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"light painting" basics...

PostPosted: Feb 13, 2007 2:18 pm
by graveleye
I am curious as to what your settings are when you "light paint" a lengthy exposure in a cave. I have an old Fujica slr that I really dont use a lot, but it takes good pictures, and I can keep that shutter open as long as I want.
I'm curious as to how you go about it though - how long of an exposure and what speed film you are using. I am planning on getting one of those gazillion candlepower lights in the very near future.
Ideas?

PostPosted: Feb 14, 2007 12:36 am
by fuzzy-hair-man
With my digital camera (Canon PowerShot S3) I use ISO 80 or 100 generally the longest exposure I can 15 seconds and to light it I use my Apex headlamp on high using the Luxeon waving it around in the picture frame (more so in the distance).

It works out OK for me :kewl: but it is a trial and error thing so digital cameras' ability to display images back to use is very useful. Don't keep the light in the one spot too long other wise you'll get a bright spot.

Hope this helps

PostPosted: Feb 14, 2007 8:59 am
by graveleye
I was curious about that, but I figured that it was a trial and error type of thing. I think you can do prolonged exposures with my wifes camera (Cannon A540 or something like that), so that will be a good one to experiment with - cheaper than film! Thanks!

PostPosted: Feb 14, 2007 5:42 pm
by fuzzy-hair-man
I'm not sure but I suspect the lower output lights make light painting less fiddly ie if you have very high powered lights I think it's easy to accidentally get bright spots. Unless there is a large cavern but it is possible to get some else further down to light this area with a light similar to what your using (otherwise it might upset your white balance).

PostPosted: Feb 14, 2007 6:47 pm
by MoonshineR DavE
graveleye wrote:I was curious about that, but I figured that it was a trial and error type of thing. I think you can do prolonged exposures with my wifes camera (Cannon A540 or something like that), so that will be a good one to experiment with - cheaper than film! Thanks!


Hey Graveleye I just bought a Canon A540 and the longest exposure time it will do is 15 sec. But you can set the film speed to asa 800 so it kinda makes up for the whole 15 sec. thing a little.

PostPosted: Feb 14, 2007 6:55 pm
by fuzzy-hair-man
As I said before in my experience 15 sec is long enough for most short - medium range shots and I have my ISO set to 80 or 100 so the sensitivity is way down so I don't think you need to put it at ISO 800. These high ISOs get pretty noisy so I tend to only raise the ISO only if I can't manage to get enough light out there to do it which seems to rarely happen in anytthing but big caverns.

I haven't done a huge amount of these photos though.

Too long an exposure and taking photos will take forever, and if you have people in you light painting photos, there's generally a limit on how long they will stay still (cavers must have short attension spans :kidding: )

PostPosted: Feb 14, 2007 7:22 pm
by MoonshineR DavE
I agree that the high ISO does give a lot of noise. I just got my camera over the weekend so I haven't got to play in a cave yet. But I hope to soon. :grin:

PostPosted: Feb 14, 2007 8:31 pm
by Realms

PostPosted: Feb 14, 2007 8:37 pm
by Teresa
Graveleye,
On the 35mm side the film speed print film generally needs to be 200 or 400, depending on the size of the space to be lit. We just did a really nice open shutter paint with flash down a 125 ft 20 ft diameter borehole with two flashes with 200 speed Elitechrome--me at about 60 ft, and hiding the flash with my body. Just remember this works best with the camera on a tripod, and the lens covered and uncovered with an opaque black hood or snood over the lens. The speed does depend on distance and the guide number of the flash you are using. I've also seen a 100x300 room painted with 8 flashes over 30 minutes. Make sure the lens is covered if people are moving about, or you get ghosts/headlight streaks, etc. That shot was with 64 ISO Kodachrome, so the film doesn't have to be all that fast if you've cumulatively got enough light.

PostPosted: Feb 15, 2007 6:57 am
by Brian Masney


Great photos Nathan! Thanks for sharing.

I see that those photos are from Helectite Heaven in Fern? How long does it take you to get back there from the Johnston entrance? I've only done the standard tourist trip to Surprise Pit, although I know where the other entrances are.

Brian

PostPosted: Feb 15, 2007 9:55 am
by Realms
here is another deal we did a couple weeks back using only LED



No post on the colors. thats how it really looked.http://www.realmsofreality.net/williams_digital_rumble_room.jpg

PostPosted: Feb 15, 2007 2:33 pm
by bigalpha
Realms -- that shot looks familiar. It's like I've been to that cave before.