By Ked · June 2026

Film Camera Batteries and Mechanical Shutters: What You Actually Need to Worry About

June 2026

One of the most common worries from people considering a used film Leica is the battery. "What if I buy an M5 and can't find batteries for it?" "Does the M7 still work if the battery dies?" "I heard the meter on my M6 uses some weird old mercury battery." Some of these worries are right; most of them are wrong; and the right ones aren't usually the ones people are worried about.

This post lays out, body by body, which battery each film Leica actually uses, whether you can buy it today, what the workaround is when you can't, and, most importantly, why the battery question is mostly a non-issue compared to the real long-term threat: electronic failure on a body with no replacement parts left in the supply chain.

The Pure-Mechanical Bodies: No Battery, No Worry

The cleanest category. These cameras don't take a battery at all. The shutter is wound by hand, timed by gears and springs, and released mechanically. There's no meter, no electronics, no circuit. They work the same in 2026 as they did the day they left Wetzlar.

• Screw-mount bodies (1925–1960): Leica I, Standard, II, IIIa, IIIb, IIIc, IIIf, IIIg, plus the f/g variants of I and II. All fully mechanical. No battery anywhere.
• M3 (1954–1967) and M2 (1957–1968): The original M bodies. Cloth focal-plane shutter, mechanical timing, no battery, no meter.
• M1 (1959–1964) and MD/MDa/MD-2 (1964–1987): Scientific/industrial Ms, either viewfinder-only or no viewfinder at all. Mechanical.
• M4 (1966–1975), M4-2 (1977–1980), M4-P (1981–1987): The non-metered Ms of the 70s and 80s. Mechanical shutter, no meter, no battery.
• M-A (2014–present): The current-production mechanical-only M. Same architecture as the M3/M2/M4 line; no meter; no battery. Built new in 2026 and designed to be serviceable for the next century.

For these bodies, the battery conversation is over before it starts. The only thing they need is a periodic CLA (clean, lubricate, adjust) every 20–40 years from any competent rangefinder technician.

Mechanical Shutter, Battery Only for the Meter

The next tier: the shutter is still fully mechanical, but a small battery powers an in-body light meter. If the battery dies, you lose the meter. You do not lose the camera. The shutter fires at all speeds regardless. A handheld meter, a phone app, or Sunny 16 gets you through the roll.

• M5 (1971–1975): one PX625 mercury cell (1.35V). The famous problem child. PX625 mercury batteries haven't been manufactured since the late 1990s due to mercury bans. Workarounds below.
• CL (1973–1976) and Leitz Minolta CL: one PX625 mercury cell (1.35V). Same battery story as the M5.
• M6 Classic (1984–1998): two LR44 or SR44 button cells (1.5V / 1.55V). These are the small silver button cells sold in every drugstore, every hardware store, and every electronics aisle in the world. Cost $1–3 for a pair. Will outlive the camera owner.
• M6 TTL (1998–2002), MP (2003–present): two LR44 or SR44 button cells (1.5V / 1.55V). Same batteries as the M6, same easy availability.
• R6 (1988–1992), R6.2 (1992–1997): two LR44 / SR44. Leica's mechanical SLRs. Shutter is fully mechanical; battery powers the meter only.

For everything in this tier except the M5 and CL, the battery question is trivial. LR44/SR44 are among the most common batteries on Earth. They're not going anywhere.

The PX625 Mercury Problem (M5 and CL)

The PX625 mercury cell was the standard 1.35V battery for light meters from the 1960s through the early 1990s. Mercury cells held their voltage flat for the entire life of the cell, reading 1.35V on day one and 1.35V on the last day before dying. That meant a meter calibrated for 1.35V stayed accurate the whole time. The mercury content got them banned for environmental reasons starting in the late 1980s in Europe and rolling through the 1990s elsewhere; PX625 production wound down across the mid-1990s and effectively ended that decade. New old stock dried up years ago.

For an M5 or CL buyer in 2026, there are three real options:

• WeinCell MRB625 (zinc-air, 1.4V). Sold specifically as a PX625 replacement. Available from photography specialty shops (B&H, Freestyle, KEH). The voltage is close enough (1.4V vs 1.35V) that meter readings are within a stop. The drawback is short life: once you peel the air seal, the cell starts discharging whether you use the camera or not, and typically lasts 2–4 months. Cost is around $8–12 each.
• MR-9 adapter. A reusable brass adapter the size of a PX625 that holds an SR43 silver-oxide cell (1.55V) and includes a Schottky diode that drops the voltage to ~1.35V. The adapter is a one-time purchase ($30–50), and SR43 cells are widely available and cheap. This is the right long-term solution. Sources include CRIS Camera Services and various eBay sellers.
• Just use an LR44 or SR44 and accept the calibration offset. The meter reads about 1/3 to 2/3 of a stop off because of the voltage difference. If you shoot negative film (which has wide latitude), this is barely noticeable. If you shoot slide film, you set the ISO dial 1/3 stop higher to compensate. Many M5 and CL owners just do this.

None of these are showstoppers. The PX625 problem is real but not fatal. It's a $30 adapter or a small calibration offset, not a dead camera.

Battery-Required Bodies (Electronic Shutter)

The last tier: the shutter itself is electronically timed. Without a working battery, the camera doesn't fire, or fires only at one or two mechanical fallback speeds. These are the bodies where battery dependency is real, but the batteries are still readily available and inexpensive.

• M7 (2002–2018), 6V total: either two 3V CR 1/3N lithium cells stacked, or one 6V 4LR44 / 4SR44 silver-oxide. Both options are still in current production by Energizer and Duracell; the lithium pair is preferred for cold weather, the 6V silver-oxide for room temperature. A pair of CR 1/3Ns runs $8–12; a 4LR44 runs $3–6. Critically, the M7 has two mechanical backup speeds (1/60 and 1/125). If the battery dies in the field, set the shutter dial to one of those speeds and the camera fires mechanically. You lose all other speeds and the meter, but you don't lose the camera.
• R3 (1976–1979): two SR44 / LR44 (3V total). Based on the Minolta XE chassis. Electronic Copal CLS focal-plane shutter, with a single mechanical X-sync speed (around 1/90s) and Bulb that fire without battery. It isn't practically useful as a fallback: you can shoot bright daylight at 1/90s f/16-ish, or do bulb exposures, and nothing in between.
• R4 (1980–1987), R5 (1987–1992), R-E (1990–1994): two LR44 / SR44 or one 3V lithium CR1/3N. Minolta-XD-11-derived chassis. Electronic shutter with a confirmed mechanical 1/100s X-sync speed plus mechanical Bulb that work without battery. That's the same limited "shoot at one fixed speed or bulb" fallback as the R3. All these cells are standard drugstore stock.
• R7 (1992–1997): 6V silver-oxide (commonly a PX28L or 4LR44 / 4SR44 stack of the same form factor). Leica's first microprocessor-controlled body, designed from scratch rather than on a Minolta basis. Fully electronic; no useful mechanical backup beyond Bulb. PX28L and its equivalents are sold at any battery retailer.
• R8 (1996–2002), R9 (2002–2009): one 2CR5 lithium pack (6V). The big late-model R bodies. The 2CR5 is internally two CR2-sized cells in one shrink-wrapped pack, and you buy it as a single "2CR5" (also sold as DL245) at any battery retailer for $8–15. Electronic shutter; mechanical Bulb only without battery.
• Minilux / Minilux Zoom / CM / CM Zoom: small lithium cells (typically two 3V CR 1/3N per Leica's published specs; check the manual for your specific body). Modern lithium cells, all widely available.
• Mini / Mini II / Mini Zoom: small alkaline cells (commonly AAs per published reviews; verify against the manual). Standard drugstore stock.

For every electronic Leica film body, the battery itself is still made and still cheap. The list above contains no truly extinct batteries; even the 4LR44 / PX28L 6V cells used in some R bodies are sold in any drugstore (they're standard for small electronics and dog collars).

Why Batteries Aren't the Real Problem

Step back. For a mechanical-shutter body, the battery powers only a meter, and a handheld meter, a Sekonic, or even a phone light-meter app does the same job. Leica owners often carry a Voigtländer VC Meter II or similar shoe-mount meter and ignore the in-body meter entirely. The body works regardless.

For an electronic-shutter body, the battery is genuinely required, but the batteries currently used (CR1/3N, 2CR5, LR44, SR44) are all standard cells with broad commercial markets outside photography. None are at risk of going away. Even the worst case, the PX625 mercury cell, has a clean $30 reusable adapter solution.

The battery question, in short, is a manageable problem with known answers for every Leica film body ever made.

What's Actually Hard: Electronic Failure With No Parts

This is where the real long-term risk lives. A mechanical camera is a collection of springs, gears, levers, and cloth, all of which can be repaired by any competent watchmaker-style technician with access to a parts bin or the ability to fabricate a replacement. An electronic camera is a collection of integrated circuits, custom flex cables, and proprietary boards. Almost none of those are made anymore, and most were never sold as service parts to begin with.

• M7 electronic shutter board. The M7 uses a custom Leica-spec shutter timing circuit. Owner reports of failed timing boards exist, especially on heavily used examples, and there is no drop-in replacement. Leica Wetzlar services the M7 from their parts warehouse, with a finite (and slowly thinning) supply. When that runs out, the M7 becomes a paperweight at any speed except the two mechanical backups. The runway in 2026 is not a hard published date; call it a few more years optimistically.
• R4 / R5 / R7 electronic shutter and metering boards. The R4 in particular has a community reputation for main-board issues, though objective failure-rate data isn't published. Leica officially ended R-line service in the late 2010s. Don Goldberg (DAG) and Sherry Krauter, the two main independent Leica service technicians in North America, keep some R-line parts in stock, but the supply is finite. When their parts run out, a dead R4 is a dead R4.
• Minilux / CM electronic boards. The Minilux's "E02" error (widely reported as a shutter solenoid or board fault) is generally fatal: no replacement boards are in production, and the body was never built to be repaired. A working Minilux today is a working Minilux because it hasn't failed yet.
• R8 / R9 electronic systems. These bodies are 2000s-era electronics with the same parts-availability sunset as the R7. Leica's R-line service ended years ago.
• Digital sensor failures (digital Ms). Slightly outside this post's scope but related: M9 CCD sensors have a known corrosion problem. Leica replaced affected sensors under a service program that's widely reported to have ended around 2020. After that, a corroded M9 sensor either gets replaced at the owner's expense (when Leica still has a sensor in stock, which is increasingly never) or the camera becomes unusable. The digital-era version of the same problem.

The pattern across all of these: the camera is fine right up until a single electronic component fails, at which point the entire body becomes a parts donor with no donor pool to feed.

The Service Network Is Shrinking

Two technicians have long handled the bulk of independent Leica film-body service in the US: Don Goldberg (DAG Camera) in Wisconsin and Sherry Krauter (Golden Touch) in New York. Both have been doing this work for decades. Kanto Camera in Japan and a small number of German technicians (mostly former Leica Wetzlar employees) cover the rest of the market. As with any specialized-technician trade, the pool is finite and slowly shrinking, and books that are full today may not have successors tomorrow.

These technicians can keep a mechanical M3 or M4 alive indefinitely. The parts are simple, often interchangeable across years, and a good machinist can fabricate what isn't available. They cannot keep a 1985 R4 main board alive once the last spare is gone.

This is the most important long-term consideration in buying a film Leica today: a mechanical body's lifespan is bounded by the lifespan of the materials (cloth shutters, springs, the brass body itself), which is well over a century with care. An electronic body's lifespan is bounded by the smallest, most failure-prone IC on the main board, plus the date the last replacement board was sold to a service technician. That ceiling arrives much sooner than a century.

Practical Implications by Body

• Buy with no battery anxiety: M-A, MP, M6, M6 TTL, M4, M4-2, M4-P, M3, M2, M1, IIIg, IIIf, IIIc, R6, R6.2. These will work as long as the mechanical components do, which is essentially forever with periodic service.
• Buy with mild caution: M5, CL. Mercury battery requires a one-time MR-9 adapter purchase or accepting a small meter calibration offset. The cameras themselves are mechanical and serviceable.
• Buy understanding the electronic-lifespan caveat: M7. Excellent shooter, but the electronic shutter has finite parts availability. The two mechanical backup speeds (1/60, 1/125) keep the body usable in a degraded mode after a shutter-board failure.
• Buy with real awareness of the risk: R3, R4, R5, R-E, R7, R8, R9, Minilux, CM. When the electronics fail there is no fallback and increasingly no repair path. (The R3–R5 / R-E do have a single mechanical X-sync speed plus Bulb that fire without battery, but you can't realistically shoot a roll with one fixed speed.) These are wonderful cameras to shoot today; they just have a sunset date.

The film Leica market has been around long enough that this isn't speculation. We see it in the prices: mechanical M3/M2/M4 bodies hold their value remarkably well precisely because they have effectively unlimited service life. R4 and R7 bodies, which were once close to their mechanical equivalents in price, have steadily declined as the electronic-lifespan issue has become more visible.

Bottom Line

The battery on your film Leica is the part of the question you can stop worrying about. The button cell at the bottom of the M6, the 3V lithium in the M7, even the mercury-cell replacement in the M5: these are solved problems with $5 to $30 fixes that any owner can handle.

What deserves the worry is the silicon. If you're choosing between a mechanical body (M-A, MP, M6, M4, M3, IIIg, R6, R6.2) and an electronic one (M7, R4, R5, R7, Minilux), the mechanical body buys you decades more usable life. The electronic body buys you features such as aperture priority, electronic shutter precision, and autofocus in the compacts, all at the cost of an eventual end-of-life date that no amount of battery shopping will solve.

Browse current M-A, MP, M6, M6 TTL, M7, M5, M4, M3, and R6.2 listings on UsedCameraTracker to see what's available across the mechanical-versus-electronic spectrum.