View Full Version : Solar Filters


darkrainfall
06-03-2004, 12:44 PM
I have a friend... no really, this actually is for a photographer friend who seems to think that I have all the answers to his photo questions... *smile* He is obviously mistaken...but he wants to photograph venus as it passes over the sun and he does not now have the time to order a solar filter for his camera. He uses the same equipment as me... Nikon D100, F100...
Does anyone have any suggestions for my friend in his attempt to photograph the sun?

Thanks to all in advance.

Michael Fanelli
06-03-2004, 01:16 PM
I have a friend... no really, this actually is for a photographer friend who seems to think that I have all the answers to his photo questions... *smile* He is obviously mistaken...but he wants to photograph venus as it passes over the sun and he does not now have the time to order a solar filter for his camera. He uses the same equipment as me... Nikon D100, F100...
Does anyone have any suggestions for my friend in his attempt to photograph the sun?.

Obviously, the solar filter is the way to go. However, you could try the pinhole trick: cover the lens completely and poke a tiny pinhole through it. This sometimes works. I am not responsible for destroyed equipment or eyes!

Speed
06-03-2004, 07:16 PM
I have a friend... no really, this actually is for a photographer friend who seems to think that I have all the answers to his photo questions... *smile* He is obviously mistaken...but he wants to photograph venus as it passes over the sun and he does not now have the time to order a solar filter for his camera. He uses the same equipment as me... Nikon D100, F100...
Does anyone have any suggestions for my friend in his attempt to photograph the sun?

Thanks to all in advance.

Is the safest, and most enjoyable way to go. There are other options though.

The pinhole trick Michael suggested is one. I would avoid it if possible. He warned you. Another is to use projection. Some folks use a piece of cardboard with a pinhole and then let the sun's image shine through onto a sheet of white or black paper. Try both and see which gives the better image. You can then photograph the image on the paper.

Another method is to project the image with a telescope or spotting scope. Same principle, but you have to be careful. Some telescopes (Schmitt-Cassegrains) will build up internal temperatures that can ruin your scope. A basic refractor should be fine.

Hoya makes a Neutral Density Filter (ND400) that is safe for photographing the sun. Check your local camera shop. It reduces the light by nine stops.

You can also stack ND filters to achieve the nine stops you need to reduce the light by. More glass means less detail, but it can be done. And if you don't have enough ND filters, you can add your CPL on top of them. At full polarization, a CPL reduces the light by two stops.

Also, you can check your local hobby stores that carry telescopes. They may have mylar filters, or even mylar sheets that he can place over his lens and rubber band into place.

You can try Orion Telescopes (www.telescope.com) and have a filter sent to you by next day air. It'll cost him, but it'll save his eyes.

Hope this helps. And by all means, if he can't safely photograph the sun, then he shouldn't try! It's not worth damaging your eyes over. Besides, Venus transits the sun again in eight years. Here's a good source of info and ideas:

http://skyandtelescope.com/observing/objects/article_1258_1.asp