Advice on a shooting subject I've never been able to figure out.

[mkilgour]

So the last time I posted here you brilliant photographers were able to help me correct my mistakes, I'm hoping you can give me some guidance on how to fix a problem I've never been able to figure out.

My buddy has painted his wheels "highlighter yellow". I can not seem to take a picture of them that doesn't come out blurry, washed out or just generally looking terrible. The picture below is shot at 1/1250 f/4, I get the same strange effect shooting a panning shot at 1/160 f/7.1 or anything in between.

Sorry for the subpar example shot, it was hot yesterday and I wasn't really feeling it


Anybody have any ideas?

[Richard Lane]

What focal length were you using? Is the image cropped?

Does this happen on other cars with different wheels?

Are you referring to the washed out look at the bottom of the wheel or wheel motion?

How fast is he going?


I'll take a few guesses and I would like to emphasize "guesses."

1) The wheels are over-exposed at the bottom due to the harsh overhead light hitting the bottom of the rim (6 O'Clock position). See the Sun hitting the right front fender. The top part of the wheels are partially blocked by the wheel well.

2) 1/1250sec is not fast enough to freeze wheels. Depending on how fast the car is going 1/2000sec may not freeze them either.

3) The front wheel is vibrating more because he is on a curve and it may not be tracking as steadily (skipping). The back wheel is going slower because he is braking in a turn.

4) Moire' : Two intersecting parallel lines in motion, that can fool the sensor.

http://en.wikipedia.org/wiki/File:Moire02.gif

[Agilulfo]

Hi mkilgour

There are two different subjects here: exposure and motion blur.

Exposure. Because of the contrast between the body and the wheels, the easier way is to expose mostly to the body and process the wheels exposure. There are many ways to do so if you work in raw, the brush tool in Camera RAW it's quite simple.

Motion blur. If you want an action shot like this, the background, the track an especially the wheels must be moving. The more motion blur, the more effect of speed. For panning, select Tv in your camera, start with a speed a little less than the focal you are using: if you're going to use a 200 mm, select 1/160 s. Once you get a valid take, change to a slower speed (1/125 or even less). For these shot, a tele works much better than a standard lens.

If you want to show the detail of the wheels, you'd better take a still picture. It makes little sense taking a shot of a moving subject and freeze the movement, unless you want to show something you can't capture if the subject it's steady.

In every case, try to give more space in the front of the car than in the back. Like in a portrait, giving space to the "sight" of the car usually produce better results.

In panning, you can start in continuous drive. Then try single shooting, you'll have only one picture every time the car pass in front of you, but you can frame exactly the picture you want (composing, background) if you do so.

Please excuse my English. I know it seem like I'm commanding, but it's only lack of lexicon.

[Busted Knuckles]

1 exposure - dark car and bright wheels = tough. Seems to me this is the crux of dynamic range that has been chatted about on other threads.

In Raw you might be able to pull down the over exposed wheels with masking/layering a reduction of highlights (it might pinpoint the sun reflection like on the front fender) in our post production software of choice.

2 motion of wheels on vehicles - get some reflective tape and put a patch on a bicycle tire and have a friend ride perpendicular to you at night while you hold a flashlight - you will not see rotation - you see a very fast leap, stop, leap, stop, leap. As the tire comes into contact with the ground it "stops" relative to the ground and to you, then when it leaves the ground it races up, forward and down, to reach the ground again. First time I saw this a busted out laughing at the effect.

You might want to think about it as the top of the wheel is actually circling the contact point of the ground vs. the center of the wheel in order to calculate how fast it is going something like (Wheel diameter+ side wall) in inches x speed of the car in inches per second. the top is moving quite quickly compared to the effectively stationary bottom.

So you get weird effects. bottom rim is perfect, top is blurry! huh! Panning a a slowish shutter speed, you get spots on the wheel that are perfect just above the ground, and the bottom looks blurred backward and the top is blurred forward.

Stopping the wheel completely takes a very fast shutter speed relative to the speed of the car and anything else you ever photographed.

FYI this also is the issue w/ runners, but their feet don't move that fast compared to cars.

Hope this something clearer than pure mud

[Joel Eade]

Agree with advice given,,,prob mostly over-exposure,,,increase your shutter speed and shoot maybe 1 1/3 stop underxposed.

In post you can open the hue/saturation adjustment and selectively de-saturate the yellows.

You can also open the selective color adjustment and add black to the yellows.

[Agilulfo]

An example of how the wheels look with at slow shutter speed (1/60 s f/8 with a 300 mm lens).

[Busted Knuckles]

Good catch on the color specific de-sat

Agree with advice given,,,prob mostly over-exposure,,,increase your shutter speed and shoot maybe 1 1/3 stop underxposed.

In post you can open the hue/saturation adjustment and selectively de-saturate the yellows.

You can also open the selective color adjustment and add black to the yellows.

[mkilgour]

Thanks for the ideas, I will try adjusting them a little in post, I've never really messed with anything other than cropping and exposure adjustment so I'll give it a go. I do have some "better" pictures of it where the technical aspects are better (shutter speed, panning, motion blur, etc) this one was just the first one I noticed that highlighted the lack of detail in the wheels. It was way to hot to put a lot of effort into shooting this weekend, I have a couple shot at 1/2000 standing still on a tripod and the wheels always come out with the same effect.