70d focus issues or maybe I'm doing something wrong...

[canonvaggio]

It's an internal service advisory. Call Canon and tell them you have a problem with larger aperture lenses using the higher precision AF sensor - but you'll need to speak to the service manager at the very least.

It was investigated, documented and the advisory produced internally - it may affect as few as 1 in 100 bodies before Dec 2014 (my estimate) and only with certain lenses and one or other AF point - usually the center double-cross type f/2.8 or greater enables sensor.

If such a document exists, it would have been leaked on the internet long ago, like all other "internal" service advisories, yet... I don't see it anywhere in Google results. Where is it?

 

[WilbaW]

The 50mm f/1.8 II is excellent optically for instance but was never meant to resolve the sensor densities we have today on APS-C mechanically - that's precision well beyond the original design.

No, that lens is capable of focussing tighter than 5% of the thinnest possible DOF according to standard calculations, or 0.02% of the MFD. It's only when the focus error is measured by a PD AF sensor that we get gross misfocus. It's not the precision of the design that's the problem, it's the measurement of focus error by phase detection.

 

[cberry]

It's an internal service advisory. Call Canon and tell them you have a problem with larger aperture lenses using the higher precision AF sensor - but you'll need to speak to the service manager at the very least.

It was investigated, documented and the advisory produced internally - it may affect as few as 1 in 100 bodies before Dec 2014 (my estimate) and only with certain lenses and one or other AF point - usually the center double-cross type f/2.8 or greater enables sensor.

If such a document exists, it would have been leaked on the internet long ago, like all other "internal" service advisories, yet... I don't see it anywhere in Google results. Where is it?

Ask Snowden as the end of the world surely depends on a couple of bodies here or there misbehaving in some circumstances with some lenses.

It looks something like this: Should the customer experience poor focus with wide aperture lenses with some AF points and not others, perform procedure X, checking AF calibration on the sensor with the particular lens.

In layman's terms, this is an extension of send your lenses in to Canon for them to calibrate the body to the lenses - basically what Lensrentals says about small differences between bodies and lenses.

To me, it was far more worrying that the 50 f/1.8 II is not fit for purpose when coupled with cameras with resolution of 10Mp or more if they're APS-C and there was no fix. Hence the STM 50mm.

Heck - I'm seriously wondering why I'm even bothering to respond to you - fr1ggin take it or leave it buster.

cb

 

[cberry]

The 50mm f/1.8 II is excellent optically for instance but was never meant to resolve the sensor densities we have today on APS-C mechanically - that's precision well beyond the original design.

No, that lens is capable of focussing tighter than 5% of the thinnest possible DOF according to standard calculations, or 0.02% of the MFD. It's only when the focus error is measured by a PD AF sensor that we get gross misfocus. It's not the precision of the design that's the problem, it's the measurement of focus error by phase detection.

Very right. Canon can't get it to work properly with the 70D, 700D or 650D.

cb

 

[WilbaW]

The 50mm f/1.8 II is excellent optically for instance but was never meant to resolve the sensor densities we have today on APS-C mechanically - that's precision well beyond the original design.

No, that lens is capable of focussing tighter than 5% of the thinnest possible DOF according to standard calculations, or 0.02% of the MFD. It's only when the focus error is measured by a PD AF sensor that we get gross misfocus. It's not the precision of the design that's the problem, it's the measurement of focus error by phase detection.

Very right. Canon can't get it to work properly with the 70D, 700D or 650D.

I've tested multiple instances on the 450D, 60D, 7D, and 5D and got the same behaviour. There's no evidence that it's body-specific.