Camera shutter won't open for night shots

I'm new, so forgive what I hope is a simple question.

Last night I tried to take pictures of lightning in the clouds. I put the camera on the tripod, set the mode to Shutter Priority, set the shutter to 2 seconds and hit the button. Nothing happened. The shutter wouldn't open. I set the exposure consecutively longer until I hit 30 seconds. Once or twice it would open, but generally no luck. I then set the mode to Manual, set the shutter to Bulb, went to the largest aperture, set the ISO to 3200 (!) and STILL couldn't get the shutter to open.

I don't mind getting a bad picture but I'm pretty unhappy the camera wouldn't let me take a picture at all!

I went back through my stack of books but couldn't find an answer. What am I missing?

Brian

Welcome to the site Brian!

Did the camera try to focus and not really lock in on anything? (the light comes on, it focuses in and out) Did you try setting the lens to manual focus?

jdeg said:

Did the camera try to focus and not really lock in on anything? (the light comes on, it focuses in and out) Did you try setting the lens to manual focus?

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I didn't try manual focus. I think you found the problem. I tried "Live View" and the square in the center was red, not green.

The camera won't take a shot until it is focused. Unfortunately that doesn't help when doing night shots. I tried some star shots the other night and found that putting it on "dynamic" focus range helps and so does manual focus. Play around with those 2 and I'm sure you'll get it to fire.

You know its not all that often that I can help in these forums, and it really annoys me that other people give the answer I would have before I get there!!! LOL
Boomer I have had a similar problem from time to time in dark conditions, usually catches me out for a few seconds. Welcome aboard

theregsy said:

You know its not all that often that I can help in these forums, and it really annoys me that other people give the answer I would have before I get there!!! LOL

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Mark, don't feel bad, bud. Happens to me all the time. A day late and a dollar short.

Best to practice with manual focus in the daytime first. I found that turning the focus ring all the way to to the stop is not really Infinite... It's somewhere beyond. I can only assume this extra movement is to allow the focus motor room for overshoot. It's even harder to set in the dark. I went out one day and found infinite focus and put a small piece of painters tape on lens and focus ring. Then I slit the tape along the edge of the focus ring. Now at night, I can use a flashlight and align the tape and I have the right focus. I use painters tape because it doesn't leave a residue if removed the next day.

I shoot lightning pictures, yes you have found your problem. It's your auto focus. In order for the auto focus to work it needs contrast. So with that said when your shooting at night and everything is black where is your auto focus going to find contrast? It's not so it going to keep looking till it finds some, now it not going to unlock your shutter button till is can find that contrast and tells itself it's in focus.

Everyone is right, the walk around to this is to switch into manual focus. One of the ways as pointed out here by Mike is to somehow during the day mark you lens where Infinite is. Mike is right turning the lens all the way past Infinite is not Infinite because the lens need to go past Infinite to get to Infinite.

Another way to set your lens is find Infinite focus in day light and switch your camera using the menu to manual focus. At night you can do the same thing just point your lens toward a light in the distance and in the menu switch to manual focus.

If you use a switch on your lens to switch to manual focus that will work too HOWEVER if you touch or move the focus ring on the camera it going to change and your not going to know it.

I found this out the hard way once. I set my Infinite focus at the house, put my camera in my bag and went out, took it out of the bag and set it up on a tripod and started shooting. Thought I didn't have to worry about focus because I set it at home and it was right on and everything looked fine through the view finder and live view. Downloaded my photo's and they were just a touch out of focus enough that anyone could see it. Hope this helps.

Thanks for everyone's feedback. It was really helpful. I tried star shots last night and they turned out pretty good for a first try. I think the manual infinite focus wasn't perfect, but I'll work on that. If you zoom in on the photos the stars were small lines, which I attribute to my light tripod, rickety deck, and my inability to stand still for 30 seconds. Again, all fixable.

I do have a question. I have the D3100 set to capture NEF+JPEG pictures. The save times for the images were very long, maybe 30+ seconds. Normally the save time is less than a second. I didn't think about it until later, when I wondered if it was due to the JPEG compression processing for the mostly shades of black image. The jpegs are about the same size as others I've taken during normal daylight photos.

Any thoughts?

For long exposures, the camera will do some noise reduction to prevent hot pixels. This takes time and is usual for long exposures. I don't think it has anything to do with the fact that you are saving Nefs and Jpegs at the same time.

That could depend on the sd card being used too. Is it at least a class 4 SDHC?

jdeg said:

That could depend on the sd card being used too. Is it at least a class 4 SDHC?

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Class 10, so it shouldn't be a problem.

You guys pointed me in the right direction and I found this in the manual under "noise reduction," "The time required for processing is roughly equal to the current shutter speed." Question answered!

I just tried a couple of nightshots of about half an hour each testing for star trails.

The wee light stayed lit for ages. I got a bit worried and actually switched the camera off. Class 6 SDHC.

Bilko said:

I just tried a couple of night shots of about half an hour each testing for star trails.

The wee light stayed lit for ages. I got a bit worried and actually switched the camera off. Class 6 SDHC.

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Depending on what filters you have switched on your camera, it's going to take a long time to write all the information to your card no matter what class you are using. Just because you may have a class 10 in your camera, doesn't necessarily mean your camera is going to write at a class 10 speed. Check your owner's manual and see what class and brand has been recommended for your camera.

I would expect a 30min exposure to take quite some time to write. If your "wee light" was on, your camera was still writing information to the card. Try it again and don't worry about something being wrong...let the camera do its work.

Thanks for the info.