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Exposure at night for timelapse?


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#1 Hunter Hampton

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Posted 23 November 2008 - 11:58 AM

I am planning on doing some night timelapses of Portland and the night sky from about 15 miles away on a hill. The city isn't incredibly bright but there is a nice little golden glow and it carries into the clouds. The trouble I am having is my meter (L-758) wont give me any stop reading even when I set it to 30 minute exposure (on spot or incident), I have done night timelapses digitally and I know I can "see" the city and the night sky, but how can I get a decent exposure on film? Any precautions I should take? Thanks.
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#2 David Rakoczy

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Posted 23 November 2008 - 12:03 PM

You absolutely need an accurate Spot meter. It is a must. Your Spot reading is what you need.

I just shot a bunch on Vivid 160 using up to 15 second exposures and looking back I could have used a much slower stock. Next time I will.

1. What format are you shooting?

2. Camera?

3. What Intervalomater?
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#3 Patrick Neary

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Posted 23 November 2008 - 12:51 PM

Hi-

Another good tool is the "Black Cat" exposure guide (Blue Moon over in St. Johns has them) or there are a few online night/time lapse exposure guides as well that tend to be very accurate even though their method, kind of like the old "cloudy bright" picture guides, seems simple and archaic. The thing about longer time exposures is that you can get sloppier as the exposures get longer, in that 1 second more or less in a 30 second exposure isn't going to have the same impact as plus or minus 1/2 a second in a 1 sec. exposure!

Remember to add any reciprocity correction if it's called for.
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#4 John Brawley

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Posted 23 November 2008 - 04:44 PM

I am planning on doing some night timelapses of Portland and the night sky from about 15 miles away on a hill. The city isn't incredibly bright but there is a nice little golden glow and it carries into the clouds. The trouble I am having is my meter (L-758) wont give me any stop reading even when I set it to 30 minute exposure (on spot or incident), I have done night timelapses digitally and I know I can "see" the city and the night sky, but how can I get a decent exposure on film? Any precautions I should take? Thanks.



Which camera are you using ? What time options do you have with your camera setup ? Do you want to see stars or just the skyline ?

Lot's of things will affect how much you see. Clouds can act like giant bounce sources too.

Point sources like street lights will burn out. Have a look at this clip here IN the last seconds of the clip you'll see some night timelapse. It's hard with the compression, but the idea was to see stars moving above the city. These were 30 second exposures @ T2.8 using vision 2 500T

jb
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#5 Hunter Hampton

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Posted 23 November 2008 - 08:11 PM

Thanks for the example. (That film freaked me out!)

I am using an aaton a-minima with its built-in intervalmeter (I think the exposure is adjustable from 1/4sec to 255 seconds in that mode). I would like to see the night sky and stars if possible. There are also many planes coming and going and it would be great to get some of those swimming around. Is there a good staring point similar to the sunny16 rule?

Thanks.
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#6 John Brawley

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Posted 23 November 2008 - 09:14 PM

Thanks for the example. (That film freaked me out!)

I am using an aaton a-minima with its built-in intervalmeter (I think the exposure is adjustable from 1/4sec to 255 seconds in that mode). I would like to see the night sky and stars if possible. There are also many planes coming and going and it would be great to get some of those swimming around. Is there a good staring point similar to the sunny16 rule?

Thanks.



Hi Hunter and thanks for the kind words.

If you want stars and you're shooting 500T then I can't see that you'll have anything less than 30 second exposure times.

Testing is a good idea though, and the great thing with timelapse is that you never end up shooting more than a few feet of film so it's always cheap in terms of stock.

Reciprocity will mean that the difference between 10 seconds and 30 seconds won't be much, but I've found that 30 seconds to be good for stars.

I think you'll find with planes though that they will move a fair distance through each frame within that 30 seconds, (1/4 second interval) so they will read as streaks depending on how far you're away from their flight path. I found I can often pick up planes (at cruising altitude) and satellites with 30 seconds exposure times.

The moon will also make a big difference to your exposures. Many of the tx shots in the film you watched were shot with a waning or no moon. The moon will however bring out a lot of exposure detail.

Also, don't forget to take a external batteries, preferably with an in-line voltage indicator and a Y splitter so you can cascade your batteries. With the Aaton, i think when you *hold* the shutter open you're burning battery.

jb
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#7 Hunter Hampton

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Posted 23 November 2008 - 10:24 PM

John- The b-roll you captured was excellent- and then the content freaked me out! (I guess that was the complement) :lol:

Maybe I will just give it a try and see how it turns out. Thanks for everyone's tips!
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#8 Anthony Schilling

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Posted 24 November 2008 - 08:23 PM

I had excellent results with stars in a full moon sky on 64T with 30 sec exposures. Tried it again with a dark sky and a little under. I used this- http://joeorman.shut...estwilight.html
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#9 Hunter Hampton

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Posted 24 November 2008 - 10:25 PM

Thanks Anthony, Thats exactly what I was looking for.
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