Focusing problem with K10D

http://cgi.ebay.com/NEW-TIFFEN-52mm-STANDARD-HOT-MIRROR-FILTER-NR_W0QQitemZ170064857502QQihZ007QQcategoryZ15220QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

No point in spending a whole bunch....... May have to fight off some Leica users... They seem to need a whole bunch
--
360 minutes from the prime meridian. (-5375min, 3.55sec) 1093' above sea level.

'The exposure meter is calibrated to some clearly defined standards and the user needs to adjust his working method and his subject matter to these values. It does not help to suppose all kinds of assumptions that do not exist.'
Erwin Puts

The reason behind misspelling the two names in this posting is that I did not want to pollute the search engine with insignificant mentioning of the two brands which will not lead to a helpful finding based on keyword search.

Now, if you excuse me I will continue to misspell brand names when if find it necessary.

KSV said:

Laurens said:

The FZ20 probably uses the main CCD for focus, the advantages and
limitations are different, not to mention the DOF which is a factor
of 4 different, if you shot that 77mm at f/8 then it would be less
noticable...

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Absolutely correct. Lets compare apples to apples.

KSV said:

Please spell Canon and Nikon correct, it helps with searches.

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For absolutely incomprehensible reason some people intentionally
and continuously spelling them wrong

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--
http://www.flickr.com/photos/voe/

jeffkrol said:

http://cgi.ebay.com/NEW-TIFFEN-52mm-STANDARD-HOT-MIRROR-FILTER-NR_W0QQitemZ170064857502QQihZ007QQcategoryZ15220QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
No point in spending a whole bunch....... May have to fight off
some Leica users... They seem to need a whole bunch

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I'm afraid you will find that the end price will be much closer to $65 it goes for at B&H ; )

jeffkrol said:

and it is due to IR contamination just try a Lecaish IR cut filter
(hot mirror filter, watever) on the lens and see if improves AF.
Have yet to see anyone try this.

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jeffkrol said:

IF this is the case than a IR
coating on the AF optical path would "cure " it. You would not be
able to AF if you wanted to do IR photography anymore (as has been
reported previously for Pentax bodies). This may just be an
"engineering tradeoff" at this point. To AF w/ IR or not...

Click to expand...

I think a better (but maybe more expensive) solution is to use
achromatic separator lenses in the phase detect focussing system.

I suspect the ambient light dependency problem comes from use
of single lens elements making different colours focus at
different places on the monochromatic focus sensors
(cf. chromatic aberrations).

Using achromatic separator lenses, designed to cope with IR too,
would mean the IR light could contribute to a good focus, which
is better than cutting it off and be left with less light to focus with.

For current cameras though, a hot mirror on the lens would be
worth investigating. Or use MF with a split prism.

AF problems is not a particular Pentax thing, it's not uncommon on
most other SLR forums (with the possible exception of Oly, but their
AF is comparably slow on the other hand). It's the main reason I
never bought a 350D.

Just my two oere
Erik from Sweden

Quick note. About a year ago, I switched just about every bulb socket in my home to Costco's fluorescent bulbs. That's the source I used in all my tests. Some had mixed daylight and fluorescent. It is possible that the particular light source is problematic.

As it is, I did all tests simultaneously with the Canon 350D which came out spot on just about every time. So I'm staying with Canon. This foray cost me a good bit of $$ but well....learned a big lesson.

THanks for this thread which is very helpful in validating what I was finding with both my k10D and lesser extent, the K100D.

MTMT

There is a chance that they completely different light bulbs in Japan, so they can't even see the problem...

Yeah, I know, that wasn't funny...

MT said:

Quick note. About a year ago, I switched just about every bulb
socket in my home to Costco's fluorescent bulbs. That's the source
I used in all my tests. Some had mixed daylight and fluorescent.
It is possible that the particular light source is problematic.

As it is, I did all tests simultaneously with the Canon 350D which
came out spot on just about every time. So I'm staying with Canon.
This foray cost me a good bit of $$ but well....learned a big
lesson.

THanks for this thread which is very helpful in validating what I
was finding with both my k10D and lesser extent, the K100D.

MTMT

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KSV said:

Lance B said:

I don't particularly want them coming over here and
gumming up the works with their biased attitudes.

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Are you trying to say that we are not biased? Me definitely

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Ah yes, but at least we are on the right forum for being biased. ;-)

--
Lance B

http://www.pbase.com/lance_b
GMT +10hours

dvse said:

• Front focus in tungsten light

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Thank you very much for noticing this!

I can confirm this!
I have just tested it.

Tungsten light: Front focus on Tim Jackson's chart about 2-4 cm depending on lens.
Normal daylight: Perfect focus!

Strange! This should be investigated!

lock said:

Thanks James. This hot mirror, that's going to obstruct some of the
light you want to have on the ccd. So there is a disadvantage to
it. But is it sufficient to use Hoya filters such as the IR721 ? Or
should it be the internal IR filter tat has to be exchanged ?

Click to expand...

A hot mirror only blocks IR, it's clear to visible light. The disadvamtage there is imperceptible.
The hoya IR 72 only passes IR, and blocks ALL visible light

We're not talking about changing internal filters ... Some people who are seriously into IR photography, have removed the internal hot mirror from the imaging sensor. If a hot mirror on the lens works then Pentax, Nikon et al need to put Hot mirrors on the AF sensors.

If some of the observations on this thread is accurate, I'm surprised that there are no more complaints about out of focus shots indoors in the last few months. Obviously I was testing for focus the moment I received my K10D & K100D so it is no surprise that I found that right away.

However, I'm surprised that so few are complaining.

Do people:
1. Seldom shoot indoor without flash like I do?

2. Use mostly zooms with small apertures which hides misfocusing from their depth of field?
3. Seldom shoot primes at wide apertures?

Alternatively, it could be that most units really have no problem focusing under inddor incandescents or fluorescents?

I'm checking this thread to see if there's some sort of definitely conclusion eventually.

Thanks,
MTMT

Yes...is there anyone out there that tested their K10d (as dvse did) and did NOT have this same focus issue (with ANY fast lens) ?? I have mine on order with Dell. However, if everyone has this same focus issue then I might cancel my order. I am interested in available light pics...and I am concerned about the slow low-light focus lock and the out-of-focus issues. The SR would help with low light hand-held shots. However, if they are out of focus then the SR looses some of its appeal.

It seems to me that your camera is OK. Please remember that the area which seems to be in focus is twice as large behind the focus point than it is in the front.

Thats funny as the DA21 had FF for me on the K100d but on the K10d I have no problems at all???

HerbChong said:

the DA 21 on my K10D just doesn't sometimes and at other times it
does in identical lighting conditions, usually just a few seconds
later. i can be pointed at a sharp high contrast edge and it just
won't focus. point to a low contrast edge right beside it and it
focuses no problem. i have occasionally had the same thing happen
on my FA 31. almost all of the time, i am locked to the center
focus point, so there is no issue about the camera trying to decide
which focus point to use.

i think it is a body calibration problem and bodies that have AF
problems need to be calibrated by a service center. there may be a
firmware problem in AF, but i tend to doubt it. i doubt the lens
being a problem at all because all of these lenses work reliably on
my *istD.

Herb...

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--
------------
Joel - K10D/DS/SFX
http://www.pbase.com/joele

Correct. Though I did find some links and Tiffen also has them:
http://www.tiffen.com/displayproduct.html?tablename=filters&itemnum=52SHM

They also call it a hot mirror, but it's a screw on filter (52 mm) but also others sizes ae available.

lock

In a german forum some reported the issue with tungsten light, low light indoors: about 2 to 4 cm front focus. In daylight, no problems. But it was inconsistant. some could reproduce the problem, others did not.

Their is even the suggestion that with the kit lens at wide open, this may be the cause of structurally less sharp indoor pictures in the D series as well.

lock

but it does eem a case of the older non-DA lenses that is causing the issue. My DA lenses are fine, it's my FA 50mm that causes me grief.

I have gone throught three, yes three, bodies and all show nasty front focus under these conditions with that lens.

MT said:

If some of the observations on this thread is accurate, I'm
surprised that there are no more complaints about out of focus
shots indoors in the last few months. Obviously I was testing for
focus the moment I received my K10D & K100D so it is no surprise
that I found that right away.

However, I'm surprised that so few are complaining.

Do people:
1. Seldom shoot indoor without flash like I do?
2. Use mostly zooms with small apertures which hides misfocusing
from their depth of field?
3. Seldom shoot primes at wide apertures?

Alternatively, it could be that most units really have no problem
focusing under inddor incandescents or fluorescents?

I'm checking this thread to see if there's some sort of definitely
conclusion eventually.

Thanks,
MTMT

Click to expand...

--
***********************************************
Please visit my gallery at http://www.pbase.com/alfisti

Thanks for the info lock. I think most people that have commented on this issue are the ones that are experiencing the focus problem. It's reassuring to find that some people are NOT able to consistently reproduce this. I already bought a Pentax smc A 50 f1.7 and have the kit lens comming with the camera (hopefully in Jan). I also plan to look at the new DA stars comming in March. Hopfully these all work with the K10d.

Wow, you have me beat. After two bodies, I 'surrendered'. Way to go for your persistance.

MTMT

Yes three.

At first I thought it was the lens so sent it back and came to me with "no error found".

Tried 2 more bodies with the same damned results, took the camera to pentax, they said the focus charts i was using were not their "standard" but they fiddled with it a little and set the camera to "Pentax Standards".

From that point my DA lenses have been OK but the 50 f1.4 continues to front focus badly under incandescant light unless I use the bottom corner focus points.

MT said:

Wow, you have me beat. After two bodies, I 'surrendered'. Way to
go for your persistance.

MTMT

Click to expand...

--
***********************************************
Please visit my gallery at http://www.pbase.com/alfisti

KSV said:

There was quite a few threads about this topic in resent times. So
lets employ our collective brain and try to figure out:
1. In which situations it happens most and in which less. Lets
collect statistics. At first glance appears like low-light and in
particularly incandescent light make more trouble then anything
else.
2. How do you battle this. Manual focus could be solution. Some
said that centre focusing spot not as reliable as corner one. Some
suggest that because hand-held camera actually moves between focus
lock and shutter release enough to be out of focus. Anything else?
Lets share our observations, collect statistics and hopefully we
figure out what to do to battle this.
Cheers.
PS. Those who believe that they do not have any focus issue could
help also by sharing what lenses and under which conditions they
using.

Click to expand...

I have yet to find the time to perform more detailed tests, but I had a large percentage of OOF shots from my afternoon/evening with the in-laws on Chrustmas eve.

These were all indoors, mainly tungsten, but mixed with flash/natural (yes, the lighting was a nightmare for color balance).

I set up the test chart and tested the camera with the following lenses:

DA 40mm pancake
FA 50mm F1.4
DA 16 - 45
31mm Limited
F 50mm F1.7

All were tested wide open, on a tripod. I adjust the lens manually until it is completely OOF, and then let it focus on the spot as described on test sheet.

All front focus significantly on my K10D copy. The lighting was mainly tungsten with some natural light mixed in the overall from a window nearby.

The same tests on my K1100D show spot-on focusing.

I am going to try and get more testing done this week before I decide to send it back to Pentax for adjustment.

I am interested in testing my *istds as well as repeating the tests in daylight.

Ray
--
Current Pentax Lineup:

*istDS(2), MZ-S(2), ZX-L, PZ-1, 645(2), F50mmf1.7(2), FA50mm f1.4, DA 40mmF2.8 pancake, FA31mm LTD, FA43mm LTD, FA77mm LTD, FA28-70 f4, FA 24-90, FA70-210mm, DA 18-55mm, DA 16-45mm, DA50-200mm