What is a Penta Prism?

[icecruncher]

Can anyone explain, in simple terms, what a penta prism is and how it is used?

I read the specs but I'm apparently still not sure of the way it works.

 

[paul1598419]

Yeah, they are used to get a 90* output regardless of the angle in the incident beam. Since it is reflected twice, its handedness is the same as the incident beam too.

 

[icecruncher]

Thanks, nothing listed on forums regarding them. But Meredith Instruments has a laser Penta Prism for sale on ebay.

I wondered why you would use one and obviously if no one has ever posted anything about them on here or PL then they aren't very common in laser systems.

Apparently they are common in SLR cameras, as you said they keep the handedness the same on an optical image.

Wikipedia helps with optical path at least.

I don't see any reason to ever use one, Meredith lists it as helpful for IR and UV lasers ????

 

[paul1598419]

I've got a lot of different prisms. They are sort of a sideline for me. Glad I could help a little.