Do you worry about absolute accuracy of your meter

jjstafford · Jun 27, 2005

I grew up using Weston Masters. Later I had a Minolta IVF. From time to time it flakes out with extraordinarily unbelievable readings. So I think, "Naw. That's way wrong. It should be (whatever)" and check it with a Weston. The Weston is old and no longer correct either, but closer.

The point is, I know the proper reading from experience. I really, do not _need_ a light meter. I'll bet you don't either.

noseoil · Jun 27, 2005

I have only one meter and one thermometer. The spot meter is a Pendax digital and is perfectly accurate. The thermometer is a $5.95 special which is also perfectly accurate. Together, these make up a team. Life is good! tim

P.S. Not sure if this team is accurate, but at least it is consistent.

127 · Jun 28, 2005

Bentley Boyd said:
no two ever give the same reading

I also think that no meter will ever give the same reading twice!

Take a reading, then take another which should be itentical, and chances are it'll change! (At least for reflective and incident meters in real world conditions).

That's why a prefer my old westons (if I meter at all) to the fancy sekonic I could use - with a needle you SEE it moving around, and can make sensible choices about how accurate it is - a digital read out gives a single number. You've no way of knowing if thats a flukey high, low or a sensible mid value.

Ian

benjiboy · Jun 28, 2005

Same Result.

eric said:
Like my meters, I have 3 darkroom thermometers. Each one has a different reading. I put all 3 in and average it out. Somewhere in there, is the right temperature.

I bet that if you only used one of them you'd still get a correct result, don't ask me why, it's just one of the truths about photography.

stark raving · Jun 29, 2005

I don't worry about the meters too much, because the mechanical shutters on the older cameras I use aren't too accurate anyway. I bracket. For color slides, I bracket a lot.

Whiteymorange · Jun 29, 2005

Control is an illusion.

dancqu · Jul 1, 2005

BobF said:
I was looking for someone that does require
absolute meter precision but I guess no one does.

Absolutes are hard to come by; for a light meter and many
other measuring devices. Something of the nature of THE
INTERNATIONAL STANDARD CANDLE as light source does
exist in electric form.

Under STP, standard temperatures and pressure, using A
STANDARD VOLTAGE and CURRANT, and ... You get the
idea. I've ph buffer solutions used to calibrate my ph
meter which are traceable to the NBS, National
Bureau of Standards.

I think most meters are somewhere in the ballpark as far
as their readings compare with the international standard.

Linearity IS something about which to be concerned. I've
not done it but think a clear glass light bulb as sole source
of light will do. Meter the source at 2, 2.8, 4, 5.6, 8, 11,
16, 22, 32, 45, and 64 feet. Dan

Keith Tapscott. · Jul 2, 2005

BobF said:
Because of a recent thread about meters I have been obsessing about my meter's accuracy and metering technique. With all the inherent inaccuracies of metering and metering technique I am wondering about how many of you worry about half stop differences in different meters or in my case a reported half stop difference between my Seckonic L508 in spot vs. incident mode. I personally don't experience problems with B&W but I suppose it could be a problem with transparencies.

In trying to see if my meter has a problem I started thinking about the problems of how to check against a standard, and we have 12% vs. 18% gray as a standard. Then of course different light cell's response to different light wavelengths. Also there is technique, such as angle of gray card or incident dome to light source and in spot mode which green grass or other surface is truly representative of 18% gray (or 12% gray depending on the meter). Which shadow is spot metered for detail and the film and development you are using. I guess we should also consider what printing method you use, contact, condenser, diffusion. To further complicate this we have new MC lenses vs. old single or uncoated lenses that may actually flare enough to effectively preflash the film. I could go on about bellows extensions etc. and I am sure you can add more variables.

With all of the above either separately or cumulatively it is no wonder everyone seems to arrive at their own metering technique and EI for different film/dev. combinations and therefore the common advise to test for yourself with your equipment and your technique.

So my question, do you obsess about absolute accuracy of your meter/meters (if there is such a thing) or like me have you developed a "system" with your equipment and technique that works for you and you don't sweat the half stops.

Bob

No.

Ed Sukach · Jul 2, 2005

The ISO Standard for light energy is the Candela, defined as "The amount of light emitted by the surface of 1/600,000th of a square meter of freezing platinum."

Too many variables exist to require, or allow - really accurate light energy measurements in photography - not the least is the manufacturer's tolerances of film speeds. Measuring techniques are very important ... there are tolerances on the accuracy of exposure meters..

The best - only way - to survive is by establishing individual procedures based on experience.

gnashings · Jul 6, 2005

I find I took some of my favorite photos with a little needle on the top plate of my Zenit EM... I am told its wildly off (and i tend to believe it) - but I knew how to react to it, and compensate and it taught me alot about "feeling" my way around... so no, I don't think absolutes are important as long as one can interpret what you are being told. If I look at a light source and say it has the strength of three chickens and half an orange, am I wrong? I think that depends on wether I know what app and shutter to use for that particular light to get a good exposure. If my picture is fine, then I guess I was right. If not - more likely - I just need my medication

I got a Weston Master II recently - and had a hell of a time with it against a meter in a modern SLR - but, I found its very consistant and as such, perfectly useful!

ilfordrapid · Sep 18, 2005

Hi BobF,
It is my finding that when you do your film speed tests, and development tests that any error that may be in the meter is automatically compensated for. Just be sure that your methods are consistant. also changing to a different lens or film can also change the end result so through testing should be done.

cvik · Sep 18, 2005

It doesn't really matter if the meter is correct or not as long as it is consitent. If it always underexposes a half stop (more than you want it to) you just adjust for it (either permanetly in the meter itself or by adding the half stop each time you measure).

You can of course get an accurate meter such as gossen starlite. It is created for photography and cine but also for photometry. The mode (photo,cine,photometry) is adjusted by dip switches. It is accurate within 1/10th stop and provides readings such as f4 2/10 at 1/125.

eumenius · Sep 19, 2005

In our country (USSR by the time) we didn't have any reliable meters, even those inside the cameras were usually well off. And the film speed tolerances were not less than a stop... this taught us much about the exposure Well, in two of my cameras (Kiev-II from 1949, and Voigthlaender Vito CLR) old selenium meters give me the exposure within 1/3 stop from the reading of my Sekonic L-418. What else can I say if 95% of slides (Sensia 200) shot by my Olympus-Pen EE-2 are exposed correctly?

Zhenya

seadrive · Sep 19, 2005

If you use a particular meter to determine your personal film speed and development time, then all that matters is that it continues to do what it did when you did your testing. Your ISO setting on the meter automatically adjusts for any built-in inaccuracies.

If you have two meters that give different readings, just adjust the ISO on the meter you didn't test with, to compensate. Now, they should give the same exposure recommendation for a particular film.

Don Mills · Sep 24, 2005

Have a fun time and use a black cat exposure calculator. Needs no batteries!

Chan Tran · Jun 29, 2006

I am a year late to this thread but any way this is my opinion. I think it's difficult to get an exposure more accurate than a half stop even if the meter is absolutely accurate. Other factors like film speed variation between batches, f/ stop marking is not in t stop and shutter speed variations make it difficult to get exposure more accurate than 1/2 stop.
However, I do want my meter to be accurate within 1/10 as indicated in its specification. When you compare reading between incident and spot, the flat diffuser should be used. Also, the different between 12% and 18% calibration standard for the reflected light would account for 6/10 of a stop different.

Claire Senft · Jun 29, 2006

jd callow · Jun 29, 2006

BobF said:
So my question, do you obsess about absolute accuracy of your meter/meters (if there is such a thing) or like me have you developed a "system" with your equipment and technique that works for you and you don't sweat the half stops.

Bob

For colour film I obsess about my metering technique. I try to stay consistent so that the information gained from testing a new film will be useable.

kb244 · Jun 29, 2006

Yea I just got a digital light meter ( Minolta Auto Meter IVf ), and now that I develop my own e6, I'm gona have to actually get used to the camera, meter, film combination so that with metering the results correspond with my own development and such.

As a friend once told me, The more meters you own, the more likely they are all to become inaccurate.

Ed Sukach · Jun 29, 2006

I think you are right, if not optimistic, about 1/2 stop being about all that can be expected as far as exposure accuracy.

Be careful with meter accuracy. The digital meters will read to a resolution of +/- 0.1: one-tenth stop ... but that does not neccessarily equal accuracy.

I use a Gossen "Utra-Pro". That will read (resolve to) in tenths of a stop; but Gossens literature specifies accuracy as being +/- 1/3 stop.

At times, manufacturers bury information like accuracy deep in their specifications ... I remember, in the dim past, calling Honeywell repeatedly to try to determine the accuracy of their "1/21" meter. It was like pulling teeth but their final answer was +/- 1/2 stop.

Your best course of action, IMHO. is to keep metering and processing, and analyzing, ... until you determine your own personal "E.I." - Exposure Index - which may... or may not, conform closely to all the indicated system parameters.

Daniel_OB · Jun 29, 2006

A meter is a part of the photographic system (meter, film speed, enlarger, shutter on the camera errors, F openings errors developer, paper,.) that is characteristic for one photographer. The system consist of many variables and if any fail and the system will fail. This make very difficult to use meter properly and out of the system, or not connected with other parts of the system. There is no universally reliable way (yet) to connected all into the system and control it. This is a reason many refuse to bother and accept an average and use tables like clouds, clear sky,. But in that way we get whatever comes out but not what we want, and we are left to like it or not just when we see the result.
But once mastered personal system control all is very easy. It all just works and photographer even not notice that he is doing complicated job. Just like walking.
I do care how accurate (better is consistent) is my meter. But also accuracy is not important at all for the meter is JUST a part of the system. I use whole system I work with, and no instrument out of the system is included in any step of making my photographs, film testing, measuring exposure, printing,. I know my cameras and lenses,

Whenever I shoot I need just once to do it, pack my stuff and go away smiling and singing, for I am sure 100% I got exactly what I want right the moment my shutter click. That is nice filling.

Yes there are and conditions when 35 mm has to work fast and set the camera on P.

www.LEICA-R.com

benjiboy · Jun 29, 2006

I don't worry about the accuracy of my meters , because after more than twenty years I know that if the exposure is incorrect it's the way I have taken the reading thats at fault
I would think in general that more exposure inacuracys are caused by operator error than meter error.

benjiboy · Jun 29, 2006

To Daniel Ob,
What a good posting, I agree with you entirely.

Gerald Koch · Jun 29, 2006

Fortunately there is enough slop in the photo process that worrying about a tenth of an EV or degree or whatever is foolish. Even color positive films have a 2 stop latitude and for B&W negative it is more like 4 stops.

As far as obsessive testing goes, it is for people that don't like to take pictures.

JBrunner · Jun 29, 2006

For me, because incident meters are averaging meters, I tend not use them except for an average exposure information. I find much more information that I personally find important to calculate an exposure, from spot meter readings. It is much faster and easier to use an incident meter, but I have found that I produce much better negatives, since I learned to interpret spot meter readings.

Because an incident meter dome is averaging up to around 180 degrees vs a smaller field of view for reflected readings, I have rarely found incident and wide field reflected readings to agree, unless I hunt around and find an average reflected area that matches. To me it feels like pointing the meter around until I get the stop reading I want. Hardly a precision approach. It is usually the sky that biases the reading the most. I view wide field reflected readings as the most difficult to interpret of the bunch.

As far as accuracy to a standard goes, as long as a meter agrees to another of similar type within a third or so, I don't worry, as that usually falls well within the latitude of my exposure.

Do you worry about absolute accuracy of your meter

jjstafford

noseoil

127

benjiboy

stark raving

Whiteymorange

dancqu

Keith Tapscott.

Ed Sukach

gnashings

ilfordrapid

cvik

eumenius

seadrive

Don Mills

Chan Tran

Claire Senft

jd callow

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kb244

Ed Sukach

Daniel_OB

benjiboy

benjiboy

Gerald Koch

JBrunner

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Do you worry about absolute accuracy of your meter

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