[jolepp]

I understand that BF/FF in general is about the image sensor plane and focus sensor (and/or focusing screen) being misaligned. With the AF sensor, a software adjustment like that available with the K-5 and K-7 may be sufficient to deal with the problem. With the focusing screen different shims to adjust the location of the screen slightly are a solution. Where things get tricky and there seems to be no really convincing explanation as to what is going on is that BF/FF can also be a lens (unit/copy) specific issue. With these some people have reported a happy outcome from having their body and set of lenses adjusted (by Pentax service, apparently).

The above problems and solutions apply to all DLSR brands and models. Some copies of bodies, lenses and combinations thereof have these problems, some don't.

The original BF/FF problem thread was about a theory that with the K-5 there might be a color temperature and/or low-light specific part to the BF/FF puzzle, that is, it was speculated whether there was a systematic problem with K-5's autofocus such that it would only appear under low light and/or specific color temperature conditions after, presumeably, eliminating any BF/FF in bright daylight conditions. It would still seem to be unclear to which extent this problem exists and whether it affects all K-5s. Speculation about the possible causes include the new AF sensor overcompensating for color temperature. This might be a firmware problem, or could perhaps be rectified by firmware even if not a strictly speaking a firmware bug.

The point of the above is that BF/FF issues as such are a fact of life with DLSRs (and can be dealt with). There would seem to be an AF problem in specific conditions with some/all K-5s to which there is no known solution (except maybe using different AF compensation values in the problematic conditions). Continuing the discussion here hopefully helps to clarify the issue.

[pcarfan]

It is also worth mentioning that the K-5 had this FF issues where as the K-7 did not in the same identical situation.

[filorp]

It is also worth mentioning that the K-5 had this FF issues where as the K-7 did not in the same identical situation.

worth to mention about some other pentax cameras like k10, k20, k100 as well - i had never any problems....

[Gimbal]

My K10 does have the same problem, although with that camera it wasn't such a big problem as there was no point in shooting handheld at that light level anyway.

[Tommot1965]

My K10 does have the same problem, although with that camera it wasn't such a big problem as there was no point in shooting handheld at that light level anyway.

what happened in low light if you used a Flash ? you'd still have FF but good exposure

[Tommot1965]

I was messing about with my K5 last night..I was taking pictures of a chq book no less, that was on a beside table, lit by my bedside lamp....the chq book extended away from the lamp....anyway.....I put my to AFC...and all it took was to move the focal point along the chq book by a inch, to get the FF...as I moved the lens towards the better lit part of the chq book the Lens would shift..then shift back again as I move it to a dimmer area..to get it to focus Id have to Af fine adjust +10 ..it was really quite comical.. doesn't solve our problem..but thought Id share

here I was was focused on the little golden emblem next to "B" for Bendigo, nearer the light source ..



here It was on the "B" for bank.....a inch and a half further away from the light source..badly FF..check out the controls on the remote..the function are quite clearer proving FF..also looks like a over exposure of the well lit area of the lamp-stand...as the shutter speed changed for the slight difference in metered light at "B" for bank

[Gimbal]

what happened in low light if you used a Flash ? you'd still have FF but good exposure

Probably, but I don't know really, I never used the flash.

[pcarfan]

what happened in low light if you used a Flash ? you'd still have FF but good exposure

Well as you know all cameras FF with tungsten light, especially the K10D without the extra sensor. Also, it had like 9 zones of metering or something like that and the exposure wasn't reliable in evaluative mode (I only used pont metering of a neutral area) and P-TTL wasn't that great compared to the current cameras but useable. So, to answer your question, with flash it will get the exposure right most of the times.

Then the K-7 came out with the extra sensor to compensate for different wavelength of light and the 77 (?) or zone metering. The focus in dim light was excellent, tungsten light AF was fine and P-TTL was a dream to use.

I used the K-5 and the tunsten light AF is off, couldn't use the flash well as when the pop-up flash was used it overexposed a lot of times AND the focus was OFF. This is a majot step backwards from the K-7, which had point and shoot simplicity with metering, tungsten light focus and P-TTL. That's why I returned the K-5.

But, the K-5 has so many other advantages, and I can't wait for these to be resolved so I can get one.

[jolepp]

I can't help wondering whether the K-5 low light / tungsten focus issue might only occur with some lens + body combinations (akin to FF/BF in general). This would explain the differing experiences. It still might be something that *could* be compensated by FW, not an actual bug in the FW, though. But then that might imply a FW solution that could eliminate the lens/body combination specific BF/FF issue in general (would be grand, but probably pretty difficult to pull off as it has not been done already and would seem like a selling point: "But Mr Customer, Sir, BF/FF is just a Canikon problem, the SAFOX++ algorithm deals with that." .

[bjan]

I can't help wondering whether the K-5 low light / tungsten focus issue might only occur with some lens + body combinations (akin to FF/BF in general).

The problem as been reported in many forums with all relevant PENTAX lenses and several third party lenses . No fast lens from PENTAX (3.2 and faster) is excluded according to the reports of extreme FF with the K5. With all slower lenses the issue also occurs but is more difficult to spot of course.
It is a body/ ALL LENSES issue Jolepp with some exeptions reported from some people that seem to have no issue at all with no lens.
I have tried 3 K5`s myself and I came to the conlusion that I would need 2 K5s .
One for daylight and one adjusted for artificial light . AND THAT IS THE WHOLE TRICK !!
When you read the small letters in the manual it is written that you need 2 camera`s to be succesfull with the K5. Stupid that no one has noted this before and how clever Marketing Strategy from PENTAX HOYA isn`t it ?

[filorp]

I came to the conlusion that I would need 2 K5s .
One for daylight and one adjusted for artificial light . AND THAT IS THE WHOLE TRICK !!
When you read the small letters in the manual it is written that you need 2 camera`s to be succesfull with the K5. Stupid that no one has noted this before and how clever Marketing Strategy from PENTAX HOYA isn`t it ?

one of my lenses da50-135 needs 0 daylight and more than +10 bulb light second needs -5 during the day and +7 with tungsteen. So, even if i sent my k5 for adjustment i couldnt be using it with my second lens anymore. So, id ended up with solution: 1 body for 1 lens and i'v got 11 pentax lenses. No bjan, no, 100x no!!!!!!!!! or i didnt read your sarcasm...

and im gonna tell something more i was very succesfull with ONE berrowed nikon d3000 and pentax 540 flash during my staff party http://www.facebook.com/#!/profile.php?id=100000936679932&sk=photos and it started to drill a hole in my Pentax heart....

[jbinpg]

I would look this up myself if I had my manual handy, but can the focus adjustments be saved with the USER modes? Seems the best way to handle this situation where you have different focal planes with different EV levels.

[Gimbal]

Got my first limited yesterday, the 35 macro. It's a bit early to be really sure but first impression is perfect focus in good light, and FF in slightly less good light. That would be in line with the other lenses I have so it's probably the way it is.

A bit frustrating not knowing if the indoor light is enough to get correct focus. And the camera won't tell as it always behaves like everything is just fine even when it isn't.

[bjan]

Nice new tool Gimbal your new 35mm macro. Congratulations. What would you say if somebody asks you to make pictures on his or her birthday party in the evening under artificial light conditions and knowing you have this wonderfull PENTAX K5 cam ?
Man I would do everything to get this baby moving as it should. I tried everyting possible to provoke PENTAX to move by writing to them. Calling them. Posting on the internet but till today I am afraid I have to shift my focus and find an other big brother for my CANON S95 wich is nice for P&S but there is always a shade of dissapointment when lookin at the pic quality having so long been shooting with the K7. PENTAX MOVE NOW !! PLEASE !!!

[Tommot1965]

Nice new tool Gimbal your new 35mm macro. Congratulations. What would you say if somebody asks you to make pictures on his or her birthday party in the evening under artificial light conditions and knowing you have this wonderfull PENTAX K5 cam ?
Man I would do everything to get this baby moving as it should. I tried everyting possible to provoke PENTAX to move by writing to them. Calling them. Posting on the internet but till today I am afraid I have to shift my focus and find an other big brother for my CANON S95 wich is nice for P&S but there is always a shade of dissapointment when lookin at the pic quality having so long been shooting with the K7. PENTAX MOVE NOW !! PLEASE !!!

Bjan

do you still have your K5 ?

if so.. maybe do what Im intending...to see if 1.03 fixes it..if not Im going to return it as a faulty product , by then if its a hardware problem, hopefully the new batch will sort it..if not Ill try a calibration..if that's a bust...I will consider a refund..and move on...I will see what develops.....

of course in the meantime...we can just stop down to F4...or use LV.....its not a perfect situation I know , but one that I personally can deal with ....thankfully the outcry has been forthright and consolidated enough for Pentax to take note Im sure