Steve's Digicams Forums

Steve's Digicams Forums (https://forums.steves-digicams.com/)
-   Newbie Help (https://forums.steves-digicams.com/newbie-help-16/)
-   -   Camera's With B setting (https://forums.steves-digicams.com/newbie-help-16/cameras-b-setting-21051/)

Jimboy Feb 25, 2004 10:15 AM

Camera's With B setting
 
I am looking for a Digi Camera with 4 - 5 Megpix with a 'B' Bulb function.

I know of only two ... Canon 300D & Nikon Coolpix 5400.

Can you list me anymore so I have more of a choice and can compare.

Thanks James

NHL Feb 25, 2004 10:29 AM

The Minolta D7's/ A1, and A2 have it too...

However be careful because they all have a maximum time limit, especially on the Dimages. This is because on long exposures theses cameras take two shots: One shot at regular exposure time (ie 15s for example) and a second shot with the same exposure time (another 15s based on this example) but with the shutter close instead to subtract out the dark current noises! :wink:

bcoultry Feb 25, 2004 1:16 PM

My Olympus E-20N has a bulb setting, and because Olympus has come out with its new E-1 system, the E-20s are dropping way down in price.

Why, if I may ask, are you interested in such long exposures? Do you do a lot of night photography?

gibsonpd3620 Feb 25, 2004 2:54 PM

The Nikon 5700 has the setting to set Bulb times.

Jimboy Feb 26, 2004 3:00 AM

Quote:

Originally Posted by bcoultry
Why, if I may ask, are you interested in such long exposures? Do you do a lot of night photography?

Yes. On my conventional SLR I can have the shutter open for many minutes and would need the same from a digital camera, ie the need for B' or T' setting

Alan T Feb 26, 2004 3:49 AM

With long exposures you need to be well aware of the noise issue, as alluded to in NHL's reply. You'll probably be disappointed relative to your silver halide film results unless you use a noise reduction system as he describes, or unless you use heavy post-processing of the image with software like "Neat Image" to subtract the noise pattern. Electrical noise from the CCD looks rather like horrible grain from a film camera or a filmscanner.

I suggest you search the forums under 'noise' and 'noise reduction' to explore the issues, and maybe ask folk here which cameras give the least noisy results.

BTW, my 5Mpixel Casio QV-5700 has a 'B' setting up to 60 seconds, but as there are few of them about, and it's noisy at the best of times I wouldn't recommend it for your applications.

BillDrew Feb 26, 2004 7:51 AM

Though I've not tried it, Max Lyons' Stacker (http://www.tawbaware.com/imgstack.htm) gets good coments for synthetic long exposures.

Jimboy Feb 26, 2004 7:52 AM

I am very interested in the Canon Powershot G5. I understand it has a maximum open shutter of 15sec and ISO speed up to 400
In digital terms would this record image in a similar way to film, or would I be able to capture say a Street Scene at night without using such a long exposure on a digital camera :shock:
If that makes sense.

Hmmmm ... what I am trying to ask is if there is any sensetivity difference between Digital and Film. Would a Digital Image of a Street Scene at night require less exposure than an exposure to film? :D

Jimboy Feb 26, 2004 8:03 AM

Thanks BillDrew .... Excellent

Top Nurse Mar 4, 2004 3:21 AM

I just bought a Nikon 5400 JUST because it had a Bulb setting and I am planning on doing afocal astrophotography with it.

The really fancy cameras have what is called an auto-dark sequence (mentioned above) that somewhat subtracts out the dark current noise inherrent in any CCD detector. The way to minimize dark current is to figure out how to keep your camera CCD detector cold. Sitting on a mountaintop in the winter at night would probably help. Also single purpose astro cameras usually have a peltier cooler (and sometimes water assist) attached to the back side of the CCD to keep the detector to around 40-50*F below ambient.

For those of us on beer budgets and champange tastes you need to do your own dark frames and subtract out the electrical noise in post processing. There is quite a few astrophotography software titles that will do this for you semi-automatically. Another trick is to do light frames (you take a frame of your camera lens in a light box) to get better balance in your photo.


All times are GMT -5. The time now is 10:09 AM.