Exposure and Spotmeters

[@robinchaplik2340]

Thank you! I found this very helpful. I particularly appreciated your tying together the metering decisions with the processing decisions. I won’t forget that. Thanks, again!

[@TeddyCavachon]

I learned the Adams Zone System from the 1968 edition of his Basic Photo series using an earlier model of the Honeywell/Pentax 1° Spot meter you used. In the mid-70s I worked reproducing photos and illustations (halftones/ color separations) using analog screen methods at the National Geographic Photo labs. Back when Adams developed the system he used a wide field Weston Meter and metered an 18% gray card (or palm of his hand) to determine the “middle gray” exposure. With that exposure the card reproduced on the print would also reflect 18% of the light which perceptually appears halfway between max black and paper base white on a print. It is widely misunderstood that Zones = f/stops which is incorrect. Adams simply divided the tonal scale of the print first into ten steps (0-9) and then later added “Zone 10” because originally he failed to assign a zone designation to specular highlights on solid white objects which in some cases are the only perceptual clue a object in a 2D print in actually 3D. It is also important to understand the underlying technical goal of his system was to make all prints, regardless of scene range, on #2 grade print paper because of the characteristics in the toe portion of the DlogE curve on the print. To do that one must first adjust the ASA/ISO of the meter until the exposure reading off the 18% card creates a slight density on the negative above film base +fog so when making a print and giving it just enough exposure to render the clear areas of the negative Max Black (Zone / Print Value 0) the density on the negative will be dark gray Zone / Print Value 1 which is a black object barely visible in deep shadow. In my experience that required more exposure that the meter set to the nominal ASA (e.g. 400 for Tri-X) and using a series test shot bracketing exposure by changing ASA setting on the meter (and adjusting shutter speed accordingly) one would arrive at the actual ASA which would expose the Zone 0 Max Black vs. Zone 1 first visible shadow detail optimally down on the curve toe of the response curve not higher up on the straight line portion. I realized using the Spot meter allowed metering the shadows of scene directly instead of trying to read and interpolate exposure off an 18% gray card or some middle value in the scene. I used a Zone / Print Value 2 area of the scene which Adams defined as a dark near black tone where detail and texture could be seen. Then it was simply a matter of making a larger reduction in the indicated ASA speed for the film to get the ideal Zone 0-1-2 rendering on negative and print. What I did by metering off Zone 2 and changing ASA setting was changing the meter’s calibration baseline from 18% = Zone V to whatever % light was reflecting off the Zone 2 detailed shadow. Again keeping in mind always using #2 grade paper the next calibration step was to photograph a subject cross-lit in direct sunlight wearing black and white clothing or holding black and white draped fabric and then exposure based on on the Zone 2 read and try different development times until the highlight separation between Zone 9 solid white (which is actually a light gray on the print) and the Zone 10 specular reflections on the white objects (reproduced with just the paper base) was perfect. Too little development would result in the highlights on the print being too dark and too much would blow out the separation between Zone 9 and 10. That became what Adams called “Normal” (e.g. Sunny 16) scene contrast and with the spot meter you knew exactly how many stops / EV there was on a cross-lit sunny day between a Zone 2 texture shadow like the tread of a black tire in the shadow of a wheel wheel on a car and the Zone 9 value of the white body of the car in direct sunlight. You never measured the brightest Zone 10 specular reflections off the paint or chrome you just developed the film to preserve that tonal difference on the print. The same development time test needed to be repeated for scenes with lower EV ranges between Zone 2 and 9 values in the scene such as open shade, cloudy, overcast but with the spot meter you can quantify it by EV range rather than just interpolate if only metering the the 18% card. Because Adams system requires different development based on scene range it is only really practical for sheet film cameras unless one has a camera with interchangeable backs or several camera bodies. The Kodak method of developing all scenes for the same time then changing Polycontrast paper grade via yellow / magenta filtration as needed is simpler and what I used for my 35mm photojournalism shooting. I would still spot meter Zone 2 for exposure and Zone 9 to know what the EV range of the scene was but always developed film for the EV range of a cross-lit sunny day. From notes on the EV range for each frame I’d know in advance what Polycontrast filtration I’d need when printing using the color head of my enlarger. Nowadays if scanning negatives instead of printing one would need to spot expose for ideal Zone 0-1-2 rendering on the negative and adjust development time of the negatives until the range of the negative always exactly matched the dynamic range of the scanner sensor under different lighting conditions or alternately develop so the most contrasting scene encountered (e.g., snow scape) did not exceed the range of the scanner. That would require adjustment of contrast with levels or curves for less contrast scenes in post processing.

[@philpritchard5173]

Great video thanks. Any leads on what type of batteries the Pentax spot meter uses?

[@giuseppecrescitelli4505]

Hi Mr.David Chalmers, many thanks for the video, you clrarified aspects about the zone system chat were not cleare me. I Havel a Minolta Spotmeter F, lightmeter, for the average exposure bet wen the shows and the highlights at the A button everythings is cleare to me. While wuold like to understand why when I want to highlight only the readering of the shadows, S key, or only the highlights, H key, the digital screen gives me, for example, for iso 100 and time of a 125s, the reading is indicator of f.11,5 while on the scale that goes from f.1,4 to f.45, the reading is indicated by two arrows on the diaphragms f.5,6 and f.11,5 . Perhaps it is the aperture range of the diaphragms on which i can operate the display choice , also in relation the zonal system? Thanks for your attention. Kind regards.

[@Blue_Newt_01]

So glad I ran across this video. Been wanting to purchase a spot meter but the new digital ones with the spot metering feature are incredibly expensive. Saw these old types for sale but was not sure if they were still applicable. But of course why not... I’m still using the old needle type light meter and the newer Nikon z6 camera for improvising with a spot meter reading.

[@DavidChalmersPhotography-UK]

Excellent-spotmeters are so invaluable especially the needle version. Thanks for watching.

[@inevitablecraftslab]

love the wavefolder soundtrcks

[@zabtej1645]

what film do you use that you said has shallow latitude?

[@DavidChalmersPhotography-UK]

I like to us Ilford HP5 plus which is a 400 iso negative film. The latitude is shallow when compared to most high end digital SLR's so I like to make the point that exposure calculation is more critical with film. thanks for watching

[@tigerhunter8878]

Dude. Has anyone ever told you that you look like Eddie Van Halen?

[@andyvan5692]

nice explanations, but doesn't the " zone system" require an exquisite knowledge of how your type of film responds to light, contrast, etc. as I understand it is a holistic process, with everything considered for each stage, from film choice for an image, to development of the final print, so without this know how there is a lot of film wasted finding all of this out, or trialling exposures to discover ones niche style of photography.

[@DavidChalmersPhotography-UK]

Thank you Well indeed experimentation on zone system is essential in order to obtain the type of image that you want to create. This requires a few dedicated tests on film speed and and development times. However this is time well spent in order to have full control over your desired exposure and development. Ultimately, as film photographers we must understand these variants in order to produce consistent results.

[@mamiyapress]

Sample images please.

[@DavidChalmersPhotography-UK]

To follow soon my friend -when I publish the darkroom sessions. Thanks for watching

[@giuseppecrescitelli4505]

Thanks! Bye.

[@jeffreygoldammer1741]

tough to hear

[@TheSololobo]

Why are you whispering

[@letmebereal]

I can hear him perfectly, maybe you need to clean your ears out.