Focus/shutter-speed/aperture question.

[VisualEchos]

How was this picture created?

http://www.photoend.com/data/media/103/bugatti-veyron-in-rain_wallpapers_1572_1024x768.jpg

What I mean is, how was the shooter able to capture clear focus on the front of the Veyron with it moving towards him at speed? What I'm after is how was it done, technically, as there is time between when the auto-focus beeps and the picture is taken, regardless of shutter speed. In this instance that time would result in the car traveling a distance, making the subject soft in the front (disregard for the moment that this particular pic is slightly soft, as it is probably due to the resolution).

The only way I can figure it is that the photographer manually focused on one of the lines in the road, locked it there, waited for the car to come into the focus area, and then took the shot, maybe even doing a burst of several pix to capture it just right. Is there another way to do this?

 

[JakeEbersole]

Probably used the 3-D tracking, or prefocused as you suggested.

 

[threecats]

Called trap shooting

I have done it at horse races a couple times


Trap focus

A method variously referred to as trap focus, focus trap, or catch-in-focus uses autofocus to take a shot when a subject moves into the focal plane (at the relevant focal point); this can be used to get a focused shot of a rapidly moving object, particularly in sports or wildlife photography, or alternatively to set a "trap" so that a shot can automatically be taken without a person present. This is done by using AF to detect but not set focus – using manual focus to set focus (or switching to manual after focus has been set) but then using focus priority to detect focus and only release the shutter when an object is in focus. The technique works by fixing a focal distance (turning AF off), then setting the shooting mode to "Single" (AF-S), or more specifically focus priority, then depressing the shutter – when the subject moves into focus, the AF detects this (though it does not change the focus), and a shot is taken.[2][3][4]
Trap focus is possible on some Pentax, Nikon, and Canon EOS cameras. The EOS 1D can do it using software on an attached computer, whereas cameras like the EOS 40D and 7D have a custom function (III-1 and III-4 respectively) which can stop the camera trying to focus after it fails. On EOS cameras without genuine trap focus, a hack called "almost trap focus" can be used, which achieves some of the effects of trap focus.[5]

 

[VisualEchos]

Whoa!

 

[WayneF]

What I mean is, how was the shooter able to capture clear focus on the front of the Veyron with it moving towards him at speed? What I'm after is how was it done, technically, as there is time between when the auto-focus beeps and the picture is taken, regardless of shutter speed. In this instance that time would result in the car traveling a distance, making the subject soft in the front (disregard for the moment that this particular pic is slightly soft, as it is probably due to the resolution).

There is less relative motion in this case (coming straight at the camera), than if the car were going sideways.

Sideways, the car is moving fast past us. Maybe it moves one foot during the brief shutter time? It is at a great distance, but that could represent blur.

Direct forward, the motion is not very apparent. The car is slowly growing larger, but this is nothing like the movement if it were going sideways.
So it moves the same foot in the shutter time, which is a tiny percentage of its distance, and becomes perhaps imperceptibly larger (during that shutter time). Depth of Field should cover its focus shift.

 

[threecats]

Whoa!

Whoa what?

 

[Russ_]

Just how fast does the trap focus of Nikon react? A runner coming straight at you more or less filling the frame - will he be in focus using the method?

 

[Kingfisher]

Looks to be a good bit of DoF he is working with as well. The lens must be stopped down a good bit. If I were to guess I would say he was close in shooting around 70mm.

 

[Seneca]

Or photo shop.

 

[Kingfisher]

Or photo shop.

I'm sure this one is heavily photoshopped. It still is a nice grab.

 

[JohnJS]

It appears that it should be straightforward: continuous focus AF-C, single focus point on the grill, high speed continuous shutter release, and a long AF-S lens. Run off a bunch of shots at 5-8fps and pick the one with the right framing. Or am I missing something with this particular image?

 

[VisualEchos]

There is less relative motion in this case (coming straight at the camera), than if the car were going sideways.

But with the car moving sideways, panning is not only an option, but a probability. Can you imagine trying to wait for a car to run sideways through your frame before you pressed the shutter? At any sort of speed we would probably get nothing, maybe a trunk.

Whoa what?

Whoa, sounds involved.

Looks to be a good bit of DoF he is working with as well. The lens must be stopped down a good bit. If I were to guess I would say he was close in shooting around 70mm.

600/4 I believe.

It appears that it should be straightforward: continuous focus AF-C, single focus point on the grill, high speed continuous shutter release, and a long AF-S lens. Run off a bunch of shots at 5-8fps and pick the one with the right framing. Or am I missing something with this particular image?

You're not missing anything, save for the fact that I pretty much shoot stationary objects, so I'm not familiar with using Nikon's tracking bits.

 

[silver]

I suspect it's pre-focused and a burst shot

 

[bett]

It appears that it should be straightforward: continuous focus AF-C, single focus point on the grill, high speed continuous shutter release, and a long AF-S lens. Run off a bunch of shots at 5-8fps and pick the one with the right framing. Or am I missing something with this particular image?

Bingo. D2h, continuous focus, high, mash the shutter for about three seconds, then pick the best one when you get home.

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[VisualEchos]

Thanks for that input!

 

[Lurker]

I'm sure this one is heavily photoshopped. It still is a nice grab.

I've seen hundreds of razor sharp pictures of formula one racing cars from similar angles. Some of them taken even before photoshope existed.

• You can use technology like a focus trap.
• You can prefocus and hit the shutter when the car passes a landmark (which can be out of view - you've prefocussed and aimed the camera on a tripod. No need to look through the viewfinder).
• You can use 3D tracking - remember that in that case the camera will anticipate where the focus object will be when the shutter opens

I'm sure it can be Photoshopped, but why PS when the shot can be achieved SOOC without too much trouble?

 

[PeteZ28]

If your AF beeps, you're on AF-Single. If you're on AF-Single, you're in the wrong AF mode. AF-Continuous would be the correct mode for moving subjects.

Also, just because it is a Bugati, that does not mean it is moving at 250mph in this picture. Could very easily be doing 30mph for the photographer, although the mist cloud behind tells a slightly different story.

 

[VisualEchos]

I understand that it may not be moving at 250mph, but even at 50mph, there is still a delay if one isn't shooting in the correct mode. Thanks for helping me out guys!

 

[WayneF]

I understand that it may not be moving at 250mph, but even at 50mph, there is still a delay if one isn't shooting in the correct mode. Thanks for helping me out guys!

The speed is not a big factor, in this case.

Making up numbers, say the delay is 100 ms (shutter lag on a D300 is about 52 ms, shutter trigger to flash trigger).

Say the car is coming at us at 100 MPH.

100 MPH is 68 feet per second. 1/10 second delay is 6.8 feet travel.

Speed might be double that, but lag might be half that too.

Say the car is at 200 feet, with a 200mm lens (probably farther).

Depth of field at 200mm 200 feet, f8, DX camera, extends from 161 to 264 feet (a sloppy concept, computed precisely).

Piece of cake.

 

[MikeMcA²]

The autofocus and tracking capabilities of modern cameras are [edit for subject/verb agreement lol] incredible. I used to have to shoot to a static mark and trap the image when the subject crossed into that area of focus. Now, the cameras are able to track very rapid objects. Tak was probably traveling close to 160 MPH at this point, and this is simple autofocus tracking with the 400 f/2.8 AF-S II.

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