Luna Pro SBC

[ColColt]

Today I thought I'd break out the Gossen Luna Pro SBC meter to see if it was still up to snuff if needed...if wasn't. With a new battery and all things checked it was consistently reading about 1 stop under two other known good cameras, the F2A and Nikkormat FT3. Those read the same thing. They would read in sunlight 125 @ f/11 whereas the Luna Pro indicated f/16.

I decided to see what my D7000 thought of the Luna Pro's exposure recommendations and used what it showed. Each shot was underexposed by 2/3-1 stop in comparison with what the D7000 meter displayed. This was true in sunlight or shade with the Luna Pro showing underexposure each time.

I'm not sure how to fix this problem, if I can. It would work if I set the ASA dial to 200 instead of 400 but, that's not a proper fix. Any suggestions? I know there's nowhere to send it to have it recalibrated anymore most likely.

 

[AgX]

Gossen officially does no longer repair it.
I assume due to lack of parts. But if your sample does not need parts... (except maybe the aluminum plate, which maybe you might omit)
But I would inquire at Gossen anyway.

There was a workshop specialized in meters in California too.

 

[Arvee]

It's not a problem; Gossen meters (Germany) typically give readings similar to what you are seeing. I have several Gossens, old to current, and they all read about the same and are about 1/2 to 2/3 stop underexposed compared to my D7100. Just set the ISO setting for 1 stop more exposure, as you said, 200 instead of 400. The meter is working to spec.

SBC's were cal'd for slide film so they wouldn't blow out the highlights, hence the slight underexposure.

 

[ColColt]

What's puzzling is I measured a white wall with the digital camera on manual...125 @f/4. The Luna Pro measured the same thing. Earlier it wasn't doing that. I metered the grass and got the same reading this time as I did with the digital camera. I then tried to meter a house across the road with still a bit of sun on it with the camera and got 125 between 8 and f/11. the Luna Pro metered it at a bit over 125@f/16.

 

[AgX]

All german meters had to work accordingt the same official german standard.

 

[Arvee]

What you saw was a slight difference in the linearity of the two different metering systems, and, if you're using the digital camera in matrix mode, there will additional differences because of Nikon's interpretive firmware for the metering system.

Don't worry about it; you're comparing apples/oranges and they will never confirm each other's readings. From the exposures you have passed along for the SBC, it's on the money and I recommend you simply adjust the ISO to get the desired result you like.

 

[rthollenbeck]

The SBC is my favorite meter.
I don't guess I ever noticed but I just compared it to my phone/app meter and there is about 2/3 to a full stop of difference.

 

[ColColt]

I had decided to take a few shots with the digital camera with it's recommended exposure and then shot the same scene with the Luna Pro's. You could see distinct difference in exposure.

BTW-I was using matrix metering.

 

[ColColt]

Unfortunately that's the Luna Pro...not the SBC which is a bit different and uses a 9V battery.

 

[Sirius Glass]

The only thing that I do not like about my Luna Pro SBC is that sitting in its case, it likes to eat 9 volt batteries.

 

[ColColt]

This is the SBC...

http://www.micro-machine-shop.com/Gossen_Luna-Pro_SBC.pdf

 

[Sirius Glass]

This is the SBC...

http://www.micro-machine-shop.com/Gossen_Luna-Pro_SBC.pdf

Yours has a needle that sweeps across the scale, mine has three LED lights: under exposure, correct exposure, over exposure.

 

[Arvee]

OP, if you still think you need to have the meter cal'd, you can sent it to Quality Light Metric in Hollywood, CA. It'll cost you somewhere between $60 and $80 for a calibration. I seriously doubt you'll see much difference in your results based on the readings you have posted here for the SBC.

 

[ColColt]

If I were shooting B&W or even color negatives I could live with that. However, you all know transparencies don't have a wide latitude and therein lies the rub. Still, underexposure is worse than overexposure with negatives. Once the detail is gone, it's gone.

 

[ColColt]

There is a little green mark, for lack of a better word, on the far left side of the meters face. You take the battery out and make sure the meters needle aligns with that green mark...I did that. I double checked that I was on ASA 400 and that the other marks listed in the manual lined up. Everything should have been good to go but wasn't.

 

[Arvee]

You're right; if you were to use the D7000 to expose chromes, I would venture to say you would have blown highlights. Since the SBC was designed/manufactured during the time when chrome was the popular medium, it will protect those highlights in light of chrome's short exposure latitude. It all depends what film you're going to be using.

I shoot my 7100 at -2/3 exposure comp to get results that are comparable to my chromes from the past and keep detail in the highlights.

GL

PS The exposure dial on the SBC can sometimes drift off the zero mark for no exposure comp. Check the outer ring to see there is no exposure comp dialed in.

 

[ColColt]

For most scenes on mine I have to go +.3, which isn't much but makes a difference. It could probably just stay at zero null and be fine-especially when you're just shooting RAW or jpegs. Many changes can be made in post processing.

 

[AgX]

ColColt, thank you linking to that manual. As that Berkey version is different from the original Gossen version.

 

[ColColt]

Yes, they are a bit different. The Luna Pro uses the now defunct in the states, the 1.35v mercury battery whereas the SBC uses the standard 9v battery.

PS The exposure dial on the SBC can sometimes drift off the zero mark for no exposure comp. Check the outer ring to see there is no exposure comp dialed in.

I overlooked that part initially and yes, that was one of the first things I checked.

 

[ColColt]

I ran across this in my venture to find info about the calibration. Does it ring a bell to anyone?

"I have a Luna Pro SBC that was off and there is one adjusting POT on the left front as you look at the back pointing it as if you were using it. The little screw in the center of the plate is the only one holding it on. The way I adjusted mine, I held it to a known light source that was measured with my digital Nikon D2x and while holding the measure button in I turned the adjustment until the center LED light up. that easy. It takes a 9v batt."

I didn't know there were any LED's in that meter.

 

[MattKing]

Yes, they are a bit different. The Luna Pro uses the now defunct in the states, the 1.35v mercury battery whereas the SBC uses the standard 9v battery.



I overlooked that part initially and yes, that was one of the first things I checked.

There is an original Gossen manual for the Luna Pro SBC - known everywhere as the Profisix except in the USA. That manual differs significantly from the Berkey Marketing version.

 

[MattKing]

I ran across this in my venture to find info about the calibration. Does it ring a bell to anyone?

"I have a Luna Pro SBC that was off and there is one adjusting POT on the left front as you look at the back pointing it as if you were using it. The little screw in the center of the plate is the only one holding it on. The way I adjusted mine, I held it to a known light source that was measured with my digital Nikon D2x and while holding the measure button in I turned the adjustment until the center LED light up. that easy. It takes a 9v batt."

I didn't know there were any LED's in that meter.

That is for the Luna Lux SBC - a slightly different meter, in that it replaced the display needle with several LEDs.

 

[ColColt]

I thought they were one and the same, only being called differently depending on where they were sold.

We must have typed at the same time. That comment above was for Post #23.

 

[MattKing]

I thought they were one and the same, only being called differently depending on where they were sold.

The meters (Profisix and Luna Pro SBC) are the same, but the manuals are not.

 

[MattKing]

And the Luna Lux is a different meter. It may be known as a Lunalite in some markets.