Adding Real TTL Exposure meter To A Canon P Rangefinder

Apr 18, 2015

Udi Tirosh

Udi Tirosh is an entrepreneur, photography inventor, journalist, educator, and writer based in Israel. With over 25 years of experience in the photo-video industry, Udi has built and sold several photography-related brands. Udi has a double degree in mass media communications and computer science.

Adding Real TTL Exposure meter To A Canon P Rangefinder

Apr 18, 2015

Udi Tirosh

Udi Tirosh is an entrepreneur, photography inventor, journalist, educator, and writer based in Israel. With over 25 years of experience in the photo-video industry, Udi has built and sold several photography-related brands. Udi has a double degree in mass media communications and computer science.

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Yup, you heard right, true TTL on a (1959) Canon P Rangefinder. TTL stands for Through The Lens, which would be kinda impossible for that manual-focus,  manual-exposure camera. Yet, Kevin Kadooka (who also made the beautiful LUX TLR) managed to build one using some 3D printed parts and a Trinket Pro 3V microcontroller.

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Here is a brief description of the project:

The goal of this project is to add a TSL235R light-to-frequency converter to the exposure chamber of a Canon P rangefinder to produce a TTL-off-the-frame exposure meter for convenient and accurate exposure metering in a wide range of lighting conditions #

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The project uses a light-to-frequency converter to measure the light bouncing of the center of the frame inside the camera.

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This involves taking the camera apart, drilling a few holes for the wires, and fitting the exposure chamber with a light sensor, so this is definitely not for the faint of heart.

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The back side however is quite elegant and is encased in a 3D printed shell that only displays old school 7 segment LEDs, which shows the exposure.

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Here is a video showing the functionality of the unit:

If you are brave enough to try this yourself, there is a step by step tutorial over at hackaday.

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Udi Tirosh

Udi Tirosh

Udi Tirosh is an entrepreneur, photography inventor, journalist, educator, and writer based in Israel. With over 25 years of experience in the photo-video industry, Udi has built and sold several photography-related brands. Udi has a double degree in mass media communications and computer science.

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2 responses to “Adding Real TTL Exposure meter To A Canon P Rangefinder”

  1. Ralph Hightower Avatar
    Ralph Hightower

    Slick!

  2. Dave Cramer Avatar
    Dave Cramer

    Great build! May I please ask if you would share a list of each item you used for this? I am looking at replacing dead light meters in Canon RM cameras and on old 50’s and 60’s rangefinders. Thank you.