Headline - DSLRs have imprecise focusing due to their mirrors

Started Apr 5, 2014 | Discussions thread
EthanP99 Senior Member • Posts: 2,436
Re: Its inconvenient when facts get in the way of a hypothesis
3

Ontario Gone wrote:

Greg A A wrote:

Ontario Gone wrote:

Greg A A wrote:

You are making hypothetical claims. There's no assumption in my statement. Measured results show that contrast detection isn't always more accurate than phase detection. I didn't say that phase detection was always more accurate than contrast detection. Clearly the mirror doesn't only give you imprecise focusing as this was proven with several cameras.

The point is at best PDAF will break even. It will never be more accurate, it's using distance measurements to judge. CDAF for example uses the actual sharpness of the image to judge. Think about focusing with your own eyes. Why don't you ever accidentally focus in front of or behind? Because you can sense when it's the sharpest and you stop adjusting your eye's lens, CDAF works exactly the same way.

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"Run to the light, Carol Anne. Run as fast as you can!"

The theory says one thing, measurements on real cameras show in several cases phase detect was more accurate and repeatable than contrast detect. You can theorize all you want, but actual real life measurement trump theory.

Real life measurements are subject to a slew of difficult to control factors. For one, it's very difficult to choose exactly where the AF square locks on to, because it's not a point. If you compare a Panasonic MFT camera for example, they have "pinpoint AF", it literally is the size of a dot on the full screen composition, far easier for the user to be precise.

I find it odd that even in the face of professionals who use DSLRs you argue against a consensus understanding of technology. I wonder, do you have a link to the "several cases" you mention? Any websites displaying this? Surely if DSLR owners could silence the critics about BF/FF they would be more than willing to share the proof. I think your example of a minority shouting nonsense is backwards, most people know PDAF is subject to errors, but a select few refuse to admit it.

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"Run to the light, Carol Anne. Run as fast as you can!"

I've had plenty of cameras, mostly pro bodies and the most accurate were contrast detect for still portraiture.

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