# Photographing at night.  Star trails?!?  Lightening!?!?



## D-B-J (Apr 19, 2010)

So i read that on some dslr's, by leaviing the shutter open for say, forty five minutes, can overheat the sensor.  I have a nikon d200.  My question is, how long can i safely leave the sensor open.  Or, should i just set it up with automatic exposure at 5 second intervals, with a 30 second exposure each for a total of the forty five minutes?? 

What is the best idea?

Also, as a side note, i want to be able to take the longer exposures of lighting so i can get multiple ones on one exposure.  If i get the cord where i can lock the shutter open, how long can i expose it safely.


So basically, how long can i leave the shutter open without overheating it, 
And if i set it at 30 second exposures, how long should i leave inbetween for cooling?!!??!

Thanks in advance!!


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## Big Mike (Apr 19, 2010)

Long story => short.  Don't worry about it.  Your sensor (in all likelihood) will not overheat...especially with night photography.


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## D-B-J (Apr 19, 2010)

Haha, i am just worried about it.  Because if it goes, i, as a teenager, will not have the money to fix it. hahaha.


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## TheSolicitor (Apr 19, 2010)

I've done hours after hours of 30 second exposures trying to get it right, and I've never had an issue overheating my D5000, so I wouldn't worry too much.  You're showing good responsibility by worrying, but in this case it's very much like a rocking chair, and will feel good while you're doing it, but won't get you anywhere.


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## Phranquey (Apr 19, 2010)

TheSolicitor said:


> I've done hours after hours of 30 second exposures trying to get it right, and I've never had an issue overheating my D5000, so I wouldn't worry too much. You're showing good responsibility by worrying, but in this case it's very much like a rocking chair, and will feel good while you're doing it, but won't get you anywhere.


 
Same here.  My average exposure time when storm chasing is about 20-30 seconds, and I have done this back-to-back for hours.  If you are in a cooler environment like night-time, I think the bigger worry with longer exposures would be excessive digital noise.


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## D-B-J (Apr 19, 2010)

Thanks guys.  I just wanted to make sure.  Can anyone suggest good settings for lightening in the pitch black?


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## Phranquey (Apr 19, 2010)

D-B-J said:


> Thanks guys. I just wanted to make sure. Can anyone suggest good settings for lightening in the pitch black?


 
For pitch black, I will usually shoot f/8 to f/11 at about 20-30 seconds, chimp to make sure I'm not overexposing any ambient light in the area, and make any adjustments as required. If you don't get any lightning in the shot, it should still be a pretty dark exposure, as you want the bolts to be your "flash" to light up the foreground.
The hardest thing about very dark conditions is getting your focus correct on distant objects like tree lines or structures. Just setting the lens on infinity will usually not work. I will carry a high power spot-light which will (most of the time) give me enough illumination to focus on something in the distance.

EDIT: Thread of mine from a couple years ago.... Scroll down to post #15 for the "How to"

http://www.thephotoforum.com/forum/landscape-cityscape/114461-little-lightning-anyone.html


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## Big (Apr 19, 2010)

Phranquey said:


> Just setting the lens on infinity will usually not work.


I wish I knew this before I just did my star trail for an hour! :blushing:


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## Sw1tchFX (Apr 19, 2010)

gimme a sec.


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## Sw1tchFX (Apr 19, 2010)

If you want really good star trails, you have to get far out of the city.
I go up to Mt. Hood do do star trails, it's 60 miles away, and with no clouds i still get light pollution from portland.


Also, you need to be patient. I know it's exciting, but unless your exposure is going to be more than an hour, you should be shooting at ISO 100 or ISO 200, especially on the D200, i can get away with 400-800 on my 700. At 800, the sensor's too amplified and you'll be getting more noise than you need, and the trails are less dramatic because it's a shorter time.



The best way to do it digitally i've found is this:

Put the camera on a tripod with manual expsoure and Kelvin WB, duh.

compose the picture and focus, duh.

If you have a camera that can do it, use contrast detect AF in live view. If you have a lens like the 24 1.4 or a 50 1.4, you can set the lens to f/1.4, and use Contrast AF in Live View to focus on a bright star, if it doesn't catch,  which it usually does for me, you can manually focus. Once you've done that, flip the lens to MF so it won't try and reaquire. Reason I do this is so that I know focus is perfect beyond shadow of a doubt.

Than set your WB to something cool, i usually start at 2500 and go up from there if needed.

Crank the ISO to 25600, you'll have to use 3200 (Hi 1).

Set your shutter speed between 5-30 seconds.

I usually leave the aperture close to wide open.

Now the first shot's going to look like sh*t, but that's ok. We just want to get our ballpark exposure without waiting 15 minutes, just to find out we got it wrong.



So here's a shot of mine, the initial exposure was ISO 25600, 4 seconds, f/2:






It's about a stop dark, so we'll compensate for that and double the exposure. But it's in the ballpark 

So now that we have our base exposure of 8 seconds ISO 25k, f/2, now we just have to crunch the numbers down to the same exposure at ISO 200ish and stopped down a little more!

Easy.

about 32 minutes, ISO 200, f/2.8. Rack it off:







And once you figure out this system, you'll be shooting pictures about 10 minutes after you put your tripod legs down. 
Really can't beat it.

Also, since the D200 is a little noisy, you'll need to use Long Exp. Noise Reduction. bummer about that is that it doubles your exposure times. SO that 15 minute long exposure will take 30 minutes.

I know the D200 doesn't have that great of battery life, i'm not sure how long it will last. You might only be able to do up to 30 minutes if Long Exp. NR is on. 



So, to put it in perspective,
Just the other day, went up to white river. Hiked down to the river, composed, racked off a shot at ISO 25600, 30 seconds:





PERFECT! Nailed it right on, so now all we have to do is some basic 3rd grade arithmetic and do the same thing at ISO400, f/5.6, 1 hour.






Once you do it a few times, night photography is easy photography.


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## Big (Apr 19, 2010)

^^^ Damn... amazing... Thanks!


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## TheSolicitor (Apr 20, 2010)

Switch, thanks!  That's awesome!!!


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## altitude604 (Apr 20, 2010)

awesome!!!

i'm going to have to try that now.


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## Dykstra (Apr 21, 2010)

Thanks for that, Switch. Awesome. I'll have to use that from now on.

Another thing to think about DBJ is temperature. Obviously the lower the temperature, the less likely any issues with overheating are to occur.


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## gpardo64 (Apr 21, 2010)

Amazing shots. Thx for the info.


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## twostep376 (Apr 21, 2010)

OK. So....I am embarrassed to ask this question. 

How do you do these calculations. :blushing:

From what I can tell...its not a simple ratio...right?


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## Garbz (Apr 22, 2010)

Every time you half the ISO, double the shutter speed. Don't even worry about the maths, just count the number of times you click the scroll wheel on the camera for the ISO setting, and replicate the opposite direction on the shutter speed


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## D-B-J (Apr 22, 2010)

Some flawless shots switch.  Thanks for the tips and advice everyone.  I ordered a remote shutter release from amazon the other day, so once it comes in, ill give it a test in my backyard for now.  I know, i should do it in a lightpollution free area, but i should test it out first.  

Thanks all!


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## jrabold (Sep 7, 2011)

THANK YOU SWITCH FOR SOLVING THIS ONE FOR ME TOO!!!!!


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## Bram (Sep 11, 2011)

Those photos are legit! I've done a 14 minute exposure of my living oom and outlined everythign with an LED flashlight. Looked pretty sick. I want to give this a try though.


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## robertandrewphoto (Sep 11, 2011)

Just for ease of mind DBJ, I have taken a 45 minute picture with my d5000. I'm 19 now. Still works great 2 years after that long and boring exposure


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