Why I switched to an OM-D Locked

Started Feb 11, 2013 | Discussions thread
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Anders W Forum Pro • Posts: 21,466
Re: Has nothing to do with reality

PerL wrote:

Anders W wrote:

qianp2k wrote:

I am not sure if worth than a Rebel T4i or T3i however especially if I mount EF lenses thru adapter (so saving in weight/size become irrelavent) that no matter how Canon improve CDAF speed, still will be slower than EF lenses on native EF mount.

For those interested in how matters actually stand when it comes to AF performance:

When it comes to AF-S, MFT cameras are already as fast as, or faster than, most DSLRs. They are also more accurate than most DSLRs when it comes to systematic error (front focus, back focus) as well as random error.

When it comes to AF-C, I suggest to take a look at the results published by the French Fnac labs.

In one of their tests, they simualte a car approaching the camera at a speed of 50 km/h. The camera is fired in burst mode with a 200 mm (EFL) lens. At the outset, the car is fifty meters away. Obviously, it gets more and more difficult for the AF system to keep up, the closer the car gets. So one significant measure is the distance of the car from the camera when the last reasonably sharp shot is caught. Here are the results from this year's roundup:

CDAF

Panasonic GX1: 2.5

Panasonic G5: 8

Panasonic GF5: 8

Panasonic GH3: 9.5

Sony NEX F3: 11

Sony NEX 7: 12.5

Sony NEX 5R: 13

Sony NEX 6: 15

Samsung NX1000: 19

..........................

CDAF/PDAF

Nikon J2: 6.5

..........................

PDAF

Canon 650D: 6

Canon 7D: 6.5

Nikon D4: 7

Nikon D800: 8

Canon 5DIII: 8.5

Nikon D5100: 8.5

Nikon D600: 8.5

Canon 1100D: 9

Nikon D3100: 9.5

Pentax K-5: 9.5

Pentax K-30: 9.5

Nikon D3200: 10

Sony SLT-A57: 10

Nikon D7000: 10.5

Sony SLT-A65: 10.5

Canon 600D: 11.5

Sony SLT-A37: 11.5

Canon 60D: 12.5

Sony A-77: 13.5

As expected, the PDAF systems do better on average on this test. However, the difference is not all that big and the faster/better CDAF cameras beat the slower/worse PDAF cameras.

Source:

http://multimedia.fnac.com/multimedia/editorial/labo/reflex_2013_v8.pdf

Note: I have excluded the results for the Olympus E-PM2 and E-M5 since the result pattern in both cases leaves me uncertain as to whether the camera was properly set up for the test (very high frame rates at the beginning combined with strange results at the end). With respect to the E-M5, there have additionally been reports that AF-C performance has been radically improved with later firmware, which might not have been used in the tests reported here. 

Just by looking at the results one can see that this test has very little to do with performance in the field. Panasonic GX1 has better AF-C than Nikon D4? Canons entry level 650D has better AF-C than 7D and 5DIII? That is just a few of many unbelievable results.

My own experience with testing AF-C with CDAF vs PDAF is totally different and so is every practical review I have ever read.

If you have made any systematic tests of AF-C performance, please feel free to make a post carefully describing your methods and results.

As to the tests reported by the FNAC lab, they describe rather carefully what they are doing and their test setup makes good sense as a test of AF-C performance. If you think differently, please spell out what you find wrong with it.

As to the outliers, like the results for the 650D and the GX1, everyone familiar with tests involving a probabilistic element (as does this one) realize that these may occur and should be discounted. If you do so, you find the expected DSLRs at the top (7D, D4, D800, 5DIII) at between 6 and 8.5 meters, to be compared with the Panasonic G5, GF5, and GH3 at between 8 and 9.5 meters. If you look at the pattern as a whole, you can conclude exactly what I concluded, namely that the best DSLRs (pro, semi-pro) are still ahead but only by a whisker and that the fastest CDAF cameras beat many DSLRs.

 Anders W's gear list:Anders W's gear list
Panasonic Lumix DMC-G1 Olympus OM-D E-M5 Olympus E-M1 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS Panasonic Lumix G Vario 7-14mm F4 ASPH +28 more
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