What settings for Dirt track night time pictures

Question

So I just started taking pictures at a dirt track and having problems with getting them crystal clear at night races. I'm using a Nikon D-90 with a tamron 70-300 lens. I have my ISO on 2500 and shutter speed on 1/2000. I'm trying to get the sharp pictures of them in the corners where they are throwing up dirt. They are just not going out sharp. What am I doing wrong? Thank you in advance

Answer 1

I see two main problems:

1. Too slow shutter speed.

2. Overexposure.

The first goes directly to the issue you ask about. You are stuck with whatever lighting there is, so you can only trade off ISO, shutter speed, and f-stop (short of using a different camera with a more sensitive sensor).

You did a good job of following the motion. That's why the car looks reasonably sharp. However, that's also why the background and the dust does not look sharp. They weren't moving at the speed of the car, so were moving relative to the picture.

To freeze both scene elements moving at different speeds, you need a faster shutter speed. There is really no practical way around this. That means you have to use higher ISO or a lower f-stop to compensate. Only you can say how high ISO you can use with your camera and still tolerate the resulting noise. If the pictures will be used at smaller size than the originals, then you can afford more noise in the raw images. Filtering down to a smaller size will reduce the overall noise.

Wider f-stop gives you less dept of field. At your distance and depth of the scene, it looks like a shallow depth of field isn't much harm. Go ahead and open the lens, and see where the tradeoff is.

My point #2 is that this picture is over exposed. That can be seen by the white highlights of the car, which should clearly be yellow. This is actually good news, since it means you can probably increase the shutter speed by 1 f-stop without changing anything else.

In the end, there may simply not be enough light for that camera to allow a combination of ISO, shutter speed, and f-stop that you like. That's life. However, you should experiment to see where the limits are. Otherwise you won't know whether what you want to do is possible or not.

Answer 2

Sometimes things are blurry because the subject is out of focus.

Sometimes things are blurry because the subject or the camera is moving faster than the shutter time used will allow. In the case of a panning shot, this would translate to the subject and the camera moving too fast in less than identical directions.

Sometimes things are blurry because they are overexposed or due to the noise reduction needed when things are underexposed.

Your example image shows evidence of at least the second and third factors listed above, and possibly the first as well.

Exposure

The first thing you need to do is get control of exposure. The car is overexposed by what looks to be a couple of stops. This is causing a loss of detail in the brightest parts of the car and can also cause "blooming" which is when the excess charge generated in one pixel well of the sensor bleeds over to adjoining pixel wells. This makes subjects that were properly focused look blurry due to lack of details. For more about how overexposure, even if just in one of the three color channels, can cause well focused images to look blurry please see: Blown out blue/red light making photos look out of focus, particularly this answer, as well as What went wrong with this concert photo and what could I have done to make it better?

If you are using an automatic or semi-automatic exposure mode, such as Aperture or Shutter Priority, you would be better served to switch to Manual exposure mode and learn how to use spot metering and your camera's histogram to set exposure manually. The camera is trying to balance the brightest and darkest parts of the scene equally. But you want to make sure the car is properly exposed, even if that means the trees outside the track are lost in the darkest shadows. Another tip: The dirt is several shades darker than the bright yellow car. If you are metering the dirt, reduce exposure by a stop or two to compensate for the difference between the dull brown dirt and the brighter cars.

Since your example image is overexposed, your first move should be to reduce the shutter time (increase the shutter "speed"). This will help both to correct your exposure and to shorten the amount of blur for the same amount of camera and subject movement.

At the other end of the continuum, if a subject is grossly underexposed raising the exposure in post processing also raises the brightness of the noise recorded in the image. Noise reduction can help with that noise, but it also will reduce the amount of subject detail.

Shutter Speed

Even when panning, there is a limit to what you can do. If the shutter time is too long (shutter "speed" is too slow) you'll have enough camera movement that doesn't match the movement of the cars and they will look blurry. If your lens has image stabilization with a 'panning mode' try turning it on and see if it helps. Some lenses with IS have a switch for panning mode, some switch to it automatically if the lens senses smooth movement along one axis. Some older implementations of IS actually hinder panning as you'll be fighting the IS which will be resisting your efforts to pan with the moving subject.

The key to smooth panning is to begin the panning movement well before pressing the shutter button and continue following the subject after the image has been taken. During the panning motion the same spot of the subject should occupy the same spot in the viewfinder the entire time.

This image was shot while panning a plane over half a mile away with the pilot flying like his hair was on fire - at night.

_{Shooting an airplane doing aerobatics while going about 300 mph from a position a half mile or more away - in the dark - is a challenge. I was using a Canon EOS 7D with the EF 70-200mm f/2.8 L IS II lens. Exposure settings were ISO 6400, f/2.8, 1/60 second. I was panning with the plane using IS mode 2 to get anything resembling sharp. Some of the pans I shot matched the speed of the smoke more than the speed of the plane (the smoke slows ever so slightly as it is buffeted in the plane's turbulent wake before eventually slowing until it 'hangs' in the air several hundred feet behind the plane).}

As mentioned above, reducing the shutter time (increasing the shutter "speed") will help with reducing motion blur.

Autofocus Accuracy

Tracking moving subjects in low light is very challenging for even the best AF systems. To get the most out of them takes a lot of practice and studying the AF system of your camera to learn how it works. Only when you learn how to tell the AF system in your camera what you want it to focus on will you get the best AF performance it has to offer. Although AF systems vary widely from one camera maker to the next, and even from one model to the next within the same manufacturer's product lines, there are some general principles that apply to most of them.

• The actual areas of sensitivity for each "focus point" are usually quite a bit larger than those little squares that mark the center of each one in your camera's viewfinder.
• The AF system will usually lock onto the area of greatest contrast over all the active AF areas, even if it is on the edge of an AF point and not covered by the little square for that AF "point" in your viewfinder.
• With newer AF systems that have increasing number of AF "points", the coverage areas of the AF "points" often overlap.

You really need to find a resource that shows the actual area of sensitivity for each AF "point" in your camera's AF system and learn it.

Although not about the Nikon D90, the following questions here at Photography.SE show some of the ways different AF systems work, how to use them more effectively, and how the characteristics of the particular AF system one is using will affect the best way to use them:

How do I diagnose the source of focus problem in a camera? with lots of useful links in the accepted answer.
How can I optimise and improve my auto focus?
Pictures of surfers start in focus then go out of focus?
Should Canon 5D mk II autofocus be accurate enough for a f/1.2 lens?
Why does my DSLR focus on the background instead of my subject when taking shallow DoF photos?
Are cross-type focus points more accurate, or just faster?

From a comment by the OP to another answer:

So are you saying I need a better camera...:0)

Probably not, you just need to learn how to use what you already have more effectively. A newer camera would allow you to use a higher ISO before noise becomes a limiting factor and a newer, higher tier camera would probably have better capability using autofocus to track moving subjects. A newer lens with wider maximum aperture would allow a faster shutter time at the same ISO.

For more on that, please see: the best way to improve image sharpness on Canon 700D

Answer 3

I can't tell for sure, but this looks like you probably took the shot toward the beginning of the corner, just as the car started to turn.

At least in my experience (shooting on film--the last time I shot dirt track racing was around 1990 or so) it helps a lot to set up for shooting right where the cars are coming out of the corner, where they hit the throttle entering the straightaway. This is where they're generally moving the slowest, which helps a lot. At the same time, they're normally hitting the throttle there, so they send up a fairly impressive rooster tail.

If possible though, by far the biggest help is to shoot early in the evening, around late May or early June when the days are longer. Even a little bit of daylight makes the job tremendously easier.

Answer 4

I've never shot dirt ovals (they're not common in the UK), but plenty of other circuit motorsports, including under floodlights like this.

1/2000 is more than enough shutter speed to freeze a properly tracked race car. I've had good results from 1/200 up where circumstances allow, but I'd normally be working between 1/400-1/1000. ISO 2500 will be giving a little softness on a D90 because the noise reduction is beginning to kick in and take out detail, but not disastrously so. The Tamron 70-300 you've mentioned isn't the sharpest lens - not bad for the budget (I used to have one), but it's noticeably sharper in my experience, particularly under poor light, when stopped down just a little - even a third of a stop could make a real difference on mine.

Autofocus accuracy is definitely an issue with this sort of subject; it's not magic, AF-C (for continuous tracking) isn't perfect and it can be a bit behind the subject. It's worth taking the time to learn what the system's quirks are from getting out there, shooting more, seeing what works and what doesn't. Remember the centre point is more sensitive than the outer points, so will give more accurate results in high-stress scenarios such as a moving subject under low light.

Looking at your image, it's a little soft to be sure but my best guess is that a bit of panning practice will help. I suspect you're not quite panning accurately enough to get a sharp image. When you get it right you should be able to take a whole sequence with the camera in continuous drive where the car is basically static in the frame and the track moves around it. Easier said than done, particularly at first, but that's the sort of precision it really needs to get properly sharp shots.

If it were me...

• Get back out there to the track. Aside from being a fun trip, practice helps.
• Camera in AF-C, centre focus point selected, multi point AF, high speed continuous shooting.
• Select manual exposure - 1/800s, f/6.3. They're the variables that'll have the most impact on your final image, so keep them under control. You'll be able to go slower on the shutter and get more sense of movement with practice, but that's a reasonable starting point.
• Take a few test shots of the static track and check your histogram - it'll be close enough to what it'll look like with cars on it, and you can do that while you're waiting for the races. Set the ISO to whatever gives a good broad histogram that isn't clipping particularly at either end. If you need more light to get the ISO into an acceptable range, drop to anything down to 1/320 - below that is getting dicey. If your ISO is below 1000 you've got a safety margin, so stop down the lens more, up to f/11.
• Practice your panning. Try to visualise the spot on the car you want the AF to hold on to (such as the base of the A pillar at the top of the hood) and try to hold the point in the viewfinder over that as closely as you can. I find this is easiest with my left palm under the lens (not beside it), elbows tucked in against my ribs and my feet in a fairly wide-spaced V shape so I'm nice and stable as I'm turning quite quickly. Aim to pick up the car, wait until it feels like you've got it, fire off as many shots as you can hold it in the frame for, then reset back to the start of the corner and grab the next car.
• Pick your spot. Panning difficulty rises with the car's angular velocity relative to you - that is, how fast it's crossing your field of vision. I quite like corner entries because you've got time to acquire the subject as it's heading down the straight, then it goes slower as you're ready to shoot it.

Have fun, and show us what you manage next time!