16-50 gross AF inaccuracy in PDAF - only in some AF points?

rrstuff · 11-18-2016, 11:18 PM

Hi,

I am having trouble with the accuracy of the vertically distributed AF points on the AF 16-50 / K-3. Everything in the horizontal center line is fine (see below; green - ok, red - grossly off).
The contrast AF turns out fine, so it's not the optics.

The inaccuracy is very severe, beyond what could be corrected with microadjustments.

Any thoughts on what could be causing this?

Attached Images

**UncleVanya** · 11-18-2016, 11:21 PM

Other lenses work ok?

rrstuff · 11-18-2016, 11:22 PM

Originally posted by UncleVanya

Other lenses work ok?

They do.

**UncleVanya** · 11-18-2016, 11:29 PM

The AF points are in the camera. But calibration data is in the lens. Did you ever back up your lensrom file?

Do you have access to pull the lensrom file? You do it the same way you convert to screw drive. If damaged it can screw up focusing from what I have seen people post. Each is unique to your lens. A few people have used others files when desperate.

rrstuff · 11-18-2016, 11:40 PM

Originally posted by UncleVanya

The AF points are in the camera. But calibration data is in the lens. Did you ever back up your lensrom file?

Do you have access to pull the lensrom file? You do it the same way you convert to screw drive. If damaged it can screw up focusing from what I have seen people post. Each is unique to your lens. A few people have used others files when desperate.

Thanks. I will look into the rom file. The error is consistent, so maybe I can recalibrate it.
Hell, maybe I will even contact Ricoh tech support. My first instinct was to come here...

wibbly · 11-18-2016, 11:52 PM

how good is the lighting during your tests? are you outside in good light? or indoors with a screen

rrstuff · 11-18-2016, 11:56 PM

Originally posted by wibbly

how good is the lighting during your tests? are you outside in good light? or indoors with a screen

Happens in both cases. I have some outdoors shots that were grossly off. They are off enough that even at f8, the shots aren't sharp. All fine with the center focus.
I have a feeling occasionally they turn out fine, but it's almost as if that's because AF missed in those cases, just in the correct direction.

**UncleVanya** · 11-19-2016, 08:15 AM

The few cases of damaged files I have heard of gave focus problems at various focal lengths and distances. I don't recall the problem involving the focus point used. I could be sending you down the wrong path.

wibbly · 11-19-2016, 10:58 AM

if i were in your position i'd convert to screw drive and re-test.

**UncleVanya** · 11-19-2016, 11:29 AM

Originally posted by wibbly

if i were in your position i'd convert to screw drive and re-test.

That is certainly a doable thing. I don't know that I've ever heard of this type of behavior from failing SDM however. I'd love to see the lens tested on another camera myself.

11-18-2016, 11:18 PM	#1
rrstuff Veteran Member Join Date: Sep 2013 Location: Pasadena, CA Photos: Albums Posts: 1,126	16-50 gross AF inaccuracy in PDAF - only in some AF points? Hi, I am having trouble with the accuracy of the vertically distributed AF points on the AF 16-50 / K-3. Everything in the horizontal center line is fine (see below; green - ok, red - grossly off). The contrast AF turns out fine, so it's not the optics. The inaccuracy is very severe, beyond what could be corrected with microadjustments. Any thoughts on what could be causing this? Attached Images

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11-18-2016, 11:21 PM	#2
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,407	Other lenses work ok?

11-18-2016, 11:22 PM	#3
rrstuff Veteran Member Join Date: Sep 2013 Location: Pasadena, CA Photos: Albums Posts: 1,126 Original Poster	Originally posted by UncleVanya Other lenses work ok? They do.

11-18-2016, 11:29 PM	#4
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,407	The AF points are in the camera. But calibration data is in the lens. Did you ever back up your lensrom file? Do you have access to pull the lensrom file? You do it the same way you convert to screw drive. If damaged it can screw up focusing from what I have seen people post. Each is unique to your lens. A few people have used others files when desperate.

11-18-2016, 11:40 PM	#5
rrstuff Veteran Member Join Date: Sep 2013 Location: Pasadena, CA Photos: Albums Posts: 1,126 Original Poster	Originally posted by UncleVanya The AF points are in the camera. But calibration data is in the lens. Did you ever back up your lensrom file? Do you have access to pull the lensrom file? You do it the same way you convert to screw drive. If damaged it can screw up focusing from what I have seen people post. Each is unique to your lens. A few people have used others files when desperate. Thanks. I will look into the rom file. The error is consistent, so maybe I can recalibrate it. Hell, maybe I will even contact Ricoh tech support. My first instinct was to come here...

11-18-2016, 11:52 PM	#6
wibbly Veteran Member Join Date: Nov 2014 Location: Edmonton Posts: 600	how good is the lighting during your tests? are you outside in good light? or indoors with a screen

11-18-2016, 11:56 PM	#7
rrstuff Veteran Member Join Date: Sep 2013 Location: Pasadena, CA Photos: Albums Posts: 1,126 Original Poster	Originally posted by wibbly how good is the lighting during your tests? are you outside in good light? or indoors with a screen Happens in both cases. I have some outdoors shots that were grossly off. They are off enough that even at f8, the shots aren't sharp. All fine with the center focus. I have a feeling occasionally they turn out fine, but it's almost as if that's because AF missed in those cases, just in the correct direction.

11-19-2016, 08:15 AM	#8
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,407	The few cases of damaged files I have heard of gave focus problems at various focal lengths and distances. I don't recall the problem involving the focus point used. I could be sending you down the wrong path.

11-19-2016, 10:58 AM	#9
wibbly Veteran Member Join Date: Nov 2014 Location: Edmonton Posts: 600	if i were in your position i'd convert to screw drive and re-test.

11-19-2016, 11:29 AM	#10
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,407	Originally posted by wibbly if i were in your position i'd convert to screw drive and re-test. That is certainly a doable thing. I don't know that I've ever heard of this type of behavior from failing SDM however. I'd love to see the lens tested on another camera myself.