Chris_Malcolm
Is it safe to shoot the sun through my XCSource 10 stop ND filter? An experiment.
It never occurred to me that it might not be, so I've already tried it out and shot some sunspots with it. But then I started reading all the terrible warnings about not using a real solar filter, risking melting my camera sensor, and so on, because ordinary photographic ND filters didn't necessarily stop IR, just visible light. I also discovered that those few ordinary photographic ND filter makers who bother to specify IR transmision specify it being blocked as well as the visible light. Plus a few knowledgeable optical lab people who said that at least most ordinary ND filters were also IR safe. So I googled for tales of people melting their cameras etc. by ignorantly using an ordinary ND filter to photograph the sun. All I could find were stories of people who had caused damage by obvious stupidity, such as not using any filter at all, or mounting the filter at the end of the optical path instead of the beginning.
I'm starting to suspect all these dire warnings about ordinary photographic filters may be no more then urban rumours propagated by people who don't know and have no confidence in their own native ability to find out.
To get an initial feel for the IR blocking capabilities of my XCSource big stoppers I measured the temperature of a small portable gas soldering iron bit using a remote temperature sensor. It measured 241 degrees C. I then put the big stopper in between the tip and the sensor. The temperature measured the ambient room temperature, not even a tenth of a degree above.
So far so encouraging! But not conclusive. More experiments later.
Original: DSC09935X
Is it safe to shoot the sun through my XCSource 10 stop ND filter? An experiment.
It never occurred to me that it might not be, so I've already tried it out and shot some sunspots with it. But then I started reading all the terrible warnings about not using a real solar filter, risking melting my camera sensor, and so on, because ordinary photographic ND filters didn't necessarily stop IR, just visible light. I also discovered that those few ordinary photographic ND filter makers who bother to specify IR transmision specify it being blocked as well as the visible light. Plus a few knowledgeable optical lab people who said that at least most ordinary ND filters were also IR safe. So I googled for tales of people melting their cameras etc. by ignorantly using an ordinary ND filter to photograph the sun. All I could find were stories of people who had caused damage by obvious stupidity, such as not using any filter at all, or mounting the filter at the end of the optical path instead of the beginning.
I'm starting to suspect all these dire warnings about ordinary photographic filters may be no more then urban rumours propagated by people who don't know and have no confidence in their own native ability to find out.
To get an initial feel for the IR blocking capabilities of my XCSource big stoppers I measured the temperature of a small portable gas soldering iron bit using a remote temperature sensor. It measured 241 degrees C. I then put the big stopper in between the tip and the sensor. The temperature measured the ambient room temperature, not even a tenth of a degree above.
So far so encouraging! But not conclusive. More experiments later.
Original: DSC09935X