Solar Photography sensor damage question?

I was thinking about shooting the solar eclipse coming up this weekend and was wondering if I used a 10 stop ND filter, if that would be enough protection from the sun's rays. Or would I still be risking damage to the sensor?

I dont know the 10 stop ND but I have used a number 10 welding lens to video the sun with no problems and they are pretty cheep.

Never tried it on camera tho, so not sure about how much light you'll get for photos.

According to this post in another thread, it's not enough. They don't specifically say the sensor, though, they mostly reference "eyes" and "optics", so maybe you could ask there as well...

ohata0 wrote in post #14453876
According to this post in another thread, it's not enough. They don't specifically say the sensor, though, they mostly reference "eyes" and "optics", so maybe you could ask there as well...

As the author of that post, I'll answer here.

A 10-stop ND filter will block 99.9% of visible light. However, it will almost certainly block a lot less infra-red. My Heliopan 10-stopper is only a 4-stopper when used with my IR-adapted 20D. The Sun produces a lot of IR, and it's the IR that tends to be very damaging to eyes, sensors and shutter curtains.

I certainly wouldn't trust anything apart from a recommended filter. That's Baader Astrofilm or #14 Welders Glass (and it must be #14). Or a H-Alpha filter, but they're massively expensive.

There is a pro named Bob Atkins that has a recently written article on solar photography (and a current sun spot) at http://www.bobatkins.c​om …ls/solar_photog​raphy.html.

Scroll down as he recommends the filters ($50 range) made by Thousand Oaks at http://thousandoaksopt​ical.com/solar.html.

The usual recommendation is not less than an optical density of 5 (that's 100 000 times or 16.6 stops.) You also need to keep the aperture down to less than three inches - my 4.2" scope is certainly way too bright for comfort with an OD 5 solar filter.

For photography, you can use short exposures so (at least to some extent) you can control the threat to the sensor. What you can't do is control the danger to your eyes while focusing the camera. Your camera will work like a telescope (albeit not a terribly good one and you have a fair chance of burning a hole through the focusing screen. Alternatively, you're going to destroy the autofocus sensor because it's getting the sun beamed directly into it.

On Thousand Oaks
They offer at least three kinds of white-light solar filters. Among them, the photographic filter has an optical density of 4 - in other words it attenuates the sun's energy about 10000 times - roughly 13.3 stops. Their visual filters have an optical density of more than 5 and attenuate the sun't light at least 100000 times. Unfortunately, you're not going to have time to obtain one - the eclipse is tomorrow evening. There is probably still time to get a filter in time for the transit of Venus (5/6 June, depending on where you are relative to the international date line.)

Number 14 welding glass tends to scatter light, so it's not a very good alternative. Been there, done that. There are some recipes for using several layers of aluminised mylar - as Frank pointed out above, this can block the visible light while exposing your eyes to the sun's infrared.

My best suggestion would be to go to your local astronomy store and try to get some Baader Observatory black film. It's relatively inexpensive and is safe. Alternatively, try to hook up with the local astronomy club.

Thanks for the great info. Now I know what not to do and that is obviously very important.

noisejammer wrote in post #14455135
The usual recommendation is not less than an optical density of 5 (that's 100 000 times or 16.6 stops.) You also need to keep the aperture down to less than three inches - my 4.2" scope is certainly way too bright for comfort with an OD 5 solar filter.

For photography, you can use short exposures so (at least to some extent) you can control the threat to the sensor. What you can't do is control the danger to your eyes while focusing the camera. Your camera will work like a telescope (albeit not a terribly good one and you have a fair chance of burning a hole through the focusing screen. Alternatively, you're going to destroy the autofocus sensor because it's getting the sun beamed directly into it.

On Thousand Oaks
They offer at least three kinds of white-light solar filters. Among them, the photographic filter has an optical density of 4 - in other words it attenuates the sun's energy about 10000 times - roughly 13.3 stops. Their visual filters have an optical density of more than 5 and attenuate the sun't light at least 100000 times. Unfortunately, you're not going to have time to obtain one - the eclipse is tomorrow evening. There is probably still time to get a filter in time for the transit of Venus (5/6 June, depending on where you are relative to the international date line.)

Number 14 welding glass tends to scatter light, so it's not a very good alternative. Been there, done that. There are some recipes for using several layers of aluminised mylar - as Frank pointed out above, this can block the visible light while exposing your eyes to the sun's infrared.

My best suggestion would be to go to your local astronomy store and try to get some Baader Observatory black film. It's relatively inexpensive and is safe. Alternatively, try to hook up with the local astronomy club.