a700 AF and tracking very slow and blury

[LightBright]

I feel like my a700 has a hard time tracking and accurately focusing on my moving subjects even in broad day light. I use center focus and continuous AF but it tends to have a hard time. Even when I have my center box on a still non moving subject, it sometimes has a hard time telling the subject matter from the background and even when it does, half of my shots are always blurry. I also have AF priority on so that it would supposedly accurately focus before it can release the shutter but many of my shots still come out blurry. Btw I use very fast shutter speed so its not a shutter problem. I don't have much problem with my 30mm f1.4 sigma (because i believe its short focal length is easy to auto focus), but the 70-200 f2.8 shots get blurry. I think
thats due to the length of the lens and how many more turns it has to do to achieve critical focus through out the 70-200 range and that continuous AF is lagging a lot. My most recent game which was yesterday suffered from out of focus pictures, it being a night game with dim lighting maid it worse.

I do not know if its normal on my camera system or not but as a reference I met this one guy with a Nikon d3 with a 70-200 f2.8 and even he was having a much tougher time getting sharp images in day light. I played with all my settings and maid sure everything was right but its still all the same.

Any advice will be greatly appreciated.

[LightBright]

Ok i feel kinda stupid. I always thought "Center AF area" was the only way to go but when I tried wide it actully tracks my subjects much better. Another plus with the "Wide AF area" selected with Continuous AF is that it seems like it puts emphasis on the center so it doesn't place focus where ever it wants like I originally thought, but if the selected subjects gets out quickly enough, it switches to another AF point.

[NoKnees]

Glad you found something working better for you. I have done a bit of "action" work with my a700 without quite the difficulty you described. I started with the old 70-210 f4 beercan and did okay, then moved up to an old Minolta 80-200 f2.8 HS, and had a much higher hit rate thanks, I believe, to the really fast (but loud) high speed gearing. 90% of my shooting is center spot, but sometimes I'll use wide when I'm not too worried about background elements distracting the camera. Still, it's very much just a "shotgun approach" relying on a high frame rate to get a couple good shots per bursts..

Anyway, all my recent shooting is beach volleyball tourneys... Mostly bright daylight, shorter range, so the conditions are easier than what you are most likely seeing. I found when I can fill the frame pretty well with the subject, wide works best. When it's a little further out, I switch to spot focus as the wide jumps around a little more due to other objects being around, unless I can shoot from a low enough angle (or high enough, looking down) to have a very flat/distant/non-distinct background... Most of the time I'm shooting close to, or wide open, 100-200 iso with shutter speeds of 2000 or more... Oh, and always keeping the focus limiter on for when I do loose focus, and the lens has to do a quick hunt and return to the subject...

I'm please with my current results, but can't wait to see what the next generation of AF improvements bring to the alpha line... Reading about the recent Nikon and Canon improvements in this area has me yearning for a bit more...

If you post the same question over on the Sports board, you'll probably get some better responses as there are a few pro-semi pro guys and gals over there that really know their stuff..

[LightBright]

Thanks Noknees. Thats the word I was looking for "Hunting" it hunts alot when the subjects are far. I never use the focus limiter, I think this will help since I tend to lose many of my shots when the af goes in and out of focus with a close subject and a far background especially in soccer when there body moves all over the place.

[Anbesol]

If you use center AF area in tracking mode, you track the subject, in wide - the camera takes over. I've found them each to have their place.

[Anbesol]

WOW! Lol, sorry, my routers been bouncing in and out of low signal, it must have resubmitted information a few too many times. I wonder why this board doesn't have flood control?

[DonSchap]

Well, I successfully used the "tracking focus" option versus an F-22 Raptor during an exhibition display at Oshkosh, AirVenture 2008

The aircraft was opening its weapons bay and it does this a relatively lightning speed to avoid 'radar signature' and detection.

Settings: A700 ver 03, Spot Focus; Spot Metering; Continuous Adv. - Hi; 750mm (equiv); f/5.6; 1/1000 sec.; ISO-400; DRO Lvl 5; WB = 6000K; IQ -= XFine JPG

Here's the result:

Seven image sequence


100% crop of sequence image #1, nose of F-22


100% crop of sequence image #4, nose of F-22


100% crop of sequence image #6, nose of F-22


I thought it worked pretty well, to be honest, and this was at easily 300mph, head to head. I must admit, I did not attempt altering zoom during this pass, because you get only ONE shot at this and admittedly, I had the TAMRON SP AF 200-500mm f/5-6.3 Di LD fully stretched to get it

Also, with DRO @ Lvl 5 ... the a700 becomes a noise generator ... but, it was at a somewhat acceptable range with this exposure (below), as I really wanted the "shadowed" interior of the bomb bay.

100% crop of sequence image #7, F-22 Weapons Bay

[Canuck935]

Saw that aircraft the local air show last year. That thing is one insane freakshow of an aircraft. The sound that thing makes is something else altogether as well. Aw man, I'm getting butterflies just thinking about it..

[LightBright]

Great shots Don!

"Saw that aircraft the local air show last year. That thing is one insane freakshow of an aircraft. The sound that thing makes is something else altogether as well. Aw man, I'm getting butterflies just thinking about it.."

Are they still going to display the f22? I heard somewhere they are going to stop showing it flying in air shows. I hope not!

[Canuck935]

I think they did stop.. They did not have one at the MCAS Miramar air show this year..

[DonSchap]

My shots were from the AirVenture 2008 ... I skipped 2009 because of weather concerns and the cut-backs in showing off the modern day military hardware. If there is one thing I cannot support, it is military hardware cuts. I think blatant US-Military-Muscle needs to be reinforced ... and if people do not like it ... they do not have to attend. Funny thing is, though ... the more military involvement, the bigger the crowd. And I am not talking about military transport ... I mean the bombers, fighters, stealth and "jammers" running around, strafing the place. Go figure. Your tax dollars at work ... and play.

THEN ... call it a day!

[LightBright]

Even more nice shots Don! I agree, I love military aircraft especially AH-1 Super Cobra's.
Well the f22 is done with but at least we still have the amazing JSF, well I hope so anyways.