Noob questions about fast moving object


instinctloh

Member
Nov 25, 2008
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Hi,

Recently I tried to take some pics of a radio control airplanes but no matter how I try I face all this difficulties with tripod:

1) do I use auto focus or manual focus?
I tried both but really lack of skills... If I use auto focus the cam can't pick up the object that I'm shooting and off focus v badly. And if I use manual, the plane is too fast for me to capture or focus on. It turns out off focus.

2) do I use mutiliple shots (fast shots) dun care if is clear or blur... Shoot first...

Thks.
 

Well, since you didn't mention what cam and lens combination you are using it is quite hard to tell where the problem area is.

This is how I will go about it. Get a large aperture fast focusing tele or zoom lens, switch to AF continuous, multipoint focus.

Try to stand where the plane path is perpendicular to you and follow focus the plane as it crosses you.

Shutter release continuous high. Release the shutter when the plane is about cross in front of you.

Shutter speed 1/1000, ~1/2000 maybe suffice. You will need to try a few rounds.
 

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Well, since you didn't mention what cam and lens combination you are using it is quite hard to tell where the problem area is.

This is how I will go about it. Get a large aperture fast focusing tele or zoom lens, switch to AF continuous, multipoint focus.

Try to stand where the plane path is perpendicular to you and follow focus the plane as it crosses you.

Shutter release continuous high. Release the shutter when the plane is about cross in front of you.

Shutter speed 1/1000, ~1/2000 maybe suffice. You will need to try a few rounds.

Oh sorry miss out that part....

I'm using Sony a33 with telezoom 18-200.

I even tried burst mode but still off focus.

I tried on a fast moving cars and I manage to do it.

But somehow the plane is too small and too fast for me to focus on

Will try again and hopefully I can get it right...
 

Try this if it helps turn on Object tracking and keep the focus point in middle. Half press and get focus right before releasing shutter.
 

Check your manual about the selective usage of AF points (use the center one or center group if the camera has it) and the AF tracking mode (continuous focusing). Don't 'zoom in' too much, leave space in the frame that you can crop later. But in return you lower the chance that the object is cut off.
Use a bit higher ISO to get faster shutter speed. Don't use widest aperture, the chance of mis-focusing is high due to thin Depth of Field.
 

You're asking a lot of your body and lens -- focusing on fast moving, small objects that can change direction quickly is always going to be tough.
You could try continuous focus and try to keep the subject on your focusing point long enough, but that's not easy. I'd suggest that you work with the person flying the plane. Are you shooting for them, or are they just strangers? It helps tremendously if you know beforehand where the plane is going to be. It's easier for an AF system to track something moving ACROSS your field of view (the relative speed is not that great), provided you can keep your AF point on it -- a constant speed helps there, which is why it is better if you work together with the pilot.
One other option is to pre-focus (again you need to know in advance where the plane is going to be). This may be a little trickier because there is nothing in mid-air to prefocus on. Perhaps a lamppost or pylon?
 

Oh sorry miss out that part....

I'm using Sony a33 with telezoom 18-200.

I even tried burst mode but still off focus.

I tried on a fast moving cars and I manage to do it.

But somehow the plane is too small and too fast for me to focus on

Will try again and hopefully I can get it right...


It will be easier if the size of RC plane is large scale ( some half size of real plane) like this:


[video=youtube;CDhcB2hTyCU]http://www.youtube.com/watch?v=CDhcB2hTyCU[/video]


Here are a few tips which is based on science.

1 - An object travelling across your view is faster if it's near you (distance vs angle of view subtended ).

2 - An object travelling towards you seems stationary because there is no lateral movement
and gets bigger so easier for auto focus to catch it similar to going away but smaller size.

3 - The reason why you are successful with cars is because it is big . More areas for sensor to train on and same with large scale RC planes. Small planes are smaller versus large areas of sky.

4 - Whether plane is big or small you can ask person to throttle down to fly past you to take
a portrait. Another way is when plane is landing as speed will be slower or if person
is skilful he can land dead stick ( engine cut off so speed is dependent on plane's velocity and it is gliding which is slower ).

5 - Following plane with camera instead of being stationary gives a better chance of getting focus. If you use a 200mm minimum shutter is double focal length or 1/500th sec. but better if 1/1000th sec. or better so up ISO to maintain shutter speed. A tripod may hinder movement because nature of flight is more fluid.


Hope to see good results from you.
 

Ok, here's a few of my rules when it comes to panning a fast moving object:

1. Shutter speed affects the effect of motion. Slower speeds will induce more "blur" to the background, faster speeds will make the background more static. Slower speed will be more difficult to shoot as you'll need to be "on track" for longer.

2. Panning is basically moving your camera to follow the trajectory of the object. Basic guide is to move only your waist. Legs stay in place, camera and upper body as well. Start with your body half-twisted toward the object and turn to half-twisted in the other direction by the time you end.

3. Follow-through. After you fire your shot, do not immediately move your camera away. Follow through the shot for a bit more, keeping the object on track. This helps reduce the likelihood of a shot gone bad because it wasn't done processing.

4. Aperture. Because you're going to be reducing the shutter speed to induce motion, you can either adjust compensation by either lowering ISO closer to 100, tightening your aperture, or both. Personally, I'd do both and have aperture closer to between 7.1 to 11.0. In panning, the background will be blurred anyway, so bokeh is not a factor and it increases the overall sharpness of the object. May vary if lighting conditions are not ideal.

5. Panning is easiest when the plane is going from left to right (or right to left). This is because the distance between you and the object will not change too much, allowing the camera to easier maintain focus. This direction also produces the best "motion blur".

6. A near object will be easier to focus but will be crossing your shooting area faster. A far object will be harder to focus but will be crossing your shooting area slower. The latter gives you more time to react and take the shot but at the expense of higher chance of focusing issues. The former increases your focusing success but less reaction time to take the shot.

7. GOLDEN RULE - know your activity. You must know what you are shooting in order to do it well. How the plane flys, where it will be flying, speed it will be flying, altitude or change of altitude through the flight path etc. You need to anticipate the shot.

Other than that, it's all practice practice practice. Cars, birds, planes, bicycles, people, football, whatever.

Good luck!