Luna Pro SBC

Arvee · Jul 19, 2015

ColColt said:
If it was calibrated to underexpose approx. 1 stop, that hardly seems industry standard.

Therein lies the problem: no industry standard. German cameras/meters are calibrated to 5600K standard; Japanese meters/cameras are calibrated to a 3400K standard. There is no universal standard and each mfr. has the freedom to use his/her K factor based on how they want the measurement system to perform.

Perhaps you should trade your German meter for a Japanese meter; you will likely come closer to a situation where you might get some semblance of consistency since you are using Japanese cameras.

Google: Exposure meter calibration standards; you will be opening a can of worms

Again, I repeat, apples vs oranges. Good luck!!

rthollenbeck · Jul 19, 2015

Fred Aspen said:
Perhaps you should trade your German meter for a Japanese meter; you will likely come closer to a situation where you might get some semblance of consistency since you are using Japanese cameras.

Assuming both meters read on the same curve: Why not just adjust one or the other(like with the ISO setting) to read the same. Which ever gives you the better results.

At least I would prefer that to trading off equipment I like just to gets something else to match nation of manufacture. You'll have to remember to always ad/subtract that value of adjustment.

ColColt · Jul 19, 2015

It makes me wonder what a Leica R camera is calibrated for. I never had one of those but did have an M2 and it responded well in exposure to the readings of a Japanese camera meter.

rthollenbeck · Jul 19, 2015

Why wouldn't the M2 respond well? The assertion here was that the meters have some slight difference in calibration. The time value should be the same on m2 as any other shutter. ie 1/2sec is 1/2sec anywhere.

ColColt · Jul 19, 2015

I was referring to the meter calibration. If they're one way for Japanese cameras why wouldn't they be different for a German camera?

German cameras/meters are calibrated to 5600K standard; Japanese meters/cameras are calibrated to a 3400K standard.

I don't understand the logic there. What does the color temperature in degrees Kelvin have to do with a given shutter speed calibration? 125 is 125.

ColColt · Jul 19, 2015

I'm just trying to get a handle on this.

benjiboy · Jul 20, 2015

Fred Aspen said:
Therein lies the problem: no industry standard. German cameras/meters are calibrated to 5600K standard; Japanese meters/cameras are calibrated to a 3400K standard. There is no universal standard and each mfr. has the freedom to use his/her K factor based on how they want the measurement system to perform.

Perhaps you should trade your German meter for a Japanese meter; you will likely come closer to a situation where you might get some semblance of consistency since you are using Japanese cameras.

Google: Exposure meter calibration standards; you will be opening a can of worms

Again, I repeat, apples vs oranges. Good luck!!

Degrees Kelvin aren't a measure of exposure that can be calibrated in a light meter, ° Kelvin are purely measurements of the colour temperature of light https://en.wikipedia.org/wiki/Kelvin

ColColt · Jul 20, 2015

Thank you, sir...great explanation to a novice. Changing the ASA does yield better exposures compared to my cameras but it's not consistent-close, but no cigar. I haven't noticed any loss of voltage from the battery as yet but it's relatively new. The 9v batteries are not cheap anymore, in fact, most batteries are twice what they do and should be, IMHO. I just paid a tad over $10 for two PX625A batteries to be able to use my old Nikon FTN again.

Arvee · Jul 20, 2015

If I'm not mistaken, your FTN requires tow of the 1.35V mercury cells which are no longer available. Those PX625A (1.5V alkaline cells) will cause large errors in the meter circuitry unless the camera has been modified for the higher voltage cells.

ColColt · Jul 20, 2015

That's right, that's why the FTN's have been inactive for some years till I learned of the various ways to override the fact old mercury batteries went defunct years ago in the states. Robert Decker was the one that mentioned the PX625A batteries are the same size as the old PX13 or PX625 batteries but were, of course, the wrong voltage. Those cameras have been sent to him for proper calibration and a general CLA.

ColColt · Jul 23, 2015

Speaking of the SBC, I talked with a fellow this afternoon at Quality Light Meter in LA and told him what my meter was dong. He said send it in and they'd give an assessment and give me a call before doing anything.

I've also looked at the Gossen DigiPro F2, seems like a decent up to date meter but know nothing about it other than a few reviews. I may check into that one as it seems a decent price for a meter that does all and more I need.
[h=1][/h]

kobaltus · Jul 24, 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.

I think it is nothing to fix in your SBC meter. I have just test my 2 profisix SBC and east german weimarlux cds meter against my nikon analog and digital cameras.
The test shows equal result for all german meters and readings in my old nikon d80. But meters in analog cameras( 2 F2 AND 2 nikkormats) shows the same 1 stop overexposure.
So, my conclusion is that cameras from seventies are calibrated for bw film (+1). German meters are calibrated for dias (-1), the same as my digital camera ( pixels does not like overexposure like dia films).
It is not scientific conclusion, but my hand meters never let me down, when I shot dia films. And for bw a slightly overexposure is a golden rule for masters like A. Adams and B. Barnbaum.

ColColt · Jul 24, 2015

I don't know, I still think there's a problem. I know some indicate that's the way the meter was set up but what good is a meter that underexposes for to days(or yesterdays) cameras? Slight overexposure is fine if you're shooting a camera with a larger negative but with 35mm it leads to more grain and a too dense negative. Sharpness can be hurt as well. With transparencies it's the death knell as they won't take much overexposure before you loose all detail.

kobaltus · Jul 25, 2015

ColColt said:
I don't know, I still think there's a problem. I know some indicate that's the way the meter was set up but what good is a meter that underexposes for to days(or yesterdays) cameras? Slight overexposure is fine if you're shooting a camera with a larger negative but with 35mm it leads to more grain and a too dense negative. Sharpness can be hurt as well. With transparencies it's the death knell as they won't take much overexposure before you loose all detail.

Maybe? We all have problems. But in this case the problem is not your SBC hand meter.

Roger Cole · Jul 25, 2015

I have an SBC. It works great and agrees pretty much across the board with my Pentax LX and MX (as well as my Soligor Spot and my Mamiya 645 Pro AE prism finder.) Oh of course there will be some slight variation but allowing for differences of area read and such they all agree pretty closely and all give well exposed film for both negatives and transparencies. Of course color neg you can just about guess at and do ok, but it's a myth that black and white, if you're a careful worker anyway, is all that forgiving and transparency least of all.

Newer cameras are harder to compare because they have matrix metering that reads different areas and gives a computer assessment of what it thinks is best based on similar scenes. It can work very well but makes it hard to compare them with a conventional meter unless you read something very uniform like a gray card.

ColColt · Jul 25, 2015

kobaltus said:
Maybe? We all have problems. But in this case the problem is not your SBC hand meter.

Really? Then what is your assessment of the problem? When it doesn't agree with my F2A, Nikkormat FT3 or FTN, I remain curious as to what the problem is if not the SBC.

bdial · Jul 25, 2015

I would expect it to be within a stop of any of those cameras when metering a uniform target like a grey card or blank wall or whatever.
Quality Light Metric does good work, and they are quick, life is too short to handicap yourself with gear that's suspect.

kobaltus · Jul 26, 2015

ColColt said:
Really? Then what is your assessment of the problem? When it doesn't agree with my F2A, Nikkormat FT3 or FTN, I remain curious as to what the problem is if not the SBC.

Yes. I agree. And maybe the absolute truth lay somewhere between 1 stop difference among german sbc meters and nikon cameras. Then we have 2 big problems.
Find the solution may be an endless project for apug helpful membersheeps.

ColColt · Jul 26, 2015

And maybe the absolute truth lay somewhere between 1 stop difference among german sbc meters and nikon cameras.

I suppose the only thing to do to ease my mind is send it to QLM as it doesn't make sense to me how someone with a Japanese camera goes to Frankfurt and can't get a proper meter reading due to underexposure. Did not the fellows at Gossen not think their meters were going to be used around the globe and calibrate it accordingly? I guess I'm just thick headed and can't see the logic.

Sirius Glass · Jul 26, 2015

kobaltus said:
Yes. I agree. And maybe the absolute truth lay somewhere between 1 stop difference among german sbc meters and nikon cameras. Then we have 2 big problems.
Find the solution may be an endless project for apug helpful membersheeps.

My Hasselblad PME, MyGossen Luna Pro SBC and my Sekonic Flashmate F-307SG all agree.

Arvee · Jul 26, 2015

There is absolutely no guarantee that the meter will ultimately agree with your other cameras even if you send it to QLM.

You can, however, send in all your other cameras as well and have them all calibrated to each other. George can do this. Perhaps this will relieve your anxiety, but I guarantee, it ain't gonna be cheap!!

Or, you could just take a Zanax, adjust your exposure compensation dial and go merrily on your way!

thuggins · Jul 26, 2015

This has been a lot of time and effort devoted to a big, clunky, cheap, "plastic fantastic" meter. Apparently Gossen didn't have a whole lot of faith in the accuracy since page 9 of the Super Pilot manual has a section titled Setting Your Own "Standards". Among other things it tells you "If your color slides are consistently too light, simply set your Super Pilot SBC for a higher ASA number; if they are too dark, use a lower ASA number.".

Why not just buy another meter? My personal favorite is the Ikophot in the white Bakelite case. I've got two that both meter dead on. They are compact, well made, don't need a booster cell or shutter, and best of all, no battery. In general I have found selenium meters to be more accurate and dependable than CdS, which is even more notable given their greater age.

MattKing · Jul 26, 2015

thuggins said:
This has been a lot of time and effort devoted to a big, clunky, cheap, "plastic fantastic" meter. Apparently Gossen didn't have a whole lot of faith in the accuracy since page 9 of the Super Pilot manual has a section titled Setting Your Own "Standards". Among other things it tells you "If your color slides are consistently too light, simply set your Super Pilot SBC for a higher ASA number; if they are too dark, use a lower ASA number.".

Why not just buy another meter? My personal favorite is the Ikophot in the white Bakelite case. I've got two that both meter dead on. They are compact, well made, don't need a booster cell or shutter, and best of all, no battery. In general I have found selenium meters to be more accurate and dependable than CdS, which is even more notable given their greater age.

The Profisix (Luna Pro SBC in the USA) was Gossen's system meter in its day - top quality and very flexible. It also has/had exceptional low light capabilities.

The Super Pilot was a much cheaper option.

Roger Cole · Jul 26, 2015

thuggins said:
This has been a lot of time and effort devoted to a big, clunky, cheap, "plastic fantastic" meter. Apparently Gossen didn't have a whole lot of faith in the accuracy since page 9 of the Super Pilot manual has a section titled Setting Your Own "Standards". Among other things it tells you "If your color slides are consistently too light, simply set your Super Pilot SBC for a higher ASA number; if they are too dark, use a lower ASA number.".

Why not just buy another meter? My personal favorite is the Ikophot in the white Bakelite case. I've got two that both meter dead on. They are compact, well made, don't need a booster cell or shutter, and best of all, no battery. In general I have found selenium meters to be more accurate and dependable than CdS, which is even more notable given their greater age.

Nonsense. The Luna Pro SBC was a premium meter in its day as Matt says. And if you keep buying another meter every time your slides aren't perfect you may run through an awfully lot of meters, even the most expensive ones.

There is nothing magical or carved in stone about meter calibration, handheld or in-camera, nor manufacturer's speed ratings, nor are all shutters perfectly calibrated - in fact pretty much ALL leaf shutters run slow at the faster speeds - and sometimes even aperture diaphragms, and in black and white there's development times and temperature and agitation and...on and on. I remember reading an article in Pop Photo back in the 70s where one of the editor was talking about this. A friend of his complained his camera was no good as his Kodachromes were always dark. The editor asked to see the camera and quietly changed the speed dial from 64 to 50 or 40 or even 32, I forget, and handed it back to the guy and told him to shoot a roll. He did and, voila, slides were perfect. "What did you do!" he asked. "I changed the film speed to XXX." "You can't do that! Kodachrome is 64!" "Sure you can, you just turn this little dial right here..." "You can't do that! Kodachrome is 64!" Argh. Not being able to get away with whacking that dude over the head with his own camera I'm sure I would have just walked away muttering.

That's nonsense about selenium cells too. Selenium cell meters can work well, but even the best have very limited low light capability compared to CdS or, more so, silicon blue cells (the "SBC" in Luna Pro SBC) or other, more modern sensors. Furthermore, selenium cells will age and eventually become worthless. They can be replaced but will have to be eventually. I think a little selenium cell meter (whose one virtue is in fact the lack of need for batteries) can make a dandy backup for the day the battery is dead in another meter - but then so does the light meter ap in my iPhone which is always with me and virtually never has a run down battery.

bdial · Jul 26, 2015

A meter can be perfectly accurate and you can still get over or underexposed film if the camera isn't perfectly accurate too. Then they all need to be accurate to the meter manufacture's standard for it all to work perfectly, not to mention that of the film manufacture too. Then there is the standard in your own head as to what a good exposure looks like.

In real life, rather than ISO tests, that doesn't happen, which is why they all say that you may need to compensate a little to get the results you want.

Though it happens quite a lot, it's not really reasonable to expect that different meters in different equipment would match exactly in all light. But, they should be close, and I'd generally expect differences to be less than one stop.

Luna Pro SBC

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