What heat distortion is
Heat distortion, usually called heat haze or heat shimmer, happens when light passes through layers of air at different temperatures. Warm air is less dense than cool air and bends light differently, a process called refraction. When the air is turbulent, those small shifts make distant objects appear to wobble, blur or ripple. A mirage is a related effect caused by the same basic principle.
Heat haze typically appears over hot roads, sun-baked ground, runways, rooftops, engines and exhaust, and it can also appear when you shoot across a large distance on a warm day.
What it looks like
- Distant subjects look soft or wavy, even when focus is correct.
- Straight lines look slightly ripply.
- Fine detail, such as feathers or text, loses crispness.
- The effect often changes from frame to frame, since air moves constantly.
Longer lenses make it more noticeable, because they magnify both the subject and the air in between. Wildlife and sports photographers who shoot long distances often run into it.
Is it really heat haze?
Many photos blamed on heat haze have a different cause. A photography forum thread on this subject is a good example: replies suggested flare from a missing lens hood, light condensation from a lens that was colder than the air, or a twig or leaf close to the lens that was out of focus. A few checks help:
- Does the softness change across the frame? An obstruction near the lens may blur only one area.
- Is the entire image hazy and low in contrast? That may be flare or condensation.
- Are only distant subjects affected, with closer ones sharp? That is more consistent with heat haze.
- Is the sky or ground hot and shimmering visibly? Look at the image in Live View, where shimmer is often visible.
- Did the lens move from a different temperature? If so, wait and wipe the front element.
Reducing it while shooting
You cannot remove the air, but you can reduce its influence.
- Shoot earlier or later. Early morning, before the ground heats, generally gives clearer air.
- Get closer or use a shorter focal length. Less air between you and the subject means less distortion.
- Gain height. Shooting from higher above hot ground can help, since the distortion is often worst near the surface.
- Avoid shooting over hot surfaces. Asphalt, dark roofs and sun-baked fields produce more turbulence.
- Use faster shutter speeds. This freezes individual moments of shimmer, although the blur may still be visible. Take several frames and pick the sharpest.
- Use a stable support. A tripod avoids adding your own shake to the problem.
- Consider overcast days. Less sun heating means less shimmer.
Fixing it in editing
Editing offers limited help. You can restore some contrast and sharpness with careful adjustments, and some software can reduce mild distortion. Stacking multiple frames helps in some fields, such as astrophotography, but results for general photography vary. Choosing the best frame from a burst is often the most practical fix. Do not expect a heavily affected shot to be rescued completely.
If your question is about lens distortion, such as curved lines caused by the lens design, that is a different issue and lens correction profiles in editing software are the usual remedy.
Using it creatively
Heat shimmer can be a deliberate effect. Telephoto shots over a hot road, an airport runway or desert landscape show an abstract, dreamlike look. Long-lens shots of vehicles in a heat haze can add atmosphere. As with any special effect, use it purposefully. For another weather-related effect that softens a scene, see our fog photography guide.
Heat and your gear
Photos are not ruined by heat in general, but heat can cause practical problems.
- Hot cameras and lenses may warn about temperature, and some cameras can shut down or limit video recording to protect themselves.
- Avoid leaving gear in a parked car, where temperatures can climb quickly.
- Keep equipment shaded and use a light-colored cover where possible.
- Moving cold gear into hot, humid air can cause condensation on the lens, so let it adjust in a closed bag.
- Sensor noise can increase when the sensor is warm, especially in long exposures.
FAQ
What is it called when heat distorts the air? Heat haze or heat shimmer. A mirage is a related effect.
How do I fix distortion in photos? If it is heat haze, reduce distance, change your timing and take multiple frames. If it is lens distortion, use lens correction in your editor.
Can photos get ruined in heat? Heat haze can soften shots, and very hot conditions can stress your equipment. Careful planning reduces both risks.
Does a faster shutter speed remove heat haze? It can reduce motion within a frame, but it does not remove the effect.