Minolta HiMatic 7sii, using LR44 batteries

[zanxion72]

Is it possible to use LR44 batteries on Minolta HiMatic 7sii? Will they cause underexposure, if yes, would it be noticeable?

 

[bernard_L]

LR44 (alkaline) does not have a constant voltage during lifetime. Better to use SR44. If you feel up to the task, you can solder a small Shchottky diode in series inside the camera: will make a pretty good job of lowering the voltage to that of a mercury cell.

 

[zanxion72]

Does the up ratted voltage of the LR44 cell influence a lot the exposure?

 

[Kirks518]

I'm using a 7sIi with an LR44, and not having any problems. The battery I have currently installed has been in there so far for about 4 months. I like the LR44's simple because you get 4 of them in every 4LR44, so they cost less then a buck a piece.

 

[Kirks518]

Oh, and the 7sII is supposed to use a 1.3v battery. The SR44, while longer lasting, is 1.55v, whereas the LR44 is 1.5v. Seeing as either battery isn't the correct voltage, might as well save the money (IMHO).

 

[Kirks518]

One more thing.

I know the Canon QL-17 GIII is always 'ON' (ie, the meter is always reading), and the lens cap should be kept on to reduce battery drain.

On the 7sII, I have no idea if this is the same. But, what I do, along with keeping the lens cap on, is I make sure it's not in AUTO when I put it away. I haven't found anything to say whether or not it has a battery draw when not in use, but I figure it can't hurt.

 

[Xmas]

Does the up ratted voltage of the LR44 cell influence a lot the exposure?

Yes The voltage is 1.5 v at start of life and slowly drops to 1.1v.

The meter is designed for a constant 1.3v.

The error at 1.5 v is light level dependent
The error at 1.3 negligible
The error at 1.1 is light level dependent

If you are using negative film you don't need a meter anyway guesses reasonable

If you are using slide film

Then

- hearing aid battery with size adapter
- adapter with Shockety diode and silver cell
- solder in Shockety diode into camera ditto

http://camerapedia.wikia.com/wiki/PX625

 

[Kyon Thinh]

Where do you live, I still have a bunch of mercury 675 for it.

 

[Kirks518]

Where do you live, I still have a bunch of mercury 675 for it.

I'd like to buy some if available.

 

[zanxion72]

One more thing.

I know the Canon QL-17 GIII is always 'ON' (ie, the meter is always reading), and the lens cap should be kept on to reduce battery drain.

On the 7sII, I have no idea if this is the same. But, what I do, along with keeping the lens cap on, is I make sure it's not in AUTO when I put it away. I haven't found anything to say whether or not it has a battery draw when not in use, but I figure it can't hurt.

It is the same case with QL-17 GIII. In auto the meter is always on. Putting the cap on limits the power consumption since the more light falls on the CDS the more power it draws to deflect the needle. Me too put the cap on and remove it from Auto.

Yes The voltage is 1.5 v at start of life and slowly drops to 1.1v.

The meter is designed for a constant 1.3v.

The error at 1.5 v is light level dependent
The error at 1.3 negligible
The error at 1.1 is light level dependent

If you are using negative film you don't need a meter anyway guesses reasonable

If you are using slide film

Then

- hearing aid battery with size adapter
- adapter with Shockety diode and silver cell
- solder in Shockety diode into camera ditto

http://camerapedia.wikia.com/wiki/PX625

Will that deviation be always less than a stop? What is the maximum deviation that one can get with a fresh LR44?

Where do you live, I still have a bunch of mercury 675 for it.

I'd like to have some. PM me with details please.

 

[Xmas]

Will that deviation be always less than a stop? What is the maximum deviation that one can get with a fresh LR44?

The meter system out of the factory was probably within 1/3 of a stop.

The CDS cells age with time and become less sensitive.

A fresh LR44 could easily give more than 2/3 of a stop error ditto a flat LR44. Might be addative on other errors.

The error from the battery would be dependent on the amount of calibration resistance employed in the production batch and other things.

Only worry if you are using slide film.

If you use slide film ...

http://rick_oleson.tripod.com/index-111.html

 

[Jaf-Photo]

Is it possible to use LR44 batteries on Minolta HiMatic 7sii? Will they cause underexposure, if yes, would it be noticeable?

It is better to use 675 zinc-air batteries made for hearing aids:
http://www.duracell.com/en-us/produ...es/duracell-hearing-aid-battery-with-easy-tab#

Their voltage is closer to the original mercury batteries, and I get accurate exposure with them.

If you use LR44, you should measure the under-exposure against a hand-held light meter and adjust the ISO-setting downwards. You'd probably need to go down 1/3 to 1 stop.

 

[Xmas]

If you use LR44, you should measure the under-exposure against a hand-held light meter and adjust the ISO-setting downwards. You'd probably need to go down 1/3 to 1 stop.

For a fresh battery and the other way for a used one...

-

 

[Jaf-Photo]

For a fresh battery and the other way for a used one...

-

Yeah, I always measure my 7sII against my iPhone light meter app before starting shooting. But since I swapped to 675 no issues, except that you have to replace them more often. But they're cheap enough.

 

[Xmas]

That would solve the LR44 problem...

 

[zanxion72]

Where can one get 675 batteries?
I have tried the SR44 and it seems that my little Minolta gives readings pretty close to the ones from my Gossen SBC. While using these batteries, should I care about their performance in the same way as with LR44? I mean will the voltage fall in the same way after time?

 

[Xmas]

The silver cells voltage is nearly as stable as the mercury cell.

But its voltage is higher ~1.5 as compared with 1.3.

You can set the ISO low say 2/3 of a stop, or

have the meter recalibrated or

have a Shockety diode fitted - solder iron job

to compensate for the increased voltage.

If you are not using slide film Id set the ISO low. There will be some loss in linearity but only critical with slide.

edit
http://www.rayovac.com/Products/Hearing-Aid-Batteries/Battery-Facts/Cross-Reference-Guide.aspx

 

[Jaf-Photo]

I buy 675 in the drugstore or chemist's.

Most modern batteries drop in voltage over time.

They tend to die quite quickly on me, so just keep a couple of spares.

 

[MattKing]

675 batteries are sold as hearing aid batteries. Costco has them for a relatively tiny price for 30.

 

[mklw1954]

I use 675 batteries in an inexpensive adapter for size: http://www.paulbg.com/Nikon_F_meter_batteries.htm and get good exposures. Use them in my Hi-matic 7S, SRT201 and other older cameras.

 

[Jaf-Photo]

The 7sII seems to be a very good camera. My copy has been very consistent and I've never had a frame that was completely off in exposure. This says a lot for a camera of that age.

For my copy 675 batteries work without adapters during their practical life. This is wonderfully hassle free. Shoot it for as long ad it lasts, when it dies pop a new one in.

 

[zanxion72]

I use 675 batteries in an inexpensive adapter for size: http://www.paulbg.com/Nikon_F_meter_batteries.htm and get good exposures. Use them in my Hi-matic 7S, SRT201 and other older cameras.

The good think with the lovely 7sii is that it takes the Zinc Air batteries without an adapter. They just fit in perfectly like that. I am running my last roll of Plus-X in it, half with auto metering and half with manual exposure and I cannot wait to develop it.
I love how it handles. Small, beautiful and silent. I love carrying it with me. (Will it be really silly buying a second one?)

 

[fotch]

The good think with the lovely 7sii is that it takes the Zinc Air batteries without an adapter. They just fit in perfectly like that. I am running my last roll of Plus-X in it, half with auto metering and half with manual exposure and I cannot wait to develop it.
I love how it handles. Small, beautiful and silent. I love carrying it with me. (Will it be really silly buying a second one?)

Question, my impression is that the zinc air won't last long at all. What is your experience? TY

 

[Kirks518]

Question, my impression is that the zinc air won't last long at all. What is your experience? TY

Once the little peel off sticker that keeps air from getting into the cell/activating it is removed, the life expectancy is a couple of months. Because of that, I chose to use the LR44's.

 

[zanxion72]

Now that we are speaking of how long the batteries last, how can one tell that in the 7Sii the battery needs to be replaced? Is there any battery testing procedure within the camera?