Which Film Cameras Need Batteries — and Which Don't? (Trip 35, PEN EE, Konica C35 & More)
Here's the short answer, because if you just bought a vintage camera you probably want it now:
| Camera | Needs a battery? | What to use today | If there's no battery (or it dies) |
|---|---|---|---|
| Olympus Trip 35 | No | — (selenium cell) | Auto mode locks up if the selenium dies |
| Olympus PEN EE-2 / EES-2 | No | — (selenium cell) | Same as Trip 35 |
| Konica C35 (Flashmatic) | Yes | LR44 / SR44 (on a recalibrated camera — see below) | Shutter fires, but exposure is fixed and unusable in daylight |
| Olympus 35 DC | Yes | 625A / 625G type (1.5V — see below) | Red flag appears at every shutter press; camera won't fire — no workaround |
| Clip-on flash units | Yes | Usually AA — alkaline or rechargeable (flash drains batteries fast) | Flash won't fire; camera unaffected |
Now the longer answer — because "needs a battery" and "what happens on modern batteries" turn out to be two surprisingly different questions, and the second one quietly ruins a lot of first rolls.
Why Do Some Film Cameras Need Batteries at All?
On these classic compacts, the battery never powers the shutter — the mechanics are fully mechanical, springs and gears. The battery (when there is one) powers exactly one thing: the light meter.
So the question "does this camera need a battery?" really means "how does this camera measure light?" And in this era there were two answers:
Selenium photocells generate their own electricity from light — like a tiny solar panel. No battery, ever. The Olympus Trip 35 and PEN EE series work this way, which is why you can pick one up after 50 years, and it just works. (We've written a full explainer on how the selenium photocell works.)
CdS cells don't generate power — they change resistance with light, so they need a battery to push current through them. The Konica C35 and Olympus 35 DC work this way. CdS metering is more sensitive, especially in low light — but it ties the camera to a battery. And to a very specific battery, which is where the trouble starts.
What Happens With No Battery (or a Dead Cell)?
This is what most guides skip, and it's what you actually need to know.
Konica C35: the shutter fires, but don't be fooled
Remove the battery from a C35 and the shutter still clicks — which convinces a lot of buyers the camera "works without batteries." It doesn't, not really. With no meter signal, the camera defaults to aperture wide open at 1/30s. In daylight, that's massive overexposure on every frame. You might scrape by in a dim, lamp-lit room at night, but as a practical matter: a C35 without a battery is not a usable camera.
Trip 35 / PEN EE-2 / EES-2: the red flag has the final word
These cameras don't take batteries — but their selenium cell can die of old age, and when it does, the camera protects you in a way that surprises people: in Auto mode (the "A" setting on the Trip 35, Auto on the PENs), the red warning flag appears every time you press the shutter button, and the shutter refuses to fire. The camera reads a dead cell as "not enough light" and blocks the shot — every shot. (More on this mechanism: What is the Red Flag on the Olympus Trip 35?)
There is a partial escape hatch: switch to the flash (manual aperture) settings, and the shutter fires at a fixed 1/30s with whatever aperture you choose. If you understand exposure roughly, you can shoot this way — indoors, in shade, in soft light. But at 1/30s, a bright beach or mountainside is guaranteed overexposure even at the smallest aperture. It's a workaround, not a working camera.
The honest summary: a dead selenium cell can't be replaced with new parts, so buy a verified cell, then protect it (more on that at the end).
Olympus 35 DC: no battery, no photos — period
The 35 DC takes the strictest line of all. With no battery (or a dead one), the red warning flag appears at every press of the shutter button, and the shutter will not fire. Unlike the C35, there's no default 1/30s operation to limp along on; unlike the Trip 35, there's no manual-aperture flash mode to escape into; there isn't even a bulb setting. The camera simply will not fire. If you're buying a 35 DC, the battery isn't an accessory — it's the ignition key.
The Mercury Battery Problem
Here's the trap waiting for everyone who buys a battery-powered classic: the C35 and 35 DC were designed around mercury batteries — PX675 for the C35, PX625 for the 35 DC — delivering 1.35V. Mercury cells have been banned for decades. Modern replacements fit the same hole but deliver 1.5V: LR44/SR44 in place of the PX675, and "625A" or "625G" alkaline cells in place of the PX625. (Note that the 625 type is its own shape — noticeably larger in diameter than an LR44. They are not interchangeable, so make sure you're buying the right one for your camera. The same 625 size is used by other cameras of the era too, such as the Olympus PEN EED.)
A word about a trick you may run across on forums: dropping an LR44 into a 625-size battery chamber and packing the gap with aluminum foil. It does conduct — but the contact is unstable, and unstable contact means unstable metering, the kind you won't notice until the roll comes back wrong. Add the risks of foil shorting against the chamber walls and the cell shifting as you shoot, and we don't recommend it. A proper 625-size cell costs very little; your film — and the photos on it — cost more.
That extra 0.15–0.2V doesn't sound like much. Here's what it does in practice — measured on our own test equipment, not folklore: an uncalibrated C35 running an LR44 reads 1/2 to 1 stop high. The meter thinks there's more light than there is, so every frame comes out underexposed by up to a stop.
Does that actually matter? It depends on your film.
Color or B&W negative film: mostly no. Negative film has wide exposure latitude — a stop of error usually develops into a perfectly normal-looking photo. Since nearly everyone shooting these cameras uses negative film, plenty of people shoot uncalibrated cameras for years without noticing anything.
Slide (positive) film: yes, it matters. Slide film punishes a one-stop error visibly — it's a contrasty, unforgiving medium to begin with, and it is not the "just works" choice for these cameras.
A field trick if you're stuck with an uncalibrated camera and slide film: compensate with the film speed dial. Set the ASA (that's what ISO was called then, and what the dial says) a notch below your film — ISO 100 film at ASA 64 or 50, ISO 200 at 160, ISO 400 at 320. The camera then adds roughly the exposure the voltage error took away.
Three Ways to Fix It Properly
| Approach | Cost | Upside | Downside |
|---|---|---|---|
| Zinc-air battery (hearing aid type 675) | Cheap | Correct 1.35V voltage | Starts dying once activated — about 6 months, sometimes only 3 |
| Voltage-reducing adapter | ~$10–15 | Use cheap modern cells; reusable | One more thing to buy and not lose |
| Circuit recalibration | Done in servicing | Camera just works on ordinary LR44/SR44 from any store | Requires opening the camera; on slide film a slight residual underexposure is possible — though honestly, few eyes would ever spot it |
Our approach, on every battery-powered camera we ship, is the third one: we recalibrate the metering circuit for standard 1.5V batteries as part of restoration (here's what that involves on the C35). You drop in an LR44 from the convenience store and the meter reads true. No adapters, no hearing-aid batteries, no mental math.
"No Battery Needed" Has Fine Print Too
To be fair to both sides: selenium's freedom from batteries isn't freedom from physics.
A selenium cell is a consumable on a very long timescale. Light itself slowly wears it out — years of exposure, not hours. A healthy, verified cell should keep working for another 20+ years, and there's nothing to replace or recharge along the way. But you can stretch that further with one habit: keep the lens capped when you're not shooting. The cell only ages when light hits it. A capped Trip 35 in a drawer is essentially paused.
(This is also why we test every selenium cell against reference light sources before selling a camera — "the needle moves" and "the cell is healthy" are different claims, as we explained in the Trip 35 price guide.)
So Which Should You Choose?
- Want zero battery thoughts, ever? Trip 35 or PEN EE-2/EES-2 — with a verified selenium cell, and a lens cap habit.
- Want rangefinder focusing and better low-light metering? Konica C35 — recalibrated for modern batteries, so the battery question disappears into "buy LR44s anywhere on Earth."
- Either way, if you're buying unrestored: the battery question is really a calibration question. A camera that "works" on the wrong voltage is quietly mis-exposing every frame — and with negative film's forgiveness, you may not find out until the one roll that mattered.
Every camera we sell — Trip 35, PEN EE-2/EES-2, and Konica C35 — ships with its meter verified against reference light sources, and battery-powered models are calibrated for ordinary 1.5V cells.
FAQ
Does the Olympus Trip 35 need batteries? No. It meters with a selenium photocell that generates its own electricity from light. The PEN EE-2 and EES-2 work the same way.
What battery does the Konica C35 use? It was designed for the discontinued PX675 mercury battery (1.35V). Today, use an LR44 or SR44 — ideally in a camera recalibrated for 1.5V, otherwise expect roughly 1/2 to 1 stop of underexposure.
What battery does the Olympus 35 DC use? Originally the PX625 mercury battery (1.35V). Modern 625A/625G alkaline equivalents fit but deliver 1.5V, causing the same underexposure issue unless the camera is recalibrated. Note the 625 type is one size larger than an LR44 — the two are not interchangeable.
Can the Olympus 35 DC work without a battery? No. Press the shutter button and the red warning flag appears — the shutter will not fire. There is no fixed-speed fallback, no manual flash mode, and no bulb setting. The 35 DC requires a working battery to take any photo at all.
Can I shoot the Konica C35 without a battery? The shutter fires, but exposure locks at maximum aperture and 1/30s — hopelessly overexposed in daylight. Practically speaking, no.
What happens if the Trip 35's selenium cell dies? In Auto mode, the red flag appears at every press of the shutter button and the shutter won't fire. Flash mode (manual aperture, fixed 1/30s) still fires, but bright scenes will overexpose. Dead cells cannot be replaced with new parts.
Do zinc-air 675 batteries work in the Konica C35? Yes — the voltage is correct at 1.35V — but they begin depleting the moment they're activated, lasting about six months at best, sometimes three.