View Full Version : Using a Lunasix F and a fiber optics probe

26-May-2012, 01:21

I got this Gossen accessory when I bought my Lunasix F http://www.butkus.org/chinon/flashes_meters/luna-pro_f/body38.jpg and I read it can be used to measure the light directly on the focusing screen. I think it needs a compensation of 3 stops. Did someone know about that ? How to use it ? Does it need also a compensation beacause it is used "after" the focusing screen ?

26-May-2012, 03:29
I wouldn't trust the instructions without a check against a good working meter.
Old meters can go off-specs after some time, and the light trasmission of different ground glasses can vary: an old one made in early '900 is no match for some of the very expensive ones made during the last 20 years.
Maybe there is some hype involved, but i have read some impressive numbers about the "speed" of some specialty focusing glasses (some actually made in plastic..)

I tried to win one of those fiber optic sonds for Gossen meters, with no luck. One week ago i found the "micro" adapter, which i will try for ground glass readings. I hope it would be a viable way to make new diaphragm scales for barrel lenses i have fitted in a shutter.
It could be usable as a meter for picture taking on 5x7 and 8x10, but i have to make a conversion chart before: for a shooting session you need accurate absolute readings, while designing a new stop scale needs just relative readings (wide open, close half stop, close one stop, etc.).

The accessory you own was designed for reading on top of the ground glass, so once you know if/how much you have to adjust, it would be perfect for any (large) format.
I also own a SinarSix, which is a modification of the original Lunasix, but it's limited to the 4x5" format, cause the reading arm is inside a kind of film holder. It reads under the glass, and exactly at the film plane, but the only way to use it with the larger formats is with a 4x5" reducing back.

Fortunately the sond you own can be used with second generation Lunasix meters, which have no battery problems; both my Lunasix and Sinarsix use silver oxide cells, which are unavailable.
Wein cells last very little, and other solutions need a complex readjusting of the meter.

Enjoy your sond, it's usable with any format and very practical, especially for extreme close-up.
No surprise it's a desidered item... which makes it relatively expensive, considering its simplicity.

have fun


26-May-2012, 03:43
Thanks for the answer. Here is my "meter setup" : 74209

My Lunasix F is quite accurate and doesn't need exotic batteries. Still waiting for my Sinar F2 (the postman will deliver next week).

So that' cool to know Ican use that system on my future 4x5 camera. The next step is to deal (really) with zone system.

Drew Bedo
26-May-2012, 06:49
I use a sinar Booster-1 probe with my Minolta autometer IV F. IThe probe goes into a Sinar-Six holder when shooting with my 4x5 camera.t This rig works pretty wll but I find it fidely to use in the studio and cumbersome in the field (and so I don't bring it).

The current state of the art is *(I think) the sinar probe and
broncolor meter used with the Sinar metering back—on Sinar cameras.

Are there other usable focal plane metering solutions out there now?

26-May-2012, 08:51
Thanks. It's gonna be a sinar Booster-1 probe for beggar for me...