How much focus adjustment?

It looks to me like the K10D one is showing the same general effect though, albeit a little bit back-focussed compared to the K5 one.

That would implicate the lens - or the alignment of the chart

Edited to add - try moving the tripod a centimetre or so to the right, centre the image and shoot it again to see whether it looks the same.

Hmm. Maybe I misinterpreted it. I'll do what you say.

I'm just thinking that the difference between sides is only a few mm, so it might be instructive to deliberately skew the alignment to see what happens. If it changes a lot then it suggests the alignment is very sensitive.

Mmmm. I must admit, I would have thought that any back- or front-focus would be in the same sense both sides, if the sensor itself is really perpendicular to the lens axis.

I'll try a very skewed one.

What I meant was whether the lens axis was truly perpendicular to the chart. The plane of sharp focus is only a few mm out across the chart, which could be accounted for by the lens being a few mm off the correct axis. The idea of adding a little bit of error is to see what the effect is - maybe it will look perfect with the lens moved 5mm to the right and re-aimed for example. Or not...

Yes, that is what I understood from your suggestion. I'm trying it now, but my eyes are going a bit funny now that I've been squinting at the alignment and pointing the centre of the field at the right spot for so long

And the light's starting to go now, too, and I certainly don't want to confuse the issue by changing to tungsten! I'll have another go tomorrow, I think - watch this space!

Thanks for your suggestions.

hi
as a matter of interest where did you get the chart
from and how did you set it up
neil

http://focustestchart.com/

Printed it out (just the page with the A4 chart on), stuck it on a piece of A4 card, put it on the floor.

Camera on a tripod, pointing at the chart. Ages and ages trying to get it lined up straight, possibly not yet successfully. Remote 3s release.

The idea is you point the camera at the bit in the middle where it says "focus here". You get the green hexagon to confirm where the camera thinks it's focused. Then you take the shot with the lens wide open, and see where it was actually in focus.

thanks
will give it a try
neil

Chris
I actually fiddled with micro adjustment quite recently and mine goes up to + and -20 and let me tell you, got so fed up that I ended up leaving it to 0 again. To begin with what seemed like off focus wasn't really much, and most probably was because of the angle etc. What took me to embark on this was because I had found a few shots with a 70-200 f/2.8 lens the focus which should have been spot on the eye but wasn't. One thing led me to another and I started fiddling with the micro adjustment. When I thought I had it settled at +10 I decided to close down the aperture and test again and very funny things started happening so I reset it to 0 again and tried with the aperture a few stops closed. It immediately left me thinking that the original focus was correct. I won't go into details about what was happening as it will be quite a tedious writing but sufice to see that I started seeing the DOF front and back amounts shifting so much that I realised that it was shifting off the normal parameters.

Having said that from your first images I can clearly see that yours do need a small nudge.
Good luck with it and hope you manage to sort it out.

Sorry to be pedantic, but the green hexagon tells you you're in focus, not what you're focussed on. It's the focus points that do that, and for AF adjustment you should be on centre focus.

Quite right, thanks for picking me up on that. You get the green hexagon to confirm when the camera thinks it's focused, I meant. And yes, absolutely, centre spot all the way.

The green hexagon is no use for where you're focused, since it's completely out of the frame

Chris, I wish you hadn't started this thread as it's got me on one of my hobby horses again. I have no idea why some lenses (and cameras) back or front focus, but I was on the point of returning my DA L 55-300 to the supplier as I could not get sharp pics with it and thought the lens was faulty. Then I tried it on my son's K-m and it was blisteringly sharp!

My K-x does not have the autofocus adjustment in the standard menus, you have to know how to open a debug menu to get to it (download a file to the SD card). Anyway, my camera is now set permanently to +70 (yes, +70!!!!) and it focusses correctly. Why there is so much inaccuracy / tolerance from the factory I don't know but it really isn't good enough when they don't even put the focus adjust in the normal menus!

At least on the K-5 and K-r it is more accessible.

Regards
David

A mixed blessing though - debug mode isn't yet available on the K-5 and K-r, and you'd never get an adjustment of +70 via the normal adjustment menu.