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When the eclipse is total, you can look at it with the naked eye (in fact you won't see anything if you use a filter). However - if you want to see the partial phases, please use an ISO-12312-2 certified solar film or glass. I would highly recommend NOT using welders glass or a dark filter made for a camera. For example, I'll be shooting the partial phases with an 18-stop Firecrest solar filter. However, the manufacture explicitly states not to view the sun directly with your eyes using this filter as it only blocks visible light and doesn't block the UV light that can damage your eyes.
This image shows a woman's eye with a crescent-shaped burn on her retina. This is permanent damage and does greatly impact her vision.
Protect your eyes!
This image shows a woman's eye with a crescent-shaped burn on her retina. This is permanent damage and does greatly impact her vision.
Protect your eyes!