very, very long exposures

[tungsteneer3]

I have an olympus e500, how can I get very, very long exposures? If I set my apeture to f/22 and do a 60 sec exposure I get a lot of noise. How does one do 10 min + exposures? Do I need to get a certain type of filter or lens? thanks

[mwfanelli]

I have an olympus e500, how can I get very, very long exposures? If I set my apeture to f/22 and do a 60 sec exposure I get a lot of noise. How does one do 10 min + exposures? Do I need to get a certain type of filter or lens? thanks

One weakness of digital is long exposures. My Canon 300D does have a "bulb" setting, I think your camera does too. "Bulb" keeps the shutter open as long as you need but it is manually controlled, not automatic. Read the manual. Try setting your camera to manual mode and keep increasing the shutter speed until it indicates that bulb is on. You will have to determine the exposure by external means as your camera only does auto up to 60 seconds.

More than likely, the image will so noisy as to be garbage. Noise on the E-500 is a bit higher already. Make sure you turn the noise reduction on, it seems to make a difference with the lower shutter values (30 seconds or so). Give it a try, you aren't wasting film!

Just curious, what do you need a 10 minute exposure for?

Oops, EDIT: I just read the DPReview E-500 review. The bulb setting has a maximum of 8 minutes. If you really need 10, it appears you are out of luck.

[another view]

Film is really the way to go with long exposures. I've done 30 second shots with my Fuji S2 at ISO100 and they look good, but that's nowhere close to 10 minutes. I've heard that what happens is that the sensor heats up and that's what causes the noise, so somebody tried a star trails shot up in the arctic and it looked pretty good (a little cold up there!).

I've used Fuji Provia 400F slide film for two-hour exposures before and it's a really good film for this kind of work.

[tungsteneer3]

thanks for the information... I probably should try film.

When I said I wanted a 10 min exposure, I had forgotten that my camera is limited to 8 mins... 8 mins is fine, even 5 mins.

I just thought I had read somewhere that using a certain type of filter could help with the inherit noise that comes with long exposures and digital cams.

anybody know anything about that?

Im wanting these long exposures because I live in a high (air) traffic area, and even with just a 30 sec exposure the plane light streaks become noticable... I just wanted to see what it would be like for a few minutes exposure.

[another view]

I don't think there's any kind of filter that can reduce noise, at least in the traditional sense of a glass filter that goes into the lens. There are computer programs like Noise Ninja that can do this, but they won't be able to remove that much of it.

Sounds like a cool idea for a shot. I'd definately stick with the Provia 400F (or 100F) slide film because it's very good at reciprocity failure. If you're not familiar with it, reciprocity failure is something to consider with long shutter speeds. What happens is that the "reciprocal relationship" between apertures and shutter speeds doesn't exist past certain shutter speeds. IOW, where 1/250 at f8 and 1/125 at f11 are the same exposure, when you get out to several seconds (depending on the film), a shutter speed that's one stop slower isn't exactly giving you twice as much light (at the same aperture). It's close - like maybe you're only gaining 2/3 of a stop even though your shutter speed is a whole stop difference. Film spec sheets will tell you more about this stuff than you probably want to know. Another consideration is that colors can shift with this too, and they'll make a recommendation on a filter to use to correct for it (again, may not be a big deal). This exposure reciprocity is also true with really short shutter speeds but it's not usually even worth mentioning because most films aren't affected by this at slower speeds than 1/10,000 sec (how many cameras can even do that?!).

In my experience, it's not that critical for what you're talking about but just know that this may be a consideration, especially with some films. It just so happens that Fuji's Provia films are excellent at this and very fine grained. If you used Fuji Velvia 50, you'd have to add 1/3 stop of exposure before you got to a one second exposure (if memory serves...) and the sky can turn green with really long shutter speeds.

[drg]

For this type of shot you could also do an additive type of photo. Take a few second exposure every 30 second to a minute and then overlay them to get all the light trails 'added' together. Layering is being used more and more to overcome some of the digital limitations. You would need to use a sturdy tripod and remote release of some type to keep the shots well registered to each other.

[tungsteneer3]

thanks to all for the information... I have some tinkering to do it seems...

[ekstasis16]

I've shot several 60 sec exposures and a few 3-4 min exposures with a 20D and the noise isn't really an issue provided I shoot at ISO 100. There is a noise reduction custom function but I haven't seen much of a difference whether its on or off. It might come in handy for exposures 10 min or longer, like capturing star trails in the night sky.

Any noise that crops up is usually color noise and can be easily taken out with Photoshop's Reduce Noise filter.

I found some more comments on this issue in another forum:
http://www.phototakers.com/forum/viewtopic.php?p=243574

The E-500 seems to be comparable with other cameras at ISO 100 in terms of noise, but above that the noise get pretty bad. You should be OK at 100 though.

http://www.dpreview.com/reviews/olympuse500/page17.asp

[SmartWombat]

You can also use astronomical photography software to stack photos and average out noise.
You can take a short exposure "dark" photo and calibrate the noise in the sensor when there's no light.
Then subtract that from the averaged image.
These kind of techniques can produce amazing images where you thought there was only noise and blur.