Forgotten in its old age

by Aditya

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8
votes
1answer
165 views

What kind of mirror in a mirror lens?

A normal mirror, that we see for example in an elevator, is a glass sheet with thin metal coating on the backside, so light reflecting from the metal surface goes first thru the glass. Metal mirror ...
10
votes
1answer
377 views

Why do mirror lenses have poor contrast?

I was reading this question on mirror lenses and the answers taught me a lot about mirror lenses. It is pretty obvious to me why they have donut bokeh (central obstruction) and why they are fixed ...
5
votes
1answer
811 views

Are mirror lenses appropriate for DSLR astrophotography?

There's a whole host of inexpensive mirror lenses available in the 500 mm - 800 mm range (this for example). They have slow max apertures (f/5.6-8) and a donut shaped bokeh (not a problem ...