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davea66 · 03-02-2013, 05:52 AM

Hi

I realise there have been MANY threads on this subject!
I also know the K-r can be subject to this effect too, and mine is no exception.

I have been trying to correct with the AF fine tuning but it doesn't seem to have much, if any, effect.

-10 -> IMGP2966 | Flickr - Photo Sharing!
0 -> IMGP2967 | Flickr - Photo Sharing!
+10 -> IMGP2968 | Flickr - Photo Sharing!

3 images with adjustments of -10, 0 and +10 and there seems to be no appreciable difference.
The focus point was kept the same at the number '20' but the actual focus point seems nearer the 22 or 23.
shot in natural light on a tripod. Seems similar whatever lens I use, but this one was the kit 18-55mm

Could anyone help shed any light on this for me?
It is making close up photography an entirely manual focus exercise!

Cheers

Dave

hnikesch · 03-02-2013, 06:30 AM

Did you shoot with the aperture set to it's most open position at 55mm to force the least depth of field. your exif data is not visible

Hans

davea66 · 03-02-2013, 06:54 AM

Hi

they were shot at

42mm, f4.5
ISO 1600 1/125

Lightroom must have stripped the EXIF when I exported to JPEG..

Dave

davea66 · 03-02-2013, 06:54 AM

I probably need to do this again and be more scientific!

Anvh · 03-02-2013, 09:36 AM

Don't forget that the focus is roughly the size of the circle in the middle so that means the focus also see the lines and the black letters.
It actually seem to me it focus and the letter...

Try another focus target where there is no mistake where it should focus on.
Try a line on a piece of paper for example.

hnikesch · 03-02-2013, 02:37 PM

Originally posted by Anvh

Don't forget that the focus is roughly the size of the circle in the middle so that means the focus also see the lines and the black letters.
It actually seem to me it focus and the letter...

Try another focus target where there is no mistake where it should focus on.
Try a line on a piece of paper for example.

I agree you need a better target, try to download one like the link below

PENTAX DSLRs: Front or Back Focusing Problems? Free test (Lens Alignment) charts for Pentax, Nikon, Canon, Sony, Olympus.

Hans

davea66 · 03-03-2013, 11:18 AM

Thanks for the link, I will give this a go!

Dave

03-02-2013, 05:52 AM	#1
davea66 Junior Member Join Date: Aug 2011 Location: Devon Posts: 44	Front/Back focus Hi I realise there have been MANY threads on this subject! I also know the K-r can be subject to this effect too, and mine is no exception. I have been trying to correct with the AF fine tuning but it doesn't seem to have much, if any, effect. -10 -> IMGP2966 \| Flickr - Photo Sharing! 0 -> IMGP2967 \| Flickr - Photo Sharing! +10 -> IMGP2968 \| Flickr - Photo Sharing! 3 images with adjustments of -10, 0 and +10 and there seems to be no appreciable difference. The focus point was kept the same at the number '20' but the actual focus point seems nearer the 22 or 23. shot in natural light on a tripod. Seems similar whatever lens I use, but this one was the kit 18-55mm Could anyone help shed any light on this for me? It is making close up photography an entirely manual focus exercise! Cheers Dave

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03-02-2013, 06:30 AM	#2
hnikesch Veteran Member Join Date: May 2009 Location: Michigan, USA Photos: Albums Posts: 1,316	Did you shoot with the aperture set to it's most open position at 55mm to force the least depth of field. your exif data is not visible Hans

03-02-2013, 06:54 AM	#3
davea66 Junior Member Join Date: Aug 2011 Location: Devon Posts: 44 Original Poster	Hi they were shot at 42mm, f4.5 ISO 1600 1/125 Lightroom must have stripped the EXIF when I exported to JPEG.. Dave

03-02-2013, 09:36 AM	#5
Anvh Veteran Member Join Date: Sep 2011 Posts: 4,616	Don't forget that the focus is roughly the size of the circle in the middle so that means the focus also see the lines and the black letters. It actually seem to me it focus and the letter... Try another focus target where there is no mistake where it should focus on. Try a line on a piece of paper for example.

03-02-2013, 02:37 PM	#6
hnikesch Veteran Member Join Date: May 2009 Location: Michigan, USA Photos: Albums Posts: 1,316	Originally posted by Anvh Don't forget that the focus is roughly the size of the circle in the middle so that means the focus also see the lines and the black letters. It actually seem to me it focus and the letter... Try another focus target where there is no mistake where it should focus on. Try a line on a piece of paper for example. I agree you need a better target, try to download one like the link below PENTAX DSLRs: Front or Back Focusing Problems? Free test (Lens Alignment) charts for Pentax, Nikon, Canon, Sony, Olympus. Hans

03-03-2013, 11:18 AM	#7
davea66 Junior Member Join Date: Aug 2011 Location: Devon Posts: 44 Original Poster	Thanks for the link, I will give this a go! Dave

Front/Back focus

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