achieve this?
> ...



Wow some great answers and pictures.

Let me add to the confusion. The ISO setting on the camera if you are using FILM, is irrelevant. You aren't using metering, or camera shutter speeds, you are using a watch, so it doesn't matter.

I used to do some of this and many times, I'd just put the camera on a tripod and set it for 5.6 or f/8 (ground level objects in the pictures) and push in the cable and lock it. After a few minutes, I'd release it. (highly unscientific, I wish I could find my 20 year old notes) I liked using Fuji or Ecktachrome slide film, because of the colors being more bluish than print film.

Moonlight photo, not including the Moon, sky not the subject, but using it for illumination, same deal. Focus to infinity, pick a middle setting, open the shutter, pick a time... wait. Oh yes, of course bracket the pictures, and take notes.

Try 1 minute, 2 minutes, 5, 10... and see what happens. Do not shoot wide open or you get artifacts around the edges. Oval stars and the like.

The word I wanted to mention was receprocity. For the time the film is exposed it becomes less sensitive to light. What I'm getting at is not something that changes in the film, but how the emulsion responds to light over time. It's getting more of an exposure during the first minute, than during the second minute, for example. It's still a minute, but less is captured in each subsequent minute.

Since I've never tried this with digital, is there also the same exposure reciprocity?

I'd love to try to shoot Perceids like the picture above. What was the lens?

You folks have given me a new project for things to do at night when I'm camping. Usually I shoot during the day and haven't tried low light photography in years. We can see satellites going over all night long. Something else that wasn't as common "way back when".


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## ironsidephoto (Jan 12, 2007)

the best thing to do is just experiment.


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## burtharrris (Jan 12, 2007)

What star do you aim at to get that circular look?  Sirius?  is that in the little dipper constellation?


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## astrostu (Jan 12, 2007)

burtharrris said:


> What star do you aim at to get that circular look?  Sirius?  is that in the little dipper constellation?



Stars appear to rotate about Polaris, the star at the end of the Little Dipper (note, this star is pretty faint).  But Polaris is not ON  the north celestial pole, it is about 3/4° off of it, and so it, too, will etch out a very slight trail over a night.

That's if you are in the Northern Hemisphere.  If you are in the Southern Hemisphere, there is no "south pole star" that's visible to the naked eye.

This is only if you want the trails to be in a circle about a given point in space.  All stars will appear to move over the course of the night so you can still get trails without finding a star on either celestial pole.


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## RacePhoto (Jan 17, 2007)

astrostu said:


> Stars appear to rotate about Polaris, the star at the end of the Little Dipper (note, this star is pretty faint).  But Polaris is not ON  the north celestial pole, it is about 3/4° off of it, and so it, too, will etch out a very slight trail over a night.
> 
> That's if you are in the Northern Hemisphere.  If you are in the Southern Hemisphere, there is no "south pole star" that's visible to the naked eye.
> 
> This is only if you want the trails to be in a circle about a given point in space.  All stars will appear to move over the course of the night so you can still get trails without finding a star on either celestial pole.



I hate to see this thread die off, it's such a good one, with so many answers.

I kept thinking, 1 hour = 15 degrees, what's with that, and finally I punched in 360 / 24 = 15 (DOH!) 360 degrees divided by 24 hours = 15 degrees per hour. :thumbup:

I wanted to try this digital, but don't have a remote for the 10D. I do have old SLRs and a watch. :lmao: Why not?

This is something I'm going to be doing this Summer when I'm out in the country, away from city lights. Should be interesting.


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## burtharrris (Jan 17, 2007)

I've never seen stars like I did in Harlan, Kentucky.  You could actually see the Milky Way faintly across the sky.  I think I'm going there this summer, I'll have to try it.  New York City wrecks the sky at home: all night there's still an orange haze from the east.


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## outlier (Jan 24, 2007)

Shoot Polaris to get that interesting look with the stars forming a nice circle.  Find a star chart online if you need help finding it.


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## GilTphoto (Jan 25, 2007)

My recipe for star trails:

1. a night with no moon
2. clear sky far from any city. National parks are a good bet
3. sturdy tripod, cable release, fresh batteries.
4. 100 ASA slide film
5. aperature wide open
6. lock the shutter open, go to sleep
7. wake up before sunrise, close the shutter.

I have 2 star trails pics on my site, one 4 hrs, one 7 hrs.
Check the Blacklight and Misc images link. two images on bottom of page.

http://GilTphoto.com


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