[jolepp]

The second statement is unfortunately unsubstantiated.
...

Maybe not: It does not say anything about all K-5s having a problem or not, it is merely a statement about the problem itself, when/if it chooses to surface.

[Class A]

Indeed, it's focusing ability could perhaps be regarded as superior to those cameras in low light situations (provided either Live View or AF assist was used to do the focusing). Perhaps, in that sense, it is "above" expectations - ...

It was exactly in that sense that I meant "above expectations" to be understood.

Light bends at different angles depending on frequency/colour - if you recall your high school physics.

I'm afraid I cannot draw much on high school physics because most of it has been overshadowed by the physics courses I took at my university.

I still don't know what relationship between colour temperature and spherical aberrations you were appealing to.

It doesn't explain dependency on light level, but as you can see from my test photos, the problem is not that dependent on light level ...

With all due respect but I find Falk's study much more convincing than your test photos. While there is always the possibility that your K-5 behaves completely differently, at this stage it seems unlikely.

At this stage, there is no evidence that this problem exists on all cameras to the same degree.

There is also no evidence available to me that this whole thread and forum are not just figments of my imagination. But some scenarios are more likely than others. Given the multitude of reports that are consistent with Falk's finding, I think it is pretty safe to assume that he wasn't just describing the behaviour of an individual camera copy.

The good news is - because the problem is so specific, there are many workarounds so there should be no reason why you can't enjoy your planned K-5 purchase.

I disagree. You cannot tell your neighbours to change their light bulbs, or ask a studio to change their lighting, or artificially illuminate objects that are far away, etc., etc. None of the countermeasures you describe are satisfactory for a camera in this price bracket.

Surely there are tons of ways to enjoy a K-5 despite its current problems but that doesn't mean the front-focus problem is insignificant.

[Christine Tham]

Maybe not: It does not say anything about all K-5s having a problem or not, it is merely a statement about the problem itself, when/if it chooses to surface.

Well, I'm saying that your statement about the problem itself does not seem to be what I'm experiencing with my K-5, nor is it substantiated by Falk's results.

[Class A]

I think also this is the first time pentax choose phase detection AF ...

Pentax film cameras used phase detection AF already.
It is possible, though, that Pentax improved the AF module from the K-7 to the K-5 and still has to iron out some issues.

A slight FF in tungsten light seems to be commonplace with all brands/models.

Yes, but wasn't the "+" in "SAFOX+" supposed to put an end to this? Or was it just meant reduce the amount at which prior Pentax cameras were suffering under this problem?

... They said it is a known issue, they confirmed that Pentax Japan is working on a fix, ...

Unless one questions your source, this seems as much proof as one can ask for that we are not talking about a few, select cameras being affected. EDIT: I'm not questioning your source. I posted this with the intention that some who are still questioning whether or not Falk has been testing an issue pertaining to his copy only may perhaps acknowledge that if Pentax is working on a problem then it seems highly likely that they are doing this because there is a common problem. Since Pentax hasn't been working on a K-7 front focus problem at any time, this further corroborates the notion that the K-5 front-focus problem is a new one.

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Last edited by Class A; 02-24-2011 at 04:02 AM. Reason: Restored the old content -- Class A

[Christine Tham]

It was exactly in that sense that I meant "above expectations" to be understood.

I'm not sure I understand you. I was saying that the camera can only be described as "superior" if it's Live View capability was taken into account (which you are describing as an "unsatisfactory" workaround) - the other two cameras did not have Live View.

Exactly how is this taken to mean performing "above expectations"?

I'm afraid I cannot draw much on high school physics because most of it has been overshadowed by the physics courses I took at my university.

I still don't know what relationship between colour temperature and spherical aberrations you were appealing to.

Well, I will also admit, I have forgotten most of my university physics, which I took at the honours level.

But I seem to recall (very dimly) that if you shine white light past a prism, you get a rainbow because light at different frequencies get diffracted at different angles.

What has that to do with spherical aberration? Well, I was kind of implying was that there may be a condition in which the curvature of the lens causes light at different frequencies to not be aligned when they reach the AF sensor. [Edit: I probably should have said chromatic aberration rather than spherical - but I was also thinking of spherical aberation because the problem seems to be more prominent on fast lenses wide open]

With all due respect but I find Falk's study much more convincing than your test photos. While there is always the possibility that your K-5 behaves completely differently, at this stage it seems unlikely.

I never claimed that two photos taken in non-rigorous conditions constitutes hard evidence.

Nor am I claiming my K-5 behaves "completely differently" - but clearly there are differences in behaviour in the AF assist light for example, which Falk acknowledges, and which is also substantiated by another user (dlacouture).

My tests do not contradict Falk - they are testing for conditions that Falk never tested.

I wasn't asking you to be "convinced" by my results - indeed I would be horrified if you were. I was suggesting to Falk that the parameters of the "problem" may be a little bit more complex than the position he put forward in the paper, particularly his hypothesis of the effect of different lenses, and also the significance of the colour spectrum of the light source. He has acknowledged this and said as much in his reply.

I think it is pretty safe to assume that he wasn't just describing the behaviour of an individual camera copy.

With all due respect I don't share your confidence that it is a safe assumption. Especially since Falk and I have confirmed that our cameras have different behaviours even though we have exactly the same firmware. dlacouture has suggested the behaviour difference can be attributed to different lenses - at this stage I don't know whether that is a plausible theory or not.

None of the countermeasures you describe are satisfactory for a camera in this price bracket.

Isn't that for each individual to determine? Sorry, but you can't tell others whether a workaround is satisfactory or not.

Surely there are tons of ways to enjoy a K-5 despite its current problems but that doesn't mean the front-focus problem is insignificant.

Again, isn't it up to each individual to determine whether a problem is significant to them or not? I have stated my position, others are free to draw their own conclusions. I was responding to a post by someone who said despite being disappointed by the problem, it has not stopped that person from planning a purchase. I was merely giving some workarounds to that person. Isn't it up to that person, and not yourself, to determine whether those workarounds are satisfactory or not?

[Erik]

Unless one questions your source, this seems as much proof as one can ask for that we are not talking about a few, select cameras being affected.

No, it sounded from this guy like it was all of them, possibly to varying degrees. Cameras are rolling out of the factory right this moment with the defect, and Pentax is shutting up about it and pretending like nothing. There was literally nothing they could do, he confirmed to me that they will be returning my camera unaltered. "You could try calling again in a few weeks to see if we have a fix".

The source is the company that performs all authorized Pentax service and repair in Sweden.

[Supernaut]

No, it sounded from this guy like it was all of them, possibly to varying degrees. Cameras are rolling out of the factory right this moment with the defect, and Pentax is shutting up about it and pretending like nothing. There was literally nothing they could do, he confirmed to me that they will be returning my camera unaltered. "You could try calling again in a few weeks to see if we have a fix".

The source is the company that performs all authorized Pentax service and repair in Sweden.

Thanks! It saves me an email to them.

[Christine Tham]

No, it sounded from this guy like it was all of them, to varying degrees.

That is my suspicion too - that the problem is more or less present on all Pentax cameras, not just the K-5. And in varying degrees.

Hence all the conflicting posts "None of my K5s work." "I don't have a problem" "What problem?"

And also the "never seen it on my K10D/K20D/K-7 etc." followed by "Yes, I known about the issue all along - seen it on all my cameras"

You could send the camera in and say it's defective, and ask for an exchange, or else a refund and wait for the problem to sort itself out. Hopefully, if Pentax is aware of the issue and working on a fix, far better to get a camera after they announce a fix, and avoid wondering whether it's a firmware issue or not.

I think Falk's paper is sufficient evidence that there is an issue - and you can also replicate the issue on your camera.

I have owned my K-5 for less than 1 month, I can also do the same thing - take it back to the shop and return it, get my money back, no questions asked. But I have decided to keep the camera and accept it for what it is and be happy with it.

[Erik]

That is my suspicion too - that the problem is more or less present on all Pentax cameras, not just the K-5. And in varying degrees.

Christine, I'm happy that your camera is working out for you, but I have owned or used at least one copy of each of the the following Pentax DSLRS: K100D Super, K10D, K200D, K-7, K-r, and K-5 -- and this is a problem UNIQUE to the K-5 (and possibly my girlfriend's K-r.) Maybe all DSLRs focus a bit off in artifical light, but this is a whole other ballpark of wrong. I have both the camera and lens specific focus compensations maxed out (so 20 total) and it still doesn't focus right.

It is not in my head, and it is a K-5 specific issue. A Pentax representative has explicitely confirmed this to me, so I don't see what you hope to accomplish by arguing the opposite. Just be happy that your camera works well for you.

I would like nothing more than to also just use my K-5 and be happy, but IT DOES NOT FOCUS RIGHT and there is a REAL PROBLEM here. My K100D Super takes photos infinitely sharper in the same light. So does the K200D I use regularly at work. So does my friend's K-7. Please don't try to argue otherwise.

far better to get a camera after they announce a fix

Yeah, problem is I already dropped $1900, so now all I can do is hope Pentax Japan gets their shit in line before the important paid shoot I have coming up. Never early-adopting again, that's for sure...

[ursamajor]

...this is a problem UNIQUE to the K-5 (and possibly my girlfriend's K-r)

Not possibly, but certainly it's a problem to Kr too. Look on topics from the Kr subforum.

[Christine Tham]

It is not in my head, and it is a K-5 specific issue. A Pentax representative has explicitely confirmed this to me, so I don't see what you hope to accomplish by arguing the opposite. Just be happy that your camera works well for you.

Erik, what makes you think I am arguing the opposite? If you read my post, I am saying I agree with you. I am not sure that the problem is K-5 specific, so I have deliberately opened up the possibility that it may also exist on other models, but that is a minor point.

But the bottom line is: if you are not happy with your camera, my suggestion is that it's best to return or exchange it and hope for a better outcome.

I was concerned about potential K-5 problems when I bought my camera, but the store reassured me and said that I can return the camera back to them and get my money back within a 45 day period, unconditionally. I am not sure whether that is possible for you - may be worth checking.

There may indeed be a "fix" coming, certainly I would hope that there is. But I'm not necessarily expecting that there will be, and I won't be disappointed if there isn't.

[Erik]

Erik, what makes you think I am arguing the opposite? If you read my post, I am saying I agree with you. I am not sure that the problem is K-5 specific, so I have deliberate opened up the possibility that it may have existed on other models, but that is a minor point.

Okay, cool. I may have misunderstood you a little, and I didn't want to be confrontative, I've just seen a lot of "THERE IS A PROBLEM, ACTUALLY"/"NO YOU'RE IMAGINING IT, BE HAPPY WITH WHAT YOU HAVE" bickering and wanted to make sure no one is actually denying this issue exists by now.

And I just wanted to offer anecdotal evidence that the problem is indeed K-5 specific, since I have used a bunch of other Pentax DSLRs and while they may not be perfect, they are at least in the ballpark.

But the bottom line is: if you are not happy with your camera, my suggestion is that it's best to return or exchange it and hope for a better outcome.

I'm saying I returned it two days ago, called up the repair guy, and he tells me straight up there is no solution. There is no better outcome. Now what?

There may indeed be a "fix" coming, certainly I would hope that there is. But I'm not necessarily expecting that there will be, and I won't be disappointed if there isn't.

Personally, if Pentax doesn't fix this within maybe a month, I will be RAISING ALL HELL 'til I get my money back, and then I'm either switching systems (Nikon grass is looking a lot greener right about now...) or getting a K-7. This is a semi-pro camera, this shit doesn't fly and HOYA needs to be told that in the only language they understand: cold, hard cash.

But they also explicitely told me they're working on a fix, so I'm giving them some time.

Not possibly, but certainly it's a problem to Kr too. Look on topics from the Kr subforum.

Yeah, I've seen some of that. Great, now I almost regret convincing my girlfriend to switch systems from Alpha

[jolepp]

Yes, but wasn't the "+" in "SAFOX+" supposed to put an end to this? Or was it just meant reduce the amount at which prior Pentax cameras were suffering under this problem?

Indeed. Instead the problem seems to be worse. This would seem to lend credence to the idea that this might be about botching the compensation?

[When originally replying to this I probably clicked the edit button by mistake and so I ended up messing up your post. I tried to put it back as it was. I'm sorry about the goof-up . (The interface simply offers the edit button to the moderator. Kind of elegant, but prone to goof-up, it seems. In other contexts there is a confirmation with password re-entry which would be better (akin to going "su" / "sudo" ).]

[Christine Tham]

I'm saying I returned it two days ago, called up the repair guy, and he tells me straight up there is no solution. There is no better outcome. Now what?

Have you tried going back to the place of purchase, and doing a straight return and say the unit is defective?

I have had bad experiences with repair people giving me excuses and inventing all sorts of stories.

I'm not saying that what you heard was all a pack of lies, I'm just raising the possibility that there may never be a fix despite all the "promises" from the repair person. Let's face it, we have heard various versions of "there will be a fix in two weeks time, they are testing it now" for quite some time now.

But the real issue is: there is no official response from Pentax, nothing on the website, no circular issued to dealers (that we know about). Just saying, you know.

[Erik]

Indeed. Instead the problem seems to be worse. This would seem to lend credence to the idea that this might be about botching the compensation?

If it's about an unsigned 8-bit variable flipping over from 0 to 255, as was one of Falk's theories, then why is this taking months to fix? The fix in that case would involve literally flipping ONE bit in the firmware from 0 to 1 or vice versa.

This is all speculation at this point, but I'm thinking it's something a bit more involved.

Have you tried going back to the place of purchase, and doing a straight return and say the unit is defective?

The repair guy was awesome actually, he gave it to me straight without trying to sugarcoat anything. This is probably because he is not Pentax, but an independent company that has an exclusive deal with Pentax Sweden to do all their authorized repairs.

Unfortunately, the place of purchase has a bad reputation for being very hard to get money back out of. MediaMarkt, huge European heartless home electronics chain. Sweden has all kinds of consumer protection though so I will probably be able to get my money back, but it might take a lot of time and effort.

I know there is a very real probability that this will never be fixed. Even if it is true that Pentax Japan is working on a fix, that doesn't mean they will eventually decide it is possible (read: profitable) to fix the problem. That's why I'm giving them a month, and then pursuing the money-back route.

But the real issue is: there is no official response from Pentax, nothing on the website, no circular issued to dealers (that we know about). Just saying, you know.

I know, and Pentax (HOYA) has a history of keeping things like this under wraps and then (maybe) silently releasing a vaguely-worded update, while never officially acknowledging the issue. The sensor stain thing was a welcome exception.