Comments made by johnwhit - Page 67

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The reason we have lens calibration is down to the manufacturing tolerances used in the lens mount, both on the camera side and lens side. The tolerances are very fine but slight variations cause a shift in focus point with different lens/camera combinations. I had a link to an article somewhere I'll see if I can find it.

John

Comment by johnwhit posted on Is my 40mm backfocusing at 11/07/2011 - 07:07

Glad I could be of some help, enjoy the camera.

Regards,

John

Comment by johnwhit posted on Is my 40mm backfocusing at 10/07/2011 - 21:45

I think if I try any more candid portraits I'll be using something a little longer than the DA-70 I used at Cheshire, maybe the FA-135

John

Comment by johnwhit posted on Go mad with Street Shots at 10/07/2011 - 21:43

vrapan wrote:
Live practically next door and was gonna go next weekend to give another go at the 8-16 so will ask about that. Might instead just drop during lunch time.

Hope you get it sorted if only to put your mind at rest.

John

Comment by johnwhit posted on Is my 40mm backfocusing at 10/07/2011 - 21:38

John

Comment by johnwhit posted on Go mad with Street Shots at 10/07/2011 - 21:06

I wouldn't worry too much, it could just be coincidence with two lenses however unlikely that may sound. Maybe have SRS take a look if you're passing instead of making a special journey, although I see you're in the Watford area.

John

Comment by johnwhit posted on Is my 40mm backfocusing at 10/07/2011 - 21:04

vrapan wrote:
Ok I will go there the weekend, the AF Adjust was off actually i put 6-7 to bring the 40mm to normal focusing, which is the amount required at the same distance and at 55mm for the 18-55

That sounds reasonable, at least it's within the parameters of adjustment. I tend to find that various lenses need different adjutments, be it '-' or '+' but it will vary with individual camera body obviously.

SMCP DA 15mm +5
Sigma AF 24mm -8
SMCP FA 28mm +5
SMCP FA 35mm -3
SMCP FA 50mm -4
SMCP DA 70mm -8
Tamron Di 90mm +/-0
SMCP DA*16-50mm -6

John

Comment by johnwhit posted on Is my 40mm backfocusing at 10/07/2011 - 20:51

Shaun, I've decided, you're either fearless or completely mad and I'm not sure which

John

Comment by johnwhit posted on Go mad with Street Shots at 10/07/2011 - 20:45

vrapan wrote:
Yes I did and although less visible obviously it still does it. What I also noticed though is that it happens with the 18-55 as well..... Could it be the camera that needs alignment and not the lenses?

Would Pentax be happy to do that ? It might be the reason behind the softness on the 8-16 and the 10-24 as well though if it does it by the same amount give or take for 2 lenses already

I think I'd be tempted to have the camera checked by SRS if it seems to be the case with all the lenses you've used, maybe others here with experience of the K-5 could suggest something, I only have the K20D.
Just a thought, have you checked the AF adjust menu to ensure there's not an adjustment set for all lenses by any chance?

John

Comment by johnwhit posted on Is my 40mm backfocusing at 10/07/2011 - 20:41

Well it looks like the focus is off, have you tried it a a longer distance?
From the image it does seem a fair way out.

I've micro-adjusted my shorter primes 15-90mm and 2 standard zooms, but not my 135, 200 and 300 as the distance involved made it difficult.

John

Comment by johnwhit posted on Is my 40mm backfocusing at 10/07/2011 - 19:34

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johnwhit

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