Long exposure with D30

[michaelchristensen]

Hi,

The D60 is capable of producing virtually noiseless images up to 4:30 minute exposure, but how about the D30??
How long exposures have you done with the D30 - without too much noise?

Thanks!


Regards

Michael

[gthorn]

My D30 produces very noisy pictures at 30 seconds exposure. I would go as far to say that anything above 5 seconds or so is mostly useless. The only exception I can think of is taking pictures of the full moon with a small aperture. (I don't know why I would want to do this though ?)

[michaelchristensen]

gthorn wrote:
My D30 produces very noisy pictures at 30 seconds exposure. I would go as far to say that anything above 5 seconds or so is mostly useless.

Hmm ok - but I don't agree with you on that one! I have shot A LOT of pictures with bulp 30 sek. or 1 minute with my D30 with no noiseproblem at all! What I was thinking about were if there would be a noise problem with bulp exposures over 3 minutes?

I have made my own little "bulp exposure experiment" to see how much noise there will be in a long bulp-exposure.

www.christensen.tv/bulp.htm

The experiment is with the lens cap on so I guess the result would be "ok" if there was a real object to photograph... My "lightning" photos on www.christensen.tv/d30.htm is shot with 14 sek. bulp - can you see the noise??

Regards

Michael

[roine]

Hello

What ISO are You using during long exp?

That adds problem to!

http://www.roine.nu/julen01/crw_5308.htm

Taken at:
Shutter speed: 30 sec
Aperture: 2.8
ISO: 100
Lens: 24,0 to 70,0 mm
Focal length: 24,0 mm

Roine www.roine.nu

[michaelchristensen]

ISO 100!

Michael

[KHogan]

The absolute maximum I've been able to shoot is a 1 minute exposure and even then, there is visible noise in the dark areas of the image. I've gotten very acceptable results with 30 second exposures. Between 30 seconds and 1 minute exposures, I get visible noise (despite the long exposure noise reduction) and have to be careful what types of scenes I want to photograph at those exposure times. I don't think the D30 can comfortably do 3 or 5 minute exposures but if yours is giving you that luxury, I quite envy you! :)

Kharim

[jonday]

Have you turned on the noise reduction option in the custom fundtions?

[gthorn]

I have just tried a long exposure with the lens cap on and I see no noise, irrespective of whether I use 1600 or 100 ISO or whether the noise filter is set on the custom functions.

However, when I take a normal picture and force long exposure by setting a small aperture (orchids indoors at night), the custom noise filter makes a BIG difference. I also notice that there is a loooong "busy" time after the exposure and the picture is being saved.

Interesting ....

[michaelchristensen]

ok - have you all seen my little experiment?

www.christensen.tv/bulp.htm and then www.christensen.tv/d30.htm - the lightning pictures have been shot with 14 sek. bulp.

I think it shows a lot!

Yes - noise reduction was on during the test.


regards

Michael

[Matti J]

gthorn wrote:
... I also notice that there is a loooong "busy" time after the exposure and the picture is being saved.

Interesting ....

Yes, it is interesting and the explanation is easy:

D30 uses a double exposure for cancelling dark current noise build up of the CMOS. After long exposures there is a long period for second exposure and at this time curtain closed. This second "dark frame" is then subtracted from the first exposure i.e. lowering the CMOS noise from the final shot. This explains the waiting time for the long exposure pictures.

D60 is different on this long exposure noise reduction. There is no need for waiting to the file save to happen. There may be a dark frame exposure too, but it takes a short time and saving of the shot starts instantly - it takes place just after the exposure ends.

The D60 have to have a more sophisticated software for cancelling the noise out of the pictures, because (practically) no matter how long the exposure is, the black areas stay black.