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10-10-2010, 02:18 AM   #1
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[langtitle=fr]Back focus sur Pentax 50mm f:1.4 SMC FA[/langtitle]

Bonjour,
Je ne sais pas si je suis sur le bon fil, en cas d'erreur je peux le rééditer.
je viens de m'apercevoir que mon objectif était déréglé, back focus de 10mm environ, que dois-je faire, renvoi au SAV PEntax mais objectif acheté d'occasion et pas sous garantie ou possibilité autre.
Je précise qu'à f:11 tout est OK

Je possède un reflex Pentax K10D.

Voici les photos du test

A f:1.4



A f:11




Last edited by loule; 10-10-2010 at 02:31 AM.
10-10-2010, 02:38 AM   #2
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Most of my lenses require a +10 AF adjustment when shooting in Tungsten light. You might want to try the testing outside to see if the issue is light dependent.

Thank you
Russell
10-10-2010, 04:07 AM   #3
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The test at f11 is pointless. You are just masking the BF issue with depth of field.

Russell's advice is good advice. Dont conduct these tests except in natural light.
10-10-2010, 04:52 AM   #4
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Les test ont été réalisés à l'extérieur à la lumière naturelle, donc c'est vraiment du back focus, que dois je faire,
merci



Last edited by loule; 10-11-2010 at 01:05 AM.
10-12-2010, 01:49 AM   #5
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Je n'ai pas tout compris, Russell-Evans dit de faire les test à la lumière naturelle ce qui a été réalisé dans ce test et pschlute dit "sauf à la lumière naturelle"...

Si c'est vraiment du back focus que dois je faire?
Merci
10-12-2010, 03:42 AM   #6
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I am agreeing with Russell Evans. Do the test in natural light.

If you have a BF in natural light you can correct it with the K10 using the debug menu. However , if you have firmware version 1.3 on your camera it is a little more complicated. Do a forum search to find out how it is done.

The other problem is that on the K10 you can only adjust BF/FF for all lenses...NOT individually for each lens. If you only have BF issue with this one lens you are better off not adjusting it.
10-12-2010, 08:57 AM   #7
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Merci pschlute, effectivement j'ai la version 1.3, si je modifie BF tous mes objectifs seront concernés alors que seul le 50mm est BF.
Je dois donc envoyer mon K10 et mon 50mm chez Pentax.
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