I have changed batteries several times in my Elan II, and noticed (thankfully) that all custom functions remain the same and the camera remembers how many exposures have been taken if a roll is loaded. So I assume that there is a small built-in battery in the body to keep the camera's memory alive. Do I ever have to worry about this battery going out? If I were looking at an older EOS body for a backup, would this be an item of concern?

-- Scott Flathouse (seflathouse.pampa@celanese.com), August 15, 2000

Answers

Apparantly there is either a battery for this or else the camera locks in some of the last settings before the battery was removed. I can,t find any info on this. The same thing occurs on my A2 and EOS 3 so I assume its the same for all EOS models.

-- Jeff Hallett (franjeff@alltel.net), August 16, 2000.

Hi Scott,

in most modern electronic equipments a special memory is used for this purpose (called EEPROM: electrical erasable programmable read only memory). Current EEPROM-chips provide data security much greater than 10 years. I suppose, Canon (and the other manufacturers) use such a EEPROM (which can be a part of the cameras microcontroller).

This implies that, if you remove the battery, the camera will remember the data (numbers of exposure, cf,...) nearly forever (>>10 years).

But there is another possibility: a sort of "recharegeble battery", which is in fact a big capacitor, called "gold cap". These provide backup for a few weeks or so and are "recharged" by the camera battery.

I dont think, there is a gold cap, because it is probably much more expensive than an EEPROM.

So, the answer is: no auxiliary battery. If there was one, canon would state this for sure in the handbook, because you have to change it at least after 10 years.

Regards,

Andreas

-- Andreas Theil (andreas.theil@metronet.de), August 16, 2000.

The Elan II has no 2nd battery, it uses an EEPROM to store data. EEPROMS could, in principle "wear out", but the rest of the camera would wear out LONG before the EEPROM unless you really work it by removing the battery after every shot!

However some earlier cameras did have a backup cell. I know for sure the old T90 (FD mount) did and I believe the EOS-1 did too. I don't think any other EOS bodies have backup batteries but I could be wrong on that. I'm pretty sure no current EOS bodies do.

-- Bob Atkins (bobatkins@hotmail.com), August 16, 2000.

My own experience with an Elan II and an EOS 5 is that they both remember what frame they were on, and the custom function settings don't change. On the EOS 5 (and I assume the A2 would be the same), the shutter speed reverts to 1/125, the aperture may change, the metering and drive modes may change, and the current custom function changes to CF1 from CF4 where I generally leave it. These may not be critical differences, but they could surprise you if you're not aware that it will happen. I haven't noticed any changes on the Elan II.

Since the EOS 5 is older than the Elan II, I would guess that these quirks have been fixed in later models. It's the kind of thing that is worth testing when you have lots of time, so that you won't be surprised in the middle of a shoot.

-- Geoff Doane (geoff_doane@cbc.ca), August 16, 2000.

Hello,

I've just bought a second hand Eos300 as a second body; Yesterday I tried the Battery pack in order to use standard AA batteries and I noticed a quite curious thing: It remembered the frame and everithing... fine, but when i switch back to CR2 batteries I forgot to turn off the camera main dial... it was out of film so I can't say about frame number, but it had turned on the autofocus *BEEP*, which i had turned off... I'll try if it remembers my last Tv or Av set, but I won't dare to do it with a film in to check if remembers the frame number! :P

-- Sergi Arbos (sarbos@yahoo.com), August 18, 2000.