18% Grey Card. To use it or not.

[BrianShaw]

No but because for very dark subject when metering as is would put it too close to the toe which starts to lose details and contrast. Adding a 1/2 stop bring it up into the curve where the curve is more straight and because the subject is all dark there is no danger of burning out highlight. I face fi the subject is all black you may want to put in at the center of the curve then print it darker.

Ummm, errr... the discussion about 1/2 stop correction is for NORMAL subjects and NORMAL reflectance. For dark subjects the recommended adjustment is more profound:

 

[Chan Tran]

Ummm, errr... the discussion about 1/2 stop correction is for NORMAL subjects and NORMAL reflectance. For dark subjects the recommended adjustment is more profound:

View attachment 408465

Then I guess they compensate for meter calibrated with a different K factor. May be K factor of 10? which is equal to Ansel Adam no K factor when his measurement is Candela Per Foot Squared. Adams complained that meter manufacturer use K factor to fuss the exposure so that to give inexperience photographers higher percentage of correct exposure.

 

[Stephen Benskin]

Then I guess they compensate for meter calibrated with a different K factor. May be K factor of 10? which is equal to Ansel Adam no K factor when his measurement is Candela Per Foot Squared. Adams complained that meter manufacturer use K factor to fuss the exposure so that to give inexperience photographers higher percentage of correct exposure.

Adams couldn't have been more wrong. That is not what the K factor is or does.

This is K. It's a constant that combines certain variables associated with the meter and the camera constant of q, which is the variable representing the light loss of the camera system. Through the lens metering doesn't need q, it just reads the actual illuminance, but still requires a value of K for the metering system.

1.16 cd/ft2 or 12.5 cd/m2

 

[Vaughn]

...

I don't like the digital meters, so I have not "up-graded". I like a meter that displays ALL of the f-stop and speed combinations at the same time.

That's why I like the Pentax Digital Spot -- take the reading, transfer the number(s) to the dial and one gets ALL of the f-stop and speed combinations at the same time. No bells no whistles no menus.

But besides the smaller size, what I drew me the the Pentax Digital was one less moving part to mess up (a needle and its supporting mechanism). I have had to adjust the needles on the Luna Pros and wanted to avoid that.

 

[Stephen Benskin]

Kodak's instructions (link in post #47) illustrate the complications involved when using a gray card. The first complication is trying to estimate an angle that is 1/3 of the total angle between the subject and the primary light source. Some people have "perfect pitch" -- the ability to accurately identify certain audio frequencies. What I do not have is "perfect protractor" -- the ability to accurately visualize angles in 3D space. (Probably why I am no good with a pool cue.)

And then there are the rules for when to adjust the gray card reading.
The first adjustment rule is: "For subjects of normal reflectance, increase the indicated exposure by 1⁄2 stop." I've never really understood the rationale behind this suggestion. I assume the 1/2-stop additional exposure is necessary because 18% is not the correct reflectance to represent the average reflectance of a normal scene?

Due to the high cost of Kodak brand gray cards, I was tempted into buying some Delta brand gray cards at a much lower cost. Delta advertises the same specifications as Kodak, 18% gray, plus or minus 1%. However the Delta instructions are slightly different. Delta says the correct angle is "halfway between the main light and the camera." And Delta does not suggest adding 1/2 stop exposure to normal subjects.

I still carry a Kodak gray card, but I rarely use it. For most subjects and conditions, my built-in camera meters are adequate - if used with good judgement. If I want a second opinion in difficult lighting, then an incident meter does pretty much the same thing as a gray card, and it is less fussy to use.

There was a discussion many years ago on K. I was writing my tone reproduction program at the time and steeped in theory, so I did a series of posts and later put them together as Defining K. Available Here.

Here is an excerpt that addresses your query. Sorry about the use of older nomenclature.

Here is the camera exposure based on the values defined above for a statistically average luminance range of 2.20. Flare is not included. Notice the Reflectance for Hg, metered exposure (12%). 18% is 1/2 stop above that point.

 

[DREW WILEY]

What use would a meter or its dial be if it was non-linear in the lower values? "Normal" for one kind of film or its personal interpretation is not necessarily normal for another type, or even for a different degree of development. Toe and curve shapes differ, sometimes significantly.

 

[Chan Tran]

Adams couldn't have been more wrong. That is not what the K factor is or does.

This is K. It's a constant that combines certain variables associated with the meter and the camera constant of q, which is the variable representing the light loss of the camera system. Through the lens metering doesn't need q, it just reads the actual illuminance, but still requires a value of K for the metering system.

View attachment 408470
1.16 cd/ft2 or 12.5 cd/m2

So your meter is calibrated for K=12.5. Ansel was wrong but his argument is that his EV0 is 1cd/ft^2 which is the same as K10.7. But he said since his stuff is based on 1Cd/ft^2 he used no K factor. Doing so his meter read about 0.4 stop low which is about the same as the Weston meter. By the way he was also wrong in calling it foot candle which is an illumiance measurement (which by the way he didn't care for) he only cared for the luminance.

 

[DREW WILEY]

I inherited one of those old Weston meters, and it still works. I don't have the original manual, but it would probably say something like, Aim left, aim it right, whirl it around by its cord eight times, flip a coin, examine the entrails of an owl, and see how long you can count holding your breath, and then divide the inverse of the sum by sixty.

 

[BrianShaw]

Not at all entertaining Drew. Have you been drinking? I know I have (been drinking, that is - old fashioned with Bulleit Rye) but I havent't forgot or lost my marbles to the point of forgetting that the Weston III and V that I still use are fine and capable meters. Even after all these years...

LOL

 

[DREW WILEY]

Well, if the younger generation thinks that spot meters are paleolithic, what are Weston meters? - Jurassic?

 

[wiltw]

Well, if the younger generation thinks that spot meters are paleolithic, what are Weston meters? - Jurassic?

Meters are like electronic flash units... few buy them or know how to use them. A bit like record players or rotary dial phones or FAX machines.

 

[BrianShaw]

Well, if the younger generation thinks that spot meters are paleolithic, what are Weston meters? - Jurassic?

Definitely!

 

[DREW WILEY]

The company I worked for as a Buyer mandated the use of FAX machines for submitting purchase orders, even well into the internet and cell phone era. It was distinctly more reliable because it inherently involved hard copy both ends. Same goes for rotary land line phones - not so good outside the home, but not battery and signal dependent either. I don't know how many times I've picked up my cell phone just to discover my wife had run the battery dry! Vinyl record players - we've still got one of those. A slide projector too. One of the few items of photographic gear I own which is battery dependent is the light meter.

 

[wiltw]

The company I worked for as a Buyer mandated the use of FAX machines for submitting purchase orders, even well into the internet and cell phone era. It was distinctly more reliable because it inherently involved hard copy both ends. Same goes for rotary land line phones - not so good outside the home, but not battery and signal dependent either.

When someone dies, the insurance companies only accept FAX, not PDF evidence of death...that is what we encountered when my wife's mother passed late last decade.
That is our response to incredibility expressed, "You still own a FAX machine?!"

We still have analog landline because it is self-powered in the event of power outage, and continues to work. VOIP fails because modems stop workiing. Yet the phone company keeps trying to get analog lines obsoleted by the state regulatory agency, but folks out in remote areas keep getting approval of that nixed because phone service for them is unreliable without analog phone service, and battery-backed digital service eventually will die when power is disrupted for too long. Our landline still rings even when power is out and the AC adapter to the phone carries no power (disabling the directory and autodialer). Now the phone company is even trying to offer highly discounted VOIP service to get more customers off analog lines, but we see the gun up that sleeve.

I still have a vinyl record turntable, a reel-to-reel tape deck, and both 135 slide projector and MF slide projector. I have my dad's 8mm movie projector, too, and my uncle's stereo slide viewer and his stereo slides. Mostly for nostalgia, not legitimate continued 'need'. Seeing the world's foreign lands 65 years ago in stereo is a real hoot, a bit of history not to be lost.

 

[DREW WILEY]

Where I grew up, phones came late due to the steep terrain. The only one in town was a little mahogany box with a crank on it, in a tiny store about a mile away. The switchboard operator was in a different County clear across the canyon. Cell phone reception is still nonexistent in all those deep Sierra canyons themselves. So my reference to metering light clear across a canyon was hardly hypothetical.

It got real interesting when a bull was once chasing me; so I started climbing a sheer basalt cliff above the meadow. Just as I was about to pull myself over the top, I was almost nose to nose with a coyote. But its attention was fixed on a ground squirrel right at the edge of the cliff. Hanging onto the cliff with one hand, I used my other hand with trepidation to focus and take a light reading with my teenage Pentax camera. The coyote didn't even notice me yet, even though I was only about 18 inches away. But once I cocked the shutter, it got suspicous, sniffed, and took off. No picture. Well, a better ending than either falling off the cliff or getting gored by an angry bull.

 

[MattKing]

When someone dies, the insurance companies only accept FAX, not PDF evidence of death...that is what we encountered when my wife's mother passed late last decade.

That is so modern!
When I stopped working with estates, about 16 years ago, they generally only accept mailed or delivered proof of death, and never just a photocopy.
Original Certificates of Death preferred, although notarially certified copies also worked.

 

[Grandpa Ron]

For a while, I was immersed in Black and White. Trying variations of shooting, developing, printing, cropping, techniques etc. Trying to get the perfect formula for the perfect shot.

I managed to produce a number of great pictures which I am proud of. However, eventually I discovered that the work of the experts varies considerably. It reflects what the individual photographer thinks the scene should look like.

More than once, I have looked at collections of black and white landscaped photographs and instinctively recognized the work of Ansel Adams. Yes, other photos were very good, but I found Ansel's approach particularly appealing to me.

It seems there is no universal "perfect" picture, but there is a lot of fine photographic art.

 

[DREW WILEY]

I pretty sure when I die, I won't even still remember how to work a FAX machine. And there are plenty of things I don't even remember how to do now. I never did learn how to correctly use a slide rule; so that doomed any career in rocket science.

 

[Alan Edward Klein]

That is so modern!
When I stopped working with estates, about 16 years ago, they generally only accept mailed or delivered proof of death, and never just a photocopy.
Original Certificates of Death preferred, although notarially certified copies also worked.

US doctors won't email prescriptions or reports, require fax machines or you have to use the doctor's or hospital's medical portal. This might have to do with the Federal privacy acts and that email is not considered secure. Although if the fax is using VOIP, it's going through the internet anyway, isn't it?

 

[Chan Tran]

US doctors won't email prescriptions or reports, require fax machines or you have to use the doctor's or hospital's medical portal. This might have to do with the Federal privacy acts and that email is not considered secure. Although if the fax is using VOIP, it's going through the internet anyway, isn't it?

The company I worked for had to have an analog line installed because the fax machine they had didn't work with VOIP line.

 

[DREW WILEY]

Nobody can read doctor's handwritten prescriptions anyway. All of mine are transmitted internally and electronically by the same health network.

 

[wiltw]

So your meter is calibrated for K=12.5. Ansel was wrong but his argument is that his EV0 is 1cd/ft^2 which is the same as K10.7. But he said since his stuff is based on 1Cd/ft^2 he used no K factor. Doing so his meter read about 0.4 stop low which is about the same as the Weston meter. By the way he was also wrong in calling it foot candle which is an illumiance measurement (which by the way he didn't care for) he only cared for the luminance.

It matters not if Ansel was right in his assumptions about selected values, just as it really does not matter which K value was chosen by the given meter manufacturer...
the range of K values permitted within the ISO standard only effects the end reading by 'as much as' 1/6 EV !

 

[wiltw]

Incident metering falls apart if the subject is very dark or very light, such as a snow scene. The subject needs to be an average of ~18% reflectance with normal contrast for incident metering to work- but then most subjects fit this criteria.

The meter does not need to be up against the subject, the meter just needs to be illuminated by the same light. In a studio, where the light sources are close to the subject, that does mean the meter is close to the subject.

No, REFLECTED light metering falls apart if the subject is very dark or very light. I used an incident meter when shooting bride or groom portraits because it DID NOT CARE about a white dress vs black tux on the subject in close up. The reflected light meter IS influenced by the white dress vs. black tux.

A snow scene might have more light bouncing around due to the white snow, so that the ambient light level is truly brighter than a non-snow scene, but that increase in total light does mean that we need to alter exposure due to the increased light level, and the incident meter would advise a suitable reading to render midtone gray properly.

 

[wiltw]

I can think of insurmountable circumstances that can render an incident meter useless, like trying to estimate the light falling on the opposite side of a canyon thousands of feet deep. You can't just hop over there, take an incident reading, and hop right back. Maybe you studio types scratch your head when someone like me states that; but for some of us, it's been the real world a multitude of times. A one degree real spot meter, however, makes that kind of circumstance easy.

Histograms are late to the game, and don't relate to film photography; neither do pixels.

OTOH, one has to have a somewhat trained eye to choose the point at which to aim the spotmeter, so as to be able to anticipate how the lightness/darkess of that area (relative to midtone) influences the reading.
ALL meters have a foible, and it up to us to know the limitations, so as to interpret the reading properly to achieve 'proper exposure'

 

[DREW WILEY]

It should be added that, for correct readings with spotmeters, they should be shaded just like camera lenses to prevent flare. Better ones, like the Pentax, have multicoated optics. But that is not enough by itself if facing the sun or bright reflections. Mine also carry collapsible rubber lens hoods.

The advantage of spot meters in relation to high contrast snow scenes etc is that you can compare distinct high value and low value readings and strategize from there, based on the dynamic range of your chosen film. For example, there are numerous times I've had to deal with bringing out the brilliant specular sparkle of ice or snow, which still needing to bag the distinction between black volcanic rock and little black dark pits and cracks in it. In open sun, especially at high altitude, that can easily become a 12-stop problem, and not just any black and white film can handle it. But even with the longest scale ones, you still have to give careful "placement" of key values.

And with color film, especially chrome, something is going to have to be sacrificed - either the shadows or the highlights. Or else, just move along, and look for a more suitable shot. This amounts to much of my life outdoors. It's ludicrous to defer to fill flash or imagined film "latitude" under such circumstances, especially if the anticipated outcome is an equally rich and nuanced print. Exposure needs to be on target in a manner mere averaging is incapable of.