Help with autofocussing/moving objects

Started Nov 15, 2016 | Discussions
MBC3 Junior Member • Posts: 41
Help with autofocussing/moving objects

How do you photograph moving objects e.g. kids, dogs, etc.? I have a K-1.

Sorry about such a daft question... but I am not very familiar with using autofocus.

Many thanks for assistance!

Pentax K-1
If you believe there are incorrect tags, please send us this post using our feedback form.
miles green
miles green Veteran Member • Posts: 7,053
Re: Help with autofocussing/moving objects
3

MBC3 wrote:

How do you photograph moving objects e.g. kids, dogs, etc.? I have a K-1.

Sorry about such a daft question... but I am not very familiar with using autofocus.

Many thanks for assistance!

Each situation is a little different and it takes experience with the camera to find the best possible settings for each setting. Which is why dedicated sports cameras like the Canon 1D series have so many AF settings.

The K-1 is not a dedicated sports camera, but with the right settings, it fares decently and you'll get the pictures you're looking to get.

First, I recommend you install the latest firmware (currently v1.30) it seems it makes a difference with AF-C tracking, both in the Z axis (subject soming closer / moving farther from you) and in the XY axis (ability to track the object as it moves around the frame, switching automatically from one focus point to the next).

Then you should disable all jpg corrections (distortion, peripheral illumination...) to allow the processor more power to dedicate to AF algorithms. If shooting long bursts, i woul definitely recommend jpg only with the K-1, not RAW.

If you're going to crop anyway, put the camera in crop mode, which will give the K-1 faster performance.

Personally i keep SR on, but i might be wrong about this.

The new lenses with modern AF motors will perform (AF) faster and more accurately than10 older lenses. Pentax has recently only started putting fast motors in its lenses.

Depending on the speed of the subject you need to select a high enough shutter speed. Start with 1/400 sec for moderate speeds, and faster for faster subjects. One exception is for panned pictures where you want to background to appear smeared in the direction of the subjects movement. I like to put the camera in TAv mode, setting my desired shutter speed and aperture (usually very close to wide open) and letting the camera deal with exposure by automatically adjusting ISO.

Here is where I would start with AF settings:

1. Put the camera in AF-C mode

2. AF active area set to SEL1 (spot AF) or SEL9. SEL1 basically disables XY tracking. The more you want to allow the subject to move around the frame (for different compositions) the more freedom you want to offer the camera to try and track with more AF points. If the K-1 has an Achille's heel, this would be it. But do install the latest firmware.

3. 1st frame in AF-C you should probably leave in focus priority. You can start experiment with the settings regarding the AF priority after the 1st frame in a burst

4. AF hold set to low for starting, and adjust depending on how easy / desirable it is to hold the subject over your selected AF point/area

It definitely takes some experience with tracking, panning the camera, etc, to get consistent results, so keep trying new things and and improving.

Hope this helps

-- hide signature --

Miles Green
Pentaxian with chronic LBA since 1997
Corfu, Greece
N.B. All my images are protected by Copyright

 miles green's gear list:miles green's gear list
Pentax K-1 Pentax K-1 II Pentax smc FA 31mm F1.8 AL Limited Pentax smc FA 43mm F1.9 Limited Pentax smc FA 77mm 1.8 Limited +6 more
Mordecai Papamichaels Regular Member • Posts: 329
Re: Help with autofocussing/moving objects

Personally i keep SR on, but i might be wrong about this.

With moving objects you are going to be shooting mostly 2-3 stops over the 1/fl rule so I would disable the SR for those subjects.... (that is, if you are not like me and remember to do that)

sinus007 Regular Member • Posts: 463
Re: Help with autofocussing/moving objects

Hi,

Please follow this thread:

http://www.pentaxforums.com/forums/38-photographic-technique/236970-perfect-focus-everytime.html

There're a lot of useful things.

happy shooting,

AK

John_A_G Veteran Member • Posts: 7,821
excellent advice....
1

Miles' advice is excellent.  I'd like to emphasize his advice for using 1 or 9 points - Nikon does a fantastic job of chasing a subject around the frame.

I would add this bit of advice - make sure your subject (since your subject is a moving child) is filling at least 1/2 the vertical frame when you're doing action shots of them.  Where people new to action photography get themselves into a lot of trouble is framing so loosely that the focus point(s) slip off the subject quite a bit.  Utilizing a small group of focus points and keeping your subject filling 1/2 the frame will yield a lot more keepers.

I would also agree with the poster below that turning off SR could be beneficial.  As stated, you're going to be using shutter speeds plenty fast enough for the focal lengths you're using.  SR is just one more thing you're asking the computer inside the camera to do that it doesn't need to do.  PLUS, when you have an erratic moving subject that changes directions it makes it difficult for any antishake technology to determine an intended change in direction vs. shake.  Anti shake works much better with linear tracking of a subject.

Don't be afraid of higher ISOs - keep those shutter speeds up over 1/400 - get to at least 1/1000 if you are below ISO 6400.

miles green
miles green Veteran Member • Posts: 7,053
Re: excellent advice....

John_A_G wrote:

Miles' advice is excellent.

Thanks!

I'd like to emphasize his advice for using 1 or 9 points - Nikon does a fantastic job of chasing a subject around the frame.

Thank you for filling in a few of those points!

I would add this bit of advice - make sure your subject (since your subject is a moving child) is filling at least 1/2 the vertical frame when you're doing action shots of them. Where people new to action photography get themselves into a lot of trouble is framing so loosely that the focus point(s) slip off the subject quite a bit. Utilizing a small group of focus points and keeping your subject filling 1/2 the frame will yield a lot more keepers.

I completely agree, a longish lens will help get much better pictures and better AF performance.

I would also agree with the poster below that turning off SR could be beneficial. As stated, you're going to be using shutter speeds plenty fast enough for the focal lengths you're using. SR is just one more thing you're asking the computer inside the camera to do that it doesn't need to do. PLUS, when you have an erratic moving subject that changes directions it makes it difficult for any antishake technology to determine an intended change in direction vs. shake. Anti shake works much better with linear tracking of a subject.

Admittedly i usually end up with SR on because i forget about it.... I'm pretty sure it turns itself off automatically when i start panning erratically, because i haven't seen any weird SR shake in my action shots, and the little hand indicator turns off. But it might as well be turned off as a general rule.

Don't be afraid of higher ISOs - keep those shutter speeds up over 1/400 - get to at least 1/1000 if you are below ISO 6400.

-- hide signature --

Miles Green
Pentaxian with chronic LBA since 1997
Corfu, Greece
N.B. All my images are protected by Copyright

 miles green's gear list:miles green's gear list
Pentax K-1 Pentax K-1 II Pentax smc FA 31mm F1.8 AL Limited Pentax smc FA 43mm F1.9 Limited Pentax smc FA 77mm 1.8 Limited +6 more
John_A_G Veteran Member • Posts: 7,821
Re: excellent advice....

miles green wrote:

I would add this bit of advice - make sure your subject (since your subject is a moving child) is filling at least 1/2 the vertical frame when you're doing action shots of them. Where people new to action photography get themselves into a lot of trouble is framing so loosely that the focus point(s) slip off the subject quite a bit. Utilizing a small group of focus points and keeping your subject filling 1/2 the frame will yield a lot more keepers.

I completely agree, a longish lens will help get much better pictures and better AF performance.

It may not even require that long of a lens.  The OP is wanting to photograph kids playing I believe.  The key is to frame tightly - that often means zooming in instead of zooming out for fear of missing the action.  And, sometimes it just means getting up and moving a little closer to the action.  I see a lot of lazy photographers - they just want to stand wherever and be able to take pictures.  Compelling photos are made when you put yourself in the right place.  For kids it means getting down on their level (if it's a toddler, lay on the ground for example).

With this idea in mind, the OP could be using a 50mm or 85mm lens - they just have to get close enough for subject to fill 1/2 the frame.

Mordecai Papamichaels Regular Member • Posts: 329
Re: excellent advice....

John_A_G wrote:

miles green wrote:

I would add this bit of advice - make sure your subject (since your subject is a moving child) is filling at least 1/2 the vertical frame when you're doing action shots of them. Where people new to action photography get themselves into a lot of trouble is framing so loosely that the focus point(s) slip off the subject quite a bit. Utilizing a small group of focus points and keeping your subject filling 1/2 the frame will yield a lot more keepers.

I completely agree, a longish lens will help get much better pictures and better AF performance.

It may not even require that long of a lens. The OP is wanting to photograph kids playing I believe. The key is to frame tightly - that often means zooming in instead of zooming out for fear of missing the action. And, sometimes it just means getting up and moving a little closer to the action. I see a lot of lazy photographers - they just want to stand wherever and be able to take pictures. Compelling photos are made when you put yourself in the right place. For kids it means getting down on their level (if it's a toddler, lay on the ground for example).

With this idea in mind, the OP could be using a 50mm or 85mm lens - they just have to get close enough for subject to fill 1/2 the frame.

I think that what he was trying to say is that long-lenses are usually made for sports and therefore they carry "better" in-lens motors.

Tatouzou
Tatouzou Senior Member • Posts: 1,815
Re: Help with autofocussing/moving objects
2

MBC3 wrote:

How do you photograph moving objects e.g. kids, dogs, etc.? I have a K-1.

Sorry about such a daft question... but I am not very familiar with using autofocus.

Many thanks for assistance!

My 2 cents handling tip:

(I dont have K1, I use k3 and K30, but it works on all camera with a back AF button.)

Pentax AF-C is not stellar, but it does a better job in Z axis than tracking across ther frame in X and Y axis, where it will often loose the target and then refocus on anything else.

Thus, after trying different settings, I get best results this way (the menu names can be different in K1):

  • In the capture menu, set AF button to AF2. This setting disables AF via the shutter release and enables AF only while the back AF button is pressed.
  • set burst mode to AF priority in the custom menu
  • set AF mode to AF-C, and SEL 1: this way you manually select the single AF point the AF will focus on, which allows some freedom in framing when you dont want your target to be just in the center of the frame.
  • press the AF button, select the AF point using the 4 ways navigation buttons
  • track the target by panning the camera while keeping the AF button pressed with your thumb. You must maintain the selected AF point on the target.
  • when you are ready to shoot, if you need to recompose a little, and the target doesnt move too fast in the Z axis, release the back AF button, to prevent the camera to change focus. You will get better results if you dont need to recompose a lot, which means choosing an AF point close to the final focus target. It is also better not to use the two outer AF points which are not cross type and can easily be fooled
  • If you plan to track a target moving in the Z axis, ensure you track accurately the target by panning the camera, choose a wider framing so that you dont need to recompose, and keep the back  AF button pressed during the burst. There are lots of pixels, you will adjust the framing in PP.
  • AF hold can be adjusted if there are disturbing objects around the target, like twigs

As some of these settings are buried in the sub-menus, you may find convenient to program them in one or two of the custom user's modes, so that you can recall them easily.

IMO, getting used to AF only via the back AF button is the only safe way to prevent any attempt of the camera to change focus when you press the shutter release. It takes just a little training to get used to it.

You will notice that  it works in all kind of scene, since you dont need to switch to AF-S for static scenes: as the camera wont refocus if you dont allow it, you can stay in AF-C all the time and just press the back AF button a short while, and release it  once  AF is locked on the target.

Last tip: though the Pentax P and AV modes can be tuned in K3 (and I guess in K1) to rise the ISO and shutter speed faster, my experience is that the camera tends to choose too low shutter speeds, rather than rise the ISO. Thus it is safer to use the TAv mode, in which you select shutter speed and aperture and the camera chooses the ISO to adjust the exposure.

You can always reduce the high ISO noise in PP, but you cannot really improve a blurred picture. On K3 and K 30, for action shots in which you dont need lots of details, ISO 1600 is OK, ISO 3200 still good, and ISO 6400 can save the shot and deliver acceptable IQ. On K1, you can double the matching ISO value and yet get a better IQ.

-- hide signature --
 Tatouzou's gear list:Tatouzou's gear list
Panasonic Lumix DMC-LF1 Pentax K-3 Panasonic Lumix DMC-GM5 Panasonic Lumix DMC-GX8 Pentax smc DA 17-70mm F4.0 AL (IF) SDM +23 more
miles green
miles green Veteran Member • Posts: 7,053
Re: excellent advice....

Mordecai Papamichaels wrote:

John_A_G wrote:

miles green wrote:

I would add this bit of advice - make sure your subject (since your subject is a moving child) is filling at least 1/2 the vertical frame when you're doing action shots of them. Where people new to action photography get themselves into a lot of trouble is framing so loosely that the focus point(s) slip off the subject quite a bit. Utilizing a small group of focus points and keeping your subject filling 1/2 the frame will yield a lot more keepers.

I completely agree, a longish lens will help get much better pictures and better AF performance.

It may not even require that long of a lens. The OP is wanting to photograph kids playing I believe. The key is to frame tightly - that often means zooming in instead of zooming out for fear of missing the action. And, sometimes it just means getting up and moving a little closer to the action. I see a lot of lazy photographers - they just want to stand wherever and be able to take pictures. Compelling photos are made when you put yourself in the right place. For kids it means getting down on their level (if it's a toddler, lay on the ground for example).

With this idea in mind, the OP could be using a 50mm or 85mm lens - they just have to get close enough for subject to fill 1/2 the frame.

I think that what he was trying to say is that long-lenses are usually made for sports and therefore they carry "better" in-lens motors.

not really.. i'm just agreeing with John that you need to fill the frame as much as possible. So either you get a long lens... or go closer.

The OP's question is quite general, so i my answer is a bit generalized/unspecific, my apologies.

-- hide signature --

Miles Green
Pentaxian with chronic LBA since 1997
Corfu, Greece
N.B. All my images are protected by Copyright

 miles green's gear list:miles green's gear list
Pentax K-1 Pentax K-1 II Pentax smc FA 31mm F1.8 AL Limited Pentax smc FA 43mm F1.9 Limited Pentax smc FA 77mm 1.8 Limited +6 more
OP MBC3 Junior Member • Posts: 41
Sincere thanks...

I would just like to say a big thanks to everyone for all your very thoughtful and helpful hints!! Wow...

Keyboard shortcuts:
FForum MMy threads