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Get the Picture: Digital Cameras on Jobsites


By Robert Ikenberry

About 17 years ago I wrote an article for JPCL called “The Internet Today–What’s in It for Painting Contractors?” Personal computers and the world wide web became available for average members of the public (or at least, for me) about 17 years before that, with the introduction of 2400 bit-per-second modems and an early graphical user interface (GUI) program called Prodigy in 1984.

Looking back, I thought it would be interesting to follow one particular technological development over the past 34 years: photography. In 1984, if you were talking about photos and photography, everyone knew you were talking about film negatives and paper prints (or maybe color slides). Today, pretty much everyone will assume you are talking about digital devices (your phone or a digital camera) and images displayed on a screen.

In 2001, things were just beginning to change. Digital photography was in its infancy, but it was clear that there was something with real potential in an electronic image-capture device and the ability to share and display images. My first digital camera was a Sony Mavica FD-5 that produced 0.3 MP (Megapixel) images (640 x 480 pixels) and saved them on a 3.5” floppy disk—right in the camera! Each 720Kb disk (that’s kilobytes, not megabytes or gigabytes) held about 10 images. This soon was replaced by an upgraded FD-83 camera with 0.8 MP images (1024 x 768 pixels) and a 10x power zoom lens.

This was state-of-the-art when I wrote the 2001 internet article, and was the camera I was using at the time. In the article, I cautioned about sending digital pictures in emails and indicated that a resolution of 640 x 480 was generally about right while 320 x 240 pixels was often enough to convey the needed information, and anything bigger than 800 x 600 was likely to overwhelm the file size and display capabilities of your recipient’s email server.

320px res
Images courtesy of the author unless noted

An image at 320 x 240 pixels

640 x 480

640 x 480 pixels

800 x 600 px

800 x 600 pixels

It was enormously liberating to be able to go out to the jobsite and document the status of the project (or to illustrate issues or problems) and have them up on your computer in minutes rather than waiting days, or even an hour, for prints at your local drug store. It’s even easier and better today.

Digital Cameras Today

Digital cameras are wonderful tools today and every contractor should make images a part of every job file or project record. However, effective and efficient use of digital imagery takes some planning and effort. Modern smartphones take photos with a resolution of 8 MP to 12 MP (typically about 3200 x 2400 pixels to 4000 x 3000 pixels). That’s plenty of detail for most typical needs. If you want to take images that can be blown up for office art, you may want a resolution of 24 MP or more, but short of that, 8 MP is plenty (and more than you can probably see on your computer screen anyway). The maximum resolution of my computer screen as I write this is 1920 x 1080, or 2 MP.

On the other hand, the sensors on your smartphone or point-and-shoot pocket cameras are tiny, on the order of the size of this box: [6x4]. (The actual size of the preceding text obviously depends on your display size, but the sensor on your phone is about 1/4 inch in its longest dimension.)

While we can pack a great number of picture elements (pixels) into this space, physics limits how well the camera can see in low light. When it’s not bright outside, there just aren’t enough photons striking each pixel to make a very good image. Also, phone camera lenses are usually fixed, with a moderate angle of view (often equivalent to 35mm to 40mm on old film cameras) and can’t provide wide-angle views of an interior or zoom in on a distant detail. So you may want to consider supplementing your phone photos with a more professional large-sensor camera.

The main advantage of a camera with a bigger sensor is better low-light performance, but they may also open you up to interchangeable lenses (IC) and the ability to shoot RAW files. (More on that later.) For less than $1,000 (and in some cases, less than $500) you can get a camera with a APS-C (or Micro 4/3s or 1") sensor that will take superior pictures compared to a phone or other tiny sensor imager.

I’m partial to interchangeable-lens cameras, since I grew up using 35mm film SLRs (full frame-see sidebar below on sensor sizes), but you can take great photos with any modern digital camera if you are aware of its limitations.

Making Cameras Work on the Jobsite

Effective camera use for painting contractors starts with the job walk. Take lots of pictures of the project, the site and the surroundings. Particularly, note the areas available for laydown areas and access to the workzone. The unobtrusive camera on your phone is particularly effective for this phase. For one thing, you have it with you, and additionally, you can just delete these photos if you don’t get the job. If you are successful, these pictures should end up in the job file folder on your computer. They help to define the scope of the work, the promised access, and conditions you saw when at the site before preparing your quotation.

When you actually start work, it’s time for more photos. Bring your “good” camera if you have one. Carefully document the starting condition of the project, including the condition of plantings and landscaping, as well as adjacent structures surrounding your work area. If things have changed since the bid walk, document how they may have limited your access or otherwise made the job more difficult. Save all these start-of-work pictures to your computer’s job file folder, too. If you use photos in your promotional materials, these can be the ugly “before” pictures to contrast with the final, attractive “after” shots.

Shooting RAW

Jobsites can be tough places to get good photos. High-contrast areas, deep shadows, backlighting, night work—they can all confuse image sensors. If your camera allows it, shoot RAW files in addition to standard JPGs. RAW files are “digital negatives” and contain much more information. The industry standard file suffix is actually DNG, but many manufacturers use their own flavor. JPGs are essentially digital prints with exposure and color balance fixed and all the extra information from the sensor tossed out in favor of having small, manageable files.

If you've ever worked in a darkroom, you know it’s amazing how much information there is in a film negative. Using burning and dodging techniques to expose parts of the negative with more or less light from the enlarger, you can dramatically enhance the image. RAW files are the same thing. Using special computer programs, you can bring up detail in shadows, tone down overexposed highlights and adjust color balance to make more lifelike colors.

The penalty with RAW has always been file size. They are big files. As computer hard drives and digital storage cards have grown dramatically in size, it’s no longer as big a problem to have image file sizes that are much bigger than a megabyte or two. RAW files for a 12 or 16 MP image may approach 20 megabytes each, and a 24 MP RAW can be up to 40Mb. But even at those levels, a 64GB SD card will hold up to about 2,000 images. Compare that to a 24-picture roll of film and you can see just one of the advantages of digital photography.

If you’ve taken an important photo of a major facet of your project or to highlight a critical problem and it just doesn’t look right, or doesn’t capture what you saw with your eyes, manipulating the RAW file can bring out hidden detail. You will need a special program, but this isn’t “Photoshopping” out a model’s blemishes or getting rid of unsightly wires, this is bringing to light actual details that are really there. Adobe’s Lightroom is the industry professional standard and works with about every RAW file type, but there may be a free program from your camera maker (like Canon’s Digital Photo Professional) or one of several other smaller (and cheaper, or even free) competitors to Lightroom. Adobe’s own Photoshop Elements, Phase One’s Capture One, Skylum's (formerly Macphun's) Luminar, and the free Gimp will all process RAW files.

As the job continues, photos are great for documenting progress and highlighting issues that could impact the project (like blocked access to your agreed-upon storage site). They are also valuable for internal correspondence, advising site personnel of hazards needing correction or providing examples of good practices that should be followed. Construction progress photos belong in the job files.

Finally, end-of-job “exit” photos can document the completion of punch-list items, and verify that the site was left in a clean and intact condition. Final photos can save a lot of finger-pointing if a part of the jobsite gets damaged later by others. Good, overview images of fresh paint jobs can be the great “after” image in your marketing efforts, too.

Digital cameras are fantastic, easy-to-use tools, and the photos they make are great documentation that belongs in every project file. Even if you never go beyond the basic camera in your smartphone, the regular use of photographs can dramatically help your business.

Making Sense of Sensor Sizes

The gold standard in photography for many decades was the 35mm film camera. These cameras, with a negative size of 36mm x 24mm (I know, they should be 36mm cameras, but they just aren’t), could provide images suitable for large prints and publication and were the workhorse of professional photographers.

A “Full Frame” digital camera with the same sized sensor as an old film camera gathers about 30 times as much light as the much smaller sensor on a typical iPhone camera. An image in a 35mm camera that looked about like the perspective that our eyes see came from a lens with a focal length of 50mm, so that was considered a “standard” lens and focal lengths much shorter were “wide-angle” lenses while focal lengths much longer were “telephoto” lenses. Movies also used this 35mm film, but since they turned the film sideways and ran it through the motion camera vertically, rather than horizontally, they made images on the 24mm wide part of the film.

Sensor sizes
RenniePet, public domain, via Wikimedia Commons

Since a big portion of the cost of a modern digital camera is the physical size of the sensor, manufacturers are trying to find the sweet spot between big, expensive sensors like full-frame (the same size as film) and tiny sensors (a phone sensor is about 6mm x 4mm).

Today, digital cameras that use a sensor about the equivalent of movie film (approximately 24mm wide by 16mm high) are called APS-C sized sensors. Since they are smaller, the image from a lens from a 35mm film camera would overshoot the top and sides of the APS-C sensor. It essentially zooms in on a cropped portion of the center part of the image, making it appear like it was taken with a longer lens. An APS-C camera (film or digital) therefore has a “Crop Factor” of 1.5. To get that “Standard View” with one you need a lens with a focal length of about 34mm.

Since a big portion of the cost of a modern digital camera is the physical size of the sensor, manufacturers are trying to find the sweet spot between big, expensive sensors like full-frame (the same size as film) and tiny sensors (a phone sensor is about 6mm x 4mm). The next size down with interchangeable lenses is called Micro Four Thirds (M4/3s) (I don’t know why), with a sensor area of 17.3mm x 13mm. These are slightly smaller than APS-C cameras and have the advantage of using physically smaller lenses.

A “Standard View” lens is 25mm, as these cameras have a “Crop Factor” of 2. While not as good in low light as Full Frame or APS-C cameras, M4/3s cameras are one of my favorites and the ones I take when I travel. I routinely make prints at 19 inches by 13 inches from these cameras and could go to 30 by 24 or even bigger if needed.

The final size I want to highlight is what is called a 1" sensor, and has a “crop factor” of 2.7. It’s not one inch in any dimension I can see, so I don’t know why it’s called that, but it is still big enough to give significantly better shots than a phone camera. The sensor is 13.2mm by 9mm and gathers about five times as much light as a phone camera. Most 1" sensor cameras use fixed, rather than interchangeable, lenses and can have built-in zooms that range from about 3x up to 20x. Sony makes a family of 1"sensor compact cameras called the RX100 series that are tiny and terrific. Panasonic makes the FZ2500 with a 1" sensor that zooms from (35mm equivalent views of) 24mm to 480mm, and last week released the much smaller ZS200, with a 1" sensor and a zoom range of 24-360mm equivalent in a pocketable camera.



Robert Ikenberry

Robert Ikenberry, PCS, has been in industrial painting and construction since 1975. Now semi-retired as the Safety Director and Project Manager for California Engineering Contractors, Robert stays busy rehabbing, retrofitting and painting bridges. His documentary on the 1927 Carquinez Bridge was the pilot for National Geographic’s Break it Down and an episode of MegaStructures.



Tagged categories: Bridges; Program/Project Management; Marketing; Technology

Comment from trevor neale, (4/10/2018, 10:06 AM)

Excellent contribution from Robert however the photographer should check with plant security or contract management to be sure that photography is either permitted or controlled. Found this can an issue on several industrial facilities

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