AF fine tuning

Xtreme · 04-12-2015, 11:59 PM

Hi

I've been playing with my K-S1 for a while now and I have noticed that some lenses for example Sigma zooms need at least +10 correction to the autofocus. I could even try a bigger correction if it were available.
But my actual problem is the tuning needed for the manual lenses. Older manuals can't be saved in the "use one" mode, cause the camera can't identify the lens.

I have saved corrections for ~10 lenses and now I would need to know, if I change to "use all"-mode, will it erase my "use one" settings ?
And why I need to tune AF on manual lenses ? Well, the hexagon and beep to verify focus are crucial at some cases when my eyes can't be sure enough.

sterretje · 04-13-2015, 01:08 AM

Originally posted by Xtreme

And why I need to tune AF on manual lenses ? Well, the hexagon and beep to verify focus are crucial at some cases when my eyes can't be sure enough.

The problem lays in the different paths. The path from the lens mount to the AF sensor might be slightly longer or shorter than the path from the lens mount to the image sensor.

I however would definitely not rely on the hexagon for critical focus. You will notice that once the hexagon is on, you can still change the focus distance slightly without loosing the hexagon; this means that there is a range in which the camera thinks that the subject is in focus.

The two solutions are to use focus-peaking or to get a 3rd party focusing screen (e.g. focusingscreen.com or katzeye). Not sure if focusing screens are available for the K-S1.

Xtreme · 04-13-2015, 01:31 AM

Originally posted by sterretje

The problem lays in the different paths. The path from the lens mount to the AF sensor might be slightly longer or shorter than the path from the lens mount to the image sensor.

I however would definitely not rely on the hexagon for critical focus. You will notice that once the hexagon is on, you can still change the focus distance slightly without loosing the hexagon; this means that there is a range in which the camera thinks that the subject is in focus.

The two solutions are to use focus-peaking or to get a 3rd party focusing screen (e.g. focusingscreen.com or katzeye). Not sure if focusing screens are available for the K-S1.

Hi and thanks for your input.

I'm aware of the "hexacon range", but I would like to have the range to be somewhat consistant with different lenses.
Focus peaking is all right with non-moving objects, but I can't imagine using it when taking pictures of moving objects, cause I like to have my eye on the finder.

04-12-2015, 11:59 PM	#1
Xtreme Junior Member Join Date: Nov 2010 Posts: 26	AF fine tuning Hi I've been playing with my K-S1 for a while now and I have noticed that some lenses for example Sigma zooms need at least +10 correction to the autofocus. I could even try a bigger correction if it were available. But my actual problem is the tuning needed for the manual lenses. Older manuals can't be saved in the "use one" mode, cause the camera can't identify the lens. I have saved corrections for ~10 lenses and now I would need to know, if I change to "use all"-mode, will it erase my "use one" settings ? And why I need to tune AF on manual lenses ? Well, the hexagon and beep to verify focus are crucial at some cases when my eyes can't be sure enough.

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04-13-2015, 01:08 AM	#2
sterretje Veteran Member Join Date: Dec 2008 Location: Roodepoort, South Africa Photos: Gallery \| Albums Posts: 3,561	Originally posted by Xtreme And why I need to tune AF on manual lenses ? Well, the hexagon and beep to verify focus are crucial at some cases when my eyes can't be sure enough. The problem lays in the different paths. The path from the lens mount to the AF sensor might be slightly longer or shorter than the path from the lens mount to the image sensor. I however would definitely not rely on the hexagon for critical focus. You will notice that once the hexagon is on, you can still change the focus distance slightly without loosing the hexagon; this means that there is a range in which the camera thinks that the subject is in focus. The two solutions are to use focus-peaking or to get a 3rd party focusing screen (e.g. focusingscreen.com or katzeye). Not sure if focusing screens are available for the K-S1.

04-13-2015, 01:31 AM	#3
Xtreme Junior Member Join Date: Nov 2010 Posts: 26 Original Poster	Originally posted by sterretje The problem lays in the different paths. The path from the lens mount to the AF sensor might be slightly longer or shorter than the path from the lens mount to the image sensor. I however would definitely not rely on the hexagon for critical focus. You will notice that once the hexagon is on, you can still change the focus distance slightly without loosing the hexagon; this means that there is a range in which the camera thinks that the subject is in focus. The two solutions are to use focus-peaking or to get a 3rd party focusing screen (e.g. focusingscreen.com or katzeye). Not sure if focusing screens are available for the K-S1. Hi and thanks for your input. I'm aware of the "hexacon range", but I would like to have the range to be somewhat consistant with different lenses. Focus peaking is all right with non-moving objects, but I can't imagine using it when taking pictures of moving objects, cause I like to have my eye on the finder.