[quote name='oneguy' timestamp='1300167044' post='6786']
And according to IR and all other reviews, it does match. Where are your crops from DPRreview anyway, like you have been doing for IR?
[/quote]
NO other review, anywhere, has stated they tested the AF tracking ability, or shown its results. Crops from dpreview? Why can't you keep a discussion clean? Dpreview has used the camera, and stated that the AF capabilities do not match the high FPS modes (the modes that suggest it should be a sports camera candidate). They never stated that they put the camera next to a 7D or a D300 and then compared results, they never showed crops from one camera and not the other.
You keep ignoring the fact that the crops they did show (from the A55v) on IR did NOT show good focus performance.
So in case of IR we have the following situation:
- The only site which apparently was allowed to publish a review with samples on the date of the release of the camera.
- They claim they shot side by side with a 7D and that they "felt" that the results were comparable, but they never show the 7D results next to the A55v results, something I have NEVER seen from ANY review site.
- They claim that the most out of focus shot was due to "camera shake", which is impossible as it is a shot from a sequence of 9 shots within the same second, the shutter time was too high for camera shake (150mm, f2.8 lens, sunny conditions), the camera has in-body IS.
Now why would you doubt what dpreview says it found? I have no reason to doubt that dpreview is correct in their assessment, especially since the results from IR from a relatively slow moving car appear to be totally in line with what dpreview says about its tracking ability.
If any 7D, D300, 60D, D7000 would be that bad in tracking a car traveling at 50km/h, I would suggest that the owner either lets the camera be serviced, or that the owner selects a different lens.
Yes, I know all those cameras are more expensive, but that is beside the point (point being: is the A33 very suitable for sports). I promised you I would do a test with my 450D and 70-200 at 150mm, so we can compared with camera that is more in the same class. Be patient, I will try to get around it as soon as I can.
[quote name='oneguy' timestamp='1300167146' post='6787']
They show AF tracking in 10 fps mode. Works just fine.
[/quote]
They do not show that, though.... We see images with even seconds apart... the 3rd boy in the 2nd image did not materialize. And the 3rd image also is clearly not a next frame of a 10fps sequence.
What they DO show is that you can make photos with the camera from a field sports game. But that is normal, is it not? People were doing that with EOS 350D's 5 years ago too.
[quote name='Brightcolours' timestamp='1300188741' post='6799']
You keep ignoring the fact that the crops they did show (from the A55v) on IR did NOT show good focus performance. [/quote]
The AF perforamnce macthed that of 7D according to IR. How do you know that 7D did better than A55 in this test, when IR, who tested it, said otherwise?
[quote name='Brightcolours' timestamp='1300188741' post='6799']
Now why would you doubt what dpreview says it found? [/quote]
So since DPR hasn't posted any proof for whatever you claim they said, we don't have any reaon to doubt it and must accept it (since there are no crops). Nice logic.
[quote name='Brightcolours' timestamp='1300189019' post='6800']
They do not show that, though.... We see images with even seconds apart... the 3rd boy in the 2nd image did not materialize. And the 3rd image also is clearly not a next frame of a 10fps sequence.
What they DO show is that you can make photos with the camera from a field sports game. But that is normal, is it not? People were doing that with EOS 350D's 5 years ago too.
[/quote]
The person who took the photos (in 10 fps mode) claims that vast majority of them were in focus and AF tracking worked just fine in 10 fps. Better than most cameras in this price range. Just because he hasn't posted all similar/identical series to flickr doesn't mean AF tracking wasn't working in 10 fps mode.
The AF tracking works just fine in 10 fps, as IR, most reviews, and user report.
[quote name='oneguy' timestamp='1300192427' post='6805']
The AF perforamnce macthed that of 7D according to IR. How do you know that 7D did better than A55 when IR, who tested it, said otherwise?
We already know the 7D can do fine, enough people use it for sports and therefor enough information is available about that specific camera.
So since DPR hasn't posted any proof for whatever you claim they said, we don't have any reaon to doubt it and must accept it (since there are no crops). Nice logic.
[/quote]
It is not what I "claim" dpreview says, I am very sure YOU have read it there yourself too. Yet, for unknown reasons, you choose to disregard it.
Now, about IR, we KNOW the crops show nothing successful. And we KNOW, that while they say they did a comparison, they do not show the comparison, which really is quite odd (first time ever I have seen that on internet, actually). We also can see that they claim silly stuff (one shot out of a sequence within one second "camera shaken". And that under conditions you can't even imagine camera shake. And a test that is not really all that taxing.
So, it is clear what my objections are about the so called "test" of the AF tracking by IR. They are logical and I have explained them very clearly. Can you now stop arguing about it?
What your reason is to dismiss dpreview's assessment is not clear. They gave no specific details, so one can not fault their methodology, for instance. We can also not say it does not follow the trend, as we have no sources that seriously test the AF tracking performance of that camera's AF module.
We can however match it with statements of people who actually have used both (like Yakim).
Like I said, I will try to make a 1 second sequence with my camera and 70-200mm lens, mimicking as close as possible what IR describes. Then we will have something to compare the IR results with.
[quote name='Brightcolours' timestamp='1300193458' post='6808']
We can however match it with statements of people who actually have used both (like Yakim).
[/quote]
Funny you mentioned one poster Yakim but the review itself rated A33 four for sports. There are hundreds of posters on various forums who claim A55 has faster/better AF than A700. Why just Yakim?
SLT cameras by very nature would become (future models) vastly superior for AF tracking than a traditional DSLR, including professional models like 1D IV. It's pretty simple. Tradition design has to use predictive AF since the AF sensor loses track of the subject every time the mirror flips. With pellicle mirror, the AF sensor gets contant light from the subject.
Even with entry level model (A55), no camera short of 4K can do 10 fps with AF tracking, so higher end models would be even better.
[quote name='Yakim' timestamp='1300172336' post='6790']
It could be much simpler though. I had AF problems but Klaus and others didn't. Either we shoot in different conditions or we have different expectation or my cam was somehow faulty (though checked by a Sony expert) or any combination of the above.
[/quote]
Another possibility is that the lenses you used with the A33 are slower (to focus) than the lenses you use with the 7D. To really test this you need to use each camera with a lens that's known to be fast (to focus), or ideally to use the same third party lens (e.g. Sigma 70-200/2.8 HSM) on both cameras.
[quote name='boren' timestamp='1300199679' post='6814']
Another possibility is that the lenses you used with the A33 are slower (to focus) than the lenses you use with the 7D. To really test this you need to use each camera with a lens that's known to be fast (to focus), or ideally to use the same third party lens (e.g. Sigma 70-200/2.8 HSM) on both cameras.
[/quote]
This is not the case for sure as lenses were very similar. See the link in my first post in this thread. Also, I never really tested the AF. I just used it the way I always do. The most "testing" I did was shooting both side by side in as similar as possible conditions. That was after I got the initial feeling that something is not working well in the AF of the A33 in normal shooting.
03-15-2011, 05:06 PM
(This post was last modified: 03-15-2011, 05:35 PM by boren.)
Most user reviews in dyxum.com say that the Tamron 60/2.0 is slow to focus. The Canon 60/2.8 on the other hand is known to be one of the faster-focusing macro lenses around (at least according to user reviews in fredmiranda.com). Testing the Tamron on the EOS-7D will give you a better point of comparison.
The kit lenses are a similar story. One of the users at dyxum.com had this to say about the Sony 18-55 SAM: "Extremely poor auto-focus (slow and unreliable in anything but good light)". This is from a user who also used the following lenses: Sony 16-105, Sony 18-70, Minolta 17-35, Minolta 20-35, Minolta 24-50. He has enough experience to compare its performance. Another user had this to say about the lens: "slow to almost none af in low light". Among the 44 review at fredmiranda.com I couldn't find a single one that complained the the Canon 18-55 IS is slow to focus. In fact, quite a few of them raved about its fast and accurate AF.
Bottom line: SAM motors are very different than SSM motors. The former are a marketing trick. They are slow and noisy and were only released to the market by Sony as a cheap answer to "those in the know" (e.g. salesmen and Canikon FUD-spreading fanboys) that claim screwdrive AF is a disadvantage. Tamron isn't known for fast focusing lenses and the 60/2.0 is a typical example, if not the worst. Both Canon lenses you've used are much better, and this means that your findings, as interesting as they may be, are not really valid. At least not as a comparison of the AF capabilities of these cameras.
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