What Do I Need to Shoot the Sun Safely?

[zoiberg137]

I've been trying to find a direct answer to this question and can not seem to find one!

I have a canon 40d dslr. Say I want to take pictures of an eclipse, or just point the camera directly at the sun. What do i need to do this safely? I've read that a neutral density filter is required...but I've also read that not all ND filters are safe.

Few months back when Venus was passing the sun I called around a couple local camera shops, and they both acted like it was a weird question and didn't give me a straight answer or even offer to order something for me. They had lenses for telescopes but not cameras. I've used my point and shoot many times taking pics of the sun/sunset/or just sky in general. But I would think there would be a "safe" way of doing this when I want to use my dslr with a zoom lens. Not too mention if I ever get a chance to shoot an eclipse again...

So what do I need??

 

[tirediron]

The safest way to do this is to project the suns image on to a flat surface and photograph it that way, however if you can't or don't wish to do that, then a piece of #14 (Notice the bold font and under-lining; the "#14" is important!) welding glass, available from most industrial supply and welding outlets, interposed between the lens and the sun will do the trick. You will need the large size used for the newer "wide-view" helmets, NOT the old 1.5x4 narrow strip.

 

[TheBiles]

I believe solar filters are in the neighborhood of 16-20 stops.


Sent from my Galaxy S III

 

[TCampbell]

A solar filter blocks 99.999% of the Sun's light AND it does this not only across the visible spectrum, but also in the UV and... ESPECIALLY in the IR spectrum (the Sun puts out enough IR to do serious damage even if you block all "visible" light.)

One of my "other" hobbies is astronomy and, in particular, solar viewing. I do most of this through a special Hydrogen Alpha solar telescope (Lunt 80mm DSII pressure-tuned scope which views the sun at a very specific wavelength and narrow bandpass). But you can do safe solar observing as long as you have the right filters and the filters are not particularly expensive.

You can get pre-made filters or the filter material online. Thousand Oaks is popular for this. For example: Solar Filters

Most of these are for telescopes, but at the very bottom of the table you can find a section of "camera thread filters" in various common filter sizes. You can also build your own -- they sell sheets of the the film (you can easily cut it to size), sandwhich it between cardboard, and affix to the end of the lens (e.g. slide it into a Cokin filter holder, etc.)

Whatever you do... DO NOT, DO NOT, DO NOT even point your camera at the Sun unless the filter is in front of the lens. This WILL damage your shutter and sensor.

To give you an example: A friend of mine built a filter for his scope, but someone had uncapped the "front" cap of his finder scope (which did not have a filter... we normally either remove the finder scopes (the small scope on the side of the large telescope) or leave the caps on.) but left the rear-cap on. The finder scope has cross-hair wires in it to help with alignment and centering of targets. Within a matter of just a few seconds, the sun had burned a hole clean through the plastic back-cap (over the eye-piece) as well as burning and snapping the cross-hair wires. Note that this was just a few seconds... not minutes.

I think the minimum safe level of blocking has to be at least 99.997% of all light (much much much more than the strongest neutral density filters on a camera can handle.)

This is a lengthy, but excellent video on observing the sun safely: ToV 2012: Ralph Chou - Observing the Transit Safely and Effectively - YouTube

Everyone sells out of the filters & filter material in the weeks ahead of a solar event. Best to get your filters ready months in advance.

Regards,
Tim