IDAS D5.2 Solar Filter
IDAS solar filter is the premium quality and the safest for human eyes as far as I know. The glass itself is quite different from the regular optical materials. Basically it is the glass for the window of the steel mill. So well protecting the energy. The glass quality still maintains the same level as the optical glasses. This is why it is the best for solar viewing.

The above description indicates each optical density in 3 spectrum regions.
- D5.2V : Density 5.2 in visual wavelength
- D8U : Density 8 in UV
- D9H : Density 9 in NIR
As far as I know, IDAS is an only company who publishes this type of the detailed specs in our industry.
Especially it is known the human eye is not sensitive in NIR. So we can’t feel the energy much even eyes are capturing high level of NIR energy through filters. So NIR is quite dangerous area for the human eyes. But don’t worry, IDAS filter is D9 in NIR.
See the OD curve at
https://www.sciencecenter.net/hutech/idas/solar/index.htm
Unfortunately 82mm is no longer available. But 52mm is still good size for binoculars. It fits Canon 10 x 42 IS Bino without adapter as shown below.
This is the best binoculars I ever own. Unfortunately it’s a bit heavy and expensive. I believe the performance justifies its price for me though. Recent 12 x 36 IS looks popular now. So we made the adapter for one of my 3 Canon Binos.

Each filter costs $99.00. I set the kit price including the adapter at $169.00.
Each filter is easily removeable from the adapter. So it can be used for other optics too.
Enjoy the safe solar viewing with the reliable filters!!