Brand new Pentax DFA* 70-200 focus weirdness with K1. Please help

stevebrot · 07-07-2021, 02:57 PM

Originally posted by sbc

a far fetched idea is that Pentax camera AF with PDAF, the mirror flips up, CDAF takes over, locks focus and snap.

Remember that the shutter must open at some point in that sequence with either the shutter closing again or electronic first curtain shutter taking over.

Steve

**matroxication** · 07-07-2021, 04:28 PM

Originally posted by sbc

No. What I am putting forward for a far fetched idea is that Pentax camera AF with PDAF, the mirror flips up, CDAF takes over, locks focus and snap.
Anyway, I am just exploring ideas, nothing serious.

Thats great to know. Then we can expect a better AF performance from upcoming cameras from Pentax

**matroxication** · 07-13-2021, 05:32 PM

Just got off phone with the Service personnel (C.R.Kennedy) and he advised that there was slight back focusing but not by that much. He has fixed that and he hopes I will be happy with the result. He was recommending using live view rather than view finder to get the accurate shots. Am bit skeptical and also asked if they have any spare 70-200 lens to compare the test results but unfortunately they dont. Told him that the amount of money and weight compromise I made on this lens is to get accurate results but he stated its the zoom lens which is always hard to calibrate at all focal length. Anyway he got calibration done at 200mm. They might ship the lens and camera today and hopefully I should be able to get it by Friday. Will have to wait and see.

**clackers** · 07-13-2021, 06:30 PM

Originally posted by matroxication

Just got off phone with the Service personnel (C.R.Kennedy) and he advised that there was slight back focusing but not by that much. He has fixed that and he hopes I will be happy with the result. He was recommending using live view rather than view finder to get the accurate shots. Am bit skeptical and also asked if they have any spare 70-200 lens to compare the test results but unfortunately they dont. Told him that the amount of money and weight compromise I made on this lens is to get accurate results but he stated its the zoom lens which is always hard to calibrate at all focal length. Anyway he got calibration done at 200mm. They might ship the lens and camera today and hopefully I should be able to get it by Friday. Will have to wait and see.

Yeah, being a zoom, you should calibrate at the length either you'll use most often or the length for type of work where the exact point is critical.

Paul the Sunman · 07-13-2021, 07:36 PM

Originally posted by matroxication

Just got off phone with the Service personnel (C.R.Kennedy) and he advised that there was slight back focusing but not by that much. He has fixed that and he hopes I will be happy with the result. He was recommending using live view rather than view finder to get the accurate shots. Am bit skeptical and also asked if they have any spare 70-200 lens to compare the test results but unfortunately they dont. Told him that the amount of money and weight compromise I made on this lens is to get accurate results but he stated its the zoom lens which is always hard to calibrate at all focal length. Anyway he got calibration done at 200mm. They might ship the lens and camera today and hopefully I should be able to get it by Friday. Will have to wait and see.

Are you in Melbourne?

**matroxication** · 07-13-2021, 11:09 PM - **1 Like**

Originally posted by clackers

Yeah, being a zoom, you should calibrate at the length either you'll use most often or the length for type of work where the exact point is critical.

True. Think I expected way too much from this lens

Was juggling between this one and DA* 200 and finally pulled trigger on this one.

---------- Post added 07-13-21 at 11:12 PM ----------

Originally posted by Paul the Sunman

Are you in Melbourne?

Nope, Sydney. Apparently C.R.Kennedy in Sydney does not do any repairs and it gets sent to Melbourne branch.

**matroxication** · 07-15-2021, 02:19 AM

Finally received my camera and lens today. Took some test shots within my apartment and I can definitely see some improvement with focus. Autofocus is more consistent now. But I need to take this beast outside to actually test it completely. However need to wait until the lockdown has been lifted.

**Ash** · 07-15-2021, 05:30 PM

Originally posted by matroxication

Finally received my camera and lens today. Took some test shots within my apartment and I can definitely see some improvement with focus. Autofocus is more consistent now. But I need to take this beast outside to actually test it completely. However need to wait until the lockdown has been lifted.

You'd be limited to doing more short focal length testing for now. I feel for you in Sydney.
I'm glad there is already a discernible improvement in the focusing, but I am skeptical when any technician says that you should not get consistently good results with PDAF. It's the most used and should be reliable.
You don't invest that much in a lens that is off the mark.
Hope it works out.

**matroxication** · 07-18-2021, 05:12 AM - **2 Likes**

True. I told the technician the same and also stated I hated using live view. So far, happy with the results when I tested in nearby park. Can test the lens more once the lockdown has been lifted.

tibbitts · 07-20-2021, 05:08 PM - **1 Like**

Originally posted by matroxication

My expectation is to have sharp images at 2.8 in 200mm using phase detect focus.

My Pentax bodies and lenses are older than yours (except for one) but I've thrown in the towel on PDAF, so my solution was to adjust my expectations. Maybe I'll try again someday if I get a mirrorless body, or a dslr body/lens combination that allows multiple PDAF adjustments at different focal lengths and maybe focusing distances.

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07-07-2021, 02:57 PM	#31
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by sbc a far fetched idea is that Pentax camera AF with PDAF, the mirror flips up, CDAF takes over, locks focus and snap. Remember that the shutter must open at some point in that sequence with either the shutter closing again or electronic first curtain shutter taking over. Steve

07-07-2021, 04:28 PM	#32
matroxication Site Supporter Join Date: Dec 2016 Photos: Gallery Posts: 169 Original Poster	Originally posted by sbc No. What I am putting forward for a far fetched idea is that Pentax camera AF with PDAF, the mirror flips up, CDAF takes over, locks focus and snap. Anyway, I am just exploring ideas, nothing serious. Thats great to know. Then we can expect a better AF performance from upcoming cameras from Pentax

07-13-2021, 05:32 PM	#33
matroxication Site Supporter Join Date: Dec 2016 Photos: Gallery Posts: 169 Original Poster	Just got off phone with the Service personnel (C.R.Kennedy) and he advised that there was slight back focusing but not by that much. He has fixed that and he hopes I will be happy with the result. He was recommending using live view rather than view finder to get the accurate shots. Am bit skeptical and also asked if they have any spare 70-200 lens to compare the test results but unfortunately they dont. Told him that the amount of money and weight compromise I made on this lens is to get accurate results but he stated its the zoom lens which is always hard to calibrate at all focal length. Anyway he got calibration done at 200mm. They might ship the lens and camera today and hopefully I should be able to get it by Friday. Will have to wait and see.

07-13-2021, 06:30 PM	#34
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by matroxication Just got off phone with the Service personnel (C.R.Kennedy) and he advised that there was slight back focusing but not by that much. He has fixed that and he hopes I will be happy with the result. He was recommending using live view rather than view finder to get the accurate shots. Am bit skeptical and also asked if they have any spare 70-200 lens to compare the test results but unfortunately they dont. Told him that the amount of money and weight compromise I made on this lens is to get accurate results but he stated its the zoom lens which is always hard to calibrate at all focal length. Anyway he got calibration done at 200mm. They might ship the lens and camera today and hopefully I should be able to get it by Friday. Will have to wait and see. Yeah, being a zoom, you should calibrate at the length either you'll use most often or the length for type of work where the exact point is critical.

07-13-2021, 07:36 PM	#35
Paul the Sunman Pentaxian Join Date: Aug 2011 Location: Melbourne Photos: Gallery Posts: 4,846	Originally posted by matroxication Just got off phone with the Service personnel (C.R.Kennedy) and he advised that there was slight back focusing but not by that much. He has fixed that and he hopes I will be happy with the result. He was recommending using live view rather than view finder to get the accurate shots. Am bit skeptical and also asked if they have any spare 70-200 lens to compare the test results but unfortunately they dont. Told him that the amount of money and weight compromise I made on this lens is to get accurate results but he stated its the zoom lens which is always hard to calibrate at all focal length. Anyway he got calibration done at 200mm. They might ship the lens and camera today and hopefully I should be able to get it by Friday. Will have to wait and see. Are you in Melbourne?

07-13-2021, 11:09 PM - 1 Like	#36
matroxication Site Supporter Join Date: Dec 2016 Photos: Gallery Posts: 169 Original Poster	Originally posted by clackers Yeah, being a zoom, you should calibrate at the length either you'll use most often or the length for type of work where the exact point is critical. True. Think I expected way too much from this lens Was juggling between this one and DA* 200 and finally pulled trigger on this one. ---------- Post added 07-13-21 at 11:12 PM ---------- Originally posted by Paul the Sunman Are you in Melbourne? Nope, Sydney. Apparently C.R.Kennedy in Sydney does not do any repairs and it gets sent to Melbourne branch.

07-15-2021, 02:19 AM	#37
matroxication Site Supporter Join Date: Dec 2016 Photos: Gallery Posts: 169 Original Poster	Finally received my camera and lens today. Took some test shots within my apartment and I can definitely see some improvement with focus. Autofocus is more consistent now. But I need to take this beast outside to actually test it completely. However need to wait until the lockdown has been lifted.

07-15-2021, 05:30 PM	#38
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	Originally posted by matroxication Finally received my camera and lens today. Took some test shots within my apartment and I can definitely see some improvement with focus. Autofocus is more consistent now. But I need to take this beast outside to actually test it completely. However need to wait until the lockdown has been lifted. You'd be limited to doing more short focal length testing for now. I feel for you in Sydney. I'm glad there is already a discernible improvement in the focusing, but I am skeptical when any technician says that you should not get consistently good results with PDAF. It's the most used and should be reliable. You don't invest that much in a lens that is off the mark. Hope it works out.

07-20-2021, 05:08 PM - 1 Like	#40
tibbitts Pentaxian Join Date: Apr 2007 Location: Oklahoma USA Posts: 2,196	Originally posted by matroxication My expectation is to have sharp images at 2.8 in 200mm using phase detect focus. My Pentax bodies and lenses are older than yours (except for one) but I've thrown in the towel on PDAF, so my solution was to adjust my expectations. Maybe I'll try again someday if I get a mirrorless body, or a dslr body/lens combination that allows multiple PDAF adjustments at different focal lengths and maybe focusing distances.