K3 CDAF with DA*60-250

gumbee · 08-28-2014, 04:37 PM

I am past DSLR noobee and now becoming dangerous...I can tell cuz I am now noticing things that engender questions like the following:

Is it normal for long zooms to not play well with live-view?

I was using the dot-tune method to check my lenses and when using the 60-250 I could not get the target in focus with CDAF. When switching back to PDAF it was spot on. My other lenses focus just fine with CDAF, so I was wondering if this is normal or if I need to take further action. I upgraded from a K30 to the K3, and haven't been as satisfied with the 60-250/K3 for sharpness, so I thought I would test focus the best I could. Want to eliminate the gear before I blame myself

All my other lenses are just fine and I really like the K3 - I need the faster AF. Testing was done on tripod, wired remote, 2 sec delay, SR off, various focal lengths.

I have also noticed that @F4 my 60-250 is fairly soft. 1/3 stop down and noticeably sharper, 1 stop and it is super. Is this normal for that lens?

Thx,
John

JinDesu · 08-28-2014, 04:42 PM

If it's not locking focus or if it is locking but completely out of focus, send it the lens in for calibration. Some lenses have issues with CDAF, like I had with my Sigma 17-70. Sigma was able to update a chip within to work with my CDAF.

**jatrax** · 08-28-2014, 04:47 PM

Originally posted by gumbee

I have also noticed that @F4 my 60-250 is fairly soft. 1/3 stop down and noticeably sharper, 1 stop and it is super. Is this normal for that lens?

Most, if not all, lenses would benefit from stopping down 1 stop. However, I find my 60-250 quite good at f/4. Of course what I consider good might not be the same as what you consider good since it is subjective. But I have no issue using it wide open.

Originally posted by gumbee

I was using the dot-tune method to check my lenses and when using the 60-250 I could not get the target in focus with CDAF. When switching back to PDAF it was spot on.

Minimum focus distance for that lens is about 44", make sure you are well beyond that. Should not matter PDAF/CDAF but eliminate all possible errors first. Otherwise, maybe try a different target? Just to see if what you are using is causing issues with CDAF. Or test with another lens to make sure it is the lens and not the target or camera.

gumbee · 08-28-2014, 07:51 PM

I will do a few more tests to compare CDAF and PDAF. If CDAF cannot focus (it does lock, but never in focus) I'll send it in for calibration.

thx for your help.

John

**ak_kiwi** · 08-29-2014, 12:43 AM

Originally posted by gumbee

I have also noticed that @F4 my 60-250 is fairly soft. 1/3 stop down and noticeably sharper, 1 stop and it is super. Is this normal for that lens?

That would seem about right going by this.

08-28-2014, 04:37 PM	#1
gumbee Forum Member Join Date: Mar 2013 Location: WI Posts: 72	*K3 CDAF with DA60-250** I am past DSLR noobee and now becoming dangerous...I can tell cuz I am now noticing things that engender questions like the following: Is it normal for long zooms to not play well with live-view? I was using the dot-tune method to check my lenses and when using the 60-250 I could not get the target in focus with CDAF. When switching back to PDAF it was spot on. My other lenses focus just fine with CDAF, so I was wondering if this is normal or if I need to take further action. I upgraded from a K30 to the K3, and haven't been as satisfied with the 60-250/K3 for sharpness, so I thought I would test focus the best I could. Want to eliminate the gear before I blame myself All my other lenses are just fine and I really like the K3 - I need the faster AF. Testing was done on tripod, wired remote, 2 sec delay, SR off, various focal lengths. I have also noticed that @F4 my 60-250 is fairly soft. 1/3 stop down and noticeably sharper, 1 stop and it is super. Is this normal for that lens? Thx, John

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08-28-2014, 04:42 PM	#2
JinDesu Veteran Member Join Date: Jun 2011 Location: New York City Photos: Gallery Posts: 5,638	If it's not locking focus or if it is locking but completely out of focus, send it the lens in for calibration. Some lenses have issues with CDAF, like I had with my Sigma 17-70. Sigma was able to update a chip within to work with my CDAF.

08-28-2014, 04:47 PM	#3
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	Originally posted by gumbee I have also noticed that @F4 my 60-250 is fairly soft. 1/3 stop down and noticeably sharper, 1 stop and it is super. Is this normal for that lens? Most, if not all, lenses would benefit from stopping down 1 stop. However, I find my 60-250 quite good at f/4. Of course what I consider good might not be the same as what you consider good since it is subjective. But I have no issue using it wide open. Originally posted by gumbee I was using the dot-tune method to check my lenses and when using the 60-250 I could not get the target in focus with CDAF. When switching back to PDAF it was spot on. Minimum focus distance for that lens is about 44", make sure you are well beyond that. Should not matter PDAF/CDAF but eliminate all possible errors first. Otherwise, maybe try a different target? Just to see if what you are using is causing issues with CDAF. Or test with another lens to make sure it is the lens and not the target or camera.

08-28-2014, 07:51 PM	#4
gumbee Forum Member Join Date: Mar 2013 Location: WI Posts: 72 Original Poster	I will do a few more tests to compare CDAF and PDAF. If CDAF cannot focus (it does lock, but never in focus) I'll send it in for calibration. thx for your help. John

08-29-2014, 12:43 AM	#5
ak_kiwi Site Supporter Join Date: Jul 2011 Location: Auckland, New Zealand. Posts: 328	Originally posted by gumbee I have also noticed that @F4 my 60-250 is fairly soft. 1/3 stop down and noticeably sharper, 1 stop and it is super. Is this normal for that lens? That would seem about right going by this.

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