Jump to content


Photo

Dirty spot in Bolex Reflex Viewfinder


  • Please log in to reply
5 replies to this topic

#1 Lauri Sundberg

Lauri Sundberg

    New

  • Basic Members
  • Pip
  • 2 posts
  • Cinematographer

Posted 10 August 2011 - 05:00 AM

Greetings.
I have noticed a small black spot in the viewfinder of my Bolex h16 Reflex and have a hard time locating it even after opening the viewfinder.
What I was wondering is whether this is just a cosmetic problem or if it will show up in the film.

Any help is much appreciated.

-Lauri
  • 0

#2 John Holland

John Holland
  • Basic Members
  • PipPipPipPip
  • 2248 posts
  • Cinematographer
  • London England

Posted 10 August 2011 - 05:18 AM

I expect its dust or dirt on the prism and wont show on the film .
  • 0

#3 Glenn Brady

Glenn Brady
  • Basic Members
  • PipPipPipPip
  • 327 posts
  • Other

Posted 10 August 2011 - 06:41 AM

The turret can be rotated and the prism, which is hinged, exposed for cleaning. Dirt visible in the viewfinder is usually found on top of the prism, not in the viewfinder tube.
  • 0

#4 Dom Jaeger

Dom Jaeger
  • Basic Members
  • PipPipPipPip
  • 1596 posts
  • Other
  • Melbourne, Australia

Posted 10 August 2011 - 10:21 AM

In my experience, visible specks in the viewfinder are usually either on the groundglass at the top of the prism (accessible when you rotate the turret and swing out the prism), on the optics just above the groundglass (harder to reach) or in the eyepiece.

By swinging out the prism while looking through the viewfinder you can see if it's on the groundglass. To clean it, try blowing it with a puffer or compressed air before resorting to lens tissue and isopropyl alcohol. The surface is very easily damaged, so avoid rubbing it - if a single swipe doesn't work , probably best to leave it.

By adjusting the eyepiece diopter you can see if it is in the eyepiece optics (the speck will rotate).

It won't affect the film, so you could just live with it. The only optical surfaces that really need to be clean are the front and rear lens elements, and the front and rear surfaces of the prism, none of which will be in sharp focus through the viewfinder.
  • 0

#5 Chris Millar

Chris Millar
  • Basic Members
  • PipPipPipPip
  • 1642 posts
  • Other

Posted 10 August 2011 - 06:46 PM

Best way to know if its on the ground glass (most likely) is that it'll (mostly) be in focus when the grain of the ground glass is in focus also.

Its more unlikely but possible for crap to get into the periscope prism too, but it should be blurry and can be proved via the methods Dom points out. Worst case is fungal etching, which even when cleaned will leave an area of less defined image in your finder...

Any crap o damage In all cases but the front and rear faces of the prism will have no affect on your captured footage - luckily enough those too faces are the easiest to examine Posted Image
  • 0

#6 Lauri Sundberg

Lauri Sundberg

    New

  • Basic Members
  • Pip
  • 2 posts
  • Cinematographer

Posted 12 August 2011 - 02:29 AM

Thanks for all the advice people.

It seems that the dirt is in the groundglass.
I think I will just run with it for a couple of days and shooting and than try to get around to properly clean it off.
The most important news for me is that it does not affect the pictures, as I have already shot some footage with it.

Have a good weekend everyone.
  • 0


Media Blackout - Custom Cables and AKS

Glidecam

CineTape

Tai Audio

Ritter Battery

rebotnix Technologies

Rig Wheels Passport

Gamma Ray Digital Inc

Technodolly

Paralinx LLC

Wooden Camera

Metropolis Post

Opal

Abel Cine

FJS International, LLC

Broadcast Solutions Inc

Visual Products

CineLab

The Slider

Willys Widgets

Aerial Filmworks

CineLab

Visual Products

Wooden Camera

Broadcast Solutions Inc

Opal

Abel Cine

Willys Widgets

FJS International, LLC

The Slider

Glidecam

Tai Audio

Gamma Ray Digital Inc

rebotnix Technologies

Ritter Battery

Metropolis Post

Paralinx LLC

Aerial Filmworks

Technodolly

Rig Wheels Passport

Media Blackout - Custom Cables and AKS

CineTape