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05-07-2008, 03:53 PM   #31
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What mawz said.
Also, if you are using a teleconverter to degrade your images, wouldn't it make sense to put a tripod under your camera to try to ameliorate some of the damage, thereby obviating the need for shake reduction?

05-07-2008, 04:03 PM   #32
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QuoteOriginally posted by mawz Quote
You're mistaken in a couple of regards. First off, Pentax openly supports the SD and SDHC spec's (as well as CF on the *istD), they openly advertise their support for these specifications (and a couple of others like DNG). Thus they are commited to supporting in-spec SD and SDHC devices and providing firmware updates if their products are out of spec.

Pentax doesn't openly license the KAF2 mount, nor does Pentax claim to support 3rd party lenses. The original K mount is an open spec, KAF2 is not, beyond the bayonet mount it shares with K mount. They also do not claim that 3rd party AF lenses or teleconverters will work on their cameras (for good reason, as they don't necessarily). They have no valid reason to update the firmware to handle teleconverters that they don't sell, don't claim to support and which likely do not even communicate with the body (I've yet to see an AF TC that does any communication with the body, they simply provide a pass-through for the lens). It's up to the TC manufacturers to solve the problem, not Pentax.

AF TC's are outside the K mount spec as currently known. So Pentax cannot be expected to support such devices, especially if there's no way to know the device is present. If you're having issues with TC's I'd suggest using a KA mount TC like the excellent Pentax TC's and entering focal length manually as required.
Why should I give up autofocus to get the focal length.

please note the attached image

https://www.pentaxforums.com/forums/187646-post19.html

the image is not badly degraded.

If this is the defence, then pentax needs to market a functioning TC. It's their choice, either make a working product or fix the problem, but to do nothing is a very fast way to loose market share.

If your response is representitive of pentax corporate thinking, then I think I will be soon looking for an alternative, not out of choice but because they will not remain in business

ps don't tell me they have not liscenced the KAF2 mount, did samsung steal it?

Last edited by Lowell Goudge; 05-07-2008 at 04:29 PM.
05-07-2008, 04:42 PM   #33
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Official Statement of Pentax Europe

The fault is clearly on Pentax' side.

Simply because they don't have longer than 300mm and no TC in their program. And because the fix would be spectacularly simple (remove one if statement from the firmware code).

These is two responses I managed to obtain from famous

Wolfgang Baus (Produkt Manager, Imaging Systems Division Pentax Europe):
"We will not change the operation of the camera in this regard. We ask for your comprehension because we cannot adapt our devices to possible features of other vendors."

"Your proposition will be put onto a big list. Their relevance will be evaluated by a common conference. Results will then possibly emerge in new firmware releases, to be published on the Pentax website."
(shortened by myself in translation from German)
05-07-2008, 05:28 PM   #34
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QuoteOriginally posted by Wheatfield Quote
Also, if you are using a teleconverter to degrade your images, wouldn't it make sense to put a tripod under your camera to try to ameliorate some of the damage, thereby obviating the need for shake reduction?
Have you tried running up and down a sideline at a sports game with a tripod, then setting it up for the shot? By the time you've done that they're down the other end again!

05-07-2008, 09:55 PM   #35
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The sports guys that I know use monopods.
05-08-2008, 05:38 AM   #36
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QuoteOriginally posted by Wheatfield Quote
What mawz said.
Also, if you are using a teleconverter to degrade your images, wouldn't it make sense to put a tripod under your camera to try to ameliorate some of the damage, thereby obviating the need for shake reduction?
Somehow, I think that all lens makers who also make teleconverters, including pentax in the past, would take exception to the point that the sole purpose of a teleconverter is to degrade the image.

That would be like saying that the sole purpose of other photographic tools such as, high ISO, wide open apatures, filters, etc..... are also to degrade the image.

The issue really is that the thought of autofocus teleconverters excaped the thinking of pentax. They could have easily taken control of the situation, but did not.

Now it is a mess,

As someone else stated, much of the problem lies within the fact that pentax does not have any long lenses. The 300F4 is now just out and over a year late.

Other issues raised with pentax are over 18 months old without resolution. even though they also are incredibly simple to fix.

It has to make yoou wonder why at some point.
05-08-2008, 06:40 AM   #37
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This discussion actually made it's way onto another forum I attend. Here is what they are saying:

"I don't disagree (about how it would be nice for third party TC's to work), but for the Pentax Forums simpletons to blame
Pentax for the behavior of another manufacturers product on their
camera is silly."

and:

"It's not even the 3rd-party manufacturer's fault: The teleconverters
they're complaining about were designed before the shake reduction
system was even invented!"

So you are pillorying them for not supporting a product which they don't make, have never made, and which was made prior to them making a shake reduction body.
Did your mommy have any kids that developed opposable thumbs?

You may mot like the fact that teleconverters degrade images, but no one can argue that they do, it's just a matter of are you willing to put up with the loss of image quality.
05-08-2008, 07:43 AM   #38
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QuoteOriginally posted by Wheatfield Quote
This discussion actually made it's way onto another forum I attend. Here is what they are saying:

"I don't disagree (about how it would be nice for third party TC's to work), but for the Pentax Forums simpletons to blame
Pentax for the behavior of another manufacturers product on their
camera is silly."
while everyone is entitled to thier opinion, why do other camera manufacturers have compensation within thier systems?
QuoteQuote:
and:

"It's not even the 3rd-party manufacturer's fault: The teleconverters
they're complaining about were designed before the shake reduction
system was even invented!"
Aside from shake reduction, the teleconverter also modifies the focal length as used for flash (although most people don't use one on a short lens, but could) and the actual apatures, along with the exif historical data of the shot. It also applies to lens program lines, and shutter speed selection in automatic modes, auto iso selection if activated. It is not simply about shake reduction but that is where the greatest functional difficulty lies.
QuoteQuote:
So you are pillorying them for not supporting a product which they don't make, have never made, and which was made prior to them making a shake reduction body.
Did your mommy have any kids that developed opposable thumbs?
No, I am pillorying them for not appearing to make any attempt to recognize the problem exists, and impacts many users when simple solutions exist to make it work. I also believe they should have had the simple foresight to recognize there would be a problem with teleconverters. While they do not make them at the moment, they have in the past, and hopefully will again in the future. As a manufacturer, and this applies to any manufacturer of any product, not just cameras, they do actually have some responsibility to foresee how people will use their product, within reasonable limits.

Teleconverters for AF pentax lenses existed before their first DSLR, therefore they should have also foreseen the need to accomodate them in some form.

They do not make tripods, for example, yet they advise that shake reduction should be turned off when using one, but, no where in their manuals do they advise that there is a technical issue with using teleconverters and that the shake reduction is not optimal with one, this includes the K20D manual their newest camera.


QuoteQuote:
You may mot like the fact that teleconverters degrade images, but no one can argue that they do, it's just a matter of are you willing to put up with the loss of image quality.
Teleconverters are a fact of life. it is unfortunate that they do not accompdate such a simple device. That is the real point here, the unwillingness to accomodate a simple, well known, popularly used photographic device.

Edit note;

This is not the only issue with the K10D and K20D. There is also an issue with manual metering accuracy, where pentax are still claiming that the camera can use 23 million lenses they have made in the past for the camera, yet the metering accuracy (actually consistency over apature range) with manual apature lenses is +/- 2 stops at best. This would have lead in the film era, to the camera being declared defective, but they do nothing to resolve the issue again known for over 18 months.

While this might seem like a gripe to some users, and perhaps users of some of the competition's cameras, pentax started out their pentaxian ad campaign by stating they listened to thier users. How wrong that has turned out to be.,


Last edited by Lowell Goudge; 05-08-2008 at 07:56 AM.
05-08-2008, 09:52 AM   #39
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QuoteOriginally posted by Lowell Goudge Quote
This is not the only issue with the K10D and K20D. There is also an issue with manual metering accuracy, ... the metering accuracy (actually consistency over apature range) with manual apature lenses is +/- 2 stops at best.
Thanks for the info! At least I will not waste any more time trying to figure out what am I doing wrong (inconsistency of +/- 2 stops is exactly what I observe with manual lenses on K20D)
05-08-2008, 10:05 AM   #40
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K10D and K20D exposure issue with manual lenses.

QuoteOriginally posted by ivanp Quote
Thanks for the info! At least I will not waste any more time trying to figure out what am I doing wrong (inconsistency of +/- 2 stops is exactly what I observe with manual lenses on K20D)
I appologize for hijacking the thread, and this has been reported many times before

To be specific, I believe there is a very characteristic nature to the exposure issue with the K10D and K20D.

What I have measured with my lenses to date (9 of 14 tested) is as follows. All shots done against a block wall)

at F1.4 the histogram value is about 75 greyscale where normal would be about 125. each stop is about a value of 40 therefore this is close to -1.5 stops.

As you stop down, to around f4, the exposure becomes correct. As you stop down further, and by F8 you are about 170 greyscale (roughly +1.5 stops) it can approach 185-200 by F11 (about + 2 stops) before falling back to about 175 by F32 (again plus 1.5 stops)

It is remarkably consistent in behavior with all of my lenses, including my new tamron 28-75 F2.8 if I take it out of AE mode. (note in AE mode it is almost perfect and consistent across all F stops). I intend to test my 2 sigma AF zooms and my 2 pentax AF zooms that have manual apature possibilities to demonstrate this is a generic problem related to the camera specifically. Note my *istD does not have this problem
05-08-2008, 04:28 PM   #41
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What sort of light levels are you testing at? Remember that you will very quickly run out of metering range with stop down metering, and if you are out of the camera's operating range it is hardly fair to blame the camera for not operating correctly.
Having said that, the one thing Pentax did which I find extremely annoying is the lack of inclusion of the aperture simulator lever in the digital SLR range, which hobbles the use of pre A series lenses. I believe it was complaing about this on the Pentax Discuss list that caused them to write the green button kludge that allowed metering on the istD and subsequent cameras.
05-08-2008, 05:20 PM   #42
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QuoteOriginally posted by Wheatfield Quote
What mawz said.
Also, if you are using a teleconverter to degrade your images, wouldn't it make sense to put a tripod under your camera to try to ameliorate some of the damage, thereby obviating the need for shake reduction?
QuoteOriginally posted by Wheatfield Quote
The sports guys that I know use monopods.
Exactly, as do I, so we can't always "put a tripod under your camera to try to ameliorate some of the damage". So it may make sense, but it's not always practical, so it would be nice to have some help from SR.
05-08-2008, 06:02 PM   #43
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QuoteOriginally posted by Wheatfield Quote
What sort of light levels are you testing at? Remember that you will very quickly run out of metering range with stop down metering, and if you are out of the camera's operating range it is hardly fair to blame the camera for not operating correctly.
all light levels are within the dynamic range of the metering. When I start these tests (usually when I get a new lens) I shoot wide open at between 1/2000 and 1/3000 of a second, and stop down from there. the test results have been given to Pentax along with some sample shots. The issue is real, and is repeatable on every lens I have tried to date, that I own, in non automatic mode, (or K mount). The list of lenses that have exhibited this problem that I can attest to are the following:

SMC Pentax 50mm F1.4, 105 mm F2.8, 135mm F2,5, 300mm F4.
SMC-M 100mm F4
Vivitar Series 1 70-210 F3.5 (version 1) at both extremes of focal length, Vivitar 400mm F5.6
Tamron Adaptall II 24mm F2.5, Tamron 28-75mm F2.8 Di (in manual apature mode)
QuoteQuote:
Having said that, the one thing Pentax did which I find extremely annoying is the lack of inclusion of the aperture simulator lever in the digital SLR range, which hobbles the use of pre A series lenses. I believe it was complaing about this on the Pentax Discuss list that caused them to write the green button kludge that allowed metering on the istD and subsequent cameras.
I was one of the people who wrote pentax at the time telling them that the "ability to use older lenses with some limitations" was a real stretch of the imagination without a functioning metering system, in fact, until the firmware update was released I noid not purchase my *istD. as you can see, I have a lot of legacy glass, and do not accept poor or non functioning metering as a suitable definition of "being abnle to use the lens"

But of course, we are digressing from th ediscussion thread, but it is an example of the very limited support in reality for users of existing equipment. The green button seems to be their only move ever in that direction, and this was the first firmware update on the *istD. We have been waiting 4 years for another customer prompted update.
05-08-2008, 06:43 PM   #44
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I will try to repeat your exposure variance test this weekend with my K20. I have a dozen or so pre A series lenses which get nowhere near the use they should.
My understanding from talking to people close to Pentax is that the green button thing is the best we can hope for, the aperture simulator is gone for good.
For myself, I would love to see a Pentax DSLR that solves all the problems, but I am pretty sure that it would probably be double the street price of a K20, which would certainly limit sales.
The K10/K20 aren't perfect to be sure, but for the price being asked, they are remarkably capable instruments.
05-08-2008, 06:54 PM   #45
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QuoteOriginally posted by Wheatfield Quote
So you are pillorying them for not supporting a product which they don't make, have never made, and which was made prior to them making a shake reduction body.
Why are you resorting to Dilbert cartoon like arguments here?

Following your logic, Pentax should remove support for SR with all pre-SR lenses from Sigma and Tamron. Immediately!

Now see this: Pentax even allows you to dial in a focus length for Sigma or Tamron lenses made before even AF existed! Even for Zeiss lenses!


It is just a bug in their firmware which prevents this from working with a TC, and the fix is the removal of one line of code (the 'if'-statement which grays out the menu entry).

Would Pentax run a bug-entry system like most software companies do, we woudn't even have to discuss this here.

It is this simple. Please do not complicate things.
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