Canon F-1 (Classic): Batterie wechseln — PX625-Alternative mit Typ‑675‑Hörgerätebatterien und O‑Ring‑Adapter

Canon F-1 (Classic) Battery Replacement: A PX625 Alternative Using Type 675 Hearing Aid Batteries and an O-Ring Adapter

Video thumbnail: ‘How to change Battery on Canon F-1 and use adapted Type 675 batteries (instead PX625) with adapter’

The short version

The classic Canon F-1 was originally designed to run on mercury batteries (PX625), which you simply can’t get in that form anymore. But don’t worry: a practical, inexpensive alternative is type 675 zinc-air hearing aid batteries combined with a small spacer (a rubber O-ring) or a professional PX625 adapter. They deliver a steady voltage of around 1.4 V, close to the original 1.35 V, and your light meter will work just like it did on day one.

Disclaimer: We sell some of the products mentioned here. Even so, this article is meant first and foremost as a helpful guide, not as a sales pitch.

Important: the New F-1 takes a completely different 6 V battery from the classic F-1 and F-1n. To work out which model you have and how they differ, take a look at our Canon F-1 vs F-1n vs New F-1 comparison.

Why the old batteries are a problem

Many film cameras used to run on mercury batteries. The brilliant thing about them was their extremely constant discharge voltage, which is why so many light meters are calibrated precisely to it. But since mercury batteries are now banned and almost impossible to get hold of, you need a replacement that behaves exactly the same electrically.

Why type 675 (zinc-air) is a good choice

  • Their open-circuit voltage is about 1.35–1.4 V, and a little lower under load. That’s remarkably close to the old PX625 mercury cell voltage.
  • Zinc-air batteries have a relatively flat discharge curve, so your light meter stays stable.
  • Unlike the old PX types, they’re mercury-free.

What you’ll need

  • Canon F-1 (Classic) with an intact battery compartment
  • Type 675 zinc-air hearing aid battery (available from various manufacturers)
  • A small rubber O-ring as a spacer (11 × 15 × 2 mm, i.e. 11 mm inside and 15 mm outside diameter), or go straight for a suitable PX625 adapter
  • Contact cleaner and possibly a small tool (a coin to open the cover, a fine blade or screwdriver for cleaning)

Step by step: changing the battery

  1. Open the cover: Simply unscrew the battery cover on the bottom of the camera with a coin. Hand using a coin to unscrew the round battery cover on the bottom of a Canon F-1
  1. Check and clean the contacts: Old contacts are often a little oxidized. If they look badly soiled, carefully brush them off using a small screwdriver or a fine blade, then go over them with a little contact cleaner. Close-up of the Canon F-1 battery compartment contact being cleaned with a precision screwdriver
  1. Remove the old battery: Take the old battery out, and be sure to check the compartment for any residue or corrosion. Removed battery held above a Canon F‑1 with the battery compartment open
  1. Activate the zinc‑air battery: These cells react with air. According to Energizer, once you’ve peeled off the protective tab, the battery needs about 30 seconds of exposure to air to reach full power. So give it a moment before you carry on. Peeling the protective tab off a 675 zinc‑air hearing aid battery
  1. Fit the spacer / O‑ring: 675 cells are slightly smaller than the original PX625 and would rattle around in the compartment. Use a small rubber O‑ring as a spacer: just slide it onto the battery so the cell sits snugly and makes good contact. Sliding a rubber O‑ring onto a 675 hearing aid battery as a spacer
  1. Check the polarity and insert the battery: Positive side (+) facing up, drop it in, close the compartment and screw the cap back on firmly. Underside of the Canon F‑1 with the battery cap in place; a hand holds a coin to tighten the cap.

Handy tips

  • If the meter seems off after you’ve fitted the new battery, check the contacts and the battery’s voltage first.
  • Zinc‑air batteries drain faster when they’re constantly exposed to air. It’s best to always store unused cells with the protective tab still on or in their original packaging.
  • Take the batteries out if you won’t be using the camera for a while, to prevent damage from leaking or deteriorating cells.
  • The rubber O‑ring is often the simplest DIY fix. For the other MR9 adapters out there, including ready-made ones for side contact and ones that drop the voltage for silver oxide cells, see our PX625 guide, which compares them along with what they cost over three years.

Safety and disposal

Even though zinc‑air batteries contain no mercury, they don’t belong in your household waste. Please dispose of used cells properly: just drop them in a battery take-back bin at a store or take them to your local collection point.

The bottom line

For the Canon F‑1 (Classic), 675 batteries with an O‑ring or adapter are a brilliant, inexpensive way to replace the old mercury cells. They deliver the right voltage, and your light meter keeps working accurately.

Good luck with the swap, and “good light”!

All the best, Vladi

Hands fitting a 675 hearing aid battery with an O‑ring into the camera; a screwdriver, battery and packaging are visible on the work surface

Our comparison shows which PX625 alternative suits your camera. See the PX625 alternatives.

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