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11/17/2007 09:14:16 PM · #1 |
I am assisting my eldest with a school project.
My eldest needs to take pictures of a prism and the rainbow refraction on the wall. It has to be her work not someone else's photos. Problem is the first photo shoots don't look good at all. We set it up in a dark room. Aperture is 2.4 (my lowest setting) ISO 50 (set on tripod) with shutter anywhere from 1/3 sec to 1.3 seconds.
I tried Googleing how to shoot prisms and rainbows but have not found a thing. I found one site that shows it but it does not have details on the how to's. Is a black background (the site I mentioned had a black background) better than a white one to show the refracted rainbow?
Has anyone ever done this? Any ideas? Suggestions? |
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11/17/2007 10:02:15 PM · #2 |
Are you having problems with the rainbow refraction actually appearing or just capturing it? I have never done it but I would have to imagine a black (dark) background would be best. When shooting regular outdoor rainbows I found out that a circular polarizer can make an amazing amount of difference...(I know it sounds like common sense but I didn't realize how much of a difference it makes till I forgot I had attached to my camera one day). If you have one available give it a shot.
Sorry I can't be more help...good luck. |
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11/17/2007 10:26:06 PM · #3 |
You might want to PM these guys and ask for advice on the setup. I have no ideas myself, other than that. Sorry. :)
  autool
 EVincent
  ryand |
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11/17/2007 10:27:12 PM · #4 |
There were a couple of nice entries using prisms in the recent Rainbow Challenge:
edit: beaten to the punch!
Message edited by author 2007-11-17 22:27:53. |
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11/18/2007 12:46:51 AM · #5 |
| Post a couple you shot so we can see them. |
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11/18/2007 11:29:04 AM · #6 |
Sabphoto, EBJones, David_c, and Routerguy666 thanks for your replies and suggestions on how to help.
I checked out the posted thumbnails and found that the technical details each of the shots had them using a Aperture of 9 at 1.3 seconds, Aperture setting of 11 at 8 secs, or an Aperture Setting of 14 at 6 secs.
That tells me my settings of 2.4 and shutter of 1/2 to 1.3 secs were not the correct settings for effectively capturing the prism and the refracted rainbow.
All posted thumbnails have a dark/black background. The white background we used was apparently the wrong choice to effectively illuminate the rainbow.
I did fire off some PM's to some of the photographers of the images asking for further help because we were also having trouble on how to either shine the light at a good angle to get a good sized solid rainbow (or maybe we don't have the right sized flashlight).
Routerguy666, posting a few photos of what we had would be good but we erased them because they were not good...DOH! I didn't think of saving them to illustrate what problem areas we are experiencing. But as I stated above I have gleamed some info on areas where we went wrong. |
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11/18/2007 12:52:43 PM · #7 |
They used smaller apertures so they had to use longer exposures. You used a wider aperture so you would use a short exposure. Two of those, if not all three, were probably shot on auto so god knows why the camera would pick those apertures.
My 2 cents is that just shooting against the black background would probably solve your problems completely. |
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11/18/2007 01:33:04 PM · #8 |
It really shouldn't be a problem. Just set the prism up on a black ground, find a strong ray of light, and use the EV compensation feature of your camera to take a variety of unders and overs. One of them should work.
R.
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