Did Nikon change their lightmeter calibration in the 70's?

I have 5 Nikon SLR film cameras, and since 3 of these are recent purchases, I wanted to see to what extend the meters were in agreement.

One Nikkormat EL was purchased from a reputable dealer where shutter and meter was tested to be "within factory spec" - whatever that is.

One Nikon F2 w DP-1 was purchased privately. Both from the early 70's with CdS cells.

These two camera's meters are in complete agreement.

I also own two Nikon FE2's and one Nikon F3 all from the mid 80's and all with SPD metering cells. These 3 cameras are also in complete agreement, but exposes 1/2 stop under the two cameras with CdS cells.

When using a Sekonic L308B meter, I got a reading exactly in between the above two "groups".

Given the age of the cameras, differences would not have surprised me but the consistent difference between the groups made me wonder if Nikon may have changed the meter calibration in the 70's - or if the observation can be written off as coincidence?

They're all film cameras. B&W film was quite commonly used in the 1970s and has a latitude as wide as a barn door. So half-a-stop doesn't matter, and besides, you can't set the exposure to more than that accuracy on those early cameras.

When using a Sekonic L308B meter, I got a reading exactly in between the above two "groups".

Which means, if your Sekonic meter is taken as the reference, that neither group are more than one quarter stop in error.

But if it's that important; use the Sekonic and forget those aged camera meters.

Hey Guys, So I take it it your way of saying you don’t know if Nikon changed their meter calibration in the 70’s ;-)

Hey Guys, So I take it it your way of saying you don’t know if Nikon changed their meter calibration in the 70’s ;-)

Hi, I don't know either. But I'm a bit familiar with the ANSI exposure metering standard of that era (which is fundamentally the same as the latest standards made). The standard actually set an aim color temperature of some like 4700K (from memory), as a compromise between tungsten lighting (~2800K to 3000K, more or less) and "daylight" (5500K, I think).

I know that the spectral sensitivities are different between CDS and the modern sensors. So I'd bet that the discrepancy changes if you compare under tungsten light vs daylight.

But to look for an actual calibration difference you'd wanna to compare under a full-spectrum 4700K light source. Which you probably won't be able to find; the old ANSI standard specified a certain filter to be used over a 2850K tungsten source. If you really wanted to you could probably find a color balancing filter to get close to this. (You'd probably want to use one of those old MIRED nomographs, or just use the calculations.)

Let me know if want more info on one of these.

Hey Guys, So I take it it your way of saying you don’t know if Nikon changed their meter calibration in the 70’s ;-)

I don't think they did and if they did what was the standard? I know the Sekonic was calibrated to K12.5. If Nikon calibrates their meter to K14 like Pentax and Minolta then their meters would read lower (that is asking more exposure) than the Sekonic about 1/6 stop.

I know the Sekonic was calibrated to K12.5. If Nikon calibrates their meter to K14 like Pentax and Minolta then ...

Bringing these K values up without explanation tends to have people thinking that they represent "scene reflectivity." They do not. These are some typical values when a certain part of the formula is expressed in (I think) candelas per sq meter. The values change quite a lot when using a different light unit. So this should demonstrate that it is not "reflectivity." Just fyi.

Bringing these K values up without explanation tends to have people thinking that they represent "scene reflectivity." They do not. These are some typical values when a certain part of the formula is expressed in (I think) candelas per sq meter. The values change quite a lot when using a different light unit. So this should demonstrate that it is not "reflectivity." Just fyi.

It's not about reflectivity. The K14 simply means 14 candelas per squared meter luminance value for EV0 at ISO 1.

I'll just repeat: None of your camera meters is more than one quarter of a stop away from the Sekonic meter that you're taking as God's Own Reference.

The accepted standard for photographic metering is plus or minus one third of a stop.

So none of those cameras are out of spec. A specification that doesn't need to have changed a jot for them to be within it.

Nikon camera light meters in the late 60's early 70's used a mercury button cell

No. The F2 was designed to take 2 silver-oxide cells, as was the FE. Not sure about the Nikkormat EL, but I think that's the same.

Anyway, it's irrelevant, since all the meters are within specification, as explained above.

I'll just repeat: None of your camera meters is more than one quarter of a stop away from the Sekonic meter that you're taking as God's Own Reference.

 

The accepted standard for photographic metering is plus or minus one third of a stop.

 

So none of those cameras are out of spec. A specification that doesn't need to have changed a jot for them to be within it.

 

No. The F2 was designed to take 2 silver-oxide cells, as was the FE. Not sure about the Nikkormat EL, but I think that's the same.

 

Anyway, it's irrelevant, since all the meters are within specification, as explained above.

While I didn't read anywhere official but I read that people said that Nikon calibrated their meter to K12.5 the same as Sekonic. So in that case all the cameras should read the same as your sekonic but some read above and some below but less than 1/3 stop either way. I must say all those cameras are within specs.

My observation of only 5 samples doesn't prove anything, of course, but if there is a difference beyond pure coincidence, sensitivity to color temperature, as Bill C points out, could be a plausible explanation - at least I can check.

As many have pointed out, the differences have no practical implications for my use of the cameras.

My curiosity was sparked because someone claimed to have worked in a camera shop in the 70's at the time Nikon released the FM model. The FM meter was said to be calibrated to underexpose slightly compared to earlier models due to wider use of slide film. I don't recall where I saw the statement and have not heard the claim voiced elsewhere.

Regarding batteries: The F2 uses standard SR44 cells and the EL uses a 6V battery, all easily available today, so that should not be an issue for these specific cameras.

My observation of only 5 samples doesn't prove anything, of course, but if there is a difference beyond pure coincidence, sensitivity to color temperature, as Bill C points out, could be a plausible explanation - at least I can check.

 

As many have pointed out, the differences have no practical implications for my use of the cameras.

 

My curiosity was sparked because someone claimed to have worked in a camera shop in the 70's at the time Nikon released the FM model. The FM meter was said to be calibrated to underexpose slightly compared to earlier models due to wider use of slide film. I don't recall where I saw the statement and have not heard the claim voiced elsewhere.

 

Regarding batteries: The F2 uses standard SR44 cells and the EL uses a 6V battery, all easily available today, so that should not be an issue for these specific cameras.

Back in the late 70's I read somewhere that Nikon cameras were calibrated to underexpose somewhat which is true as they are underexposure as compared to Minolta and Pentax. That leads me to believe that they calibrate their meter to K12.5 because I know Pentax and Minolta were calibrated to K14.

Be there, and f/8 to f/11 at 1/125th sec

I personally never saw any significant variation in metering on my Nikkormats and Nikons not explained by ambient conditions during the period from 1969 on.

All my Nikon's read pretty close to each others except the EM which reads 1 stop low (that is it wants more exposure) but I don't know for sure if it would overexpose because the shutter speed may be off by the same amount.

I meant to test the cameras to see how they measure up but it seems too much of a hassle. I would need a light source that has an evenly lighted area of about 6x6" or so. The color temperature should be around 4700K and the light intensity has to be adjustable from LV9 to LV14 without changing the color temperature. It seems to be a quite difficult thing to achieve.

Something I’ve done in the past to compare light meters is make a white JPG file the same resolution as my monitor. When this is displayed it makes a handy target to aim cameras and meters at.

What I’ve not tried is changing the colour of the JPG file to see if there’s a variation in response to different wavelengths. I was able to find that one hand held meter was quite a ways off and it’s no longer used. All the others were close enough not to worry about.

Something I’ve done in the past to compare light meters is make a white JPG file the same resolution as my monitor. When this is displayed it makes a handy target to aim cameras and meters at.

Glenn, computer monitors typically have pretty flaky spectral makeups. So maybe they work, maybe not, but they have little in common, spectrally, with the sources specified in the ANSI documents.

I personally wouldn't use one of these to compare exposure meters unless I knew ahead of time that the meters had identical spectral sensitivities.

... and this, my film loving friends, is why bracketing was a common occurrence, esp. with the lower exposure 'tolerance' of slide film.:D

Not really. It was why getting to know your meter was recommended, and practiced esp. by people who used slide film.

It still is the thing to do. Do not fret about differences between two meters or between a meter and some standard. Learn how your meter behaves, and it will be as good as any other one.

Bracketing is a waste of film and memory card space. It can be useful when contrast ranges are too big and you can combine the best exposed bits from different frames. But it is called HDR then.

Else, it just postpones the decision what to expose for until after the exposure.

Something I’ve done in the past to compare light meters is make a white JPG file the same resolution as my monitor. When this is displayed it makes a handy target to aim cameras and meters at.

 

What I’ve not tried is changing the colour of the JPG file to see if there’s a variation in response to different wavelengths. I was able to find that one hand held meter was quite a ways off and it’s no longer used. All the others were close enough not to worry about.

Changing colour also changes brightness of the RGB monitor. You'd first have to figure out by how much, using a meter. After that you can figure out how the sensitivity of that meter changes with colour.

Uhm...o_O