1 Preambule

Purpose of this project is to develop an easy repeatable way of retrofiting outdated CRT viewfinders from an old ENG and EFP cameras onto modern cameras, such as DSLRs, digital cinema cameras and future Apertus.

CRT viewfinders, like Sony DXF-801 or Panasonic AJ-VF20WBP are ruggedly built, output 600 tv lines (some models even 720p) on 1.5"-2" super bright CRT monitors, usually have a convenient for ENG/EFP mount for the microphone, have a standard controls on the standard ergonomic places. Most of them output tally lights which used in multicamera live TV production. They have proprietary not-standardized connection to the camera, and because of that they cost next to nothing on the eBay.

This project is about modifying those viewfinders to the proposed standard, and providing the ways for Apertus (and any other modern cameras) to communicating with viewfinders, while retaining as much features of viewfinder as possible.

2 Components

2.1 CheapReTroViewfinder connector standard

In order to provide plug-n-play user experience, connector standard must be developed. It should support as much common features as possible, current list:

  • Peaking/zebra/display on/off controls
  • Tally/rec indication
  • Low battery indication
  • Video format signaling (4:3/widescreen PAL/NTSC) - for Plug-n-Play. - (Proposed way to implement it through resistor of known value)

Proposed physical connector is mini-DIN 9 pin. Currenly looking for other non-proprietary alternatives with convinient form-factor and more pins.

For wider compatibility, video connector is a separate RCA plug (passing signal in PAL or NTSC), and 12v DC 2.1mm plug

2.2 Model specific viewfinders modification guides

See CheapReTroViewfinder/Viewfinder modification guide template

2.3 Apertus Gamma Retro ENG module

Module that provides CheapReTroViewfinder connector and ENG B4 lens connector, effectively turns Apertus Gamma into ENG/EFP camera head.

2.4 Modern camera adaptor

Device that has:

  • CheapReTroViewfinder connector
  • HDMI input/HDMI output (passthrough/splitter)
  • LANC controller output - to control camera and receive status updates from it.

Design - simple arduino kind of controller + HDMI to composite conversion chip. Estimated cost - $30

2.5 Modern cameras (without adaptor)

Due to usage of quite popular RCA composite plug/12v dc plug, CheapReTroViewfinder compatible viewfinder can be connected to many cameras with no specific adapter, loosing all features of viewfinder except of viewfinding itself. For use in camera without composite output HDMI to composite conventor required. Tested conventors:

  • to be done

Blackmagic cameras have a major problem with compatibility with those adapters, by manufacturer its stated, that "If you have selected to record in 25 fps or 29.97 fps on the Blackmagic Cinema Camera, and set the SDI overlays to Off, the SDI output will be set to 1080i50 and 1080i59.94 respectively. This allows you to work with most switchers, which only support interlaced high definition formats.". Tested and work on fps different from 25 and 29.97:

2.6 Modern camera adaptor (future vision)

Same as Apertus Gamma Retro module, but with LANC/HDMI connection to a modern camera.