Sports Photography Class: Heat Distortion

October 16, 2020  •  Leave a Comment

HOW HEAT WAVES CAN LEAD TO DISTORTION AND RUIN YOUR PHOTOS WHEN USING A TELEPHOTO LENS

Sports Photography Class with Pavely Photography

 

Have you ever taken pictures at your kids sporting event on a warm, sunny day thinking it was perfect for pictures, only to find out your end result was a lot of out of focus pictures that looked like a filter had been put over all of the images?

 

I was recently asked this question, and around the same time I found myself in a similar situation. I was at a warm turf field on a sunny morning, using a 200-400mm for a soccer game. When the subject was far away, and I shot up the field at 380mm, all of the images looked out of focus. Sometimes, from the waist up they were sharp, but overall, all of the images in this situation were useless when the action was far away.

Camera: Nikon D3S    Lens: 200-400mm    1/2000 sec.    f/5.0    ISO 640    Exposure: Manual

 

Why is this? Has it ever happened to you?

 

The cause of this is heat distortion and it occurs when there is a significant temperature difference between the ground and the air above it. When the sun beats down on a turf field, in this instance, the result is heat transferring from the surface to the air. Then, while the heated air rises the cooler air descends. This difference in the air density of cool air and warm air creates a filter-like image of a shimmer or a mirage.

 

It is common on a hot summer day looking down a road or above an automobile as the sun bounces off. But it also happens at turf and grass fields regularly. When using a long lens on an open playing field, this distortion is magnified. It has happened to me during NFL games at stadiums as well as youth soccer playing fields.

Camera: Nikon D3S    Lens: 200-400mm    1/2000 sec.    f/5.0    ISO 640    Exposure: Manual
 

Heat distortion can ruin the end result of captured images with the effect described above, but it can also confuse your Auto Focus sensor on the camera. The AF sensor can be tricked trying to find focus focus and bounce back and forth as it tries to lock in on something sharp. The result may be a lot of out of focus images due to the AF sensor and not the actual heat distortion. And this is not good when you have to shoot a fast paced game and get the images.

 

This can happen in most places any month of the year, even here in rarely sunny Pittsburgh, PA. 

 

WHAT IS THE SOLUTION?

 

So, can you avoid heat distortion? No. Not in certain instances. But you can try a few things to mix it up to see if it becomes less of an issue. You cannot change the fact that there will be a distortion on certain surfaces due to a change in temperature. Being a sports photographer, you have no control over when or where the game is, so you have to adapt. No fancy camera, expensive lens, or filter will eliminate this issue. 

 

But, you do have several options.

 

1. ANGLE    You can change your angle. I typically like to kneel when shooting sports to get a cleaner background. However, being closer to a warm turf surface on some sunny days, I stand to get above the heat waves as much as possible when shooting down a long field. If you are already standing, then change your location to see if there is a different spot to shoot from that does not display this effect as much. If possible, walk all sides of the field to see if the effect is less visible from a different spot.

 

2. TIME    The time of day may be worse in the morning or afternoon. Therefore, the effect may be different at the start as opposed to later in the game. The temperature may change slightly too and the sun will change location. Waiting is an option, but not always a viable one.

 

3. CLOSER    GET CLOSER! If you have to photograph the event, the best solution is to get closer to the action. But be aware not to get too close for your safety. Pay attention to your surrounds and get closer to the action if possible. As the players get closer to you and fill up more of the frame in your camera, the effect won’t be as visible as the less air that the heat passes through, the less likely you will encounter distortion due to heat waves. If you use a long lens to compact the image, you are also compacting heat waves which results in soft out of focus pictures. So, pay attention to your surroundings and change lenses to get closer to the action if needed. The reward will be usable images that are not out of focus due to the temperature on the ground and air.

So, next time you are at a sporting event trying to get images and you experience heat distortion, don’t give up or make an excuse to buy new gear. That won’t solve the problem. Try getting closer to the action if possible, or changing your lenses so you do not have as long of a telephoto lens on. If you can take the pictures another time, that may also work but that may also be unreasonable. Or, change your angle or place you are shooting from.

 

Good luck and if you have any specific questions related to making better sports photographs that you would like to ask, email me at [email protected] or comment on this link, or you can find me at www.PavelyPhotography.com

 

Thanks, and happy shooting!

 

-Phil

 


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