Using rechargeable batteries with Canon EOS 7 (aka ELAN 7)

Garb · May 3, 2024

I have a Canon EOS 7 and sometimes I'll go to events which have me shoot about 10 rolls in a day. I want to minimize buying CR123As, so I got the BP-300 battery pack and Eneloop Pros.

Now to get some things out of the way:

The battery pack asks for 1.5V batteries and the Eneloop Pros are 1.2V. (Yet some people claim to have used NiMH batteries in the BP-300 for years without issue)
Searching online for reputable 1.5V rechargeable batteries, there appear to be none with the level of quality as the Eneloops, they all have some flaw: low capacity, few recharge cycles, shoddy non-reputable company

That being said, I've used it with the EF 100mm f/2.8L IS USM Macro, no issues after more than 10 rolls on a single charge. Yesterday, I used it with the EF 24-105mm IS STM, and observed:

Shut down once with low battery warning on the 2nd roll when firing the shutter
Turning the dial to off and then back on allows the camera to continue working despite the earlier low battery warning
After about 6 rolls, it was shutting down about every 3 shots, and eventually, started shutting down each shot making it no longer usable
Same BP-300 and same set of batteries used with both lenses (freshly recharged for each outing), IS enabled with both lenses
Different EOS 7 body used when using the 24-105mm
Temperature is above 20C

Theories:

Somehow the 24-105mm lens uses more power, either during IS or firing the shutter, or focusing (it does advertise one more stop of stabilization IIRC)
Since the camera can turn back on, the battery hasn't actually dropped below what the camera considers depletion voltage. Maybe the voltage drops for an instant at the moment current is drawn for firing the shutter.

So yes, it's not technically supported, but any tips on how I can get the Eneloops to work properly with this lens, the way it works with the 100mm lens?

Garb · May 4, 2024

After some experimentation with changing lenses and bodies, I was able to determine that the issue was not specific to the EF 24-105mm IS STM lens. It seems that the problem is on the body itself.

But now that begs the question, did using the 1.2V batteries cause the body to fail? Or is it just coincident that the body started failing when the 1.2V batteries were used?

neilt3 · May 4, 2024

Garb said:
After some experimentation with changing lenses and bodies, I was able to determine that the issue was not specific to the EF 24-105mm IS STM lens. It seems that the problem is on the body itself.

But now that begs the question, did using the 1.2V batteries cause the body to fail? Or is it just coincident that the body started failing when the 1.2V batteries were used?

Using 1.2v batteries won't cause the body to develop a fault .
Otherwise the alkaline batteries they are designed to be used with would have caused the same damage when they ran low .
It's come up here a number of times about issues with using 1.2v vr's 1.5v batteries.
I've used them in some of my bodies though without issue , EOS 1n , EOS 3 and Elan 7ne .
But I've done a single roll of film on one charge , not 10 .
So my batteries were still well charged up .
For AF and IS for ten rolls , that'd deplete the batteries further .
I can't remember the brand , but I have some rechargeable AAA batteries that are the 1.5v rather than 1.2v for a flash used two batteries and wont work with 1.2v batteries as it shuts down when you turn it on because it thinks there dead already .
These work fine and I've had them around five years .
When I got them they were the only ones I could find on Amazon.

Chan Tran · May 4, 2024

How many CR123 if you use them? How many AA for the pack?
There are rechargeable 1.5V AA. They are actually 3.7V Li-Ion with a regulator built in.

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Some even USB rechargeable

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Chan Tran · May 4, 2024

Just checked The EOS-Elan 7 uses 2 CR123 which has a voltage of about 3.2 or 3.4V. The BP-300 takes 4 AA so the voltage of the BP-300 is slightly lower than 2 CR123 when used with alkaline. With NiMH the voltage is too low and thus the camera would indicate low battery before the batteries a depleted.

Bushcat · May 4, 2024

Canon Japan site states the pack can use alkalines, Ni-cd, Ni-MH. So Canon obviously thinks rechargables are OK. Have you scrubbed every contact you can see, including the cells themselves?

The numbers show that Ni-MH perform better than alkalines and CR123A; Ni-cd perform worse. You should be getting around 100 rolls of 24-exposure film on a set of cells, without strobe.

So, I really would polish the contacts with the appropriate tool, including those between the BP-300 and the camera, especially since you're nowhere near those numbers with in-camera cells either.

【フィルムカメラ(一眼レフ)】EOS 7機種仕様

faq.canon.jp

Garb · May 4, 2024

Using 1.2v batteries won't cause the body to develop a fault .
Otherwise the alkaline batteries they are designed to be used with would have caused the same damage when they ran low .

I hadn't thought of it this way before but this is a really good point that puts my mind at ease about the low voltage not being the reason my camera stopped working.

There are rechargeable 1.5V AA. They are actually 3.7V Li-Ion with a regulator built in.

Yes, I know they exist. But I haven't really heard good things about them. Except some individual posters praising some particular brand. No one 1.5V rechargeable battery receives universal praise.

How many CR123 if you use them? How many AA for the pack?

The body without the battery pack/grip takes two CR123A, and the battery pack/grip takes either 4x AA or 2x CR123A. I use it with 4x AA.

Have you scrubbed every contact you can see, including the cells themselves?

I hadn't thought about dirty contacts. I can give this a try somehow don't feel confident this will fix it.

You should be getting around 100 rolls of 24-exposure film on a set of cells, without strobe.

I depleted CR123A numerous times but never counted how many rolls. If I had to guess, I'd say 20 rolls of 36 per set of batteries, and flash has its own batteries. Note that I use AF and IS. Also leave the camera on all the time but I don't think it drains battery just by being on. I have never depleted 4xAA batteries as I recharge them every 10 or so rolls, max 15 rolls.

Radost · May 4, 2024

My Elon 7n drains the batteries when Off. When On it does not.

Garb · May 4, 2024

Visually inspecting the contacts, there is no visible dirt on it. It seems unlikely that the camera would receive power (enough power to rewind the film even) but not enough to fire the shutter. I think in 99% of cases, either it makes contact with the batteries or it doesn't. There's no in-between.

As another data point, I'm recalling now that showing the low battery indicator does not necessarily indicate a power issue, it is a a general error indicator. I previously had a different defective lens which on the EOS 7 produced a low-battery shutdown when the shutter is fired but on a digital body, the same lens produced an error on the screen when the shutter was fired, so something bad with the lens. Which is evidence that the low power indicator on EOS7 is a general error indicator.

On this body, I took the film out and fired with the back open. The shutter moves, but it never opens completely. Maybe the camera is trying to report that the shutter has failed. Which is not surprising given the age of the camera and the fact that I probably put hundreds of rolls through it. It probably died of old age. Too bad because if I am to replace it, it will cost double what I paid for it originally.

loccdor · May 5, 2024

Garb said:
As another data point, I'm recalling now that showing the low battery indicator does not necessarily indicate a power issue, it is a a general error indicator. I previously had a different defective lens which on the EOS 7 produced a low-battery shutdown when the shutter is fired but on a digital body, the same lens produced an error on the screen when the shutter was fired, so something bad with the lens. Which is evidence that the low power indicator on EOS7 is a general error indicator.

On this body, I took the film out and fired with the back open. The shutter moves, but it never opens completely. Maybe the camera is trying to report that the shutter has failed. Which is not surprising given the age of the camera and the fact that I probably put hundreds of rolls through it. It probably died of old age. Too bad because if I am to replace it, it will cost double what I paid for it originally.

Yes, I remember seeing that in the manual about the indicator.

I have a Canon EOS Elan 7E, Canon EOS 650, and Canon T90.

My 650 had a shutter problem that I think I solved by dipping small strips of paper in isopropyl alcohol and very carefully putting them through the shutter blades. Do you have degraded foam that is causing black gummy streaking on your shutter? If so, try using these paper strips and q-tips very gently to get all the black stuff off, while actuating the shutter. That's a last resort if you're going to have to throw it out otherwise, but it worked for me. My camera was taking blank or unevenly exposed shots about 1/3 of the time.

The T90 takes 4AA batteries and I use rechargeable in it. It can go extreme amounts of time without a recharge, more than a year, but it does not have autofocus or IS. They say it can do about 100 rolls.

I can confirm that heavier lenses and ones with IS do drain batteries faster in testing with my Elan 7E. I used Tamron 45 and 85mm lenses which both have IS and get about 10 rolls per battery load if the weather is cold. That's with the CR123As.

Garb · May 6, 2024

Do you have degraded foam that is causing black gummy streaking on your shutter? If so, try using these paper strips and q-tips very gently to get all the black stuff off, while actuating the shutter.

There is no gunk or dirt visible on the shutter curtains when I open the back. And regarding the isopropyl alcohol fix, even if I fix it now, I don't think I'll trust this camera again. Either the shutter will fail again when I'm out and about or it won't expose properly and it'll be too late before I realize. I'd rather pay the 10,000 yen to buy another one (although I suppose I would never know if the previous owner had issues with it that he or she repaired at home).

Garb · May 14, 2024

I previously said the battery pack specifically has the words "1.5V" printed in the battery compartment. However, Bushcat previously linked to the EOS7 spec sheet confirming NiMH is supported in the battery pack.

I have replaced my EOS7 with an EOS 7s, the spec sheet for this also confirms that NiMH is supported on this body as well.

リチウム電池(CR123A)2個、またはバッテリーパックBP-300 （単3形アルカリ乾電池、単3形Ni-Cd
電池、単3形ニッケル水素電池のいずれか4本、または、リチウム電池(CR123A)2個収納）

This indicates NiMH is in fact supported. These is also a chart showing how many rolls you can expect ("給装本数") which estimates 140 rolls of 24-exposure with no flash and with eye control auto-focus enabled using NiMH batteries, 155 rolls with eye control disabled. The chart doesn't include any info about whether IS or autofocus are on for the estimate.

hap · May 15, 2024

Garb said:
Visually inspecting the contacts, there is no visible dirt on it. It seems unlikely that the camera would receive power (enough power to rewind the film even) but not enough to fire the shutter. I think in 99% of cases, either it makes contact with the batteries or it doesn't. There's no in-between.

As another data point, I'm recalling now that showing the low battery indicator does not necessarily indicate a power issue, it is a a general error indicator. I previously had a different defective lens which on the EOS 7 produced a low-battery shutdown when the shutter is fired but on a digital body, the same lens produced an error on the screen when the shutter was fired, so something bad with the lens. Which is evidence that the low power indicator on EOS7 is a general error indicator.

On this body, I took the film out and fired with the back open. The shutter moves, but it never opens completely. Maybe the camera is trying to report that the shutter has failed. Which is not surprising given the age of the camera and the fact that I probably put hundreds of rolls through it. It probably died of old age. Too bad because if I am to replace it, it will cost double what I paid for it originally.

I have an Elan 7ne which I never use. However, does the eye focus pocus add to the drain?

Garb · May 15, 2024

Based on the spec sheet, yes, it does. I have not verified this personally. It would make sense that it drains battery because there is probably a smaller camera in the viewfinder that watches your eye. However, I can't say how much impact it has on battery drain compared to say leaving the camera on all the time, or using AF or IS.

koraks · May 15, 2024

Garb said:
there is probably a smaller camera in the viewfinder that watches your eye

'Camera' is a bit much. It's probably a small photodiode array.
I don't expect it's a big factor in battery drain - at least I never noticed this on the several Eye-control EOS bodies I've used over the years.
Of course, what will drain batteries faster is if you enable eye control in combination with continuous-mode auto-focus. Most of the power drain, however, will be in the focus motor, not so much the eye control as such.

Using rechargeable batteries with Canon EOS 7 (aka ELAN 7)

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