Long Exposures & Camera Limitations

[benjyman345]

Hello,

I have an Olympus E410 DSLR and want to take very long exposures of the night sky to get star trails. My camera has a limitation of a maximum shutter speed of 8 minutes when set to bulb mode. I have bought a remote for my camera so I can lock the shutter open.

Seeing as I want an exposure longer than 8 minutes I thought I could take one shot after the other and combine them with software. Now the problem is after I take a long exposure shot on my camera it takes 5 minutes + for the image file to save and I can not take any photos until it finishes... Is there anyway around this so I can take a photo soonh after if not straight after the first shot???

Why does it take so long to save the file. The file size is much the same size as a normal photo and normally saves instantly???

Thanks heaps.

 

[Steph]

Why does it take so long to save the file. The file size is much the same size as a normal photo and normally saves instantly???

Thanks heaps.

This is because of the noise reduction feature of your camera. For long exposures the camera will produce a lot of noise due to the sensor warming up. To reduce the noise, the camera takes two pictures: your long exposure and a picture with the shutter closed for the same length of time. That way the second shot shows the noise generated by the long exposure and that can be susbtracted from the 1st shot. On most cameras that can be turned off but the results will be noisier images.