Lunasix 3 black version, what batteries?

[Helge]

The black version of the Lunasix 3 is supposed to work on silver oxide batteries. Is this true?
Does that mean that it works correctly with 1.5V batteries?
It would be tempting to get some passive adapters and load them with SR44 batteries.
Would this work?

 

[MattKing]

There are a couple of minor versions of the Lunasix 3 that differ slightly, but any that I have encountered - including black ones - required a 1.3 volt battery or some sort of adaption.

 

[wiltw]

Metering circuits that employ the Wheatstone Bridge design can get away with 'wrong Voltage' battery, but many meters do not use such a design. Best to find a thread that discusses your specific meter with 'wrong' battery.

 

[BrianShaw]

Most are PX-13, mercury cell. Might not be insensitive to voltage as Sekonic offered a voltage-reducing silver cell adapter, which works quite well in that meter. It was pricey and now out of production.

Camerapedia indicates that "later ones" were 1.5v... but I've never had clarity on how to identify a "later one". I thought the black ones were the "later ones" and used RM625 1.5v cells. It should state the battery requirement near the batery compartment.

 

[wiltw]

At one time, Gossen offered an adapter for putting 2xSR44 in a LunaSix and Voltage converted right output voltage. The existence of this makes it less likely that the meter was not Voltage dependent for its accuracy.

Someone posted in 2020, "My Lunarsix 3 showed a variable error when fed with 1.5 volt cells. Not far off in the middle of the scale but increasingly less accurate at the high end."

Might this product be still available?

PX14 Adapter - Gossen Lunasix Voltage Reducing Converter replacement for mercury batteries PX14, 2MR9, EPX14, V14PX, H-2D.

 

[Helge]

Metering circuits that employ the Wheatstone Bridge design can get away with 'wrong Voltage' battery, but many meters do not use such a design. Best to find a thread that discusses your specific meter with 'wrong' battery.

PX-13, mercury cell. Might not be insensitive to voltage as Sekonic offered a voltage-reducing silver cell adapter, which works quite well in that meter. It was pricey and now out of production.

There is always the option of using two of the expensive adapters. But that’s about plus $70 in Denmark.

Numerous places on the web mentions that the black version in particular was made for use with silver oxide batteries.

I don’t know about the 3s version.

I guess people back then had qualms about using mercury cells, or thought they were too expensive?

 

[BrianShaw]

I don’t know about your part of the world, but where I live the mercury cells were banned decades ago due to environmental concerns. That’s why we stopped using and having access to them.

 

[Helge]

I don’t know about your part of the world, but where I live the mercury cells were banned decades ago due to environmental concerns. That’s why we stopped using and having access to them.

Well, that seems to be the problem.

 

[wiltw]

I don’t know about your part of the world, but where I live the mercury cells were banned decades ago due to environmental concerns. That’s why we stopped using and having access to them.

Europe banned mercury in batteries in 1991. A law was passed in 1996 making the sale of mercury in batteries illegal in US for anything but military/medical/industrial uses in larger batteries.. Interestingly, some batteries containing mercury were still available in 2016, according to one report.
www.newmoa.org/prevention/mercury/imerc/factsheets/batteries_2018.pdf

 

[BobD]

I've seen two 'Luna Pro S' meters (same as Lunasix 3) that used 1.5v batteries. Actually, one of those may have been a regular Luna Pro -- I'm not sure of my recollection on that. They were black but I have also seen many of them that are black that use the mercury cells so you can't go by color. The only way I know to tell is to look at the printing under the battery cover on the back. Gossen evidently made very few of the 1.5v versions. I say that because I have spent quite a bit of time looking for one. Maybe they're easier to find in Europe?

YouTuber "Fix Old Cameras" has a video on converting a Luna Pro to use 1.5v cells via diode installation if you are comfortable with disassembly, soldering and reassembly.

Another solution is to get one of the Luna Pro models that use 9v batteries. I recently found a Luna Pro F in mint condition that works perfectly. It's a bit large, however. I think the Luna Pro SBC (also 9v) might be a little smaller.

 

[chriscrawfordphoto]

All Lunasix 3, Luna Pro, and Luna Pro S meters were made to use 1.3v Mercury batteries. Near the end of production of the Luna Pro S, the last version of this meter made, they included a battery adapter that lowered the voltage of 1.55v silver oxide batteries to match the voltage of the Mercury cells the meter was calibrated for. This adapter was also sold separately so people with the older meters could buy the adapter and use it on their meters. The meters that came with the adapter were marked "1.55v Silver Oxide" on the bottom plate; but it is important to know that this applies ONLY if the meter still has the adapter. If a previous owner lost it or kept it, the meter still requires the 1.3v mercury cells!

 

[Helge]

All Lunasix 3, Luna Pro, and Luna Pro S meters were made to use 1.3v Mercury batteries. Near the end of production of the Luna Pro S, the last version of this meter made, they included a battery adapter that lowered the voltage of 1.55v silver oxide batteries to match the voltage of the Mercury cells the meter was calibrated for. This adapter was also sold separately so people with the older meters could buy the adapter and use it on their meters. The meters that came with the adapter were marked "1.55v Silver Oxide" on the bottom plate; but it is important to know that this applies ONLY if the meter still has the adapter. If a previous owner lost it or kept it, the meter still requires the 1.3v mercury cells!

That is the most succinct and precise explanation of the history I’ve come about. Thank you! Explains a lot of the confusion.

I've seen two 'Luna Pro S' meters (same as Lunasix 3) that used 1.5v batteries. Actually, one of those may have been a regular Luna Pro -- I'm not sure of my recollection on that. They were black but I have also seen many of them that are black that use the mercury cells so you can't go by color. The only way I know to tell is to look at the printing under the battery cover on the back. Gossen evidently made very few of the 1.5v versions. I say that because I have spent quite a bit of time looking for one. Maybe they're easier to find in Europe?

YouTuber "Fix Old Cameras" has a video on converting a Luna Pro to use 1.5v cells via diode installation if you are comfortable with disassembly, soldering and reassembly.

Another solution is to get one of the Luna Pro models that use 9v batteries. I recently found a Luna Pro F in mint condition that works perfectly. It's a bit large, however. I think the Luna Pro SBC (also 9v) might be a little smaller.

I have quite a few of vintage Gossen in various states. The F with 9V and flash measurement is fine, but it doesn’t go that low, they are big and they are somewhat unreliable IMHE.
The unreliability is also a problem with the Pro SBC. And again it’s the same size.
I’d love a good copy of that though.

The Lunasix/Pro line of CdS meters are super simple, rugged and go incredible low considering their age. Lower than many modern meters and lower than the F.
And they look damn good.

 

[BrianShaw]

All Lunasix 3, Luna Pro, and Luna Pro S meters were made to use 1.3v Mercury batteries. Near the end of production of the Luna Pro S, the last version of this meter made, they included a battery adapter that lowered the voltage of 1.55v silver oxide batteries to match the voltage of the Mercury cells the meter was calibrated for. This adapter was also sold separately so people with the older meters could buy the adapter and use it on their meters. The meters that came with the adapter were marked "1.55v Silver Oxide" on the bottom plate; but it is important to know that this applies ONLY if the meter still has the adapter. If a previous owner lost it or kept it, the meter still requires the 1.3v mercury cells!

Makes sense.

… and then there is this, which may be adding to the (my) confusion:

https://www.cameramanuals.org/flashes_meters/gossen_lunasix_electronic-02.pdf

 

[chriscrawfordphoto]

Makes sense.

… and then there is this, which may be adding to the (my) confusion:

https://www.cameramanuals.org/flashes_meters/gossen_lunasix_electronic-02.pdf

What I wrote about the Lunasix 3 also applies to the original Lunasix, the meter that instruction manual is for.

 

[chriscrawfordphoto]

That is the most succinct and precise explanation of the history I’ve come about. Thank you! Explains a lot of the confusion.



I have quite a few of vintage Gossen in various states. The F with 9V and flash measurement is fine, but it doesn’t go that low, they are big and they are somewhat unreliable IMHE.
The unreliability is also a problem with the Pro SBC. And again it’s the same size.
I’d love a good copy of that though.

The Lunasix/Pro line of CdS meters are super simple, rugged and go incredible low considering their age. Lower than many modern meters and lower than the F.
And they look damn good.

The Luna Pro SBC looks just like your Luna Pro F and also uses the 9v battery. The SBC does not meter flash, but has the same low-light capability as the older CdS Luna Pro meters.

 

[Helge]

The Luna Pro SBC looks just like your Luna Pro F and also uses the 9v battery. The SBC does not meter flash, but has the same low-light capability as the older CdS Luna Pro meters.

It meters flash with the right accessory.
I like the null metering, but the numbers of the Lunasix/Pro is fine too.
The (comparatively) subpar lowlight rating of the F is really the fly in the ointment. Such a big meter should be able to do better, otherwise it’s not pulling its weight.
Low light metering is really one of the most important things about having a meter because low light is so hard to judge.
If you can get away with 1/30th then why go with 1/15th?

 

[Helios 1984]

Actually, the Luna Pro is more sensitive than the SBC in low light.

- Luna Pro -8 LV
- SBC -5 LV
- Lunasix 3 -4LV
- Luna Pro F -1 LV

The Luna Pro SBC looks just like your Luna Pro F and also uses the 9v battery. The SBC does not meter flash, but has the same low-light capability as the older CdS Luna Pro meters.

 

[chriscrawfordphoto]

Actually, the Luna Pro is more sensitive than the SBC in low light.

- Luna Pro -8 LV
- SBC -5 LV
- Lunasix 3 -4LV
- Luna Pro F -1 LV

That's not true. The Luna Pro only goes to EV -4 at ISO 100, same as the SBC.

 

[Helios 1984]

That's not true. The Luna Pro only goes to EV -4 at ISO 100, same as the SBC.

You are correct, my comment was based on incomplete information.

 

[mug]

Recalibrate with silveroxide batteries is my recommandation.

https://learncamerarepair.com/downloads/pdf/Gossen-Lunasix-Repair-Article.pdf

 

[Helge]

Recalibrate with silveroxide batteries is my recommandation.

https://learncamerarepair.com/downloads/pdf/Gossen-Lunasix-Repair-Article.pdf

Recalibrating seems like a nightmare. It requires closing the case each time, perfect light and worst of all you bring the pots and cell into extremes where they are most likely less linear.

Either I’ll try my hand at installing a diode, or I’ll bite the bullet and buy two more adapters.

 

[BrianShaw]

Recalibrating seems like a nightmare. It requires closing the case each time, perfect light and worst of all you bring the pots and cell into extremes where they are most likely less linear.

Either I’ll try my hand at installing a diode, or I’ll bite the bullet and buy two more adapters.

Bite the bullet. Having thought about modifying and destroying one meter trying (getting it appart was a lot more difficult than I imagined), so bought the corrrect adapter and never looked back. Several people here have mentioned good success with the very affordable voltage-reducing adapters sold on ebay by someone in Thailand. I bought from CrisCam and paid more but just as satified.

 

[wiltw]

Several people here have mentioned good success with the very affordable voltage-reducing adapters sold on ebay by someone in Thailand. I bought from CrisCam and paid more but just as satified.

Years ago I bought one of the ones from Thailand...unfortunately, shipping is now $10 so the savings are not as dramatic as the $20 item price.

 

[Helge]

Bite the bullet. Having thought about modifying and destroying one meter trying (getting it appart was a lot more difficult than I imagined), so bought the corrrect adapter and never looked back. Several people here have mentioned good success with the very affordable voltage-reducing adapters sold on ebay by someone in Thailand. I bought from CrisCam and paid more but just as satified.

Do you have a link to those? Can’t even find a mention of them.
That would be a game changer for everyone.
Having to put down close to $150 just to permanently load a couple of cameras with batteries and a Lunasix 3, is a bit ridiculous.

 

[BrianShaw]

Do you have a link to those? Can’t even find a mention of them.
That would be a game changer for everyone.
Having to put down close to $150 just to permanently load a couple of cameras with batteries and a Lunasix 3, is a bit ridiculous.

@wiltw (post #23) can give more details as he is (one of) the people I was mentioning who bought this:

MR9 MR-9 PX625 PX13 Battery Adapter for Film Camera & Exposure Meter / Mercury | eBay

Price is for one adapter only. Use of 386 / SR43W Silver Oxide battery (1.55 V) to.

www.ebay.com

Here is what I bought and using productively:

MR-9 Mercury Battery Adapter

Our mercury battery adapters are the perfect solution for vintage collector cameras and equipment that were designed for use with mercury batteries.

shop.criscam.com

There are others on ebay that ship from Japan and priced somewhere in between. Ironically, they all look the same... and maybe they really are all the same. As long as one doesn't make the mistake of buying the much less expensive adapters that do not do voltage reduction. As mentioned above, shipping from wherever to wherever is very costly, especially for small items.

For me these adapters are worth the price as they enable use of old gear without fiddling with modifications or short-lived zinc-air cells. I use them in a Sekonic Luna Pro, Richol Singlex TLS (my most hated camera but it is an heirloom so I use it anyway), and in the past in Canonet. They provide good and reliable service but, as you say... at a cost.