Feature image

Is my Old Light Meter Reliable? A Little Test and the Results

The seperate exposure meter was an indispensable accessory in the time before built-in and through the lens meters became the norm. Nowadays, when the attractions of old, all mechanical cameras has taken hold, exposure assessment often has to be made by the photographer in some way. In the past, a photoelectric meter could be had but a cheaper option would be a calculator like the Johnson of Hendon range, all I could afford at first, or you could just rely on the film instruction sheet. Granted, tolerances were not tight (e.g. ±30% for shutter speeds) and film could tolerate some variation so we can be moderately relaxed on the subject.

meter reliability
Bewi Automat fitted to Retina IIc 
Meter reliability
Gold mine in Otago, Nw Zealand. Rolleiflex Automat, FP4+, 6x red filter.

Aside from these, the sunny 16 convention is a good standby but a reliable means of establishing exposure is the best way to achieve consistent results, avoiding unwanted blocked shadows and blown highlights when not required creatively. Film latitude can also save the day sometimes but, again, when a full tonal range is needed good exposure is a must.

So, can I trust my old meter?

meter reliability
Selenium cell meters used.
Meterr reliability
Nikon F801
Meter reliabilty
Sony A3000

I have five light meters, hand held and TTL and of varying vintages which I use regularly, so I thought I would find out how they compare. They are, oldest to youngest, a Weston Master II from 1948, a Bewi Automat C shoe mounting from 1958, Sekonic Studio, reflected and incident, introduced in 1978, and TTL meters built into a 1988 Nikon F801 and a Sony A3000 digital from 2013.

To test them, I trained a couple of LED lights at 45º onto a plain wall to give even coverage and measured exposure with each meter from the same distance and position.

The resulting shutter speeds at ISO 100 and f5.6 in all case were as follows, working from the oldest to youngest again:-

Weston Master II – 1/40
Bewi Automat C – 1/60
Sekonic Studio incident reading – 1/40
Sekonic Studio reflected reading – 1/125
Nikon F801 with Tamron 28-200 zoom – 1/60
Sony A3000 with same lens – 1/60sec

They are within 1/3 of a stop of each other so pretty close except the Sekonic’s reflected result.

Meter reliability
Sekonic Studio with attachments.

In a seperate test to check the Sekonic’s reflected option, I saw around one stop difference between the incident and reflected readings once again. The reflected function seems to be for one of its more technical purposes according to the manual so the meter is best used as an incident meter for general photography, which is the way I use it.

Something to take into account is that the standards governing film speeds were changed in the 1980s, affecting both the 1950s Weston and the 1958 Bewi, and possibly early versions of the Sekonic. This had the effect of doubling the speed rating, ASA(=ISO)50 becoming ASA100, halving the exposure needed.

Meter reliability
Extract from The Retina Way by O. R. Croy with table of film speed eaquivalents.

Various film speed systems can also cause some confusion, my Weston being a case in point. The chart shown taken from my 1957 copy of the Retina Way may help but bear in mind the 1980s adjustment.

Meter reliability
Bewi Automat as fitted to a Voigtländer Vito BL.
Meter reliability
Shoe fitting Bewi Automat.

Operation of the Bewi is interesting. A reading is taken by pressing and holding a button which spins the dial all the way counter clockwise. On release, the dial returns clockwise until it reaches a stop, set by the light measurement it has made. I have found this can vary a little out of doors but in this case three readings gave the same result. The same type was built in to a Voigtländer Vito BL which I used for a while and was reliable.

Selenium cells loose sensitivity if they are exposed to light for long periods. A meter can be completely dead in these circumstances. All three hand held meters must have lived in their cases, protecting the cells from light, which seems to have preserved their sensitivity. Mine have clearly lived a sheltered life.

So, the answer to the question is a qualified yes. If an older meter gives a reading close to a modern one on an average subject then it can be trusted, bearing in mind there might be some overexposure indicated on a pre-1980s model.

Contribute to 35mmc for an Ad-free Experience

There are two ways to experience 35mmc without the adverts:

Paid Subscription - £2.99 per month and you'll never see an advert again! (Free 3-day trial).
Subscribe here.

Content contributor - become a part of the world’s biggest film and alternative photography community blog. All our Contributors have an ad-free experience for life.
Sign up here.

About The Author

14 thoughts on “Is my Old Light Meter Reliable? A Little Test and the Results”

  1. Floyd Takeuchi

    Tony: As someone who has a few light meters tucked away in various camera bags (including the glorious but PITA to use Sekonic Studio Master (and its filters), I found your review interesting and really useful. But I was surprised you didn’t touch on what I suspect is your go-to method for metering film: make a best guess and bracket if needed! I suspect we are of approximately the same vintage, and I find I can get within a reasonable range if I’ve been using a film stock for two or three rolls. And if I load Tri-X, I’m usually close enough after a couple of rolls. That said, the price of film has become so dear in some cases that I’ll use a digital display Minolta incident or spot meter when I’m shooting 4×5 or 120. But there’s no denying that the Sekonic looks a lot more cool than a Minolta spot meter. Thanks again for the feature.

    1. Thank you Floyd. Sunny 16 and ‘seat of the pants’ works in a lot of conditions I agree, especially once you get to know your materials. Out and about, I usually check the light level for the first exposure and then make any adjustment deemed necessary after that unless there is dramatic change in the light. Film cost and available frames do concentrate the mind though, as you say. But that is part of the game with film isn’t it? Thanks again. Tony.

  2. Jim Scheffler

    A great article about a once vital photographic accessory! I bought a Sekonic Auto Leader selenium meter in 1966 and used it for a number of years with my Pentax SV, including during my Vietnam tour. After acquiring a Pentax Spotmatic II, it saw limited use until I got into medium format with Koni Omega and Mamiya cameras. I did also have an MC meter for my Leica rangefinder.

    The Sekonic has been in my “permanent collection” for many years, but the needle still responds to light and the exposure data seem pretty close to my Canon 5D.

    Thanks for contributing a great primer for hand held meters which still have a place in the digital and now reviving analog photographic world.

    1. Thanks for the comment Jim. My photographic experiences seem to be largely the same as yours. The Sekonic is my go to meter if TTL is unavailable, which is most of the time and in incedent mode spot on.

  3. We must read the user manual of the Seconic in order to properly measure in reflected way.
    Since it was build to be used in studio works, we must point the meter to the face of the model. It consider that we is working with a Caucasian model that, in regular conditions, has something as 36% of reflectance.
    Most of the meters, including the TTL, consider an average of 18% of reflectance.
    I had that problem some 40 years ago and correct the grid, covering part of it, until it gives the result as any other meter. Hand held or TTL.
    The same “problem”, or way of work, can be found on the Seconic Dualmaster L-558, when using it as a spotmeter. I had to correct it, comparing with others spotmeters.

    1. I quite agree. The Studio meter is best used as an incident meter and the manual does go into some detail on other methods. From memory, I think the Zone system recommends one zone lighter for Caucasian skin compared to darker types so you are correct there. I haven’t tried covering part of the disc to adjust the response. Thank you for your comment, most helpful. Tony.

  4. Very interesting. I had forgotten about how the standard for film speed changed in the 1950s? 1960s? I have had trouble with the Bewi light meter on my Vito BL. If I am using a modern film which is rated ISO=100, should I set the Bewi at 50? I will do some more tests and compare with a modern Luna Pro Digital. But I wish I had another selenium meter to use in the comparison.

    In the 1980s and 1990s, I had a 1959-vintage Rolleiflex 3.5E with a Gossen selenium light meter, with the cell located above the name plate. In that case, I set the meter film speed exactly like the film I intended to use. And exposures were amazingly correct. So that meter must have been set for the modern calibration.

    The Gossen meter in my 1960s Rolleiflex 3.5F Type 4 also worked correctly at the set film speed.

    1. The change in the standard was early 1980s I believe and had the effect of doubling the earlier film speed rating. Your query raises a very important point and had me scratching my head too. An ISO 50 speed film became ISO 100 and would be set to 100 on the meter. On the other hand, a modern ISO 100 film, having increased sensitivity, would equate to ISO 50 on the old meter’s calibration, so as you suggest, the meter should be set to 50. Thank you for bringing that up.
      Why your earlier cameras gave good exposure is hard to explain. I guess it would depend on the type of emulsion involved. Prints can accommodate quite a bit of variation whereas trannies less so. Maybe the manufacturers’ basic set up of the meters varied too. Many meters had some basic zeroing capability so a slight variation there could be a factor combined with shutter speed tolerances. The main thing is the results were good.
      Thanks again for bringing this up. It fills an inadvertent gap in the article which is potentially confusing.

      1. Thank you. This is a muddle. The selenium meters on my two Rolleiflexes worked correctly and linearly within the range where selenium would register (meaning, not very sensitive in low light). I had zeroed them on the calibration lines as per Rollei’s instructions. I also had a Leicameter MC selenium meter of approx. 1967 or 1968 vintage. This was also correct when set at the ISO of a modern film. So for example, for Tri-X 400, you set it at 400 and exposures were just about right.

        Possibly the Bewi meter in the Vito BL is just enough older to use a different calibration. But which one? The camera is about 1956 or 1957 vintage, so the Bewi meter might be a year older. I’ll let you know what happens when I test it some more.

        This is my BL:


        1. Hi Andrew. Had a quick look at your BL piece and will have a longer read. I have had a number of Voigtländers, very well made and useable cameras. My first was a Vito IIa back in the 1950s as a reward for something or other, exam results maybe (see “Full Circle”). I have had two BLs, a Vitessa and a Vitomatic IIa.
          We are possibly splitting hairs just a tad trying bottom this out. Perhaps manufacturers did in fact put in their own tweaks to calibrations and acceptance angles may have a bearing too. I will be interested to see what you discover.
          Out of interest, I had a Minolta Autocord at one time which had a built in meter and it too gave perfect exposure with the modern film speed set.

  5. Thanks for pointing that out Richard. It is quite a complex subject as I have now discovered, the ASA standard being revised, as you point out, in 1960. The first ISO standard came in 1974 and aligned the DIN and ASA standards. In all likelihood meters would be matched to ASA from around 1960, the US market being very important commercially. This could explain why my Autocord and Kodachromeguy’s Rolleiflexes gave accurate readings.
    My original dating was, I confess, not based on research, just one of things you know…you know! The regular revision of standards also leads to a plethora of dates popping up.
    So thank you once again for this correction which has added to my knowledge of the subject and helped clarify some points.

Leave a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Scroll to Top