8mm Forum: Double 8 camera

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Posted by Dominique De Bast (Member # 3798) on May 10, 2016, 12:42 PM:

I know it is a precise question but you never know. Does anyone have an idea of the kind of battery requested by this Minolta 8 camera regarding the automatic cell setting ? Or does anyone know how you can change the setting manually ?

Posted by David Michael Leugers (Member # 166) on May 11, 2016, 10:07 PM:

I have never seen this model of a Minolta 8mm camera, but you can probably be sure the exact battery may not be available. Such is the case with so many old cameras. Do you know the voltage the battery is supposed to be? If so, one can use a hearing aid battery (looks like a type 13 would do you) combined with a brass adapter made on a small lathe would fix you up. If you were here in the states I could make you one. Shipping costs being what they are maybe you can have the adapter made locally. Most hobbyist lathe owners would be happy to do this project I think.

Posted by Dominique De Bast (Member # 3798) on May 12, 2016, 04:07 AM:

Thank you, David for your encouraging comment about the possibility to use a replacement system if the original battery is no longer available (which is to fear). Sadly, I don't know the voltage ; there is no indication about that on the camera and I haven't the instructions manual. This camera uses cartridges, so it has probably been manufactured around 1963-1964 but that is just a guess.

Posted by Maurice Leakey (Member # 916) on May 12, 2016, 05:16 AM:

Dominique
The camera on eBay seems to be the same.
http://www.ebay.com/itm/Vintage-MINOLTA-8-ZOOM-ROKKOR-8mm-Cine-Camera-Leather-Case-1960s-/371617387896?hash=item56861f5578:g:Q1YAAOSwNgxWD9GO
The double 8 film appears to be loaded in a cassette which is turned over half way. Do standard 8 spools of film fit into the cassette?
Can you show a photo of the battery? Some early batteries contained mercury, and these are no longer available. The newer batteries which may actually fit have a slightly different voltage which do not work well with the exposure meters as they give an incorrect reading.

Posted by Dominique De Bast (Member # 3798) on May 12, 2016, 01:53 PM:

It is exactly the same camera, Maurice. The cartridge accepts a double 8 spool, the take up part is included in that cartridge. Sadly (or fortunately as it could have been leak ?), there is no battery in the camera so I don't know at all which model is used. From the link you put to EBay, I see that the lens cap is missing on my camera but it is not a problem as the handle protects the lens when closed.

Posted by Maurice Leakey (Member # 916) on May 12, 2016, 02:03 PM:

Dominique
The eBay seller made the same comment about a battery that had leaked.
Can you show the position that the battery occupies? Long perhaps for an alkaline battery (these had a terrible habit of leaking if left in the camera for too long) or perhaps round for my previously mentioned mercury battery (or multiples of same.)
Did the battery run both the motor and exposure meter?

Posted by Dominique De Bast (Member # 3798) on May 12, 2016, 02:37 PM:

Maurice, I probably didn't express things correctly : the battery didn't leak in my camera, that's why I said I'm maybe lucky that there was no battery (as I avoided this trouble). There are two kinds of batteries : in the handle, there are four easy to find AA batteries and one battery for the cell (located in the hole that is seen on my second picture on the left). I have to say that it has been difficult to unscrew the cap of that cell battery, so maybe the EBay seller has not even noticed there is a battery there and he spoke of the other batteries (I had to clean the part of the four AA batteries before I could run the camera). I could try to measure the hole to have the size of the missing battery, however that will not tell the voltage :-(

Posted by Maurice Leakey (Member # 916) on May 12, 2016, 02:58 PM:

Dominique
The diameter and depth of the "hole" may probably give a clue to the battery/s used. But, as I said above, they are almost probably mercury cells which are no longer obtainable.
Substitute cells are available for some of the old batteries but unfortunately the voltage, as I said, is slightly different.
So, even if the exposure meter can be made to work, its readings will not be correct.
However, if you do manage to get the meter to work you could always compare the readings with a standard hand-held exposure meter to see the difference and set accordingly.
If you can state the battery "hole" dimensions we can probably compare with known cell sizes.

Posted by Tom Spielman (Member # 5352) on May 12, 2016, 04:20 PM:

Does it seem like a battery like this might fit?

If so, you might want to check out this thread in another forum:

http://www.filmshooting.com/scripts/forum/viewtopic.php?f=1&t=15850

If your camera takes the same kind of battery, the bad news it's a 1.35V battery that is no longer being made. The good news is that there are 1.5V batteries that will fit but you need to manually adjust the ASA setting to compensate for the additional voltage. The thread discusses it a little.

The thread isn't about your exact camera but I'd think Minolta would likely use the same battery in multiple models.

Posted by Barry Fritz (Member # 1865) on May 12, 2016, 04:20 PM:

What is the model number of the camera?

Posted by Tom Spielman (Member # 5352) on May 12, 2016, 04:34 PM:

Hopefully Dominique can find the exact model number. If you search for "Minoltina 8" in google images, you'll find it.

Not sure why I find this thread so intriguing, other than I like it when old things can be made to work again.

Some other info that might be helpful: http://silverbased.org/zinc-mercury-replacement/

Seems 1.35 was a common voltage for light meters and they liked mercury batteries because they maintained that voltage until the end. I guess Zinc Air batteries get close. Some people have used hearing aid type batteries of the right diameter with aluminum foil wadded up to make the right thickness.

Good Luck [Smile]

Posted by Dominique De Bast (Member # 3798) on May 12, 2016, 05:08 PM:

Tom, you are fantastic. Exactly what I needed ! Barry, the only references I can see are : Minoltina 8 zoom Rokkor 1.8/8-25.
I want to take all those who contributed to this thread. Once again, this forum has shown wonders.

Posted by Maurice Leakey (Member # 916) on May 13, 2016, 02:28 AM:

Here is a list of battery sizes. Zoom down to section 8 "Button Cells - coin, watch."
The various sizes are listed and one will no doubt fit the camera.
https://en.wikipedia.org/wiki/List_of_battery_sizes

Posted by Dominique De Bast (Member # 3798) on May 13, 2016, 04:38 AM:

Maurice, I ordered the replacement battery advised for this camera and will see if it works on mine. I should get the battery from Germany next week (but Monday is Holiday in several countries, so there may be a delay).

Posted by Terry Byford (Member # 6093) on September 26, 2017, 10:22 AM:

Hi, Everyone. First post here.

Dominique, the original battery was a mercury 1.35V Mallory RM-1. These are no longer available, but the correct size battery to fit is an LR50. Just LR50, no preface number. However, these are 1.5V. It does work in my camera but will lead to under-exposure.

Without a film to test, I can't say by how much. Fortunately, the camera indicates what aperture it is using via the little meter on the left side. So this could be compared to the reading from a reliable cds meter that has cine exposure markings, or from a reading for 1/30 sec. and which is close to the shutter speed of 1/35 sec which is quite usual for a basic point and shoot cine camera running at 16fps.

There is no direct exposure compensation setting, but there is a way around this as the ISO setting is directly coupled to the meter. Normally, one sets the ISO setting for the film in use opposite the frame speed, but as it is not interlinked exposure compensation is actually possible by setting a different ISO than the film to the chosen frame rate. Once you have determined by how much the meter under-exposes, let's say 2 stops, simply set a faster ISO speed to the chosen fps. So, if you load 25 ISO film set ISO 100 against the chosen IPS.

For those who have enquired, the cassette takes standard 8 double run spools. So no cassette, the camera is dead in the water. It was a brilliant idea at the time: pre-load all the cassettes for rapid film changes, just like Super 8!.

Posted by Terry Byford (Member # 6093) on September 29, 2017, 07:54 AM:

Ooops. Just spotted I've inadvertently swapped the ISO settings around in my advice. As the higher voltage of a modern 1.5V battery will cause the meter to underexpose, we've got to effectively get the camera to overexpose relative to the speed of the film in the camera. The compensation is to set a film ISO setting to a slower ISO speed than that of the film.

Posted by Maurice Leakey (Member # 916) on September 29, 2017, 10:12 AM:

Some interesting details from Terry.
Regarding the setting of the ISO on the camera, I should point out that many of the cheaper cameras do not have this provision, the ISO being set from a notch on the film cartridge.

Posted by Alex Muir (Member # 6131) on October 20, 2017, 05:54 AM:

Hi. I am new to the Forum. I found it because I was also looking for information on batteries for the Minoltina 8. I bought one because it uses the pre-loaded cartridges. I had problems changing over the film in my Nikkorex 8F whilst travelling on a boat on the Seine. The result was a lot more fogging than necessary at the join.
I have tried the 675ZA hearing-aid battery for the meter. It is rated 1.4V, and gives readings very close to the 16fps setting on my Sekonic L-308s meter. The original battery is much bigger, however, so plenty of aluminium foil was needed to pad it out. The 675 ZA batteries are very cheap compared to other potential replacements.
Alex.

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