Focusing of A900 vs. KM7d

I am looking to move up to an A900 from my Minolta 7d.

How much better is the focusing ability of the a900 compared to the 7d. I find I miss several shots and I always try to get pictures in focus rather than composition. This mainly occurs with pictures of children and fast action shots.

Will the a900 help to keep more pictures?

Thanks

Do you know whether the a900 is capable of focusing as a person is moving towards the camera? Not sure how the focusing compares to C or N but I hear those cameras are generally better at that type of focusing.

neilsam wrote: Do you know whether the a900 is capable of focusing as a person is moving towards the camera?

Yes. Walking, running, riding bicycles. All no problem.

5thElefant wrote: neilsam wrote: Do you know whether the a900 is capable of focusing as a person is moving towards the camera? Yes. Walking, running, riding bicycles. All no problem.

And cars too.

Yes, the saying goes that Canon and Nikon have better AF than Sony. In many real life cases, it is not so. A broad, but better generalisation would be to instead say - Canon tends to have the quickest focusing, but the worst accuracy. A900 tends to be not so quick, but exhibits the best accuracy. Nikon comes somewhere between.

There are many variables here, however. The lens choosen may throw everything around - its AF performance will have a great impact on both speed and accuracy. Canon and Nikon are usually better for subjects which changes directions a lot, while at more steady movements (as cars etc.) the A900 often performs very well. For static subjects - the A900 rules. :-)

Very few comparissons have been done regarding the focusing ACCURACY for different AF systems. However, there is one in the German FotoMagazin 2008 Nr 5. They shot half a dussin of burst series for each camera at an approaching car (don't recall its velocity). Contenders were Nikon D3, Nikon D300, Canon 40D, Canon EOS-1D MkIII, Canon EOS-1Ds MkIII, Olympus E-3, Pentax K20D (maybe some more) and the dark horse Sony A700.

Well, the A700 trounced all of the others. The testers counted how many frames were unsharp relative to the number of frames taken. A700 was exceptional - only 2% of the frames were unsharp. The prestige cameras from Canon and Nikon were five times or more worser, E-3 showed 18% and K20D 25% unsharp pictures.

Lenses used were 70-200/2,8 for all systems except the Olympus E-3, where they used the closest equivalent. This means that the high accuracy sensor in the central AF area of A700 and the Canon cameras was activated (don't know about the other cameras).


The most important thing to do in order to get good AF performance out of the A700/A850/A900 is to use spotfocus. In the center area these are using 5 sensors for 1:2,8 or better lenses (4 sensors only when using lenses with smaller max aperture). In all other AF sensor positions you will find just a single linear sensor.



Edited by Swede101 - 16 January 2012 at 23:34

My a900 tracks better than any CaNikon I've ever owned... with the right lens. 85mm f1.4 and 200mm f2.8 APO (no HS), it is darn near perfect. 600mm f4 (no HS) is very accurate as well. First version Tamron 70-210mm f2.8 SP AF, Tamron 200-400mm f5.6 SP AF, and Tamron 300mm f2.8 SP AF... all work great for AF accuracy... but not perfectly as good as the Maxxum primes.

But with 70-210mm f4 beercan, it is awful for action AF accuracy... just awful.

When you get your A900, do make sure you do the firmware update to V2 that gnatsum mentions, it makes a HUGE difference to the AF. I found it helped both tracking and tricky things like grey clouds.

I recently got a backup A900 and couldn't work out why it's AF didn't seem to be working properly as I was used to with my other one, then I remembered about the firmaware update and once I'd done that all was fine. It really does make a huge difference.

Photosopher, I haven't tried a beercan on the A900, I must have a go with it. Wonder why it doesn't work very well- does the age of the beercan mean it's specs are drifting towards incompatible in some way?

analytical wrote: And you didn't ask but the shutter sound is quite different.     7D    ping A700 snick A900 WHACK

YEP!!!! WHACK!! Very interesting sound compared to my 7D and A700 and A500 - this A900 has to be the most marvelous piece of technology yet, grandfathered by the minds of Minolta.