Two Gossen Luna Pros do not work correctly with the battery adaptor

[BetterSense]

Matt-I don't see any "transfer" scale on my meters. Perhaps I am missing something quite obvious? One simply reads the EV values, and moves the dial.

If you do that, your meter will read several stops off.

My luna-pro has a silver EV scale and a yellow transfer scale. You have to use the yellow scale to set the dial calculator. The EV scale is several stops different. I'm not sure why there are two scales at all.

[Chan Tran]

Keep the meter in exact position, open the dome to switch it to reflected mode. The reading should be 2.7 EV or so higher. If not then the meter probrably always in reflected light mode.

[MattKing]

Is this the meter you have: http://www.ebay.ca/itm/Gossen-Luna-P...item20ce27ba67 ?

If so, you can see the two different scales near the bottom.

By the way, after posting last night I figured out that the difference between the scales will vary if you change the ISO/ASA/EI setting.

Which makes sense, as EV is independent of film speed, while the exposure readings you use are not.

[AgX]

Keep the meter in exact position, open the dome to switch it to reflected mode. The reading should be 2.7 EV or so higher. If not then the meter probrably always in reflected light mode.

There is no "reflected light mode" (in any meter with a dome), in the meaning of a switch. Aside of enlarging the angle of coverage, the dome acts as 82% grey-filter. That's all.

[bobwysiwyg]

There is no "reflected light mode" (in any meter with a dome), in the meaning of a switch. Aside of enlarging the angle of coverage, the dome acts as 82% grey-filter. That's all.

Could you explain this statement in more detail?

[Fred Aspen]

Bob,

For example, Minolta meters have an electrical switch which is activated or not activated when using the dome or reflected light attachment. Gossen meters have no switch, they simply have the dome over the sensor in incident mode or moved aside during reflected mode. Sekonic meters do not have such a switch.

I think Chan was thinking of the Minolta meter when he posted.

[bobwysiwyg]

Yes, I understand. I thought you were perhaps saying something else.

[Vaughn]

We have a couple of Luna Pro SBC that match up with all the other meters in reflective light mode, but will read two stops off in incident light mode. I am wondering if the domes are aging and yellowing -- perhaps transmitting less light than originally.

[Fred Aspen]

My Gossens with aging/yellowing domes are only 1/3 stop difference from the latest Luna Pro F with the bluish dome. Two stops seems like an unlikely difference caused by dome aging, unless there is some blockage inside the dome. You might take a magnifier and look into the sensor and see if there is any grunge in there.

Insect nest inside the dome?

[AgX]

Oops, I did not know of that Minolta switch...
I'm sorry for that!


But: Why do it complicated when you can do it simple?

Answer:
That grey-filter acting dome reduces the effective sensibiltiy of the meter in the incident lighting mode. Using a switch on the electric circuit and a more transparent dome gives more sensitivity in that mode.
However, that dome will have a certain opacity anyway in order to be effective. And any photographer working under such conditions should be able to do incident light metering without dome and to re-calculate the result...