How do accessory viewfinders work?

[eIII]

another noob question. sorry.🙂

still lovin' the voigtlander prominent, but i'm still adjusting to the very small viewfinder (compared to my slr).

how does an accessory viewfinder work? can you focus through it or is it for framelines only?

i want to use this camera with its fast 1.5 nokton in low light/ bar settings, but the smallish, dim finder might be a problem.

any reccomendations?

thanks, billy

 

[wyk_penguin]

The accessory VFs are just for composing. You will still have to use the RF window for focusing. So if you can't see in the finder, an accessory VF is no use (useless you focus by guesstimation - which is not practical at f/1.5).

A RF CLA is a more practical solution to the dim finder problem.

 

[pvdhaar]

Depends on the viewfinder. Some have framelines, others have not. You'll just use the edge of the view as a frame indication.

On viewfinders that are intended for longer lenses (75 and up) there's often a parallax compensation ring. When the distance set on the lens is dialled in, the view shifts a wee bit to account for parallax.

As wyk_penguin already said, they're not for focussing, just for framing. But they can have a different magnification than the viewfinder on the body, and may make this task easier..

 

[Skinny McGee]

Take alook at Leica 50mm bright line finders

 

[Poptart]

They look really cool too.