Anyone have experience of 4 - 6 hour time exposures?

[baloghmatt]

Hi, I take photos of stars and want to lock the D70 shutter open for many hours. I have been told that the best way to do this is with the remore control.

Has anyone got any suggestions for this?

Regards Matt

[digitor]

Using B mode (one press to open the shutter, press again to close) with the remote can allow you to make long exposures, but I'm not sure of the maximum time.

In any case, an exposure of many hours may be almost useless, due to the so-called "amp glow" - which is heat from the electronics affecting the sensor.

You'd need to prepare a dark frame to subtract from your image in PP later to minimise this effect, for any lengthy exposure. Details of how to do this are easily found on the web.

Good luck - post your results!!

Cheers

Edit: A quick look at the manual says that 30 minutes is the max! Also, B mode (terminology hanging over from my film days ) is accessed by using Manual, and setting the shutter speed to --.

[Glen]

Matt, there is a question about overheating the sensor for exposures over half an hour, but I cant remember much about it as I don't do that. Look in your manual under "long exposure" mode appropriately enough, there is a special function for it.

To help you get some good answers to this, as some members do astrophotography, if you look at the top centre of the page you will see DSLR users net, two lines under that ther is a button for the search function. Try a search under astro, astrophotography, long+exposure etc, should bring up some useful threads

[xorl]

You will only get up to 30 minute exposures on a D70 (battery & hard coded limitation) - beyond that wouldn't be much use due to noise anyway. Some expensive high end DSLRs are better at long time exposures. If you are looking at a several hour exposure the best option is still a fully mechanical camera with film. Having a battery die 2 hours into a 6 hour exposure is irksome.

[gstark]

Matt, as others have pointed out, an exposure of the type you're suggesting isn't really possible with the D70. It's really beyond the camera's design capabilities.

As an aside, please adjust your profile so that it reflects something meaningful; currently it is not in compliance with our rules. Please take a few moments to acquaint yourself with our FAQ; you will find it may help you make your time here far mor enjoyable.

[Killakoala]

The D70 is very limited for Astrophotography due to the sensor heating problem.

It is possible to stack multiple exposures taken with the D70, but time consuming.

Canon make better cameras for long exposures.

Film is still the best option.

[baloghmatt]

Oh well, now I can justify keeping the old film 801S body!

Thanks for that, I might have done damage to my D70 - so you have saved it by stopping me from using it for this long exposure.

Matt

[gstark]

MAtt,

I doubt you would have caused anyu damage. I just think that any results would have been very disappointing.

[Gordon]

As mentioned by others there is the hard coded limit of 30 mins to the B exposures. BTW you have to use the remote to get the "one click for on, another click for off" . With the shutter you have to hold it down. I think the old Nikon F3 and no doubt other top end models had a setting to do this with the shuutter relase button, maybe it was T? - cant remember as its so long since I have seen one.
Anyway, you wont do any damage at all. If you are doing astrophotos with a fast lens and 30 min exposure, you might suffer from overexposure though! At f/1.4 the maximum useful exposure of the night sky is only 2 or 3 minutes at ISO1600, beyond that the background skyglow steals a lot of your dynamic range. Its much better at ISO200, but unless its very dark you will still probably overexpose in 30 mins with a fast lens.
On cool winter nights the noise isnt too bad, see some of my comet astro imaging for the results you can get. I might do a couple of wide field astrophotos tonight with the 30mm lens.

Gordon
http://www.ozemail.com.au/~loomberah