Tag Archives: exposure

Accurate Pinhole Exposure Measurement

Almost every pinhole photographer I talk to today is using a smart phone app to do their exposure measurement. There’s some holdouts who use the Sunny 16 rule. There’s the occasional pinholer who’s got a trusty Pentax Spotmeter or the latest Sekonic digital meter. But by and large, pinholers today are using smartphone apps, and so am I.

The smartphone apps are an amazing development of convenience – nobody leaves their house without their phone anymore, so it just makes sense. Getting a passable exposure is a no brainer. But we’re not here today to talk “passable” – no, today we’re going to talk about wielding this tool to create the image you’ve pre-visualized. Have you ever taken a shot where you expected a one portion of the scene to be rich in detail and tone, but what you get back from the lab in either unusably dark or completely blown out? Yep, we’re gonna fix that today!

Grab a cup of coffee or tea – this is a lengthy one

Deceptions in Smartphone Apps

The first step is to understand that while your smartphone app is amazing, if you don’t know some details, it’s lying to you. Here’s some of the ways:

  • If auto-brightness is turned on, the screen display is almost always going to be brighter than what the reading says
  • Without the spot meter enabled, it can be difficult to make decisions on the scene you want
  • Your smartphone screen has a different dynamic range than film
  • Certain screens have inherent color casts
  • Reflections off the screen can mean that problem areas of the scene aren’t noticed

Solution: Return of the Zone System

I grew up before digital, when you had to sweat it out in a darkroom for hours trying to rescue a bad exposure. While film was cheap, time wasn’t, so Ansel Adams’s Zone System was a great shorthand in that day. Lately, a lot of photographers eschew the Zone system referring to it as antiquated – in many situations, they’re right. The light meters these days are better, film and digital latitudes are longer, and if you’re shooting digital, you can “chimp” the histo till you’ve got the exposure.

But of course there’s no light meter in our pinhole cameras. And the apps have the shortcomings noted above. So once again, the Zone System becomes a useful shorthand to ensuring you have the exposure you want.

What I’m going to describe here is what I call a “loose” Zone System. Why “loose”? Because the Zone System should be used with a spot meter, and that “spot meter” on your phone isn’t a true 1º spot meter – the iPhone is more like a 10º spot, maybe even 15º. This means that when you read areas for a Zone, you’re going to be reading more than you might want to be. So Zone System purists I apologize, but everything relies on that bigger swath of metering.

What is the Zone System?
If you’re not familiar with the Zone System, I’m not going to do a full write up here – plenty others have done that job extremely well already. Here’s a very very brief shorthand:

  • There’s 10 zones, or distinct exposure levels, in print latitude. Zones correlate to stops in exposure
  • Zone 0 is pure black
  • Zone III is the lowest shadow value with detail
  • Zone V is “middle gray”, what your light meter reads, and what you expose at
  • Zone VI is typical caucasian or asian skin, while Zone V is typical African American skin, and darker skin types can be as low as III
  • Zone VII is the typical highlight value with detail – but if you know what you’re doing, you can get detail in IX or X
  • Zone X is pure white

Want to learn more? The rabbit hole is deep – here’s a good primer: Norman Koren Simplified Zone System

Applying the Zone System with a Smartphone App

As I alluded above, typically the Zone System calls for a 1º spot, but a smartphone has a 10º or 15º spot. Traditionally you use the 1º spot meter so that when you read a portion of your scene, you’re just getting that Zone of exposure. Since smartphone apps have such a large “spot”, we need to slightly adjust how we use the Zone System to get the exposure we want.

So here’s my process to get loose on this concept and still get the details I want:

  1. Determine the composition of the scene
  2. Open my smartphone app and turn on the spot meter setting
  3. Meter every area of the scene that you want detail in, writing down the EV values
  4. Mark the lowest EV value you read as Zone III
  5. Add 2 to the EV value in step 4 and that is my Zone V
  6. Add 4 to the EV value in step 4 and that is my Zone VII

Now that you have your scene “mapped” by zones, you can evaluate the exposure. If based on the above you have the shadow and highlight details you want, and your mid ranges are right, then you can expose for the reading at Zone V. However if your shadows will be too light or your detailed highlight above Zone VII, you might want to reduce the Zone V exposure by one or more stops before shooting that reading. Alternatively, if your shadows are too dark or highlights will be on Zone V, you may want to expose your Zone V reading longer. Remember when making these adjustments: 1 zone = 1 stop of exposure!

Zone system purists would tell you to get your smartphone closer to try and get more detailed reading on the shadow and highlight detail areas. For lens based photography I would agree, however for pinhole I feel that the larger sensing area of the smartphone app “spot” is appropriate due to the reduced detail available in pinhole photos.

Real World Example 1

If this your first foray into Zone System photography, the above was probably confusing to you. The following example may shed some needed light on the process.

Near my office I wanted to take a photo of some old smoke stacks. I’ve photographed them before, but they’ve always come out boring. Today was a windy day, so I thought I’d take a stab at using the wind-whipped branches blurred in the foreground to add some drama. I’ll know in a few weeks if it worked. In the meantime…

I approached the scene knowing my framing and wanting to see the range of values. I got the lowest value in the base area of the tree. I got mid values in the upper area of the tree. I got high values in the sunny mid-day sky. Here’s my readings:

[bscolumns class=”one_third”][singlepic id=441 w=200][/bscolumns][bscolumns class=”one_third”][singlepic id=442 w=200][/bscolumns][bscolumns class=”one_third_last”][singlepic id=443 w=200][/bscolumns][bscolumns class=”clear”][/bscolumns]

Note that these readings line up almost perfectly to my process:

  • Zone III: EV 13
  • Zone V: EV 15 1/3
  • Zone VII: EV 17 1/3

Also note that if I weren’t using Zones and just relying on the full screen or even on a single reading:

  • The sky would have been blown out in the EV 13 example
  • The smoke stacks and foliage would have been darker than I wanted in the EV 17 1/3 example

Ultimately I made a 1 second exposure for the photo. Since everything was going to be in motion, I was OK with losing a smidge of shadow detail, but I could gain some better cloud streaks.

Real World Example 2

I know you’re thinking that that example was just too damn convenient, because of the way the zones lined up just right. Honestly, they often do in outdoor scenes, but in this example let’s look at how zones help us when things aren’t just right.

In this indoor scene, I want to capture some details of the radiator and wall inside the stairwell as well as some of the clouds streaking by outside. When I look at the scene through my phone, it looks like it should be possible, but lets see how some of the reading stack up:

[bscolumns class=”one_fourth”][singlepic id=444 w=150][/bscolumns][bscolumns class=”one_fourth”][singlepic id=445 w=150][/bscolumns][bscolumns class=”one_fourth”][singlepic id=446 w=150][/bscolumns][bscolumns class=”one_fourth_last”][singlepic id=447 w=150][/bscolumns][bscolumns class=”clear”][/bscolumns]

If I map this the way I did in example 1, then I’d get:

  • Zone III: EV 7 1/3
  • Zone V: EV 10 1/3
  • Zone VII: EV 12
  • Zone X: EV 15 1/3

Hmm… that might not quite be the exposure I was hoping for, because I do want the clouds to streak by some, but putting the upper window are on Zone X would probably blow them out. Then again, if I put the upper window on Zone VII, that will knock the radiator down to Zone 0. A creative decision needs to be made here – the important thing to take away is that without understanding how to map these readings to Zones, my creative decision would just be a guess.

Closing Notes

I hope this walkthrough helps your creative journey. Once you understand how to apply the zones to your pinhole photography, you’ll be able to get more full rolls of “winners” and reduce your reliance on luck. My single biggest piece of advice is this: Take detailed notes! Even if you don’t use the Zone System to drive your exposure decisions, a few notes about different EV readings in the scene will help you review later what went right or wrong with the exposure decision. I keep a notebook in my back pocket constantly just for this purpose.

[singlepic id=448 w=300 float=center]My exposure notebook,
rides in my back pocket every damn day[/singlepic]

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Smartphone Apps for Pinhole Photographers

Smartphones today – whether Android or Apple – are of course ubiquitous anymore. It’s hard to find a social setting where there’s not a solid portion of the group with their faces stuck in their phones. The change in social interaction can become tiresome and, in some cases, worrisome. But of course, there’s tremendous good that we get form our phones, and today we’re going to cover one such area.

For the modern pinhole photographer, your phone can be a true godsend. For today’s article, we’re going to cover a few areas where your smartphone can make your life in pinhole photography much much easier.

Exposure Meters

Pinhole Assist (iOS only $2.99)

[singlepic id=208 w=225 float=right] [/singlepic]The aptly named Pinhole Assist (available on the app store) is the first phone app light meter I ever tried for pinhole photography. When you first open the app, you’re presented with a display from your camera, along with exposure readings based on the input ISO and ƒ-number. The upfront operation is simple: once you set the ISO (film canister icon) and aperture (aperture icon), you compose your scene in the view and the app gives you the exposure time. Playing with the buttons and menus, you’ll quickly discover some great features to help you get the right exposure. Diving deeper though, there’s special sauce to this app.

After you get your camera ISO and aperture dialed in, hit the “hamburger menu” in the top left (the three lines) – in this menu, you can choose a film if you like, and you’ll see there’s options for dialing in an exact aperture in case yours wasn’t in the regular aperture menu. Now that you have your setup exactly right, hit the “Add Combo” button in the menu, and enter a name. You’ve now saved your camera preset – this feature is a lifesaver if you have multiple pinhole cameras to manage.

Next, when you’re framing your scene in the app’s viewfinder, it’s using a general evaluative metering mode. Want to meter on something specific? Tap an area in the scene, and note the square – that’s a weighted meter now! Not quite a 1º spot, but it’ll do!

Pocket Light Meter (iOS Free, Android $0.99)

[singlepic id=209 h=200 float=left] [/singlepic]The Pocket Light Meter app is available for both iOS (app store) and Android (Google Play) and offers a solid alternative from the Pinhole Assist. This app lacks some features of Pinhole Assist – notably the ability to save camera profiles, set custom aperture values, and auto calculate reciprocity failure. But what it lacks in complexity, it makes up for in zen simplicity: dial in your ISO and aperture, and it starts measuring.

If you only have one pinhole camera, or you’re just testing the waters, Pocket Light Meter is a good option. The square in the middle acts as a center weighted average meter, and you can tap around the viewfinder to adjust this metering target. The larger viewfinder makes it helpful when double checking to make sure you’ve metered the exact area you need.

Reciprocity Management

Reciprocity Timer (iOS only $1.99)

[singlepic id=211 h=200 float=right] [/singlepic]One thing that we pinholers often run into is reciprocity compensation and management – so often that you may as well be sure you’re managing it correctly. Reciprocity Timer is available on the app store for $1.99, and was originally built for large format photographers. Over the years the app has built quite the reputation for having very exacting reciprocity tables – an advantage that can be crucial for color film such as Ektar.

But Reciprocity Timer doesn’t stop there. It has built in compensation for filters and includes a stopwatch function. Pinhole Assist also has a stopwatch built in, but for the shooter that uses films susceptible to reciprocity, it’s a very helpful app to finish your workflow in.

In the Darkroom

Massive Dev Chart (iOS $8.99, Android $8.99)

[singlepic id=210 h=200 float=left] [/singlepic]Many pinholers are processing their own film, and if you’re processing your own film, you need the Massive Dev Chart, available for Android on the Google Play Store and iOS on the App Store. The Massive Dev Chart is a compilation of a HUGE amount of film and development time combinations. In addition it has great features such as red and green light displays for use in the darkroom and multi-stage timers. For an app, it’s a bit steep in price – but to have every bit of data and timing tools you need at hand, it’s simply awesome.

What We Want

These apps are all great, and I encourage you to try them all. Having all the data that you need right in your pocket can be a huge boon to your process in the field and the darkroom. So what would you want added? What would make these apps perfect for you?

For me, it would be zone masking. I’d love to have options where a blinking mask covers everything in a specified zone, such as Zone V, III, or VII. Put your requests in the comments, and we’ll use our soapbox to reach out to app developers!