The best photo for measuring your roofline with LightCast

Stand straight on

This guide is about the photo itself; for the whole job, by tape or by photo, start with our guide to measuring a roofline for lights.

To measure your roofline from a photo, take a level, straight-on daylight shot of the front of the house with a garage door in frame, then tap the door's edges so the tool knows how many pixels make a foot.

The photo has to treat every part of the front of the house the same. That happens when your phone faces the house square: you stand opposite the middle of the front elevation, the phone is upright, and the eave line runs level across the screen. From that position a foot of eave on the left side of the house takes up the same number of pixels as a foot on the right, and a single scale reference can convert all of them.

Shoot from a corner and that stops being true. The near end of the house gets bigger and the far end shrinks, so the width of your garage door no longer tells you the width of the far gable. The measuring tool can only be as fair as the photo it is given.

1. Walk to the far curb or the opposite sidewalk.
2. Line yourself up with the center of the front wall, not the center of the lot or the driveway.
3. Hold the phone in portrait or landscape, whichever fits the house, with the screen vertical rather than leaning back.
4. Turn on the camera grid and put a gridline along the eave. If the eave climbs toward one side, step sideways until it runs flat.

Get the whole roofline in frame

Every foot you want lit has to be visible in the photo, from the outside corner of the garage to the far corner of the house. Leave a little sky above the highest peak and a little lawn on each side. If a corner is cut off, the tool cannot see where the run ends and the footage comes out short.

Decide before you shoot what you actually want lit. Most people light the front, and the front elevation is what one photo measures well. Side eaves that are visible from the street at an angle are better measured in a photo of their own, taken square to that side. If you are still working out which lines are worth lighting, the guide to how many feet of lights you need walks the whole house, and measuring gables and peaks covers the sloped edges in detail.

Your built-in ruler: garage door or front door

A photo has no size until you give it one. LightCast asks you to press Set scale and tap both edges of something whose width is known. Once it knows how many pixels make up that width, it can turn the traced roofline into linear feet, count the peaks and valleys, and price permanent and seasonal from the same number.

The garage door wins because it is wide. If your tap lands a few pixels off the edge, that error is a small share of a 16 ft door and a much bigger share of a 3 ft door, and whatever error is in the scale is carried into every foot of the roofline. Tap the door itself, where the panel meets the trim, not the outside edge of the casing.

One more rule: the reference should sit roughly in the same plane as the eaves you are measuring. If your garage is pushed forward of the main house, it still works as a ruler, but stand far enough back that the difference in depth is small compared with your distance from the house.

Wide-angle lenses and tilt

Two camera habits throw measurements off, and both are easy to fix.

The 0.5x lens

The ultra-wide lens on a phone is tempting because it fits the whole house from the sidewalk. The catch is barrel distortion: in a wide-angle image, magnification falls off away from the center of the frame, so straight lines near the edges bow outward and objects at the edges are rendered at a different scale from objects in the middle. Your garage door, usually off to one side, and your eave line, stretching toward both edges, stop sharing one scale. A photo editor can warp some of this back, but you are better off not needing it. Use the main 1x camera and walk back.

Tilting up

The second habit is pointing the phone upward to catch the peak. Photography guides call the result converging verticals or keystoning: once the camera tilts, the top of the house is farther from the lens than the bottom, so it renders smaller and the walls appear to lean inward. For a measurement that means the eaves at the top of the photo are drawn on a smaller scale than the garage door at the bottom, and the tool will read them short.

The fix photographers use is the same one we recommend: keep the phone vertical and increase your distance so you do not need to tilt. Hold the phone at chest or eye level and let the lawn fill the bottom of the frame. A photo with too much grass in it measures correctly. A photo tilted to crop out the grass does not.

Light and time of day

Take the photo in daylight. At dusk the fascia and the sky go to similar shades of gray, and the line the tool is trying to find, where the roof edge meets the sky, loses its contrast. A night photo of the house with porch lights on is worse still, because the roofline is the darkest part of the frame.

• Bright overcast is ideal. The light is even, there are no hard shadows across the front, and the eave reads as a clean edge.
• Sun behind you is the next best thing. On a south-facing house that means midday, on an east-facing house the morning.
• Sun behind the house is the one to avoid. The front falls into shadow and the roof becomes a silhouette with a glare line along the ridge.

Michigan autumn helps here. The low, gray afternoons that make October feel short are close to perfect measuring light, and the leaves are coming down at the same time, which brings us to trees.

Trees in the way: manual mode and leaf-off photos

In the older parts of Oakland County, mature trees are the usual thing standing between your phone and the eave. On the walkable blocks of Birmingham street trees line the curb, so you shoot through them, and in Bloomfield Hills whole elevations can hide behind a wooded front lot. A canopy across the eave hides exactly the edge you are trying to measure.

You have three ways around it, roughly in this order.

1. Use manual mode. If the automatic trace follows a branch or skips a hidden run, switch to manual mode and tap the roofline yourself: the eave corners, each peak, each inside corner. You know where your roof is even when a tree hides it, and the math is the same once the line is placed.
2. Find a clearer angle, then square up. Walk the curb until the eave shows through a gap, but keep the phone square to the front wall. Sliding sideways along the street is fine. Turning your body to look back at the house is not.
3. Retake it at leaf-off, if you want a cleaner trace. Once the maples drop in late autumn, bare branches cross the eave as thin lines instead of a solid mass, and the automatic trace has more to work with. Do not hold your booking for it. Measure now with manual mode, book, and the footage is confirmed on site.

Manual mode also handles a basketball hoop in front of the garage or a porch roof you do not want lit. Trace the line you want, not the line the photo happens to show.

Two-story and wide houses

A single-story ranch is the easiest house to photograph. The eave sits low, you rarely need to back up past the far curb, and one landscape frame catches the whole front. A two-story colonial is where people tilt, because the upper eave sits well above eye level from the sidewalk. Cross the street, stay level, and let the photo include more lawn and street than feels natural.

Some houses are simply wider than a street allows you to capture square. A long ranch with an attached three-car garage, or an estate with a wing on each side, may not fit the 1x frame from across the road. Two options work:

• Step back further, down a neighbor's driveway apron or the far side of a cul-de-sac, and keep the phone level. A smaller house in the frame is still an accurate one.
• Split the front into two photos, each taken square to its own section and each with its own reference in frame, then add the two numbers. Where a wing meets the main block, note which photo owns the corner so it is not counted twice.

Why the photo is worth getting right

Accuracy matters because footage is what you pay for. A roofline misread at 100 ft prices at $2,200–$3,400 for permanent lighting, while the same roofline read correctly at 120 ft prices at $2,600–$4,100. Our crew checks every measurement on site before ordering, but a good photo means the number on your screen is the one you can plan around. How that screen number turns into a written quote is covered in getting a permanent lights estimate online.

When you have the shot, run it through the LightCast measuring tool. The measuring happens in your browser and the shot is never uploaded, and if the house has you stumped, request an estimate and our crew will check the footage in person before any material is ordered.

Where this applies

Typical roofline lengths and priced examples for these communities are on their own pages.

• Birmingham
• Bloomfield Hills

Sources

1. Perspective control (Wikipedia) en.wikipedia.org
2. Distortion (optics): barrel distortion (Wikipedia) en.wikipedia.org
3. Converging verticals in iPhone wide-angle shots (Digital Camera World) digitalcameraworld.com
4. Why are my buildings falling over? A guide to perspective distortion (Digital Photography School) digital-photography-school.com