Luna Pro SBC

ColColt · Jul 10, 2015

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

Strange...

MattKing · Jul 10, 2015

ColColt said:
Strange...

Not necessarily.

For one thing, the Gossen manual has a bunch of different languages in it, whereas the Berkey Marketing version is just English.

The Gossen manual is more likely to reflect international nomenclature for things like batteries, whereas the Berkey version will be US centred.

And the manuals include references to accessories, which may differ due to Berkey's distribution choices.

Here is the link to the English portion of the Gossen version - from Gossen's site: http://www.gossen-photo.de/pdf/ba_profisix_e.pdf

ColColt · Jul 10, 2015

thanks for the explanation. The version for English looks different than the one I downloaded before. I'll have to smoke it over.

AgX · Jul 11, 2015

The Problem with Gossen is that they did not gave really good informationm on what a meter actually does and how to handle metering results. There was a book published with their consent that did not make one really wiser.

I assume the idea behind the Berkey version was to make a somewhat better manual.

bdial · Jul 11, 2015

Or else, Quality Light Metric will fix it up and have it back to you before you miss it.

semi-ambivalent · Jul 11, 2015

On the back of the meter there is a small plastic screw head. Turning it skews the meter needle left and right. This should fix your reading issue. I cannot speak to the loss of linearity though I have heard of it. My SBC (Silicon Blue Cell) decided to just stop working a couple years ago. I fixed it with a Sekonic 308S; less aggravation.

Good luck,
s-a

rthollenbeck · Jul 11, 2015

Here is the Back of my LunaPro SBC. You can see the black adjustment pot off set from cent a little high and left.

ColColt · Jul 11, 2015

I may open it up and take a look...curious as to the innards anyway.

You can see the black adjustment pot off set from cent a little high and left.

That adjustment is to bring the needle over the green mark just to the left of the 3 on the left side. It's adjusted by disconnecting power to the meter and that screw turned until the needle lines up with the green mark. It's spot on.

ColColt · Jul 11, 2015

I took the little screw out from the back thinking the two halves would separate so I could have a look, they don't.

Arvee · Jul 11, 2015

If you want to separate the halves, you must unsolder the three wires that come off of the nulling potentiometer and attach to the circuit board. You can then take a look inside. There are four pots accessible through the PCB that allow adjustment. Each has a different function. Tweaking these pots without knowing which is which will guarantee making the meter unusable!

ColColt · Jul 11, 2015

I'm not going to get into that. It's just unstable and unusable far as I'm concerned. I put the Variable Angle attachment on it today and actually got better and closer to camera readings with it than without and didn't even compensate the +1 stop for it. I just left it set as if I were using it normally. That's just not right. Without the attachment it comes closer 70% of the time giving me what the camera indicates as long as I set it on ASA200 instead of 400. It's just unpredictable.

Arvee · Jul 11, 2015

Forgot to mention - the principle of operation is designed around the nulling potentiometer, which, if it hasn't been used in a while, will form oxidation on the wiper/resistive element. Through use, the oxidation is worn away. This oxidation is simply an added resistance that will introduce an error into the nulling process. Working the dial back and forth a couple of dozen times might improve the accuracy if it has been in storage.

ColColt · Jul 11, 2015

Once I take a reading and turn the needle to null, it wants to go past it. I try and bring it back and it wants to go past on the other side. I have to do it slowly or I cant center it. The meter hasn't been used in a long time so like most electronics I guess it needs a bit of exercising.

People laugh at me when I tell them I had to exercise my Marantz receiver and Pioneer RTR tape deck. You have to keep the juices flowing.

In retrospect, I suspect my old FTN will give problems with the meter once I get the proper batteries for it since the old mercury batteries are now defunct.

Sirius Glass · Jul 11, 2015

ColColt said:
Once I take a reading and turn the needle to null, it wants to go past it. I try and bring it back and it wants to go past on the other side. I have to do it slowly or I cant center it. The meter hasn't been used in a long time so like most electronics I guess it needs a bit of exercising.

People laugh at me when I tell them I had to exercise my Marantz receiver and Pioneer RTR tape deck. You have to keep the juices flowing.

Tapes that have information that you want to keep archived should be taken out of storage wound on another reel and then replaced back on the original reel. That will keep the layers of tape residing on the same tape sections above and below it for very long periods of time, thus prevention the magnetic image from migrating or imprinting from layer to layer. This is important for both analog and digital recordings. So fire up your Pioneer RTR tape deck play your tapes.

ColColt · Jul 18, 2015

I've been fiddling around with this meter and it's been most consistent with underexposing one stop about 90% of my test. I rotated the dial to -1 on the LW/EV scale and now it's spot on with my other cameras. Wish I knew what to tweak inside to fix it there rather than do what I did to get a proper reading.

MattKing · Jul 18, 2015

ColColt said:
I've been fiddling around with this meter and it's been most consistent with underexposing one stop about 90% of my test. I rotated the dial to -1 on the LW/EV scale and now it's spot on with my other cameras. Wish I knew what to tweak inside to fix it there rather than do what I did to get a proper reading.

The dials might be attached in the wrong position.

ColColt · Jul 18, 2015

No, it looks just like the photos shown in the manual. I either have to do it that way or set the dial to 200 rather than 400.

MattKing · Jul 18, 2015

ColColt said:
No, it looks just like the photos shown in the manual. I either have to do it that way or set the dial to 200 rather than 400.

I'm talking about whether the dials themselves are assembled correctly.

ColColt · Jul 18, 2015

I'm not sure about that. With the LW/EF scale set to zero the VF/EF pointer(white) is on 1 as shown in the manual.

ColColt · Jul 18, 2015

Are those cells replaceable?

AgX · Jul 19, 2015

You do not know which component is off. And replacing likely needs readjustment.

The Profisix is such a great merter, I would send it in for a repair if economic.

Arvee · Jul 19, 2015

ColColt said:
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.

As I indicated before, the correct exposure reading for the SBC on a sunny day with no clouds in incident mode will be f16 at 125 for ISO 100. There appears to be nothing wrong with your SBC. Nikon camera meters will be making readings in reflected mode and will usually indicate +2/3 stop more.

Don't monkey with the SBC; it is calibrated for slide film and will indicate slightly less exposure than the Nikon camera meters. If you don't like the exposure you're getting from the SBC, simply adjust the ISO or Exposure Comp dial and make photographs. Reflected camera readings vs incident SBC readings is comparing apples and oranges. I have six Nikons from the F2 to the D7100 and they all indicate about +2/3 stop more exposure than my two SBC meters, my Luna Pro F and a Luna Lux (these meters are all calibrated with the same test equipment). Also true for my two Sekonic 448s and my Sekonic 398 II. Your meter is doing what it was calibrated/designed/intended to do.

Make some photographs!

Chan Tran · Jul 19, 2015

Fred Aspen said:
Forgot to mention - the principle of operation is designed around the nulling potentiometer, which, if it hasn't been used in a while, will form oxidation on the wiper/resistive element. Through use, the oxidation is worn away. This oxidation is simply an added resistance that will introduce an error into the nulling process. Working the dial back and forth a couple of dozen times might improve the accuracy if it has been in storage.

That's why I want to get my hands on a Minolta auto meter II which works the same way except that the meter automatically turns the dial to null the meter. But it seems I would have to pay more for a II than a III or a IV.

Arvee · Jul 19, 2015

Chan Tran said:
That's why I want to get my hands on a Minolta auto meter II which works the same way except that the meter automatically turns the dial to null the meter. But it seems I would have to pay more for a II than a III or a IV.

I bought both my Sekonic 448s for less than $90 (one NOS). They operate on the same principle as the Minolta Autometer II. I am really pleased with the one hand operation.

ColColt · Jul 19, 2015

I feel a hand held meter should meter the same thing as your other cameras. If it doesn't one of the other is wrong. You'll get a different exposure at 125@f8 than at 125@fll and that's especially noticeable with slide film. I can set the SBC on 200 and I'll get a proper reading in accordance with my F2A or Nikkormat FT3, both which are known to be accurate. If I meter another scene the SBC will not read the same scene as the other two cameras.

I think it may just behoove me to send it to Quality Light and see what they have to say. I don't mind having to change the ASA on the meter to compensate but when it reads differently than the other cameras under varying light conditions, that seems wrong to me-it should read the same in sunlight, partial sunlight or shade as the cameras. Else wise, what good is it? If it was calibrated to underexpose approx. 1 stop, that hardly seems industry standard.

Luna Pro SBC

ColColt

MattKing

Moderator

ColColt

AgX

bdial

semi-ambivalent

rthollenbeck

Attachments

ColColt

ColColt

Arvee

ColColt

Arvee

ColColt

Sirius Glass

ColColt

MattKing

Moderator

ColColt

MattKing

Moderator

ColColt

ColColt

AgX

Arvee

Chan Tran

Arvee

ColColt

Luna Pro SBC

Moderator

Attachments

Moderator

Moderator

Privacy & Transparency

Privacy & Transparency