Completely Dejected (auto focus K5)

Yes, I did indeed read the post. The fact that the error was consistent suggests the adjustment was not being made as per the instructions, as the eye tends to compensate. Thtat's why it's necessary for there to be a blank or defocused image. Removing the lens is another way to achieve this.

Well when it gives the same error to the front focus both ways it is.

Except the correct adjustment for your eye is probably not at either extreme, but somewhere in between (or if you have poor eyesight, somewhere off the scale entirely). The only meaningful result is when it's correctly adjusted from your eye, not when it's incorrectly adjusted for your eye regardless of to which end of the scale.

How can it front-focus at both extremes but be perfect when in the middle (it isn't perfect when in the middle by the way, it front focuses.)

I've tried it in increments, all the way across, probably about 7 or 8 and it front focuses everywhere. I am at my wits end.

i think your on cross purposes here, John is saying the dioptre has to be adjusted to your eye sight by looking through the viewfinder at a blank white sheet of paper,card,wall or whatever as long as it is plain and light enough to see the focus target then move the dioptre until the focusing target is perfectly in focus, after that do the focus tests.

Going round in circles a bit, I'll just sum up -

I experimented extensively (a few hours) with manual focus. I set the diopter as advised in the manual by looking at a plain wall. The camera front focused - that is words that were readable by looking through the lens were unreable in the image.

Just in case I hadn't set the diopter correctly I them repeated the process across the whole range of the diopter and apart from the extreme left, where everything was blurred, wherever I put it the camera front focused considerably (enough to make words unreadble that are readable through the lens.)

I then got my girlfriend to repeat the process in case my eyes were somehow at fault and she got the same results.

I cannot explain it - I have had the camera on the tripod for about 18 hours in total messing about with it and haven't got one image perfectly focused.

Am I just being too unreasonable in expecting it to focus accurately on an exact point at f1.4?

My feeling is that you're totally misunderstanding something basic. The purpose of adjusting the eyepiece dioptre has nothing to do with the lens focusing, so forget that for a moment. To focus accurately on anything manually, that is by looking to see when it's sharpest, your eye needs to be at rest at the correct "virtual distance" from the focusing screen inside the pentaprism housing. This distance is around 1 metre, so your eye needs to be able to focus comfortably on something 1 metre away. That is where the viewfinder image is. So we look at a blank wall and thenadjust until we can see the etched lines in the viewfinder at their clearest.

Now we can focus on a subject. The distance from the lens to the focusing screen (via the mirror) must be the same as the distance from the lens to the sensor, so when something looks sharp in the viewfinder it will be sharp on the sensor. This basic collimation you can do nothing about and usually cameras are spot on or so close it doesn't make any difference.

Now in its simplest form manual focusing is dead easy. We turn the focusing ring on the lens and when the image is sharpest it is in focus. Always focus after zooming by the way as shifting the zoom setting will alter the focus point with all but the most expensive zoom lenses.

The AF system also seeks the sharpest point, but errors in lens manufacture and calibration may mean it's slightly out with a particular lens. I haven't found a lens yet where it is, but some seem to find fault with every lens they have. Anyway, whatever the reason if you want to adjust you can do and each lens (up to 20) can be individually calibrated the AF adjustment.

I would feel a lot happier that you were doing the testing right if the images you were posting were better technically, being brutally honest, so the newspaper one was the best but it should be done in daylight, at various zoom settings and you should be more specific about where you were aiming for. The letter T was a big letter - where on the T were you focusing?

Get it right for daylight, starting with factory defaults to make sure there is a problem and you're not just chasing in circles.

Hope that helps!

Daydreamjay, if the lens will not focus manually either, then you have a fault somewhere.

Maybe there is a misalignment of either the position of the sensor, or the position of the focussing screen. I suspect it's the focussing screen, because if it looks in focus through the lens during a manual focus test, then it should be in focus on the sensor (they are at the same focal distance).

Although there are lots of reports of 'front focussing' K-5's, and indeed mine exhibits this very slightly in low light (in comparison to another DSLR I own), the images are still in focus, whereas yours seem to be seriously out of focus every shot by your reports. Maybe you should have it sent back to Pentax for re-alignment. It would seem the best thing to do at this stage.

Have you tried any shots with Live view?...... Zoom to full extent (I think it's 10x or 12x and slowly MF the lens, take a few shots. Then set lens to AF and use LV and Contrast Detect, you may have to change something in the menu.

Just out of curiosity I tried this afternoon with available light from a window at about the same EV your using (EV 4) using just Jpegs and an M42 MF lens (Tomioka 55mm f/1.2 at f/2) and I didn't have any problems (see shot below) It might be worth you buying a couple of Daylight bulbs from Homebase or an Arts Craft shop.



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But his earlier post (with the newspaper shots) show that his problem with the camera's focussing is that what looks in focus in the viewfinder manually focussed comes out focussed well in front of what he is seeing. He also checked across the range of dioptre settings in case it was his own vision, but to no avail. Something must be amiss somewhere, because manual focussing should be accurate, as in Algernon's shot above.

LV should be perfect, so a test using it would indicate that the viewfinder focusing screen needs shimming.

In his newspaper shots, Live View was indeed the closest 'in focus' shot, so I think you are right.

Time for him to seek a repair, or sell up and move to Canon then.

At this stage I would like someone local to me to give me a second opinion by having a go with my camera.

Are any users in the West Yorks area?

Plenty of us Jason, where are you?

At the risk of jumping in without reading the whole thread...

The diopter setting is not intended to focus the image... It compensates for your eye's ability to focus on the focus screen. I find the best way to accomplish that is to simply remove the lens altogether and look through the viewfinder at a plain wall or white paper. Of course you can achieve the same result by de-focussing the lens. Adjust the diopter to sharpen the brackets on the focus screen. That's it. You should never have to readjust the diopter setting.

Now with the lens on, carry out your lens focus tests as described throughout this thread. Don't try to improve on the focus by adjusting the diopter.

If your manual focus test fails to match viewfinder focus with resulting image focus, then your camera needs to be calibrated. There are thin shims behind the focus screen to make this correction. When I installed my Katz Eye viewfinder focus screen, I had to exchange this shim with a thinner one to get proper manual focus. The Katz Eye screen was .05mm thicker than the Pentax focus screen.

Note that the above has nothing to do with auto focus. The actual focus sensors are below the mirror, and have nothing to do with how your image looks like the viewfinder. It's quite possible for your autofocus to perfectly focus your image, and it appears out of focus in the viewfinder. As mentioned above, before replacing the shim below the Katz Eye focus screen, my auto focus worked perfectly, but the image in my viewfinder was slightly out of focus. Replacing the shim fixed that, and they now match perfectly.

Hope this helps,

Dick