Pentax Spotmeter lens cap? battery?

Just got a "new" analog Honeywell Pentax Spotmeter (no, not digital, the cheaper, older one with the needle). I am using a 1.5 V battery with a stack of copper washers, and when testing it against my old Gossen averaging meter the readings look right on, so the difference in voltage from the 1.3V mercury battery it was designed for and this 1.5V does not seem to be affecting the readings. Am I missing something? I have not shot any film with it due to lack of time. Anyone with experience in this please let me know.

Also, the meter is always "on". I have not found a lens cap for it yet. Will using a lens cap save battery life? Obviously it's good lens protection, and I hate the thought of my battery's juice being wasted. The cap seems to be a 46mm inside screw or a 47mm slip-on...again, anyone can confirm this?

Thanks!

I had one of those for quite sometime, and in only recently sold it. It's probably halfway between my house and somewhere in Canada as we speak. But I had no problem getting the battery for it. Radio Shack will order it for you. Or you can do like I always did and buy it online. It is the Mallory/Duracell 640. When they went from mercury to whatever they use now, the voltage did change, but as you pointed out...it didn't seem to affect the way the meter worked. I never noticed any difference and went through a few of those new types. They don't last as long as the mercury batteries did, but you'll still get a year or two out of them. The 9V battery in the handleis a conventional 9V like you would put in a radio or something. My newer digital spot meter uses just the 9V. The High reading gets its power from the 9V and is always on all the time. The Low reading only is activated when you press the trigger and therefore the 640 won't get chewed up from not having a cap on. So you might go through a lot of 9V batteries if you don't have a lenscap.

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Originally Posted by Rafael Garcia

Just got a "new" analog Honeywell Pentax Spotmeter (no, not digital, the cheaper, older one with the needle). I am using a 1.5 V battery with a stack of copper washers, and when testing it against my old Gossen averaging meter the readings look right on, so the difference in voltage from the 1.3V mercury battery it was designed for and this 1.5V does not seem to be affecting the readings. Am I missing something? I have not shot any film with it due to lack of time. Anyone with experience in this please let me know.

Also, the meter is always "on". I have not found a lens cap for it yet. Will using a lens cap save battery life? Obviously it's good lens protection, and I hate the thought of my battery's juice being wasted. The cap seems to be a 46mm inside screw or a 47mm slip-on...again, anyone can confirm this?

Thanks!

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I have one which I've used with the WeinCell MRB625, 1.35 v battery. Like you I have to fill the extra space.

The problem with using a 1.5 v battery is that it may read correctly only for part of the range. That was my experience when I tried a 1.5 v battery. The basic problem is that the scale is not linear.

Even with the WeinCell, I find I am off by up to half a stop at different settings. Another problem is that when the battery goes bad, it may still test okay using the standard test of comparing EV 10 on low and high scales, but it will read far off for higher EVs. I finally gave up and got a Digital Pentax.

Thanks Michael and Leonard. I am taking it with me tomorrow to the local camera store and getting a lens cap that fits. For now I found a "pinch" cap in my assorted junk box that fits if I allow the entire cap to go into the lens tube.

I also read that the correct battery is still being made by Varta in Germany...don't know how old that post was, but I will investigate.

There is an easy solution for the substitution of the original Mercury type batteries. It allows you to use readily available batteries, and downconverts and regulates the voltage to 1.3V. It's called an MR-9 adapter, and can be purchased in the USA from:

http://www.classic-cameras.com/MR-9.htm

or in the U.K. from:

http://www.smallbattery.company.org....r9_adapter.htm

I just bought a pair of them to run a Nizo Super 8mm camera that used that Mercury type 1.3V battery that is no longer available. They work great, and they fit in the space the original batteries occupied without having to resort to copper shims.

As for a lens cover, a creative solution a lot of guys use in the film industry is spring loaded rifle scope covers. They come in a variety of diameters, and they make flipping the cover up and out of the way a rather simple and easy one handed process. They have the additional benefit of ensuring that you will never lose your cover.

Here's a link to visualize what I'm talking about:

http://www.gunaccessories.com/ButCre...vers/index.asp

BTW, I have no affiliation with either of these products or vendors. I just have personally found these items to be very useful.