A cheap way to check fine focus without a monitor

[shiny4]

during a serf on the web i have seen this product.
http://www.stellar-international.com/index1.html
it is used in astromomic photography.
The new CVF Series llis a critical visual focuser mainly designed for precision WYSIWYG focusing on brighter objects be it day or night using a 35mm camera.
it has a lot of lens mount (nikon,canon,pentax and others)

it cost about from 100 to 200$.
maybe we can use it in this way.
attach the lens that you have to use and focus on the object.mark the lens on that point or in the disk of the follow focus,then attach the lens on your 35mm adapter and you have the precise focus point that you have to use in the scene.(take care:the lens mount must to be linear with the lens mount of your 35mm adapter.maybe you can attach it to the roads on one side of the adapter)
in a static scene could be ok.to be tested also in more dynamic scenes.
it is only an idea!
i accept more suggestion.
best regards
ivan

 

[Taylor Rudd]

That could be functional as a director's viewfinder, but seems like a bit of a process. You would have to be exactly lined up with the camera for the distance to be accurate and in the end you're relying on a 35mm size viewfinder to determine critical focus.

I feel like I'd still have better luck/save time using magnification + peaking if I weren't able to use a monitor

 

[davide]

That looks like it could be useful. But my question is why would astrophotographers use this? Aren't they always focusing at infinity?

davide

 

[Matty_g]

wouldn't the b ackfocus of the adapter effect this from being accurate?