D300 Mup Noise Reduction

[Spug]

I was using my D300 with a long exposure and an electronic release. The Mirror Up facilty was used and long exposure noise reduction was switched on. After I had pressed the release and the mirror locked up, I did not seem to be able to trigger the exposure immediately, but had to wait a variable time which seemed to depend on the planned exposure.

It was as if the noise reduction occurred on mirror lock-up (i.e. before the shutter had opened) and then again after the shutter had closed.

Anybody know if this is indeed the case?

Thanks

Stan

 

[Rob_p]

I'm not 100% on this but I think I heard that noise reduction works by exposing to black first or something?

Edit: Not exactly factual but taken from someone asking the same on flickr....."t works on long exposures by taking a black frame and subtracting it from the original image. I does this by reading the data on the sensor immediately after the picture is taken (while its covered by the shutter) processing it and then subtracting it from the original image - thus eliminating HOT pixels."

 

[Spug]

That's what I thought too, but it seemed to be doing this extra exposure twice with the mirror locked up, thus taking three times as long.

 

[Ozei]

.... After I had pressed the release and the mirror locked up, I did not seem to be able to trigger the exposure immediately, but had to wait a variable time which seemed to depend on the planned exposure......

The shutter should fire just after the second press of the release. Did you try it with long exposure noise reduction turned off?

 

[Spug]

No. I must do the experiment soon.
At the time I was cold and too fed up waiting for the exposure to be over.

 

[Ozei]

It's worth trying, cos something funny is going on if it does the same with LENR turned off.