Photographs of the sun

[DaveG]

I'm hoping to photograph Venus's transit across the face of the sun Tuesday
morning.

I want to know if there are any potential problems with the CMOS if I
inadvertently overexpose. I will be protecting my eyes so that isn't a concern but
I really don't want to even try it if there’s any chance that the CMOS would be
ruined.

[AzzKicker]

I read somewhere that this in fact can scrw up your sensor. YOu need to buy special lenses or filters for shooting the sun. Unless you have like 5 ND filters you can pop on :)

[Mark Kemp]

Have you ever started a fire by focusing the rays of the sun on a piece of paper or a dry leaf? This is why you DO NOT want to focus the rays of the sun on your CMOS sensor :( it could be very very bad

[robertwgross]

This is the same as trying to photograph a solar eclipse. First of all, you have to have a solar filter. There are at least two versions of that. One is a piece of very dark glass filter that screws onto the front of your lens. A cheaper one is a piece of aluminized mylar ("Space Blanket") that is stretched onto a flexible rubber push-on filter ring. In either case, that darkens the image by about 99%. In fact, it is so dark that you can look through your camera viewfinder and sometimes you can't see the sun! However, in broad daylight, you should be able to find the sun appearing as a gray disk.

That is what protects the film or the sensor from damage or overexposure.

In the case of a solar eclipse, the moon appears to be roughly the same size as the sun, so it darkens the sun at totality. Then you can pull off the solar filter and shoot directly. In the case of Venus, this is not true. Venus will appear much smaller, so you may be using the solar filter full time.

---Bob Gross---

[Mike H]

Dave, there are actually several pieces of equipment that you would need to do this type of highly specialized type of photography.

First off, realize that Venus will be a small dot across the face of the sun. The best instrument for doing this type of work is a telescope, preferably a refractor telescope. There are specialized telescopes made for solar work, but the are very expensive, and I'm assuming that you don't want to go there.

You mentioned that you will be protecting your eyes. You'll have to focus on the sun, and without looking through the viewfinder (DON'T), I'm not sure how you can do this. LOOKING THROUGH THE VIEWFINDER WOULD BE VERY DANGEROUS.

There are actually several types of filter used for solar observing and photographing. Though I'm no expert on the subject (I've only done lunar photography), I can give you some information. The little screw-in filters that Robert mentioned are regarded by many experts as unsafe. The powerful heat focused by the telescope onto those filters can break them and leave the eyes unprotected. Today, everyone doing this work uses a filter on the outside of the telescope to greatly cut down on the light (to less than 1% transmission) before it get into the scope, which can have its optics deformed by the intense heat.

It really sounds to me as though you need to do much more research before taking this on, and it's hard to imagine that you will learn that much and be able to buy and learn all of the equipment by Tuesday. I've never discouraged anyone from shooting anything in over two decades of photography, but I suggest you consider sitting this one out. What you are talking about is highly specialized work that requires some research and lots of bucks. Moreover, if you don't know what you are doing, it's dangerous. If there's one thing a photographer can't risk, it's his eyes.

For a detailed article by people who know much more about this than me, see the link below

http://skyandtelescope.com/howto/imaging/article_1255_1.asp

I hope this helps. - Mike H