AF-C mode?

[Hello_Photo]

My experience with AF-C has been mixed as well. With my DA200, AF-C on my K10D simply can't track a subject walking toward me (bride coming down the aisle, anyone?).

Rather than add any more fuel to the fire, here's a simple test that all future camera bodies must pass to be considered worthy of an upgrade from my K10D:

Set-up - camera body of your choice, set to continuous focusing/continuous drive; child on a carousel (the kind with horses and other animals that bob up and down); photographer stationed at the edge of the carousel with a DA200 let set at F2.8.

Test - The moment the child comes around, keep him/her in the frame while holding the shutter down.

Expected result - the only out of focus shots I will accept are those where the focus point I've selected "slipped" off of my intended subject. Otherwise, I expect each photo to be acceptably sharp (with a 200mm lens at 2.8, this means virtually perfect focus).

 

[brandrx]

My experience with AF-C has been mixed as well. With my DA200, AF-C on my K10D simply can't track a subject walking toward me (bride coming down the aisle, anyone?).

Rather than add any more fuel to the fire, here's a simple test that all future camera bodies must pass to be considered worthy of an upgrade from my K10D:

Set-up - camera body of your choice, set to continuous focusing/continuous drive; child on a carousel (the kind with horses and other animals that bob up and down); photographer stationed at the edge of the carousel with a DA200 let set at F2.8.

Test - The moment the child comes around, keep him/her in the frame while holding the shutter down.

Expected result - the only out of focus shots I will accept are those where the focus point I've selected "slipped" off of my intended subject. Otherwise, I expect each photo to be acceptably sharp (with a 200mm lens at 2.8, this means virtually perfect focus).

My K20D is better than my K10D in AF-C and I've been told that the K2000 is better than the K20D in AF-C. I've also been told that the K-7 is better than the K20D and the K2000 in the AF-C mode. However, I will not buy the new K-7 until I can verify this for myself, or there is overwhelming evidence in reviews and by the folks in this forum. The AF-C has been such a pain in the a$$ since every Pentax DSLR K20D and before that I think it is about time we get something that works. Otherwise, why even have AF-C as an option. It just plain sucks big time IMO.

Cheers.

--
Ron - 'We don't have time to go take pics this afternoon Carl.'
Carl - 'What do you mean? It will only take 1/1000s.'

'Keep your eyes looking forward. However, glance back now and then to see where you've come from. It will put a smile on your face.' ~ brandrx

Ron ~ Retired.

 

[azguy]

My experience with AF-C has been mixed as well. With my DA200, AF-C on my K10D simply can't track a subject walking toward me (bride coming down the aisle, anyone?).

Rather than add any more fuel to the fire, here's a simple test that all future camera bodies must pass to be considered worthy of an upgrade from my K10D:

Set-up - camera body of your choice, set to continuous focusing/continuous drive; child on a carousel (the kind with horses and other animals that bob up and down); photographer stationed at the edge of the carousel with a DA200 let set at F2.8.

Test - The moment the child comes around, keep him/her in the frame while holding the shutter down.

Expected result - the only out of focus shots I will accept are those where the focus point I've selected "slipped" off of my intended subject. Otherwise, I expect each photo to be acceptably sharp (with a 200mm lens at 2.8, this means virtually perfect focus).

I have watched these threads and wasn't going to say anything, but I think the D300 may pass your test. You can choose Release, Release + Focus, or Focus priority on AF-C. I set it at 5 fps, AF-C, Focus priority, and then shot cars coming at me at 30-40mph, with a 18-200mm consumer zoom. It did not release until in focus, and nearly maintained the full 5 fps. I tracked the cars from about 100 yards away until they passed me, zooming. Was at about 1/2000 sec at f 5.6. I'll try your test at 2.8 with a pro lens (even though I rarely shoot wide open). It is an impressive AF system, with 3D tracking that is predictive.

Good example of a D300 tracking an owl flying at the photographer here:
http://forums.dpreview.com/forums/read.asp?forum=1039&message=32202299
--
JohnE
I have enjoyed taking these images: http://www.pbase.com/jpower

Below, Phoenix City Hall with Nikkor 10.5mm on D200

 

[Stig Vidar Hovland]

And here is an example of what the old and "slow" *istDS can do. I tracked this car with AF-C and fully pressed the shutter where I wanted a picture. I believe that even my old *istDS must have predictive focusing to achive this. Car was 30m away and going between 150-200km/t.

 

[Tan68]

D TONG wrote:

depends on your settings

I think Corolla has a max speed of 120 MPH. Your question is like asking Corolla to actually give you 120 mph on the road. That is not going to happen

my Stanza made 110 with a bit more to go. it pulled good to 100. since i have no bias, i figure the Corolla should make its 120..

i doubt the engine is strong enough to pull to redline against wind resistance. so, gearing will affect your results. if it is an auto, compare third to OD. my car has a standard transmission so... YMMV.

recommended settings: windows rolled up
Corolla max speed may even be governed.
if it isn't, start with shudder-speed and back off ~5 mph

post pics of the results

 

[ManuH]

I have tons of example of using the max number of frames/second (3 for k20d) ONLY with MF and manual metering. An auto function will slow the camera down

Catch-in focus won't work for faster subject particularly in dim light

You're right Daniel, I did some tests yesterday night, switching between manual metering and automatic. In M mode, you can notice a performance increase. AF-S or Manual focusing + Manual metering and I get the fastest speed, probably close to the 5.2fps. The annoying thing is as soon as you switch to AF-C, the frame rate drop somewhat and this even if the subject doesn't move. The annoying conclusion is that the K-7 CPU is too slow to do multiple things at the same time.

--
Manu



http://flickr.com/photos/ensh/
Réflex Pentax: http://www.flickr.com/groups/pentaxfr/

My PPG: http://www.pentaxphotogallery.com/home#section=ARTIST&subSection=1312871&subSubSection=3929608

 

[Roland Mabo]

If it had 100% focus priority, then a lot of shots would be missed beacuse the focus wouldn't catch up with all movement. For moving subjects, a slight out of focus shot is in many ways perfectly acceptable because the subject is moving so the slight out of focus helps to create a sense of movement.

The MZ-serie did not have AF-C, instead it had predictive AF-S, but many wanted a classic AF-C mode instead.

The K-m / K2000 and the K-7 has faster AF processing than other Pentax DSLR's and this means that both AF-S and AF-C is faster. However, it also depends on the lens in use because the AF motor in the K-7 is not stronger nor faster. and an upgrade of the camera won't make the motor in the SDM lenses to suddenly becomes faster or stronger. But faster AF processing means nevertheless a faster autofocus, but the difference is less noticeable with lenses that are slow focusing due to the construction in the lens - such as the FA Limiteds which has a higher friction than other AF lenses in order to retain more manual focus feel. The DA Limiteds does not have this limitation.

With the faster AF lenses on the Pentax system, the faster AF processing means a bigger improvement in speed for both AF-S and AF-C than with the slower AF lenses.

--
Take care
R
http://www.flickr.com/photos/raphaelmabo

 

[stoneroses74]

I second that on the K100D as well. But, if the alternative is getting no shot at all - I´d rather have a blurred one in some situations.

--



http://photosbyhakan.fotopic.net/

 

[JimmyTheHand]

Yes useful trick to overcome lock on issues in K10D - I find happens most with wide angle lens, but not always low light. (Its the reason I might buy a K7)

--
J.