Archive 2007 · Why don't it focus?

sam ward
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p.1 #1 · p.1 #1 · Why don't it focus?

Has there been a bonafide technical evaluation of the failure of Canon's focusing system, ATi or 1Ds III? A report that points a finger at the specific cause of its weakness? And a possible cure? I'm an amateur shooting for 60 years and I was sure when I bought my first digital (350d) it wouldn't focus properly. And I was right ---right up until I tooked at some old 35mm kodachromes in PS and was amazed at how many lacked the focus the 350d now seemed to be better at. I focus frequently in lowlight mostly with the tamron 28-75 and when I hurry I'm out of focus, and when I take my time I get it. (Okay, not always.) I'm sure there must be some arbitrary time in a hurry-up situation between when I think the camera is focused and isn't and when it really is. If I spent upwards of $8K for a camera I'm sure I would find more fault with the camera's focusing mechanism. But I would like to read a technical evaluation of "Here's Why" Canon's focusing system fails.

Aug 21, 2007 at 08:32 PM

Alan321
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p.1 #2 · p.1 #2 · Why don't it focus?

If they knew then they'd have have fixed it, but the poll indicates they haven't, so they don't

It's obviously hardware related because firmware isn't temperature dependant.

They've got 4 months to find it, fix it and produce quantities of the 1Ds3 before it joins the 1D3 in the market as a risky buy. And then they've got to fix all of the defective 1D3 bodies that they've already sold.

I suspect a few Canon techies and engineers are learning what "pressure" is all about as they try to find the problem without admitting there is one. I doubt there'll ever be one officially.

You're allowed to take your time as you manually focus, but the 1D3 has to do it at 10 frames per second. Even 8fps would be useful, and nearly as good as the 1D2 did successfully for three years.

- Alan

Aug 22, 2007 at 12:44 PM

mbellot
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p.1 #3 · p.1 #3 · Why don't it focus?

Alan321 wrote:
It's obviously hardware related because firmware isn't temperature dependant.

Not true. If the chip that holds the firmware was marginally programmed it could lead to erratic program execution at elevated temperatures.

But that kind of problem should have been "fixed" for anyone who upgraded to 1.1.0 since the flash chip gets erased and reprogrammed.

I've done enough embedded design over the last 20+ years to know you should never jump to conclusions about hardware vs. software failure. Limiting your target solution(s) to only one of the two is the surest way to never find the answer.

Aug 22, 2007 at 03:58 PM

nathanlake
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p.1 #4 · p.1 #4 · Why don't it focus?

Alan321 wrote:
If they knew then they'd have have fixed it, but the poll indicates they haven't, so they don't

.....

.

- Alan

I am not sure that is true. This could be a very complex issue. First, the system does not fail to focus. It focuses on something just fine...just not the intended thing. From years of software design, I can think of a number of software reasons for this to be happening.

Like the human mind, the camera is making a calcuation based upon certain pieces of information. Not only is it sometimes making the wrong decision, but upon recalculation it sometimes makes a different decision.

Think about what it is doing. It has 45 spots that all determine a focus. The camera must then take one or more of those spots and determine which actually represents the "correct" result. The algorithm for that is undoubtedly very complex. Tweaking it could result in the focusing issue getting worse just as easily as it could getbetter. Or, it could make it worse in some situations while better under others. A tough balancing act.

I am sure Canon realizes that the camera will never focus on the object desired by the photogrpher 100% of the time. The trick is getting it to make the decision correctly at a rate that is acceptable.

Aug 22, 2007 at 04:58 PM

Canon 10D
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p.1 #5 · p.1 #5 · Why don't it focus?

Maybe the Canon's "prototype-less core technology" is to be blamed for all these AF problems

http://www.canon.com/technology/canon_tech/explanation/cae.html

Aug 22, 2007 at 06:18 PM

Alan321
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p.1 #6 · p.1 #6 · Why don't it focus?

Nathan, they've had 45-point AF tracking working at 9 fps since the 1V was introduced in 2000 or thereabouts. The complexity is nothing new to them. It's been working fine with the 1D, 1D2 and 1D2N so there is no excuse for sustained firmware or hardware maloperation three months after the 1D3 was released and much longer after its prototypes were built.

In essence there are 45 clever AF sensors individually producing data about the state of focus that they measured, and there's a program that takes the 45 inputs and considers them before acting on them. It's now old technology for Canon. All that's new is the sensors themselves and the lenses that direct light at them. Hardware.

mbellos's point about marginal firmware writing is valid but can be discounted due to the failure of rewriting firmware to fix the problems. In any case I consider it a hardware issue because hardware is supposed to record that firmware code properly.

More likely, I think, is a heat and light related failure in the AF hardware, whether it be the sensors (most likely as light is involved as well as heat in the common failure scenario) or the lenses and mirrors (unlikely) or some other hardware component/assembly causing temperature related failures of the AF (likely, but why would that be affected by light). Maybe the battery is getting too hot and cooking the AF system at the bottom of the camera, but they'd find that out very quickly with a portable external power supply.

Whatever the problem is they should have found it by now. They also should have found it in prototype testing. And they certainly should have found it before they announced the 1Ds3 - that was a gamble.

With the 1D2N gone, the 1D3 still defective, the 1Ds2 disappearing and the 1Ds3 not available for several months I can see Nikon winning another year of the pro-camera sales race against Canon before Canon gets on top of this situation.

Canon 10D, you could be right about the prototyping. I'll bet the few cameras they did test were all used in the northern winter before the camera was released. They should have come down here for some of our hot, sunny Australian summer conditions. In fact they should have let me have a go - history suggests that if there's an intermittent problem to be had with a high-tech gadget then I'll get it

- Alan

Aug 22, 2007 at 11:15 PM


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