Focus adustment on a K10D

For the last few months I have been noticing my K10D has been losing the sharpness I had when I first got it so decided to have a play with the hack that allows you to enter the debug menu for focus correction. This morning I stuck the F* 300mm and 1.7x teleconverter on and did some adjustment .. finally settled on +120 and took it out for a couple of shots.

What a difference, I urge anyone with a K10D that hasn't tried this yet to have a play (usual disclaimers apply).

This is roughly a 75% crop.

500mm hand held.

I've dialled +60 in on mine for the 50-135 Mike, for when I use autofocus with it. Everything else seems to use zero (tested using a focus chart FWIW), so it's actually more convenient not to say accurate to use manual focus, given it is easy to forget to make the adjustment every time you switch lenses.

Your focus in this shot seems spot on anyway.

Mine seems to be out on everything.

I've wondered on a couple of occasions about the sharpness of my 16-50 on my K10D, though everything else seems ok, I did consider having a go at this hacking business but as the body is now an almost permanent home to the 50-135 I think things are best left alone

It strikes me that this is likely to be a physical misalignment through age. Something has worn or become out of adjustment, maybe the mirror assemply, maybe some wear in the AF mechanism.

If so, it will no doubt drift again as time goes by.

Mike, I totally agree. I set debug mode to be active all the time and dialled up plus 150 little bits and it is sharp. The best lens for it is my DA 50-200. Crystal clear throughout. Tamron 28-300 is a bit fuzzy at the long end but if I bring it back to say 280mm it`s ok.

Cedric

Just had your bird pic flash before my eyes. Superb!

Cedric

I know I keep on about this but it's like having a new camera. Had to do a couple of pics for my FA* 200mm sale and this is the result. These were obviously resized for flickr and have lost detail but even so.

To be honest I may even keep the FA* now.

Not the best subject in the world and handheld.

Full size




100% crop

Reading this thread inspired me to have a go at my K10D this week. I have been bugged for a while now by the fact that my 16-45 would rarely lock on focus with distant shots at wide angle. I kept having to zoom in a bit, lock focus then zoom back out. Not had chance to test the full extent of the adjustment yet but it certainly seems to have cured this issue with the focus lock on the wide angle.

Ian

That is always good practice for focusing and most binocular users are used ti this way of working.

This is actually a bad idea these days as many zooms do not hold focus when we zoom. Technically, they are not true zooms, but variable focal length lenses.

The kit lens will show this very clearly - focus at one length and then zoom, watching how the image blurs.

The K10D can store only one adjustment which is applied to all lenses. This may or may not be beneficial.

The K20D/K7 can store individual adjustments for 20 or so lenses.

John,

Thats an interesting take on zoom lenses - have just tried it with 2 pairs of bin's and they work fine.

So is this a feature of current digital only zooms or present in older analog designs? I would have thought that a Canon (sorry) 100-300mm F2.8 would hold focus start to finish, else there are going to be a bunch of out of work photographers.

Peter

As well as all the corrections needed to manitain performance over all focal lengths, one of the compromises that has to be made is that of holding focus. This will depend on the lens desigmn, but also on the quality of the mechanical components as well.

A Leica zoom might be expected to hold its focus when zoomed better than any kit lens. It might cost a bit more as well.

The first zoom that wasn't was the legendary Vivitar 38-80mm, which started the modern zoom being taken seriously. It was not a zoom as it did not hold focus when zoomed. Many modern zooms are not true zooms in the same way, although even those that are probaly hold focus only approximately.

There is no such thng as total accuracy, so I always zoom first and then refocus. If you want to see the effect focus on something close with the kit lens and then zoom as you look through the viewfinder. It will go way off.

Mike,

On account of your article here, you had me looking at my AF, and sure enough, things were not the way they once were! What also prompted me was an hour or so down at the local creek today, shooting ducks using continuous autofocus (being lazy). I got home to find that there were very few keepers. Nearly everything was back-focused. I used three lenses for the shoot, so I had a hunch as to where to look...

Oddly, now one size fits all (zooms and primes). That new size is +120um on my K10 body. Fortunately, I had installed the 'Russian hack' some time ago, and kept it active so the camera stays in DeBug mode permanently.

That one setting is even the right one for the Tamron 90 mm 2.8 macro - so on this body it now appears to be a universal one, after some quick focus tests with all lenses in the back yard, at 20 paces.

Some more field tests are coming up this weekend by the looks.