Not a problem, advice needed

We have a large powerboat race starting in Alicante in a few months and as I have never taken photos of fast moving objects I went down to a dirt track with a friend, his kids and quad bike to try it out.

First of all I found out that the Pentax focus system doesn't seem too quick at tracking moving objects but also I would like to know how you get motion blur in the backgoound while keeping the main subject in focus.

A few pics showing them riding the bike but it all looks a bit stagnant to me.

[IMG]http://img.photobucket.com/albums/v188/Sockpuppetuk/Display/2749855297_7c66223495_b.jpg[/IMG]
[IMG]http://img.photobucket.com/albums/v188/Sockpuppetuk/Display/2749893103_b40903eb32_b.jpg[/IMG]
[IMG]http://img.photobucket.com/albums/v188/Sockpuppetuk/Display/2749947597_eb447dbe97_b.jpg[/IMG]
[IMG]http://img.photobucket.com/albums/v188/Sockpuppetuk/Display/2750578204_be04a5fe5c_b.jpg[/IMG]
[IMG]http://img.photobucket.com/albums/v188/Sockpuppetuk/Display/2750740840_f8aed71097_b.jpg[/IMG]

Couple of comments. First, only the 1st and 4th of these look a bit static - I certainly wouldn't say stagnant.

In the others, there's lots of blur in the wheels, which conveys the movement, and especially in the 2nd and 3rd, the subject seems quite crisp, so I'm not clear what the focusing problems were (unless these were the exception). The softness in the last one seems to be a depth of field issue, not an AF issue.

To blur backgrounds, you need to be moving the camera with the moving subject, so that it is in the same place in the viewfinder all the time. Then you use a relatively long exposure, so that the camera movement blurs the background.

This isn't possible, of course, when the subject is coming directly towards you, as it is, mostly, in these shots.

It's a lot less of a problem for the AF to capture something crossing your field of view at right angles (if you're panning with it), than it is to track something moving directly towards you - since the camera-to-subject distance isn't changing so quickly.

I'd now use Auto-AF point selection for a subject like this. And AF-C.

Motion blur occurs when you "pan" the camera, which means moving it to track the subject.

It works when the subject is moving across the frame. Your pictures, by and large, are either moving diagonally or straight at you.

By moving the camera at the speed of the subject, you can use a lower shutter speed. This is what causes the background to blur.

G

Seems Chris got there before me. He's learning!

G

As for Pentax focus speed, I can't say how it compares with other makes/models, but people shooting fast moving subjects will often pre-focus, and shoot when the subject reaches the plane of focus.

I tried shooting motor-bikes moving at 150mph a few feet away at the IOM TT in June. The go so fast that you can't press the shutter when they come into the picture, you just have to guess the right time to shoot based on the noise the bikes make.

G

I was looking for the "TT" effect such as when they come round a corner and you see the background blurred but the bike itself pin sharp but I guess maybe they were not moving fast enough to get that and the fact I was shooting at totally the wrong angle didn't help.
Thanks for the advice, will try the panning method next time on something a bit faster .. maybe I will just go up to the local through road here and try it out as the Spanish all seem to drive as if they are in a F1 race anyway.

Oh, and my apologies to Chris on the other thread, I was just a bit annoyed at being messed around and having the seller actually add words which were not even in his PM's"

The camera absolutely has to be moving, to achieve this.

[Edit: well, for it to be motion blur, which is very different from the background just looking out of focus.]

No probs

Depending on how consistent the boats are in where they pass you each time, you could manually focus on a certain corner or section of the circuit, and fire away as a boat passes through. If you can get the panning technique you get great action shots, and it also takes more skill than having a fast shutter speed and simply freezing the frame. Be prepared for a pretty low success rate though, I've used a shutter speed of about 1/250 on remote control cars, but these move through the field of view very rapidly so unless you're up close you could go for 1/125 or whatever works. Concentrate on keeping the crosshairs on the same point on the boat and track it along - it is much easier said than done

I reckon boats will be easier than quad bikes.

You'll be a lot further away, so the relative speed will be less.

Not 'as it passes through' - just before.

Agreed, although auto-AF point selection and AF-C will be fine if they're moving roughly past you at right angles.

What lens are you planning to use?

Probably the same as I used here, the SIgma 135-400mm DG APO, may take the Tamron 1.4X Teleconverter as well.
I may still go for the Pentax 55-300mm yet just for the convenience of size, especially as the Tamron 28-300mm has gone.

Unless of course Pentax release the 60-250mm before the event ...

Is this the effect you are after : Not the best example, the fence ruined the shot
I used the pan technique for this shot with the my DA* 300mm

[IMG]http://i184.photobucket.com/albums/x261/ClarkyinAus/IMGP1333.jpg[/IMG]

I didn't recognise you Mike with the name change. What gives

Yes, thats just what I am after thanks.
As for the name change, I asked for it before the weekend, I am having it done on all the forums I use as I wanted it to be the same everywhere and it is the name my flickr account is in

Also, I was bored of being a Sockpuppet, I wanted to be a real boy

Pinochio didn't change his name when he became a real boy

"Pinochio didn't change his name when he became a real boy"

Oh great.. Pinochio
There's a creepy show....
Some creepy, lonely old man, runs a toy store.
Makes himself a puppet with a nose that looks (and acts) suspiciously like a....
Some fairy comes by his place in the middle of the night, to make the puppet a real boy....
First thing the old man says is "Come on Pinochio, lets go to bed"

Creepy old Geppettophile....

Still trying to work out how we got from photographic techniqe to paedophile puppet makers.
Talking of which, I have never really noticed before but when we used to go to the park where all the duck are a few months ago everything was fine but since I have taken up photography as a hobby and take my camera even my wife comments about me carrying it around and I do get some very strange looks.

I suppose it's the world we live in today ....