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01-22-2011, 11:39 AM   #226
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QuoteOriginally posted by Ray Pulley Quote
The photographer obviously thinks these images are ok, and he also recieved many favorable comments on them.

This is not in any way meant to disrespect Paul or anyone else on the PDML thread, but the point is that it is this sort of thing that I think is going on when many say that they are getting good AF in low light from the K5.

I viewed the shots, and found them lacking in more than just focus issues, but focus was definitely lacking on many, assuming the focus point was where I would think it might have been....but I have no way of knowing that, and unless the shooter put an "X' on the spot no one else does either.
If most find these good or acceptable, then stop looking for a fix for the focus issue, it won't happen. With standards like these as a guide to what is acceptable, any cheap point and shoot will fill the need.
Regards

01-22-2011, 11:43 AM   #227
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Попробовал разные объективы с к-5, в результате получилось что 35 2.4, ФА50, 18-55 работают отлично без ФФ, только ДА70 имеет фронт фокус вместе с к-5. При таких же условиях ДА70 и К-7 фокусируются нормально.

Попробуйте проверить разные объективы!!!

Last edited by win-win; 01-22-2011 at 12:07 PM.
01-22-2011, 12:15 PM   #228
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I Have Done So

QuoteOriginally posted by win-win Quote
Попробовал разные объективы с к-5, в результате получилось что 35 2.4, ФА50, 18-55 работают отлично без ФФ, только ДА70 имеет фронт фокус вместе с к-5. При этом ДА70 и к-7 фокусируются нормально.

Попробуйте проверить разные объективы!!!
Hi Win-win,

I have tested 3 K5 bodies with the following lenses I own:


Pentax:

DA 16-45
DA* 16-50
DA 40
DA* 50-135
FA 50
FA 31 Ltd
FA 43 Ltd
FA 77 Ltd

Others:

Sigma 18-50 f2.8
Tamron 28-75 f2.8
Sigma 70-200 f2.8
Tamron 90mm f2.8 macro

The shift to Front Focus as the light is reduced can be seen in all of them. Some start out more FF or BF, which makes some of them unusable sooner, but all of them drop off very badly and will not achieve a sharp focus well before the specified lower limit of -1EV.

My K20D shifts as well, but it remains just barely in focus at the limit of its metering range, which is higher than the K5.

At this point, I would be ok if the K5 was as accurate as the K20 as the K20 was just slow at this light level.

If there were solid proof that Pentax could fix this camera, I would consider sending it in, but I have not seen any such proof that anyone has sent in a camera for repair and received back one that focuses within the published specifications. By proof, I mean before images that show FF and after images in the same conditions that show good focus.

Ray
01-22-2011, 12:48 PM   #229
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OK, what do you think is it possible to fix the problem by firmware, or it is a hardware problem?
Thank you

01-22-2011, 01:24 PM   #230
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QuoteOriginally posted by win-win Quote
OK, what do you think is it possible to fix the problem by firmware, or it is a hardware problem?
Thank you
I'm beginning to wonder if it can be fixed with FW. I say that because there seems to be a few (or maybe more than a few) that don't seem to show the FF problem. That leads me to believe that it is possibly a hardware problem or an alignment issue of some sort.

If it was a FW issue I would think that all would show the problem. Unless the problem is firmware and the K-5 that actually work have a defective wavelength sensor and no compensation is being.

I just wish we could know for sure. I love my K-5, but the focus shift with varying light levels and color temperature are driving me craze. I had a portrait session today with a one year old. I adjusted the lenses I planned to use last night with the modeling lights turned on and a 400w equiv. fluorescent spot aimed at the ceiling. This morning there was daylight added to the mix and I had to calibrate again. Other than that it was a joy doing the session with the K-5 vs the K100DS I had been using.
01-22-2011, 03:05 PM   #231
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Hola, nuevamente insisto.
El problema es de Firmware.
La Pentax K-5 comparte el Hardware de AF con la Pentax 645d.
La Pentax 645d NO tiene estos problemas.

La Pentax K-5 si los tiene, y Pentax trabaja en ello... otra cosa es que lo reconozca publicamente.

A mi me han confirmado que conocen el problema y que trabajan en ello.

Yo fui una de las primeras personas que reporte el problema directamente a Pentax, y se que mi informe llego a Japon. Esto fue hace 1 mes.
Cuando detecte el problema, realice un estudio y redacte un informe.
Desde ese momento cuando detecte el problema, TODAS las K-5 que han pasado por mis manos en la Tienda de Fotografia que dirijo (La Tienda Pentaxeros.com) en la misma situación producen identico error.

Tengo montado un banco de pruebas para poder reproducir el error, y para poder verificar cuando este resuelto.

Desde hace 1 mes, he probado mas de 100 unidades. Todas tienen un error identico.

Espero que Pentax publique la solución en breve.

Saludos cordiales...
01-22-2011, 03:47 PM   #232
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QuoteOriginally posted by Pentaxeros Quote
Hello, again I repeat.
The problem is the firmware.
The Pentax K-5 share the hardware with the Pentax AF 645D.
The Pentax 645D NOT have these problems.
Not so fast......some basic deduction does not conclude that this is a problem repairable by Firmware. We still have to ask why some K5's have the problem and some don't? If it was absolutely a Firmware/Software problem, then wouldn't they all either be good..or bad? It is unlikely they are programmed with different software? More likely that a component of the hardware is bad in my estimation. A bad batch of "thingys" could easily be the culprit, which is a fairly common occurrence in many types of manufactured goods, from airplanes to autos.

Either way, Pentax has already had adequate time to explore this and find the culprit, so a repair should be expected very soon I would think. One would be easier than the other, but either way it would clear the path and restore the confidence of potential buyers. Few are going to keep a camera with this defect, so the choices for Pentax are very limited, and with an otherwise great camera, they will not want to see sales go flat and future confidence eroded considerably.
Regards
01-22-2011, 04:16 PM   #233
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QuoteOriginally posted by Rupert Quote
Todavía tenemos que preguntarnos por qué algunos de K5 tiene el problema y otros no?
Porque el problema varia en funcion del objetivo, temperatura de color, nivel de luz, y al parecer color sobre el objeto que enfocas.

Todas las K-5 que he probado en mi estudio, bajo circunstancias controladas de luz, SIEMPRE tienen el mismo error.

Todas las K-5 que he probado son identicas. Todas tienen igual Front Focus.

He probado mas de 100, exactamente 106ud de K-5.
Las ultimas de la serie 398xxxxx

Ademas Pentax me ha confirmado que es un problema de Firmware.

Saludos...



Last edited by Pentaxeros; 01-22-2011 at 04:22 PM.
01-22-2011, 04:48 PM   #234
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QuoteOriginally posted by Pentaxeros Quote

Porque el problema varia en funcion del objetivo, temperatura de color, nivel de luz, y al parecer color sobre el objeto que enfocas.

Todas las K-5 que he probado en mi estudio, bajo circunstancias controladas de luz, SIEMPRE tienen el mismo error.

Todas las K-5 que he probado son identicas. Todas tienen igual Front Focus.

He probado mas de 100, exactamente 106ud de K-5.
Las ultimas de la serie 398xxxxx

Ademas Pentax me ha confirmado que es un problema de Firmware.

Saludos...

The thing lacking in your thinking here is that some unknown number of K5 owners report no problem at all, so your statement is saying that is not possible?
If it is possible, I think it leans to a hardware problem. If you are right, and I'm not saying you are or aren't, then you need to be the one to tell those that claim absolutely no problem that they are incorrect....I'm not going to do it, for obvious reasons.
Best Regards
01-22-2011, 05:10 PM   #235
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QuoteOriginally posted by Rupert Quote
you need to be the one to tell those that claim absolutely no problem that they are incorrect....I'm not going to do it, for obvious reasons.
Best Regards
I think there is absolutely nothing wrong in assuming that at least 10% of AF tests have a problem in the testing methodology. So, if about 90% of users report to see tbe problem, then the easiest assumption is that all units are alike. And 90% is about the rate we see here.
01-22-2011, 05:14 PM   #236
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I Hope You Are Right

QuoteOriginally posted by Pentaxeros Quote

Porque el problema varia en funcion del objetivo, temperatura de color, nivel de luz, y al parecer color sobre el objeto que enfocas.

Todas las K-5 que he probado en mi estudio, bajo circunstancias controladas de luz, SIEMPRE tienen el mismo error.

Todas las K-5 que he probado son identicas. Todas tienen igual Front Focus.

He probado mas de 100, exactamente 106ud de K-5.
Las ultimas de la serie 398xxxxx

Ademas Pentax me ha confirmado que es un problema de Firmware.

Saludos...
I would be interested in your test setup. Maybe posting a series of test images from a camera or two you have tested would help to prove what you have seen.

I have tested 97 less than you , but all had the same FF shift at very similar low light levels using a black and white test target, so I believe you that all have a very similar problem.

I also tested 11 lenses I own, including 2 from Sigma and 2 from Tamron and 7 of the best Pentax offers, SDM and screwdrive, and all move progressively to FF as the light is lowered, so I know this is not a lens issue.

At the end of the day, I only started down this road when indoor shots in a room lit reasonably well were showing significant FF. These are shots my K20 has no problem with and it took most of the AF adjust to get decent focus.

From what I have seen, I see no reason why this could not be corrected with a progressive AF offset that is applied based upon reading the light meter and color temperature sensor.

Why it is taking Pentax so long remains a mystery as it not very hard to re-create this shift.

Ray
01-22-2011, 05:14 PM   #237
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QuoteOriginally posted by Rupert Quote
The thing lacking in your thinking here is that some unknown number of K5 owners report no problem at all, so your statement is saying that is not possible?
If it is possible, I think it leans to a hardware problem. If you are right, and I'm not saying you are or aren't, then you need to be the one to tell those that claim absolutely no problem that they are incorrect....I'm not going to do it, for obvious reasons.
Best Regards
Not saying that they must be wrong, but I, for instance, stumbled on this problem some weeks ago while doing portraits (before it was published on forums), even done some tests proving it, then when the silent firmware update went out last week I tried to reproduce the problem (with the same lens/environment) and just couldn't...
As I don't think someone came and switched my camera for a working one, I really think there is something else at play here... Maybe room temperature, maybe camera orientation, I don't know, but after the firmware was installed I'd have sworn they fixed the problem...
01-22-2011, 05:24 PM   #238
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QuoteOriginally posted by Rupert Quote
The thing lacking in your thinking here is that some unknown number of K5 owners report no problem at all, so your statement is saying that is not possible?
If it is possible, I think it leans to a hardware problem. If you are right, and I'm not saying you are or aren't, then you need to be the one to tell those that claim absolutely no problem that they are incorrect....I'm not going to do it, for obvious reasons.
Best Regards
Rupert,
As far as i know, there is no published standard way of testing K5's for low light focusing. I don't think any one would suggest that a 1000 members of Pentax Forums would all test cameras in the exact same way when there isn't a published standard.

For example, see Falk's recent statement above:

QuoteQuote:
falconeye;1353547]I think there is absolutely nothing wrong in assuming that at least 10% of AF tests have a problem in the testing methodology.
The value of Pentaxeros report is that ONE individual tested 100 K5's, presumeably all in the same way.

If either Pentaxeros or some photographer more experienced than i, would write up a test procedure for testing K5 for this issue, and then talk Pentax Forums into making a sticky out of it, that might help standardize discussion of this issue. In too many threads, we get these discussions about how exactly this person or that person tested their camera - a lot of wasted posts in my mind.

best wishes,
01-22-2011, 05:54 PM   #239
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OK, just to be sure, I've ran some tests again...
I have one desk lamp, one white/red cushion and the FA50/1.4... AF assist lamp is disabled.

My K5 seems to focus quite accurately on the red/white boundary as low as 1/80, f/1.4, iso 20000... That -0.3Ev if I'm not mistaken.
At iso 25600 (Ev -0.7?) focusing fails to lock and the green hexagon blinks quickly.

When I first had the problem two months ago, it was while trying to shoot my son, at 1/30, f/1.4, 6400 iso... Ev -0.1, so nearly the same light level...
Only differences are the firmware, and the AF assist lamp is now disabled.

I know I still had the FF problem two weeks ago, with the v1.02.21.07 (I can dig up the Ev value, I still have the shots somewhere).

But since the v1.02.21.10, it seems my K5 was cured...

Intriguing, no?
01-22-2011, 06:01 PM   #240
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It's amazing how much shift occurs for a change in lighting conditions. I had all of my lenses dialed in and dead on with my portrait setup. I has two AB400's with modeling lights, one 400W equiv. CFL and daylight through the window. I noticed just before my portrait session that there was some light from the window showing through my white muslin backdrop. I closed the curtains and proceeded with the session. Upon inspection of the photos, the focus point shifted forward. The mix of light changed a bit and so did the focus.

This is very frustrating.
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