5D AF sucks---see examples

Started Nov 6, 2008 | Discussions thread
genotypewriter Veteran Member • Posts: 4,846
Re: You talk as if you tested a 5D2

Barnett wrote:

I am not telling people anything - Canon said it is the same sensor.
Trust me, if it was any better than the old one they would have said

You played with the camera in the shop and got a warm fussy feeling.
That does not count as a test, especially not a test that refutes the
manufacturer's claims. And especially not a claim that makes the
camera better than what the manufacturer themselves claim! Sorry.

I didn't know that Canon knew about the 1D3's AF problems when it was shipped because they manufactured it.

You have to be very careful when drawing conclusions from such
limited testing. It is very easy to see "what you want to see." The
only way to avoid this is by doing a much more comprehensive test:
http://en.wikipedia.org/wiki/Experimenter 's_bias

But as a researcher you really should know this.

I do... that's why I didn't claim it as gospel. So are you capable of formulating a comprehensive, unbiased, conclusive AF test? I'd like to see you or anyone else do that.


genotypewriter wrote:

Barnett wrote:

genotypewriter wrote:

Two problems with your assumption:

1. If you think the AF performance is the same and the higher res is
going to accentuate the problem, why use the higher res if you can do
with 12MP? Down scale it.

True, if you want to down scale the 5DMKII images it will be no worse
than the old 5D.

2. There are other electronics that are different in the 5D2 and they
migth have a say in the AF performance...

Speed is not the problem - accuracy is. No amount of processing is
going to change the fact that the outer AF points does not have
ability to "see" at larger apertures like the center AF point does.

You're an electronics engineer but if you ever really made anything
you'd know that specs don't dictate real-world performance.

Either way, when I tried the 5D2, I noticed the outer AF points were
a bit better than the original 5D... remember, this was side by side
using the same lens.

Canon says it is the same AND not even as good as the 50D (due to
size constraints). But you say it is better. So you are making
extraordinary claims here. That requires extraordinary proof.

I'm not saying it's better than the 50D because I haven't tested it
next to a 50D. I'm saying I noticed an impovement in the corner
points, over the 5D.

How did you test? What lenses did you use? Show us the pictures.

Focused on a point A (near) and then a point B (further away). The
test was done for myself and in a very limited amount of time,
without a CF card. A full blown AF test probably much harder to do
than a proper cross platform noise test so don't expect ever to hear
much more than "user experiences" on AF performance as you have with
all the other cameras released to date... so I recommend that you go
and try it out for yourself or stop telling people that what they
experienced isn't true because you have a gut feeling.

At least I've used a 5D2 and tested one... you're the one whose
claims are based on leprechaunian speculations.

Keep dreaming.

No thank you.


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