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Just an obvervation.

PostPosted: Mon Feb 14, 2005 10:02 pm
by phillipb
I noticed this morning that when you take a time exposure - in my case about 20 sec. - that it takes about as much time for the photo to be processed by the camera. By that I mean from the time the shutter closes to the time the photo appears on the LCD is about equivalent to the exposure time.
Anyone else noticed this? Any Idea why that would be?

PostPosted: Mon Feb 14, 2005 10:17 pm
by wile_E
hi phillipb, that sounds like the Noise Reduction thingy that the D70 has. you have the option of turning it on/off. i think it basically doubles the amount of exposure time for photos (esp long exposures) as it (from my layman's understanding of it) takes another 'photo' of a closed shutter and does some funky algorithm removal calculation.

confused?

:?

i think i've managed to confuse myself...!! but it does sound like the NR feature (which you can turn off in the menu setting).

PostPosted: Mon Feb 14, 2005 10:19 pm
by phillipb
Nope, it was turned off.

PostPosted: Mon Feb 14, 2005 10:30 pm
by Onyx
It really does sound like the NR kicking in - in the time between shutter closing and display on preview LCD, does the top LCD have anything displayed? (more specifically 'Job NR')?

I did find that out in very cold weather (below freezing), the near instantaneous shutter close and image display on the D70 becomes more Canon-like, taking a second or two. But nowhere near 20secs.

PostPosted: Mon Feb 14, 2005 10:42 pm
by pippin88
Ah, so that is what that bloody annoying Job NR is about. I assumed Job Near or something.

Turned off and now I can not waste 50% of the time taking long exposures.

Unless long exposure NR is worth it?

PostPosted: Mon Feb 14, 2005 10:44 pm
by phillipb
Onyx, I didn't take any notice of the top lcd but I do know that NR is off, even the exif says so. I will check it again tomorrow and let you know

PostPosted: Mon Feb 14, 2005 11:22 pm
by Onyx
pippin88 wrote:Ah, so that is what that bloody annoying Job NR is about. I assumed Job Near or something.

Turned off and now I can not waste 50% of the time taking long exposures.

Unless long exposure NR is worth it?


Pippin, I can assure you it's not. It merely slows your continuous shooting framerate to 1.5FPS, and for REALLY long exposures (counting in minutes) it may remove some coloured random pixels but introduces artifacts of its own.

PostPosted: Mon Feb 14, 2005 11:27 pm
by Killakoala
pippin88 wrote:Ah, so that is what that bloody annoying Job NR is about. I assumed Job Near or something.

Turned off and now I can not waste 50% of the time taking long exposures.

Unless long exposure NR is worth it?


I would recommend using NR if your shot is for more than one minute at ISO200 or 30 seconds at ISO1600.

It will remove the heat signature that appears on the top left of all D70's

What it does is take a second 'black' shot and then applies it like a layer mask to the previous 'shutter open' shot. It is possible to create your own layer masks by shooting a long exposure of the same length witht eh lens cap on and then apply the layer mask in Photoshop. But the problem with that is that the temperature of the CCD might be different and you will not get rid of all the purple heat signature. If it is done exactly afte the original exposure it will be at 'virtually' the same temperature and will do a much better job.

I hope that helps. :)

PostPosted: Tue Feb 15, 2005 8:37 am
by pippin88
Onyx wrote:Pippin, I can assure you it's not. It merely slows your continuous shooting framerate to 1.5FPS, and for REALLY long exposures (counting in minutes) it may remove some coloured random pixels but introduces artifacts of its own.

I had noticed bloody slow continuous burst, but as I don't use it much, I assumed it was due to shutter speed at the time.

Killakoala wrote:I would recommend using NR if your shot is for more than one minute at ISO200 or 30 seconds at ISO1600.

It will remove the heat signature that appears on the top left of all D70's

What it does is take a second 'black' shot and then applies it like a layer mask to the previous 'shutter open' shot. It is possible to create your own layer masks by shooting a long exposure of the same length witht eh lens cap on and then apply the layer mask in Photoshop. But the problem with that is that the temperature of the CCD might be different and you will not get rid of all the purple heat signature. If it is done exactly afte the original exposure it will be at 'virtually' the same temperature and will do a much better job.

I hope that helps. :)

Ok, I'll keep that in mind.

PostPosted: Tue Feb 15, 2005 8:51 am
by phillipb
I was wrong, I've cheked the camera settings and I did have the NR on. The exif I looked at was of a photo taken at 1/2 sec which is not long enough to activate the NR so it comes up as off on the exif.
Thanks Wile_E and Onyx, well picked up.

PostPosted: Tue Feb 15, 2005 10:02 am
by Oneputt
Phillipb - I have noted this also, but generally when using long exposures I am in no hurry and it doesn't bother me.

Have you used it that way since turning the NR off? Was there a difference?

PostPosted: Tue Feb 15, 2005 10:04 am
by xerubus
i shoot in raw without the nr feature, and shots are shown immediately....

previously i had nr on and the results we terrible as compared to the nr off shot....