Focusing problem

I pressed the shutter button 1/2 way down.

As I also have a K5 the information is useful!

I was using a Tamron 17-50 f2.8, there's no slop with the focusing.

Ok then you should expect the two images to be identically focussed.

Without being able to compare the two images we can only guess at the reason. Perhaps the OOF shot was because the AF was not able to get a good lock due to lack of contrast. It does happen.

post the pictures and tell us where you set the AF selective point.

The first image of the single car unit is the second of two and both are unsharp across the frame. The second image is the first of five all of which are sharp. the focus point was just in front of the cab in both cases.
These are the full size jpegs, I also shot in RAW.
It isn't obvious that the first one isn't sharp.

I am afraid the pictures are too small for me to able to see. Can you upload full size images with exif intact to a site like flickr ?

If you go to flickr and search for me as semi46243 the images are there. It's still not that obvious on there. When I pull the images up on my screen and enlarge them so that the unit virtually fills the screen the whole image is not sharp, I do the same with the loco hauled train and it is sharp.

I have also posted on flickr two images taken last week of a static subject, steam loco outside the shed, one sharp one not and which shows the problem to better effect. They were taken one after the other at 1/100 second, SR on with a steady hand.

Hi Steve

Just had a look at your pictures on flickr and there is clearly a problem and it has nothing to do with your focussing. Nothing at all is sharp in the unsharp pictures.

Only thing I can think of is that perhaps the shake reduction mechanism is not turning on correctly. This could be a problem on older cameras but I doubt it would be a reason on the K3. Perhaps experiment with it on/off.

Perhaps there is a problem with the lens ? You could do some experiments and see.

Other than that I am flummoxed. Anyone else got any ideas ?

I have seen similar in my own photographs particularly in rural settings, which I have shrugged off as the vagaries of Pentax auto-focussing in low contrast scenes. I perhaps unfairly malign my 16-45 as it is capable in the right conditions but dull-ish light at Blea Moor on the Settle Carlisle railway are not they!

Just had a look at the photos on Flikr and all those I saw don't look sharp at all. You need to try and identify the culprit. Is it the camera or a specific lens.
Try taking the same shot of something with one lens on both the K-3 and K-5. If one camera's image is fine and the other not that would suggest a camera body problem.
If having identified a camera problem, it could be the camera's focus adjustment has gone out or the shake reduction has gone awry. Try turning that off and try again. Really its just a matter of troubleshooting.
If it isn't a camera problem try repeating a shot with different lenses to see if one particular lens gone out of alignment.
See how you go with those suggestions to narrow down the problem and report back if that solves it or still leaves you with a problem! If a problem remains I anticipate visiting someone at Bolton fairly soon so maybe I could have a look or perhaps someone local could help (JR?) However see how you go troubleshooting first.

Thanks for the replies everyone, as suggested I am going to troubleshoot the problem and I will let you know how that works out.
Just a thought but does using a high shutter speed with SR switched on cause a problem?

I've heard these rumours over the years too.

If there was any particular combo that caused an issue, then personally I'd hope Pentax have addressed this in the firmware.

As others have said though, you need to test with other components to rule out either the camera (nothings sharp ever) or the lens (not sharp when I use this lens).

There is some adjustment capability in camera, but if it requires an adjustment beyond the camera limits, then you need to have the lens serviced.

Usual technique aspects apply. Hold camera still when shooting, have a sufficient shutter speed for the subject matter/focal length, use lens in it's strength areas (some are not ideal in certain apertures - either too large or too small, and zooms tend to be better in the middle/towards one end and not the other etc).

I have never noticed this using the K1.

SR is designed for around 1/30th sec. or slower. It usually doesn't have much effect at high speeds. I once saw some tests on a website that showed this applied to all makes.

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