Why on-chip focusing is the way forward....

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Andy
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Finally, we have a camera with both on and off-chip phase detect - the 70D

dpreview has compared the two: http://www.dpreview.com/previews/canon-eos-70d/9

Fundamentally, with shallow DoF settings, the on chip does significantly better than the off-chip PDAF. It doesn't do as well at tracking yet, but that will come.

On-chip PDAF is starting to appear (OM-D E-M1, 70D....). IMHO, it will replace off chip PDAF in a few years.

Interesting times ahead.
 
On chip can only be more accurate than relying on another device in another part of the camera with all of the possible alignment issues that brings.

It's the future :D
 
Precisely... What is interesting is how far out the phase detect off-chip is (and ultimately why I got rid of the 5D2 even though it was better in some conditions than the u4/3). Whilst it looks like they dialled it back in on the 85/1.8, it's more difficult with a zoom (and I speak from experience)....
 
I'd forgotten about the effect of all of those extra mirrors and pieces of glass.

It's a wonder SLR's work at all :D

One thing that I keep remembering is something on Canon's web site... It says that if you take three pictures you'll see focus differences between them all and that this is perfectly normal.

I've always thought that this shouldn't be the case or that at least the differences should be very very small.
 
Results for traditional AF look way out. I don't have such problems focusing.
It depends on what lens you are using, but I had exactly that with the 5D2 and a 70-200. Spot on on the centre point, off on one of the off-axis points. It was at that point (!) I finally decided to change...
 
It depends on what lens you are using, but I had exactly that with the 5D2 and a 70-200. Spot on on the centre point, off on one of the off-axis points. It was at that point (!) I finally decided to change...

I think I probably would have sent the lens off for calibration at that point but fair enough! I've had a tiny bit of front focusing that I've managed to dial out with a slight bit of MA, most of my focussing issues have been down to me rather than the kit :p
 
I think I probably would have sent the lens off for calibration at that point but fair enough! I've had a tiny bit of front focusing that I've managed to dial out with a slight bit of MA, most of my focussing issues have been down to me rather than the kit :p
Spot on on centre point, off on one of the outliers - it was more likely the camera, but the camera had already been back to Canon once with another lens and I was never happy with that either. There are only so many times you can send an expensive piece of equipment in to be "calibrated to the lens". At the end of the day it is pot luck if the lens or camera is correct. I took more pictures of test targets than photos when I had the 5D2 - yes I am that a..l.

On chip focus (in my case u4/3 but good to see it coming to Canon too) removed that completely....
 
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