Pentax or Sekonic
Early on one of the biggest hurtles for me was grasping the concept of metering light. Like most digital photographers I depended heavily on the histogram shape, how the picture looked on the back of the camera in live view, and that the needle on the EV scale was at or close to zero. I had a basic understanding of the exposure triangle; ISO controls camera sensitivity to light, shutter speed controls motion, aperture controls sharpness (aperture, depth of field, plane of focus, and focal length is a monster of a topic for another day). I’m not going to go into the different parts of the exposure triangle now, but more my different light meters as well as how I calibrated and use them.
There are many different ways to meter light. Many different videos, articles, meters, and personal preferences. What I discuss below is my personal preference of metering light and what has worked for me. Even if you shoot only digital being able to understanding how your camera meters light will help improve your exposures.
I own four different light meters, two of which get used more then others.
Pentax Digital Spotmeter #1 - Main and only light meter for years. Calibrated by Richard Ritter to 18% grey. It is not a Zone VI modified meter.
Pentax Digital Spotmeter #2 - Purchased a few years ago as a backup. This meter has not been calibrated and meters 2/3 less then my main Pentax.
Sekonic L-858D-U - Purchased new last year. This meter is a workhorse. A lot of people don’t like the touch screen but I have had no issues with it. It is a spotmeter/incident meter combo. I calibrated both to match my Pentax. It has now become my main light meter.
Sekonic Flashmate L-308x-u - Purchased new years ago for the few times I take portraits with flash. Since the 858 has an incident meter built in I no longer use the flashmate.
18% or 12% Middle Grey
When I dove down the rabbit hole of calibrating light meters I found that there is a long standing understanding (and some don’t believe) that there is two standards of middle grey; 18% and 12% (12.8% to be more accurate). Middle grey is another topic for another day but in short, it would be Zone 5 of the zone system created my Ansel Adams. Middle grey should reflect 18% of light while black (Zone 0) reflects 0% and pure white (Zone 10) reflects 100% of light. What I noticed to be true when I received my Sekonic 858 was that it metered 2/3 of a stop less then my calibrated Pentax Digital Spotmeter. My Canon 5DSR camera would meter 2/3 less as well. For the longest time I assumed that my Pentax meter was off, and consistently bracketed my exposures just in case. As you could imagine this resulted in a lot of wasted film (luckily I was still in my medium format kick). It wasn’t until I dove in and wanted to understand why.
As it turns out, it was by design.
12.8% grey is roughly -2/3 of a stop less then 18% grey. What this means is if you were to spot meter anything with any meter and use that as middle grey it would either land in Zone 5 or Zone 4 of an EV scale depending on how your meter or camera is calibrated (0 or -2/3 for the folks that use numbers). For obvious reasons this makes everyone meter differently. Since my main Pentax Digital Spotmeter was calibrated by Richard Ritter I used it as a baseline.
Now to address why the -2/3 stop difference.
18% grey was created when film was the only medium by photographers that primarily used black and white film. There was no scanning or photoshop. Only way to fix exposures was with dodging and burning in a dark room when creating a print. Negative film is able to tolerate highlights better while retaining information (development process also plays an important part). This means that even if you overexpose your highlights, chances are you can retain detail. I have heard that Kodak E100 (a color Positive film) is able to handle this as well but I have not had a chance to test this. This is where the “expose for the shadows, develop for the highlight” phrase came from.
Digital cameras on the other hand are the opposite (as well as most transparency films). They can not retain detail in highlights very well but at the same time handle shadows much better. This means that if you overexpose your negative (clip your highlights in camera) you wont be able to recover any information. The shadows on the other hand retained detail when underexposed. Because of this middle grey was set lower then in the past to help the photographer, thus 12.8% middle grey.
The next part of this article is going to assume you have a basic understanding of the Zone system or an EV scale.
-2/3 or 0
Now that we understand where 12.8% and 18% middle grey came from lets go over how I standardized my meters and camera to match using my calibrated Pentax as a baseline. Things I used:
Manfrotto EzyBalance Gray Card - Great for in the field. Have had this target for years.
Calibrite ColorChecker Passport Photo 2 - Needed for camera color balance and Sekonic camera profiles.
Calibrated Pentax, Sekonic 858, Canon 5DSR in spot meter mode.
I did this in the middle of a summer day with a clear sky.
The calibrated Pentax metered the sky at f/11, ISO400 @ 1/500s.
The Sekonic and 5DSR both metered the sky at f/11, ISO400 @ 1/800s. 2/3 of a stop less.
You might be thinking “that’s easy”. Well, there’s more two it. As your meter reads shadows and highlights it meters differently.
Just because middle grey is the same, Zone 2 may be different, or Zone 8. This is part of the reason I purchased the Seckonic. Although the Pentax was “standard” for landscape photographers due to Ansel Adams and the Zone system for years, it was first released in 1977. They are no longer serviced and can’t be calibrated by the owner. Currently Richard Ritter is the only person I have found that can calibrate them and his prices have been increasing over the years. Since there will eventually be a point where it stops working and I wouldn’t be able to get it fixed I purchased the Sekonic 858. The 858 can be calibrated by the owner! As someone who loves to past the time fixing things and figuring out how things work, this put a smile on my face.
Since I knew the meter was -2/3 of a stop off from my Pentax I had to make a decision. Leave the meter factory calibrated 12.8% middle grey but run the risk of under exposing my images, or match it as best I could to the Pentax at 18% middle grey. I chose the Pentax.
The Sekonic meter has a calibration mode where you can adjust the incident and spotmeter separately by 1/10s of a stop.
I first did this with the spot meter until the sky meter reading match my Pentax.
I next used my grey cards.
A word about the EzyBalance Grey Card: I have a love hate relationship with this target.
The angle of the card can change the meter reading, this is understandable. What I don’t like: depending on where you meter on the target you get a different reading. If you meter the grey it will be 1/3 stop less then if you meter in the center of the grey target. I have found though when comparing it to the ColorChecker that the center target is the correct reading.
I used both the EzyBlance and ColorChecker grey cards to calibrate my Seckonic the same way I did the sky. If I were to only use one, I would use the ColorChecker. Once this was done I checked various shadows and highlights to make sure the spot meters matched. I found I only needed to adjust 1/10th of a stop +/-.
To calibrate the incident meter I first used the sun to make sure it matched the blue sky and made my adjustments.
The next step was to use the grey card. This is the most important step for the incident meter. The grey card should match the incident meter 100% of the time. If you are able to do this, you no longer need a grey card in the field and could use the incident meter. The key is to meter the card in various lighting conditions (shadows, reflected light, direct sunny light, indoors, etc). This takes a little time but in the end it will be worth it.
I found that my incident meter was only off by 1/3 of a stop while my spotmeter was over 2/3 of a stop.
What about the Canon 5DSR?
For the digital camera I created a camera profile with my meter. Now a days most digital photographers don’t use handheld light meters. I on the other hand do. I also still use square filters. My goal is simple: If I only need one exposure for film, why do I need to bracket and blend exposures for digital? After all digital can capture more dynamic range. If that’s the case only one exposure is needed. When you create a camera profile it will adjust the exposure compensation in the meter automatically. Pretty cool if you ask me. Using the meter and filters, the only time I take multiple exposure with my digital camera is to focus stack.
Camera (film) Profiles
I also created three different camera profiles for my film:
Negative - Dynamic range of Zone III to Zone VIII - Used for Ektar, Portra
Positive - Dynamic range of Zone III to Zone VII - Used for Provia, Velvia, E100
B&W Zones - Dynamic range of Zone IV to Zone VIII - Used for Tri-X, T-Max, Delta
This is to place shadows in Zone IV instead of III and using my deployment process as well as +/- film exposure to control contrast range. When scanning I bring the exposure down -1 stop to retain exceptional detail in the shadows while retaining highlight texture. B&W is a pretty dense topic that I enjoy if you couldn’t tell.
Using the film profiles allows me to add a color scale to the bottom of the meter when I set a mid tone using the incident meter.
The color scale shows me where my meter readings fall compared to the mid tone and gives me a quick view of the contrast range. The Pentax did the same thing but I had to know the dynamic range of the film and remember what readings I got. In order to get a mid tone reading with the Pentax I had to use a grey card.
Using the color scale I can easily modify the mid tone and change where my readings fall. Basically it is the same process I would use with my Pentax. Only difference is the Sekonic uses f stops or EV for a scale. I have my Sekonic set to exposure values. The numbers of the scale correspond with Zones:
Zone V (middle grey) = 0
Zone VI = +1
Zone IV = -1
Zone VII = +2
Zone III = -2
etc…
You may be asking now: then why get the Sekonic 858 when you already had a calibrated Pentax?
The Sekonic also stores filter information. I have every filter I own and its factor saved in the meter. I also can easily add +/- 1/10ths of a stop when I need to factor in bellow extension.
Most importantly, it’s a modern meter that is still supported by Sekonic and its serviceable.
One year at Zion a screw came lose inside my Pentax. I questioned every reading the rest of my trip.
When I got home I emailed Richard Ritter, no response.
I then decided to dismantle it myself. I took my spare meter apart first to understand how. Then my main meter.
I found it was a screw rattling around inside the handle. After an hour I was able to find where it went and put the meter back together.
When I reached out to the only Pentax service tech I knew of and I heard nothing back I decided it was time for a new meter.
The Sekonic has been great so far. I used it on my last trip to Zion and had perfect exposures.
Although the Sekonic is now doing all the work, having an understanding of how and why readings fall where they do makes it a creative tool.