Its official. Oly AF sucks!

Started Sep 11, 2013 | Discussions thread
bobn2 Forum Pro • Posts: 58,511
Re: I would be absolutely shocked...

bobn2 wrote:

Beach Bum wrote:

PerL wrote:

esco wrote:

Pentax, Sony, Olympus id say they're all pretty similar in AF performance. Its easy to think of Olympus as only being sub-par but the af-modules and lens motors on the above brands aren't too hot either!
Photographer first, gear second

The AF-C on the Canon and Nikon prosumer models has constantly been better than those from competing models from other brands like Pentax, Olympus or Sony. They probably use the experience they have from the pro series. They put in more resources on AF R&D and have better know-how.

I would be absolutely shocked (stunned really) if Canon or Nikon had better autofocus on their price competitive DSLRs than Sony.

Judging AF performance is very hard, because little of it is about specs. Most systems will focus pretty accurately and quickly if there is some pattern under the focus point and the subject isn't moving. From there on, it's downhill, and the shape and steepness of the slope can be unpredictably different. I have four DSLR's of three different brands with radically different AF systems. For static subjects really you can't tell much difference (well, so far as the different lenses let you predict which part of the performance is the camera). By far the most sophisticated of my cameras is the D800's 51 point, and certainly it works much better than the others with unpredictably moving subjects, low light and so on, but also it's trick, choose the wrong settings for a situation and you can make it work worse than the simple systems. So, I would always hesitate to make sweeping statements about AF systems.

Admittedly, I know nothing about Pentax. But, with regard to Olympus, they've been out of the mirror box market for a while, and it's well-known that the on sensor PDAF isn't up to the speed of the dedicated PDAF sensor yet, so it's absolutely no surprise that Canon or Nikon would beat out a two year old true DSLR by Olympus.

But Sony is still producing true DSLRs, and, like I said, I'd be shocked if you have any evidence of either Canon or Nikon having better autofocus.

Sony certainly doesn't any more make 'true DSLR's'. What they make are EVIL's with DSLR similar AF systems. As for Canon or Nikon having 'better AF', the AF of the tope end SLT's is lesser specified than Nikon or Canon's second tier AF. As to how it actually performs, I couldn't say, but AF performance is one of the most fiercely fought part of the competition between Canon and Nikon. Since Sony isn't a player in the top-end PJ market where that battle is fought out, it would be strange if Nikon and Canon's engineers had done worse. Certainly Canon's new 61pt AF system seems to be a blinder.

Just to follow up, fromDPReview's comments on the A99, Sony's top end system

In practice, this dual AF system provides a marked improvement over previous Sonys, particularly when paired with the AF range limit feature we'll describe shortly. But we would hardly classify the A99 as a sports photographer's camera. At indoor events, like collegiate basketball games, the AF system can be a bit slow to lock onto fast moving subjects coming straight towards or away from the camera. In the 6 fps burst mode we often found more precise focus on the second or third frame. And once the camera does achieve sharp focus, the predictive autofocus of the AF assist points cannot reliably keep up with subjects running at full speed. In burst mode sequences shot under these conditions, we rarely found more than two consecutive frames in sharp focus.

No one could reasonably expect the A99's AF performance to be on par with the much more expensive pro-oriented Nikon D4 and Canon EOS-1D X cameras. And while Sony has made obvious strides over earlier Alpha-series models, a direct peer like the Canon EOS 5D Mark III offers a nearly equivalent frame rate, wider AF array coverage and a more robust predictive traking system.

Looks like DPReview wants to shock you.

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