Jason Somes - CAF Bearcat

[Victor Archer]

[Lance]

Re: Jason Somes - CAF Bearcat

Mr. Archer,

I like the pictures that you post but have a question. How come on pictures where the prop is completely blurred only the front of the airplane is in focus? I am not trying to criticize your picture but I have noticed that on most of the photos that I have seen were the photographer is trying to get a full prop circle on an airplane flying. Is it possible to get such a picture with the whole airplane in focus?

Lance

[Victor Archer]

Re: Jason Somes - CAF Bearcat

Mr. Archer,

I like the pictures that you post but have a question. How come on pictures where the prop is completely blurred only the front of the airplane is in focus? I am not trying to criticize your picture but I have noticed that on most of the photos that I have seen were the photographer is trying to get a full prop circle on an airplane flying. Is it possible to get such a picture with the whole airplane in focus?

Lance

Here's from another thread

Originally Posted by speeddemon
On the pictures, the nose of the plane, the name, prop, etc. is very sharply in focus, while from the cockpit back is progressively out of focus. Are you shooting this with the 'mondo lens' of yours that requires the sherpas to hold it steady from a distance, or was he right on top of you with a smaller lens? If it is with the big lens, it seems to have an incredibly narrow depth of field....is it a matter of playing with the shutter speed at the expense of field depth?

They were both shot with the big 500, hand held, no pod.
Your right about shutter speed at the expense of field depth plus at a close distance it looses even more depth of field.
#1 - 1/80s f/20.0 at 500.0mm iso100
#2 - 1/100s f/14.0 at 500.0mm iso100

I believe the answer is no is most cases, unfortunately when using a very large lens like the 500mm prime

[AirDOGGe]

Re: Jason Somes - CAF Bearcat

Sounds like a depth-of-field issue.

The smaller you can make your lens aperture ( larger F-stop number), the greater your depth-of-field, and the greater the depth-of-field, the farther said items can be from your point of focus without appearing blurred.

But unfortunately, a smaller apreture also means less light getting in to the film or CCD. Sometimes you have to sacrifice some depth of field to obtain a sufficent amount of light and a fast enough shutter speed.

Victor's camera appears to have focused on the nearest point of the aircraft, namely the left wingtip in the first photo and the cowling in the second, and so the right wingtip is blurred slightly in the first shot and the tail looks fuzzy in the latter shot.

There's some info on the topic here:

http://www.azuswebworks.com/photography/dof.html

The solution to get more plane in focus is to sacrifice some shutter speed for a smaller apreture (not good for action shots), use a larger diameter lens that can gather more light (expensive and awkward), or use a higher-power lens and shoot from farther away (not ideal on this closed circuit track).

If this is the case, then I'd say Victor is catching these shots about as well as one could hope. As long as the front/side of the plane and the cockpit appear sharp, the photos look awesome to me (and he does it without freezing the prop, no less!)


EDIT: Oops. I guess Victor was here and posted just before I did, but I'm glad to see I was on the right path - Steve
.

[Lance]

Re: Jason Somes - CAF Bearcat

I don't disagree that they are good pictures but I don't think it is a depth of field issue. I can understand depth of field from the near wingtip to the far one but this is from the front to the back where the distance from the sensor plane shouldn't be that much different.


Is it possible that the tail is not sharp on the second picture because at that shutter speed you have to pan as the aircraft passes by and the relative motion of the aircraft in relation to the sensor plane is different on the front of the airplane vs. the back?

It has been a long time since my high school photography class so I may be remembering some of the basic principles incorrectly.

[Peashooter]

Re: Jason Somes - CAF Bearcat

It's also an effect called parallax. As the airplane passes and the lens pans, the far ends of the airplane rotate relative to the center of focus. (wingtips, tail, etc if the nose is in focus) So there's a tradeoff between a fully blurred prop and/or a completely sharp airframe. The further away the subject is, the less the effect of the relative rotational motion.

The pylon shots have less parallax effect since the airplane is closer to flying an equal circumfrence around the camera resulting in less relative motion vs the camera.

That's my story and I'm sticking to it! Peas

PS Next time, we'll talk about static and dynamic coefficients of friction.

[Peashooter]

Re: Jason Somes - CAF Bearcat

Is this Jason?

http://www.youtube.com/watch?v=Kw6UWPaTUt0

[Lance]

Re: Jason Somes - CAF Bearcat

It's also an effect called parallax. As the airplane passes and the lens pans, the far ends of the airplane rotate relative to the center of focus. (wingtips, tail, etc if the nose is in focus) So there's a tradeoff between a fully blurred prop and/or a completely sharp airframe. The further away the subject is, the less the effect of the relative rotational motion.

Parallax does make some sense except that parallax is defined as viewing a single object from two different vantage points. In this case you are following an object from one point to another from a stationary point. However, the end result is similar. Inverse Parallax?

The pylon shots have less parallax effect since the airplane is closer to flying an equal circumfrence around the camera resulting in less relative motion vs the camera.

I believe you would see the same result from the pylons if anybody was bold enough to try to shoot at 1/80th of a second with a 500mm lens. Most of the pylon shots that I have seen are much faster than 1/80th of a second and the faster shutter speed minimizes the parallax effect.

Lance

[Victor Archer]

Re: Jason Somes - CAF Bearcat


1/100s f/20.0 at 700.0mm iso100 (700mm = 500mm + 1.4X)


1/60s f/22.0 at 500.0mm iso100


1/60s f/22.0 at 700.0mm iso100 (700mm = 500mm + 1.4X)

[BuckyD]

Re: Jason Somes - CAF Bearcat

Regarding the depth of field issues, I appreciated all the discussion and points raised regarding possible answers. I've noted this occuring often in my own pylon photos over the years, using various 35mm equipment (manual & autofocus) & shutter speed/aperture combinations, usually shooting Kodachrome ASA 25 & 64 slide films. Until reading this thread, my two favorite 'guesses' were: the aircraft's axis of movement in relation to the focusing point (i.e. - racer's making a tight turn around the stick - nose in focus but the tail's in a different plane of motion and out of focus 'cuz of the tail movement rather than depth of field, or in the case of auto-focus equipment & focus point sensors in AI-servo mode (panning action & viewfinder framing) priority locks focus on the nose at the instant of triggering the shutter. I had the same depth of field issues occur periodically with manual focus (100-300mm push-pull zoom) and shutter speeds from 125th up to fast 500/sec, where depth of field is obviously compromised. Same deal with upgraded EOS auto-focus gear using 35-350mm, and 100-400mm zooms and the gamut of shutter speed/aperture combos. Dunno, but I like Peas comments. Will upgrade to digital soon, as one of the last techno diehard holdouts, inspired by Victor's great results, and others. My old pal Neal Nurmi gave me my initial 35mm film tutoring back in 1980, and made the fundamentals easy to comprehend, and they're still validated every time I shoot. Would like to know the definative answer to this photo topic, for sure. BuckyD

[T. Adams]

Re: Jason Somes - CAF Bearcat

Parallax, too fancy of a word for me. It's partly DOF, and the object is not parallel to the camera sensor. At slow shutter speeds, unless the object is basically perfectly parallel to the camera sensor, part of the image will not be in focus. Thats the nature of the beast. Using my new 300 this year at f/4 and f/5.6 I noticed even shots of military jets were slighly fuzzy on one end. There is not much DOF with the 300, 2.8 even at f/4 of 5.6, so I stopped down some at the next show. It all depends on what you want to show, this photo is 1/80,(http://www.timadamsphotography.com/3...slow%20pan.jpg) and the car is flying, which is what I wanted to show. The drivers hands and helmet however are pretty sharp, again what I wanted.

This is 1/25, (http://www.timadamsphotography.com/1...eed%20Blur.jpg)
Close to getting the whole car in focus because it is real close to being parallel to me. At 1/25th though it is moving too fast to catch the instant it's parallel with my 30D.

[ignomini]

Re: Jason Somes - CAF Bearcat

If you look closely, I believe you will see on Victor's first shot its a question of motion blur. Tim is on the right track. When an object moves diagonaly in relation to the sensor, there is a "sweet spot" where the subject remains steady (or very close to it) in relation to the sensor. However, with a slow shutter speed, portions of the subject away from the sweet spot will move in relation to the sensor while the shutter is open.

[ignomini]

Re: Jason Somes - CAF Bearcat

Not exactly Victor style, but here's a couple examples to show the effect of motion. Notice on the 3/4 view how there is extreme motion blur on the front left of the car, while the door handle is sharp. Notice how the circle around the number is motion blurred more on the leading edge than the trailing edge. This is a result of motion, not DOF.

The second photo is more, but not completely, parallel to the sensor. It shows less motion blur away from the center, which on this photo is the rear wheel.

[mdwflyer]

Re: Jason Somes - CAF Bearcat

Is that Jason Somes racing a car??

[ignomini]

Re: Jason Somes - CAF Bearcat

Is that Jason Somes racing a car??

The parts falling off this car are the finest British quality...