mirror lock up for D90 HDR photos

bs0604 · May 20, 2012

I have been taking HDR pictures using my D90 on a tripod. But it is my understanding that in addition to the tripod I should also lock up the mirror to prevent mirror vibration from entering the bracketed shots. However, I don't believe the D90 can be set for mirror lock up. If I utilized a timer of 5 seconds does this lock up the mirror at the start of the five second delay thus achieving the desired lock up effect & hence reduction in vibration.

SCraig · May 20, 2012

No, however there is a shutter delay option in the menu. Menu item D10 of the Custom Settings menu will raise the mirror and delay for about 1 second before opening the shutter. Page 183 of your owner's manual.

bs0604 · May 20, 2012

Thank you. I read the relevant five lines in the manual and set the function to on. I am a little ignorant regarding the anatomy of my camera. Am I correct in assuming the purpose of the mirror is to deflect the image to the view finder and then when the shutter button is pushed the mirror moves "up" out of the way so the image can impact the sensor? If so what is going on with the mirror when you change from view finder to live view. And furthermore, in cameras where you can lock up the mirror does this mean that you won't be seeing anything in the view finder or in live view?

SCraig · May 20, 2012

You are correct. The mirror deflects the view through the lens up through the pentaprism (or on some cameras pentamirror) and through the viewfinder. Before the shutter opens the mirror flips up for the duration of the shot and then drops back down.

When in Live View the mirror is up and the viewfinder is blanked. I could be wrong but I'm pretty certain that in Live View the image shown on the LCD screen is the processed image of the sensor.

When the mirror is locked up, for whatever reason, you will see nothing through the viewfinder.