K10D Focusing, Part IV

The repairman has basically said that he can't find anything wrong with the

camera or the lens.

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Screw that — I <em>know</em> there's something wrong here. I've been

using cameras

for years, and have <em>never</em> had the difficulty focusing that I have with the

K10D. Never.

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At this point, it's obvious that in "going digital" I'm basically trading a

simple, mechanical, easy-to-understand device for a complex, electronic,

difficult-to-understand one. That wouldn't matter so much if the complex and

difficult-to-understand device worked properly for me out of the box.

Unfortunately, it doesn't.

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I <em>could</em> always spend more time trying to figure out why, of course. But

I've

already spent six weeks trying to do that, six weeks that I'd have put to more

productive use had I instead spent money improving my film camera outfit. My

spare time interest isn't fighting with computers, it's documenting the native

plants of the Pacific Northwest. And I already have an image-capturing tool

which delivers more-than-acceptable results for such purposes.

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Conclusion of story: I'm sticking with my Pentax MX and Fuji Velvia. After

recouping my costs for my DSLR debacle, I'll invest that money in improving my

film camera outfit. Part of that will include a film scanner, which hopefully

won't be the sort of PITA that digital cameras (this is, alas, not my first

disappointment in this regard) have been for me.

Is there another of our forum friends out in your area? Maybe you can get together with him/her - and with two cameras test the lenses, and compare menu settings to see what the differences are.

 

Can you exchange the camera for a different one? ...

I think I had the exactly same problem as you did. My K10D was back focusing "most of time" with "almost all the lenses". At first, I blamed myself; since there were occasional sharp (correctly focused) photos. The same problem occured with manual focusing as well; viewfinder image was fine, green hexagon and the beep was OK; the image was out of focus. It was always back focusing. The most terrible example was with FA 35mm f/2. My routine lens was also problematic (Sigma 17-70 mm f/2.8-4.5). Manual focus using SMC-A 50mm f/1.7 was seemingly OK on the viewfinder and images was terribly OOF. I was having shots "within aceptable limits" only using the FA 28-70mm f/4 lens (the one with the narrower maximum aperture).

 

I have decided to use "the reverting back to the older firmware" solution. After entering the service menu and adjusting the scale to +110 microns (after some trial); all my lenses become nicely focusing; all the time!

 

I have tried it on my K100D also (this time with +20); and, it become much better. The menu is within the official firmware for K100D.

 

Since the viewfinder image and the sensor agrees on the correctness of focus, I presume it might have something to do with the sensor position. My pet theory is that the sensor is not at the place AF mechanisms thinks it is. The adjustment is there to correct this. However, I am no engineer and really don't care much about the reason; I may be terribly wrong! Still, the thing I did removed the problem.

For years, I have read of back focus or front focus problems wit various DSLR models. Sometimes associated with certain lenses. At one point I remember Canon having a major problem with a 3rd party lens maker's lenses. I had hoped by now all that had been corrected. Apparently not.

 

There was a posting a while back by someone who found a way to electronically fine tune his focus mechanism so his 43mm Limited was sharp wide open, but I did not save the info.

 

I am also a film enthusiast, having acquired a number of 35mm film models. This is a good time to do that, as some good deals appear on the used market.

Also, see a recent posting- "My Full Frame Pentax arrived today" by Roger R. for more about film models. My two top favorites are the PZ-1p, and the compact but pro metal build MZ-S. I know the MX is a very reliable and robust all manual model.

 

I think it is perplexing that such problems still exist in the DSLR industry, although as one writer has said, digital is still in its infancy compared to film.

 

I know some design issues were addressed in the new K20D. Time will tell. I passed on the K10D, just settling back with my K100D, not even installing firmware updates.

Good, I'm not crazy. I've had the exact same problem with my manual focusing lenses. I often find myself shooting several shots and checking the focus on them and pitching quite a few. Tricky since I am mostly photographing birds this time of year.

 

I purchased the split screen aid for the K10D, I hope it will help me. The savings in film and processing has been the main attraction for me to the K10D and generally a boon to bird photography. But personally I am generally much happier with the images I return with my LX, Super Programs, or MZ-S.

Pentax has resolved these issues with the K20D and its customisable focus correction setting with memory for 20 lenses.

 

Could they give us, K10D owners, this feature with a firmware upgrade? YES! Will they do it? NO!!!!

 

Even if they don't give us the 20-lens database, I would appreciate (as would David and Doug) being able to make an overall adjustment of the AF without having to resort to hacking v1.1 firmware. I have a small AF problem that is only apparent at f/1.4, so it's not worth me hacking the firmware, but if there were a menu to fix this, I would.

 

David, can you return the K10D and buy a K20D? You really shouldn't judge a camera because of one faulty unit. The K10D is a fine instrument, but you happened to be extremely unlucky with your unit.

How exactly do you enter the service member and make the adjustments mentioned?

My K10D backfocuses with my 21mm lens but not the kit lens or the 70. When I correct it

with the services menu then the other lenses are off. Pentax said if I send the camera and

lens in they will fix the focus, and that it will still focus properly with my other lenses; so I

plan to do that soon. It is disappointing they don't allow users to fix it.

Ronald, if you supply David with the name of the rep you have dealt with, maybe he could get the same service, giving your case as a reference.

scanners are equally difficult and require some knowledge to get the most out of.

Regarding exchanging the canmera: been there, done that. That's an earlier chapter in my DSLR saga.

 

Six weeks is enough of a chance. I'm through with it.

I have recently run into a focus problem with one of my k10d and a 300mm f2.8 sigma.

My first body I added a catseye split screen and never had a problem with using this screen. 2nd body I use the standard screen and could never achieve the proper focus ( focused several inch?s behind the target). My first body is well used so I decied to change over to the 2nd as my primary body . When I removed the standard screen and istalled my split screen I had no issue with focusing. I then reinstalled the standard screen into my 1st body I ran into the same problem with focus . I took out the screen and took a good look at it to see if it was installed upside down then I notice a small bur on the corner of the screen left behind after milling of the screen(located on prism side of the screen). Upon closer inspection this bur would not allow the screen to site flat on the Prism . With a fine blade and steady hands I was able to pop this fine chip of plastic from the standard screen. I stalled it back into the body and as far as I can see this has fixed my focus problems. This is not to say that all focus problems are cause buy this but maybe that the screen is not sitting flat on the prism. The chip was no thicker than a sheet of paper so check and see if anything is ether on the screen of the prism and don?t worry about dust

Remarkable, Ian! Pentax should be made aware of this small but significant possible QC issue at time of maufacture! It could save a lot of grief for customers and for them.

David, get a KatzEye, focus manually, and stop complaining.

Not sure what the exact problem was. If manual focus was not accurate, that means the focus screen focus plane had to be re-adjusted through 3 screws near the prism (The CCD module is fixed and has nothing to adjust), so to the AF module. If it was just AF issue, download the hacked firmware and DIY.

Ian, your issue must've been with manual focus, not auto focus, right?

My friend Sean Leahy sent me an email with links to this back focus saga because we had recently discussed this issue.

 

I'm a Nikon user, and had never, ever heard the term "back focus" until 2004 when Nikon introduced the D70. I didn't even understand what it was for a long time.

 

Lo and behold, I've read that the Nikon D300 (and D3, I suspect) have a focus calibration in the camera's menu. It seems that Nikon has conceded that bodies will have variation in focus and have granted users the authority to make adjustments.

 

I got into 35mm photography in 1997 and cannot ever remember "back focus" being an issue with film cameras. Do you think this is somehow related to the smaller sensors of most DSLRs?

"Do you think this is somehow related to the smaller sensors of most DSLRs?"

 

Albeit there are issues of sample variations, bad firmware, hardware misconfigurations and other nuggets.. the big difference is that 10 years ago, not many believed in AF. Today, with 51 focusing points and a supercomputer, marketing departments go berserk trying to convince you that the camera knows best, ALWAYS. Most of us, bite the bullet and either believe that completely or bet our chances on AF.

 

The truth is that AF is great. In some applications, it's a life saver. But no matter how good the microprocess is, it cannot think, or compose for you. It makes mistakes (and very often!). Add to that the smaller viewfinders, the limited applicability of the focus screen, and our own ineptness, and many times we delegate the fault to the camera, and never assume responsibility.

 

It is your responsibility to verify that the camera is indeed focused where you want it to be. You can check that in controlled environments, you can send it off for re-adjustments, etc... but in the end, AF is like a light meter. It's a tool, it helps, but it can't read your mind.

Miserere Mei

Yes It was only an issue with manual focus. I would use AF to rough focus and fine tune it manualy and I would never be happy with the outcome. One thing I have noticed about the 10d is that it has a large AF sensor in the center of the frame . It seems that AF goes out the outer edge of the (o) and not just the square light area and remember just because the body says its in focus usually it may not be where you would like it. The body usually focuses on the first bit of contrast it reads in the sensor area Like a nose , grass in the background or even a suns reflection in the water and not the soft matte contrast like on feathers, skin or fur. One quick test is tape a dime or something with good contrast to a wall grab F 3.5 or faster lens something with a shallow depth of view. Now take a shot perpendicular to the wall & dime dead centre of the screen with the dime taking up about ? of the frame. 9 out of 10 shots have good AF . I have done this with 4 DS and 5 k10d where people have said that they have issue with the AF to show them that they had no AF Problem . Now take the same dime and shoot it at a angle to the wall & the dime taking up ? of the frame. And take several shots with a tripod not moving the camera but between shots manually un focus the shot so that the camera is forced to re focus on the dime. And most likely 1 out of 5 shots will have the same point of focus and the other 4 have different points of focus . from this you get an idea of how large the AF area is, & Nikon and canon about the same. Now that F3.5 and faster lens are getting cheaper and cheaper more people are buying them and with a shallow DOV focus is critical to a sharp photo, where as F5.6 you could focus anywhere on the subject and it & half the background would be in focus.

Ian, I asked that question because as far as I know, the focusing screen has no impact on auto focus because the light being used by the AF sensor does not pass through the screen (that for the light meter, does). The focus screen, however, *can* affect our ability to focus manually.

 

And I agree with everything you wrote in your post. AF can save the day, but it really helps to know how to focus manually and, most of all, to understand how the AF on your camera works. If you're unaware of its limitations, you'll never be able to work around them.

I found an older thread related to this subject, so please forgive the double post -

 

I wanted to add that I have found this focusing issue to be prevalent with my

experiences using the K10d. I happen to otherwise quite like my Pentax system, but

have had to learn to adjust my focus to compensate for the bad backfocus I

experience with my broad assortment of Pentax lenses - which include the 3 main

limited primes (31mm, 43mm, 77mm), an old SMC-A f/1.4 50mm, SMC 28mm, SMC -

M 55mm, SMC 135 and the DA* 16-50. I also have a few 3rd party lenses that don't

seem to exhibit the problem as much but it might be because they're not as fast as as

my Pentax ones & the wider DOF might therefore mask the issue somewhat.

 

Like I said, I've learned that in critical focus situations (where DOF is razor thin) that I

adjust my focus where it looks correct in the viewfinder & then pull it forward a bit -

making my desired focus point a tad blurry - in order to actually hit it correctly in the

resulting image (I use manual focus & full manual settings 90% of the time). For a very

long period, I blamed myself for bad shots until I was able to verify that it wasn't me, but

something amiss with the camera.

 

If it wasn't for my love of Pentax glass & my obviously sizable investment in it, I

probably would've jumped ship at that point. Though it is worth noting that I've

discovered other manufacturers have had this problem with their DSLRs as well. After

doing a bit of research online, I'm not convinced that sending my camera in would

resolve the issue either - not that I could afford to wait the ridiculously long time to get

my camera back anyway (I do work professionally as a photographer). I'd rather use

my 'adjusted focus' method & take advantage of the higher megapixels & greater

imaging of my K10, than use my older Pentax DSLR (or film SLRs!).

 

I find it VERY curious that Ian discovered an issue with his focus screen, so I'm

considering ordering a replacement one to see if I can't produce a similar correction or

even different results. I don't see how any amount of focus correction via firmware

hacking will help with my issue, so I'm going to forgo giving the debug route a try.

Maybe just removing & inspecting the screen is worth a try, though...

Shawn, these might be stupid questions:<br>

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1) Does the focus problem occur with auto focus?<br>

2) Do you have the correct diopter adjustment on the eyepiece?

One other thing to consider about Focus issues is , what terrain is between you and your subject. I know even with a 200mm glass distortions in the air , like when you are setup shooting on a road across a field the air around the road is warmer and the air in the field is cooler and more humid thus creating distortions & when a breeze mixes these two different bodies of air you get distortions . One other thing I have noticed is if these distortions are further away from the camera the easier they are to see. But if these distortions are closer to the camera the are less obvious to the eye but can throw out your focus even more than if they where at a distance, eg I was shoot on asphalt one day at a subject not to far away with mirror lockup and had nothing but grief with focus manual or AF. I was using a bigma, my first thought was lens creep, not the problem. Maybe the focus ring was moving when the mirror went up, I watched thru the body as firing and before the mirror went up it was in focus and when it came back down it was out of focus in the view finder, now I am pissed this bigma was a piece of crap. So I took several more shots and finally found the problem, watching in the viewfinder the subject would come into focus and then go out of focus ever so slightly every 2-5 sec as these distortions passed in front of the lens. I moved the camera off the pavement ( which was not too warm because it was morning ) and onto the same terrain as the subject and the affect was less noticeable.

Miserere - It doesn't matter if it is auto-focus or not. And, yes, I have adjusted the diopter

thoroughly.

 

I should note that this issue is more of a problem with subjects further away, not really

anything within 5 feet of me. That's why I was blaming myself for so long. I suppose I

really need to sit down one of these days with a back-focus chart & go through all my

lenses to get to the bottom of this. I'll report back here if there's anything substantial to

add.