Which Light Meter to Trust?

[RalphLambrecht]

Yesterday I got an incdent rreading of EV14.8 from the sun. Today I got EV14.9.tha'ts within repeatabiliry tolerance for the meter. The sun is an amazingly constant lightsourcefrom 10am to 4pm;well suited to check a meter.In that time frame ,one doesn't realy need a meterwith roughly light-balanced subjects

 

[yulia_s_rey]

Just a quick link on the spectral sensitivity of silicon photodiodes...

 

[Maris]

I trust my Sekonic L758D meter because I work backwards.

Instead of using the meter to set the camera exposure I use a known correct camera exposure to set the meter. Near my house is a standard scene (sky, clouds, trees, road, houses, etc) that never changes and always has the same subject luminances on the predictable and consistent (10am to 2pm typically) sunny days that plague my area of the world. I make a series of bracketed film exposures, run a short distance to the darkroom, process the film and pick the best negative. I run back to the scene before the light changes and follow my standard metering (shadows, highlights, mid-tones, etc) sequence. Then I tweak the ISO setting so that the meter delivers the reading that I already KNOW is correct. If I use a different film or different developer I can go back to the standard scene and do another "backwards" calibration.

 

[Sirius Glass]

I trust these light meters:

Nikon N75 and Nikon F100
Hasselblad 503 CX with the PME prism
Gossen Light Meter
​

 

[StoneNYC]

This is what can happen if you trust your light meter in extreme or "difficult" lighting conditions...



That is a model on a branch...

When I turned her (and myself) around with the sun at my back, this was the result (sorry don't have the film, but trust it was MUCH denser...)



I usually use my light meter, and had it strapped to my belt, but was balancing on a the log and figured the in camera meter couldn't have been TOO bad... Not making that mistake... At least in abnormal light conditions...

EDIT I meant on camera meter vs spot.

 

[wiltw]

As I understand it, the reason you are supposed to hold the card at an angle is that it eliminates problems with specular reflection off of the surface of the card.

Right, the point is to avoid surface reflectivity of the card itself, so that only the underlying tonality prevails.

 

[wiltw]

You can discount any meter reading you get from digital cameras from your experiments because the light meters in digital cameras are calibrated to the particular camera model's sensor not to the sensitivity of film, ie. 100 I.S.O. in a digital S.L.R. can produce a different exposure to the same I.S.O. on film

Odd, then, that my Minolta Spotmeter F pointed at a grey card gives me the same readings as my Canon 40D pointed at the same grey card?!

 

[yulia_s_rey]

I trust my Sekonic L758D meter because I work backwards.

Instead of using the meter to set the camera exposure I use a known correct camera exposure to set the meter. Near my house is a standard scene (sky, clouds, trees, road, houses, etc) that never changes and always has the same subject luminances on the predictable and consistent (10am to 2pm typically) sunny days that plague my area of the world. I make a series of bracketed film exposures, run a short distance to the darkroom, process the film and pick the best negative. I run back to the scene before the light changes and follow my standard metering (shadows, highlights, mid-tones, etc) sequence. Then I tweak the ISO setting so that the meter delivers the reading that I already KNOW is correct. If I use a different film or different developer I can go back to the standard scene and do another "backwards" calibration.

+1. After selling my sekonic digicinemat ( )I resorted back to my luna-pro. Everytime I use a new film or developer or change the batteries, I use a similar method, except around here I have to wait for sunny days. In the winter months its from ~09.00-13.00 in the spring/summer ~10.00-16.00 hrs.

 

[Dr Croubie]

Well, without getting too much into digital talk, you can always look up your camera on DXOmark and see how much it deviates from the standard (eg, the aforementioned 40D here).
I haven't read every model (and I sort of stopped caring too much about tech-specs of digicams since I started shooting more film), but of the ones I have seen they almost always dip below the 'nominal' line, which presumably means they all underexpose (for good reason, as mentioned, digital blows highlights like E6 film, and once it's gone it's gone).

But I still prefer my digisix (and still haven't gotten a battery for my L608).

 

[benjiboy]

Odd, then, that my Minolta Spotmeter F pointed at a grey card gives me the same readings as my Canon 40D pointed at the same grey card?!

That indeed can be the case for that particular model, but not by any means for all D.S.L.R's

 

[markbarendt]

That indeed can be the case for that particular model, but not by any means for all D.S.L.R's

Most meters are very accurate and I truly mean that. The only inaccurate meters I've found are the broken ones.

Beyond stuff that's broken, the wild card is us, not the meter; it's in how we set and use our metering systems, the nodifiers we dial in, our understanding of what they are seeing and what they are really telling us.

There is a huge gap in understanding about what meters tell us and what causes them to suggest various readings. That's not the meter's fault.

Part of the problem is makers trying to sell us magic bullets, the rest is us not taking the time to understand.

 

[RalphLambrecht]

Most meters are very accurate and I truly mean that. The only inaccurate meters I've found are the broken ones.

Beyond stuff that's broken, the wild card is us, not the meter; it's in how we set and use our metering systems, the nodifiers we dial in, our understanding of what they are seeing and what they are really telling us.

There is a huge gap in understanding about what meters tell us and what causes them to suggest various readings. That's not the meter's fault.

Part of the problem is makers trying to sell us magic bullets, the rest is us not taking the time to understand.

how do you knoe they are accuratewithout a known point of reference?that said, I can verify that my Gossens are accurate and precise;my reference point for accuracy is the sun and repeated measurements establish precision.

 

[giannisg2004]

I wouldn't call it ridiculous at all, like I said in a previous post (with a minor correction now) if you measure unobscured sunlight you will get 2000-3500 FCs w/ an incident meter. Ev 14 2/3 is approx ~3300 fcs. Even if you double this 6600 FCs (say if you're on the ISS or hang out in nuclear reactors), or half-it (say you're in a smoggy city) that's only one stop difference either way. I'd say that's a pretty reliable way to get the close to the determining the right exposure. And, as for perfect exposure, I think none of my negs ever where 'perfectly' exposed, as I exposed for my subject(s). In my opinion the sunny 16 principle combined with bracketing you just can't go wrong. And if your meter doesn't agree with this, wait for a nice sunny day to calibrate it.

I don't get it.

Sunny16 is a quick and dirty way to approximate exposure when no more precise equipment is available, definitely nothing on one should calibrate their meters to.

Physically, there can't be a single one sunny16.
Geographical position, altitude and events like solar storms change the brightness of the sky.
Sky brightness is a variable thing, not a universal truth meters should be calibrated to.

Meters do get calibrated, and a calibrated meter is supposed to have different readings when pointed at different skies.

 

[BrianShaw]

Most meters are very accurate and I truly mean that. The only inaccurate meters I've found are the broken ones.

Beyond stuff that's broken, the wild card is us, not the meter; it's in how we set and use our metering systems, the nodifiers we dial in, our understanding of what they are seeing and what they are really telling us.

There is a huge gap in understanding about what meters tell us and what causes them to suggest various readings. That's not the meter's fault.

Part of the problem is makers trying to sell us magic bullets, the rest is us not taking the time to understand.

Amen, brother!

p.s. my point of reference for confirming or questioning a meter's calibration/accuracy/precision is exposed negs.

 

[Mainecoonmaniac]

I hope I don't piss anybody off here, but sometimes, one can overthink exposure and meters. I use my meter and trust my gut instincts. But if a reading is way off according to my guts, most of the time it's right. Some times you're overloaded with data then confusion ensue and the game of second guessing starts. I sometimes take an incident reading then use reflected reading to see where the different parts of the scene fall into which zone.

 

[yulia_s_rey]

^ +1.
also a correction, in my previous post(s) I put 2000-3500 FCs for unobscured sunlight when that value closer to the yearly mean. After talking with a horticulturalist we got into a lengthy conversation about sunlight, and she cited levels as high as 6000-8000 FCs in the summer months (for central NJ, about 50' above sea level)

In a way I'd like to thank the OP for this thread, as I'm learning a lot from the other user's posts followed by my own research when I was in doubt or just out of curiosity on this subject. Perhaps markbarendt's post (#61) really captivates the use of the light meter when seen as a tool (whether using a digital camera, a spot or an incident) and from reading the different posts, it seems each of us have a different method of calibration, and truthfully in my opinion, that's what makes a craft like photography unique; just like no two luthiers cook up the same varnish when building a violin. It all boils down to whether or not you're satisfied with what you're looking at on the light table.

 

[BrianShaw]

^ +1.

ditto

 

[Tom1956]

how do you knoe they are accuratewithout a known point of reference?that said, I can verify that my Gossens are accurate and precise;my reference point for accuracy is the sun and repeated measurements establish precision.

Mr Lambrecht, I hate to think I might be poking a hole in your statement, but after extensive meter testing and repair, I have found linearity to be paramount. I have 2 SBC's, a regular 70's grey Luna Pro, and a Sekonic digital. Meters can be very accurate at EV18, but can be all over the place on EV2. That is to say they've lost linearity beyond the ability to adjust trim pots to correct. The cells are 1/2 dead; they have gone non-linear. I'm not talking about my meters or yours specifically. Frankly I fear that most of them out there have lost their ability for the meter cell to be linear.
This is something I have to keep on top of every minute. I might have a meter that is accurate from dark to light this year, but next year they may well be way outside adjustment.
The Sunny f/16 test can show many, if not most meters to be accurate. That doesn't mean much.

 

[Sirius Glass]

This is what can happen if you trust your light meter in extreme or "difficult" lighting conditions...

View attachment 88451

That is a model on a branch...

When I turned her (and myself) around with the sun at my back, this was the result (sorry don't have the film, but trust it was MUCH denser...)

View attachment 88452

I usually use my light meter, and had it strapped to my belt, but was balancing on a the log and figured the in camera meter couldn't have been TOO bad... Not making that mistake... At least in abnormal light conditions...

EDIT I meant on camera meter vs spot.

Your mistake was not using an incident meter when you were photographing a highly reflective subject.

 

[markbarendt]

how do you knoe they are accuratewithout a known point of reference?that said, I can verify that my Gossens are accurate and precise;my reference point for accuracy is the sun and repeated measurements establish precision.

I have tested my meters to common targets. I verify with sunny 16.

The wildest variables with reflective meters are judgement of tone (or zone) and understanding how/what the meter "sees".

Tone judgement isn't clear cut, it's a bloody mess. I have no idea how many times I've been told or heard somebody say just meter off the face and open up a stop. Problem is that that is a flawed reference; is it the light side, dark side, or do we split the difference? Include the hair or not? ... Someone with lots of experience can do this easily probably because they intuitively do certain things that make it work for them but they may have a tough time really telling their "student" how. It's tough to get people to agree on the reading off a gray card let alone a face. Metering the shadows is even tougher because the human eye is less able to deal with judging shadows than with mid tones.

Each meter has a field of view that we need to understand. When the meter is built into a camera that field of view is affected by the focal length in use. IIRC the N90s and F100 need about a 150mm FL to get to match a 1 degree spot meter. If you are using a 50mm lens you can't get there so even though we may be using the same meter and the same mode we may get a decidedly different reading just because we are using a different lens or have zoomed differently. Add in different flare characteristics for different lenses and who-the-heck-knows what reading differences you might get.

The only practical way to understand these differences is to practice and learn with each meter/lens/FL combo you own. Over time I have done this and come to understand what each combo tells me, anybody can.

I don't mean to suggest that reflective meters are tough to use, what I'm saying is that as the situation gets trickier the odds of an in camera meter getting fooled goes up a bunch.

 

[Sirius Glass]

I have tested my meters to common targets. I verify with sunny 16.

Me too.

 

[yulia_s_rey]

Tone judgement isn't clear cut, it's a bloody mess. I have no idea how many times I've been told or heard somebody say just meter off the face and open up a stop. Problem is that that is a flawed reference; is it the light side, dark side, or do we split the difference? Include the hair or not? ... Someone with lots of experience can do this easily probably because they intuitively do certain things that make it work for them but they may have a tough time really telling their "student" how. It's tough to get people to agree on the reading off a gray card let alone a face. Metering the shadows is even tougher because the human eye is less able to deal with judging shadows than with mid tones...I don't mean to suggest that reflective meters are tough to use, what I'm saying is that as the situation gets trickier the odds of an in camera meter getting fooled goes up a bunch.

again mark, you nailed it.

 

[StoneNYC]

Your mistake was not using an incident meter when you were photographing a highly reflective subject.

Agreed, I later used in incident meter and the rest of the exposures came out very well.

 

[blaine.minazzi]

This is what can happen if you trust your light meter in extreme or "difficult" lighting conditions...

View attachment 88451

That is a model on a branch...

When I turned her (and myself) around with the sun at my back, this was the result (sorry don't have the film, but trust it was MUCH denser...)

View attachment 88452

I usually use my light meter, and had it strapped to my belt, but was balancing on a the log and figured the in camera meter couldn't have been TOO bad... Not making that mistake... At least in abnormal light conditions...

EDIT I meant on camera meter vs spot.

Umm, it was denser because you not only have the Sun to contend with, but there is a fair amount of moonlight in that shot as well.

 

[StoneNYC]

Umm, it was denser because you not only have the Sun to contend with, but there is a fair amount of moonlight in that shot as well.

Yes that must have made all the difference!