K-1 w/ 100 WR - Back focus past +10? what now?

Capture Lights · 06-19-2017, 11:34 AM

My two other lens (40XS and FA50) was corrected using +7 adjustments.

With the 100WR, +10 was able to improve the backfocus by alot, however, i believe it need something like +13/15.

Is there anything i can do myself before sending either the camera/lens or both in to Ricoh/Pentax for service?

Thanks,

cali92rs · 06-19-2017, 12:04 PM

How are you testing?
Are you on a tripod? How far are you from your target?

Capture Lights · 06-19-2017, 12:10 PM

yes, im testing it on the tripod.

i guess my method is not as good as the others, but its definitely still backfocused.

1. magnified the screen, and manual focus to a point, take a shoot. perfect focus.

2. auto focus to the same point, take a shoot. back focus.

3. focus adjustment to +10, auto focus to the point, take a shoot. still back focus.

I've used this same method with my 40mm XS and FA 50mm 1.7, and their back focus was both fixed with +7 adjustment.

I believe my copy of the 100mm WR need more than +10 adjustment?

Btw, i did tried on both far and near subjects.

1. subject right under my tripod. so about 1-2 ft.

2. subject around 6-8 ft away.

DeadJohn · 06-19-2017, 02:02 PM

Try AF in liveview. That should be perfect, similar to manual focus. If not, the lens or camera is malfunctioning.

Rule out a "stupid" mistake I've made when I haven't adjusted in a while: going too far or the wrong direction. I don't think you've made such an error, but it's worth considering just in case. Make sure +10 is much better than +0, and a little better than +9. If +10 gets worse, maybe you needed to do "-" instead.

Are the camera or lens new? If yes, send it back and hope the replacement is within the +-10 range.

If not new, is either still in warranty?

Capture Lights · 06-19-2017, 02:12 PM

Originally posted by DeadJohn

Try AF in liveview. That should be perfect, similar to manual focus. If not, the lens or camera is malfunctioning.

Rule out a "stupid" mistake I've made when I haven't adjusted in a while: going too far or the wrong direction. I don't think you've made such an error, but it's worth considering just in case. Make sure +10 is much better than +0, and a little better than +9. If +10 gets worse, maybe you needed to do "-" instead.

Are the camera or lens new? If yes, send it back and hope the replacement is within the +-10 range.

If not new, is either still in warranty?

I'll try to do another test tonight. but yeah, the 100 WR is purchased used, and still within return period. i just dont want to do any unnecessary return if i can help without sending it for service.

victormeldrew · 06-19-2017, 04:39 PM

Are ALL of your lenses backfocusing significantly?

If they are all between +7 and +13 then it sounds more like your body needs +10 adjustment, and your lenses are in reality between -3 and +3, which is much more normal.

Capture Lights · 06-19-2017, 04:48 PM

all of my auto focus lens are at least +7, however, i also have Samyang/Rokinon manual lens with focus confirmation.

Both of my manual lens at 0 give me precise confirmation for focus. so i'm not sure if the body is significantly off. or all my auto focus are off.

Capture Lights · 06-19-2017, 07:53 PM

Sorry about the banding in the first two live view pictures.

Focus point was the strongest lit up section of the pole.
Two second timer was used, plus tripod.

Pic 1 - live view manual focus.
Pic 2 - live view single point auto focus.
Pic 3 - auto focus via view finder, single point af with 0 adjustment - auto focus way off.
Pic 4 - auto focus via view finder, single point af with +5 adjustment - auto focus still off.
Pic 5 - auto focus via view finder, single point af with +7 adjustment - auto focus even still off.

Capture Lights · 06-19-2017, 07:55 PM

Pic 1 in this post - auto focus via view finder, single point af with +10 adjustment - auto focus is better than +7, however, still backfocused.
Pic 2 in this post - auto focus via view finder, single point af with -5 adjustment - just to show i'm adjusting in the right direction - auto focus is miles off...

Should i return this lens as its still under returnable period?

---------- Post added 06-19-17 at 11:02 PM ----------

Dropbox - Pentax 100 WR

Uploaded photos for more details. all straight out of the camera JPEG.

rawr · 06-20-2017, 02:22 AM

That is not a good focus target - poor contrast, and also a curved object - nor is the illumination of the target ideal.

If you don't happen to have a AF test chart to hand, the front page of a newspaper, stuck flat to the wall, would probably work better.

victormeldrew · 06-20-2017, 05:27 AM

Originally posted by rawr

If you don't happen to have a AF test chart to hand, the front page of a newspaper, stuck flat to the wall, would probably work better.

I'm not sure about this, as it is would be impossible to tell the difference between front and back focusing, let alone amount.

But indeed the focus target must be flat. The focus point is not a pinpoint, but an area, so with a curved object it will be impossible to control where the focus will lock on.

Look up GhettoCal. It's a free printable focus calibrator that you can build yourself quite easily. Alternatively placing a ruler on a table and a flat vertical high contrast target in the middle would be better than nothing (or a pole).

rawr · 06-20-2017, 07:25 AM

Originally posted by victormeldrew

as it is would be impossible to tell the difference between front and back focusing, let alone amount.

It would be a starting point, that's all. Simply take a shot, if it's out of focus, adjust AF a bit one way (eg [-2]), take another image, if it looks better, then fine tune with a few more photos and AF adjustments in the same direction. If it looks worse, reverse direction.

If you wanted to be more systematic, and had the spare time, just simply start your AF adjustment at -10, take a photo of the newspaper page, set adjustment to -8, take another photo, and repeat this procedure in increments of [2] all the way up to +10, so that you have about 10 images representing the full AF adjustment range (-10 to +10). Then see which of those shots gave the most in-focus image, then fine tune it's particular AF adjustment settings with further increments of [+/-1] as needed ...

Capture Lights · 06-20-2017, 02:41 PM

Originally posted by victormeldrew

I'm not sure about this, as it is would be impossible to tell the difference between front and back focusing, let alone amount.

But indeed the focus target must be flat. The focus point is not a pinpoint, but an area, so with a curved object it will be impossible to control where the focus will lock on.

Look up GhettoCal. It's a free printable focus calibrator that you can build yourself quite easily. Alternatively placing a ruler on a table and a flat vertical high contrast target in the middle would be better than nothing (or a pole).

Thanks for the tip on GhettoCal, seems like this lens is going back to the seller if i cant help it.

Left: Live view single point AF Zoomed 100% 1:1, Chart in focus, however, ruler is pointing that focus was around 0.5.
Right: +10 adjustment, live view auto focus. Auto focus is still off, ruler is pointing that focus was around 1. As a result, even with +10, the lens is still back focused, which is in line with all my previous test.

I have also did the same with -5 just to test, and +6 +8 and finally +10.
At +10, it was the closest to the live view auto focus. however, +10 is definitely not enough for this camera/lens combination.

victormeldrew · 06-20-2017, 03:24 PM - **1 Like**

It's certainy back focusing, but it doesn't unfortunately prove that the lens is at fault. I personally suspect that your body is at fault...and getting that serviced and corrected would bring all your lenses (and future ones) within adjustment. If you're in warranty, it's a no-brainer, but if not the choice is yours...

Capture Lights · 06-21-2017, 09:10 AM

Originally posted by victormeldrew

It's certainy back focusing, but it doesn't unfortunately prove that the lens is at fault. I personally suspect that your body is at fault...and getting that serviced and corrected would bring all your lenses (and future ones) within adjustment. If you're in warranty, it's a no-brainer, but if not the choice is yours...

your absolutely right. my k-1 focus is way off the scale.

i took the questionable route, and entered debug mode. slide auto focus fine tune over +120 micrometer (maximum in debug mode), and the lens is still out of focus!

so on top of the +120 um adjustment in debug mode, i added +5 to the auto focus fine tune in the menu, for this particular lens.

i think the view finder auto focus is even sharper than live view now... but that may be a placebo effect.

06-19-2017, 11:34 AM	#1
Capture Lights Senior Member Join Date: Mar 2014 Posts: 113	K-1 w/ 100 WR - Back focus past +10? what now? My two other lens (40XS and FA50) was corrected using +7 adjustments. With the 100WR, +10 was able to improve the backfocus by alot, however, i believe it need something like +13/15. Is there anything i can do myself before sending either the camera/lens or both in to Ricoh/Pentax for service? Thanks,

06-20-2017, 02:41 PM	#13
Capture Lights Senior Member Join Date: Mar 2014 Posts: 113 Original Poster	Originally posted by victormeldrew I'm not sure about this, as it is would be impossible to tell the difference between front and back focusing, let alone amount. But indeed the focus target must be flat. The focus point is not a pinpoint, but an area, so with a curved object it will be impossible to control where the focus will lock on. Look up GhettoCal. It's a free printable focus calibrator that you can build yourself quite easily. Alternatively placing a ruler on a table and a flat vertical high contrast target in the middle would be better than nothing (or a pole). Thanks for the tip on GhettoCal, seems like this lens is going back to the seller if i cant help it. Left: Live view single point AF Zoomed 100% 1:1, Chart in focus, however, ruler is pointing that focus was around 0.5. Right: +10 adjustment, live view auto focus. Auto focus is still off, ruler is pointing that focus was around 1. As a result, even with +10, the lens is still back focused, which is in line with all my previous test. I have also did the same with -5 just to test, and +6 +8 and finally +10. At +10, it was the closest to the live view auto focus. however, +10 is definitely not enough for this camera/lens combination. Attached Images

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06-19-2017, 12:04 PM	#2
cali92rs Veteran Member Join Date: May 2011 Location: Long Beach, CA Posts: 3,354	How are you testing? Are you on a tripod? How far are you from your target?

06-19-2017, 12:10 PM	#3
Capture Lights Senior Member Join Date: Mar 2014 Posts: 113 Original Poster	yes, im testing it on the tripod. i guess my method is not as good as the others, but its definitely still backfocused. 1. magnified the screen, and manual focus to a point, take a shoot. perfect focus. 2. auto focus to the same point, take a shoot. back focus. 3. focus adjustment to +10, auto focus to the point, take a shoot. still back focus. I've used this same method with my 40mm XS and FA 50mm 1.7, and their back focus was both fixed with +7 adjustment. I believe my copy of the 100mm WR need more than +10 adjustment? Btw, i did tried on both far and near subjects. 1. subject right under my tripod. so about 1-2 ft. 2. subject around 6-8 ft away.

06-19-2017, 02:02 PM	#4
DeadJohn Pentaxian Join Date: Jan 2011 Location: New York Posts: 4,833	Try AF in liveview. That should be perfect, similar to manual focus. If not, the lens or camera is malfunctioning. Rule out a "stupid" mistake I've made when I haven't adjusted in a while: going too far or the wrong direction. I don't think you've made such an error, but it's worth considering just in case. Make sure +10 is much better than +0, and a little better than +9. If +10 gets worse, maybe you needed to do "-" instead. Are the camera or lens new? If yes, send it back and hope the replacement is within the +-10 range. If not new, is either still in warranty?

06-19-2017, 02:12 PM	#5
Capture Lights Senior Member Join Date: Mar 2014 Posts: 113 Original Poster	Originally posted by DeadJohn Try AF in liveview. That should be perfect, similar to manual focus. If not, the lens or camera is malfunctioning. Rule out a "stupid" mistake I've made when I haven't adjusted in a while: going too far or the wrong direction. I don't think you've made such an error, but it's worth considering just in case. Make sure +10 is much better than +0, and a little better than +9. If +10 gets worse, maybe you needed to do "-" instead. Are the camera or lens new? If yes, send it back and hope the replacement is within the +-10 range. If not new, is either still in warranty? I'll try to do another test tonight. but yeah, the 100 WR is purchased used, and still within return period. i just dont want to do any unnecessary return if i can help without sending it for service.

06-19-2017, 04:39 PM	#6
victormeldrew Veteran Member Join Date: Jun 2015 Location: South West UK Photos: Albums Posts: 1,493	Are ALL of your lenses backfocusing significantly? If they are all between +7 and +13 then it sounds more like your body needs +10 adjustment, and your lenses are in reality between -3 and +3, which is much more normal.

06-19-2017, 04:48 PM	#7
Capture Lights Senior Member Join Date: Mar 2014 Posts: 113 Original Poster	all of my auto focus lens are at least +7, however, i also have Samyang/Rokinon manual lens with focus confirmation. Both of my manual lens at 0 give me precise confirmation for focus. so i'm not sure if the body is significantly off. or all my auto focus are off.

06-20-2017, 02:22 AM	#10
rawr Veteran Member Join Date: Jun 2009 Posts: 11,913	That is not a good focus target - poor contrast, and also a curved object - nor is the illumination of the target ideal. If you don't happen to have a AF test chart to hand, the front page of a newspaper, stuck flat to the wall, would probably work better.

06-20-2017, 05:27 AM	#11
victormeldrew Veteran Member Join Date: Jun 2015 Location: South West UK Photos: Albums Posts: 1,493	Originally posted by rawr If you don't happen to have a AF test chart to hand, the front page of a newspaper, stuck flat to the wall, would probably work better. I'm not sure about this, as it is would be impossible to tell the difference between front and back focusing, let alone amount. But indeed the focus target must be flat. The focus point is not a pinpoint, but an area, so with a curved object it will be impossible to control where the focus will lock on. Look up GhettoCal. It's a free printable focus calibrator that you can build yourself quite easily. Alternatively placing a ruler on a table and a flat vertical high contrast target in the middle would be better than nothing (or a pole).

06-20-2017, 07:25 AM	#12
rawr Veteran Member Join Date: Jun 2009 Posts: 11,913	Originally posted by victormeldrew as it is would be impossible to tell the difference between front and back focusing, let alone amount. It would be a starting point, that's all. Simply take a shot, if it's out of focus, adjust AF a bit one way (eg [-2]), take another image, if it looks better, then fine tune with a few more photos and AF adjustments in the same direction. If it looks worse, reverse direction. If you wanted to be more systematic, and had the spare time, just simply start your AF adjustment at -10, take a photo of the newspaper page, set adjustment to -8, take another photo, and repeat this procedure in increments of [2] all the way up to +10, so that you have about 10 images representing the full AF adjustment range (-10 to +10). Then see which of those shots gave the most in-focus image, then fine tune it's particular AF adjustment settings with further increments of [+/-1] as needed ...

06-20-2017, 03:24 PM - 1 Like	#14
victormeldrew Veteran Member Join Date: Jun 2015 Location: South West UK Photos: Albums Posts: 1,493	It's certainy back focusing, but it doesn't unfortunately prove that the lens is at fault. I personally suspect that your body is at fault...and getting that serviced and corrected would bring all your lenses (and future ones) within adjustment. If you're in warranty, it's a no-brainer, but if not the choice is yours...

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06-21-2017, 09:10 AM	#15
Capture Lights Senior Member Join Date: Mar 2014 Posts: 113 Original Poster	Originally posted by victormeldrew It's certainy back focusing, but it doesn't unfortunately prove that the lens is at fault. I personally suspect that your body is at fault...and getting that serviced and corrected would bring all your lenses (and future ones) within adjustment. If you're in warranty, it's a no-brainer, but if not the choice is yours... your absolutely right. my k-1 focus is way off the scale. i took the questionable route, and entered debug mode. slide auto focus fine tune over +120 micrometer (maximum in debug mode), and the lens is still out of focus! so on top of the +120 um adjustment in debug mode, i added +5 to the auto focus fine tune in the menu, for this particular lens. i think the view finder auto focus is even sharper than live view now... but that may be a placebo effect.