Pentax Spotmatics

Ed Matthew · Mar 31, 2007

Is there a direct replacement for E400 and EPX625 mercury batteries for Pentax Spotmatics, or is it necessary to use a Wein cell and adapter?

Thanks,
Ed

Nick Zentena · Mar 31, 2007

There is a silver 400. There is also an exact same size silver battery with a different model number. Both will fit without an adapter. Locally for me neither is easy to find.

Any other silver battery small enough to fit the camera will work fine. You will likely need a rubber O ring to fit around the battery.

I'm not sure about the 625 batteries. Which model is that?

Jim Jones · Mar 31, 2007

I believe some models of Spotmatics use a bridge circuit in the meter that does not require constant battery voltage for accurate results. Information on this is available online. Perhaps a google search for Spotmatic battery will help.

Dan Fromm · Mar 31, 2007

Jim, I think that all Spotmatics including the K-mount version use a bridge circuit and can be used with nearly any battery that will fit.

gordrob · Mar 31, 2007

This has been discussed a couple of time before. Check this old thread in APUG - it gives a pretty good explantion of the battery issue.

(there was a url link here which no longer exists)

Regards
Gord

katabatic · Apr 1, 2007

The 'modern' battery you want to replace the E400 is the E387S. I'm using one now in my Spotmatic II and it works perfectly with no need for exposure compensation or adjustment as it ages. It comes with a small white plastic sleeve, which you need to make it the right diameter. The one counterintuitive thing is that the battery goes in 'upside down'...you'll see when you try it (if you do it wrong you won't hurt anything; the meter just won't deflect until you put it in right.

Chazzy · Apr 1, 2007

While we're on the subject of Spotmatic metering, would I be right to assume that all the Spotmatics use stop-down metering?

CraigH · Apr 1, 2007

The Spotmatic F meters wide open & I think the electro Spotmatics also meters wide open.

Craig

benjiboy · Apr 3, 2007

Light reading

CraigH said:
The Spotmatic F meters wide open & I think the electro Spotmatics also meters wide open.

Craig

That's right Craig, the Spotmatic F had open aperture metering, but no meter switch, the only way of switching way of switching the meter off was to put the lens cap on, I used to sell them, we used to get lots of customers bringing them back because they hadn't read the instructions .

Steve Roberts · Apr 3, 2007

Bentley Boyd said:
That's right Craig, the Spotmatic F had open aperture metering, but no meter switch, the only way of switching way of switching the meter off was to put the lens cap on, I used to sell them, we used to get lots of customers bringing them back because they hadn't read the instructions .

I always hated that system. It seemed like a really penny-pinching way of going about things. I had a K1000 where the meter was switched by the same method and although I knew the battery lasted for ages, it always seemed wrong not to be able to switch off the meter by some means other than putting the lens cap on - something I never normally do when a lens is mounted on the camera. The KM used the same system.

Steve

Chazzy · Apr 3, 2007

How is the Spotmatic F capable of doing open-aperture metering with screwmount lenses? Did Pentax make lenses with an extra pin to output aperture information to the camera? I always thought that the Practica LLC's method of doing it with electrical contacts was interesting (the camera was stolen and I miss having a camera for 42mm screwmount lenses).

Zathras · Apr 3, 2007

Chazzy said:
How is the Spotmatic F capable of doing open-aperture metering with screwmount lenses? Did Pentax make lenses with an extra pin to output aperture information to the camera? I always thought that the Practica LLC's method of doing it with electrical contacts was interesting (the camera was stolen and I miss having a camera for 42mm screwmount lenses).

The later SMC Takumar and Super-Multi-Coated-Takumar lenses had extra "thingies" on the back of the lens to allow open aperture metering with the Spotmatic. With the older Super Takumars on a Spot-F, you use stop down metering just like on the older Spotmatic bodies.

Mike Sullivan

reub2000 · Apr 3, 2007

Steve Roberts said:
I always hated that system. It seemed like a really penny-pinching way of going about things. I had a K1000 where the meter was switched by the same method and although I knew the battery lasted for ages, it always seemed wrong not to be able to switch off the meter by some means other than putting the lens cap on - something I never normally do when a lens is mounted on the camera. The KM used the same system.

Steve

Wouldn't matter to me as I always forget to turn off my cameras.

Paul Howell · Apr 4, 2007

Ed Matthew said:
Is there a direct replacement for E400 and EPX625 mercury batteries for Pentax Spotmatics, or is it necessary to use a Wein cell and adapter?

I have 2 Spots and 1 F, I use hearing aid batteries with a small rubber washer to make up for the smaller size. One of my spots has an erratic meter so I use a handheld spot meter. I have been collecting Mirandas and use the larger size of hearing aid batteries.

benjiboy · Apr 4, 2007

Steve Roberts said:
I always hated that system. It seemed like a really penny-pinching way of going about things. I had a K1000 where the meter was switched by the same method and although I knew the battery lasted for ages, it always seemed wrong not to be able to switch off the meter by some means other than putting the lens cap on - something I never normally do when a lens is mounted on the camera. The KM used the same system.

Steve

On the other hand Steve I suppose it can't break

Pentax Spotmatics

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