long exposure

[daveat22]

I was using a big stopper the other day on my X-T2 and using the B setting, and I must have pressed something and it got stuck on a 30 second fixed exposure time instead of me being able to choose how long the shutter was open. Whilst I managed to switch that off somehow after a lot of fiddling, it might happen again and I am due on a long exposure course and I dont want to be embarrassed with the tutor. How is this switched on and how do I switch it off if it happens again?

[Doug Pardee]

That happens if you set your aperture to Automatic (A) with shutter speed set to Bulb (B ). In order to compute the aperture, the camera has to know the shutter speed (and ISO). So it arbitrarily picks 30 seconds for the shutter speed.

 

See the gray box at the bottom of page 65 of the manual (the page about B mode).

Edited July 5, 2017 by Doug Pardee

[daveat22]

Thanks Doug that answers it in one, I must have flicked the aperture setting to A accidentally as I had taken several long exposures before this happened. Do you happen to know why it takes about 15 seconds for the camera to store an image taken on the B setting, I wouldnt have thought that it was a larger image file?

[X-type_user]

The lengthy (15-sec?) period might be due to the camera running it noise reduction program on the long exposures.  Most people turn off Long Exposure NR in the camera menu and just use post-processing to deal with any noise.

[daveat22]

Thanks x-m1user that is a good tip I have turned off long Exposure NR and trust it has speeded up the saving.