Ptotographing sun / solar eclipse. ND filters. 100mm square filters.

Started Mar 19, 2017 | Discussions thread
MikeInOr
OP MikeInOr Contributing Member • Posts: 892
Re: Ptotographing sun / solar eclipse. ND filters. 100mm square filters.

Chris Malcolm wrote:

That may well be true for some ND filters, but not necessarily all. I have some solar mylar film, and a 10 stop ND filter. Out of curiosity I wondered how much IR the 10 stop filter was stopping. I wasn't worried about the UV because I knew the lens was stopping that anyway. Despite all the dire warnings on the web about frying your sensor with ND filters I couldn't find any experimental data with actual measured numbers. I'm always suspicious when people can't quote numbers concerning something eminently measurable.

With the kitchen table optical lab I was able to set up I discovered that my 10 stop ND filter was stopping at least 8 stops worth of the IR. Possibly more, that was simply as far as my measurements could go with confidence. And quite far enough to be sure that using that ND filter to photograph a solar eclipse, or indeed just sunspots, would cause no problems. As indeed it hasn't.

Of course that may not be true of your ND filter. I just wanted to point out that not all ND filters will fry your sensor if used to photograph sunspots or eclipses.

Yes, I always get a lot of hear-say without a lot of facts to back it up. The ICE filters are supposed to block IR and UV. There is also an IR filter on the sensor itself. I like my A33 but it is an old camera and not worth a whole lot any more. I am going to experiment with it and the ICE ND filters in full sun.

Thank you for the feedback.

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