After long exposure my camera took a long time recording the image. Does anyone know why? Is this normal?

Question

I have canon 400D. On a COLD night when I tried to take a picture of startrails, it's like the camera took the same amount of time recording the image as the length of the exposure. 30 minutes of exposure took about the same time saving it. Is this because of the cold? or the camera? Do you have similar experience? Thank you for your help!

Answer 1

It's because it is dark. The camera is just making sure it doesn't throw away something important. The darker the scene, the harder for the camera's software to process and adjust the picture.

Answer 2

Actually it is a long exposure noise reduction feature. After taking the picture it will take a closed shutter exposure to check the sensor for hotpixels and try to subtract them out when it processes the image. At very long exposures it may not be perfectly effective, but it will probably give you fewer hot pixel speckles than if you have it turned off.

I don't have a Canon 400D, but my Nikon D60 has the same kind of feature. It can probably be deselected from the menu.

Answer 3

Thankyoumaskedman is correct, the other two are not.



You can turn off the "long exposure noise reduction" in the menu system.



It may or may not actually help, you'd have to try two shots and see if it does any good for what you are doing.

Answer 4

it is quite normal.. the longer the exposure,the more information the camera gathers, the longer it takes to write to the card.