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02-03-2008, 08:03 PM   #16
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I agree with Stewart

I disagree with Ben to. I havent touched a k20d but ive already seen enough to make up my mind that i wont be getting one,not for a while yet anyway. Ive got the k10d and im more than happy with the results im getting. I only shoot raw now n then , main reason being is that i get such good results with jpeg.I shot an Australia day event last weekend all in jpeg and all the feedback i got was tremendous. Comments ranging from beautiful,awesome,great etc. The k10d with the sigma 17- 70 gives highly detailed and sharp pics.Most importantly my customers are extremely happy with the shots ive done so that makes me happy.I dont see enough in the k20d to warrant a change and i didnt need to handle one to work it out,so good call Stewart.

02-03-2008, 10:13 PM   #17
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QuoteOriginally posted by nosnoop Quote
And you know this without having touched the camera or seen any reviews on production camera?
Who said that the AF has to be identical just because it is SAFOX VIII - just compare K100D and K10D!
Nosnoop-

The higher AF speed on the K10D relative to the K100D is due to the K10D's batteries being of a higher voltage, yes? Are you thinking that the K20D's batteries will be of a higher voltage than the K10D's?
02-03-2008, 10:33 PM   #18
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I agree with Lucky Sky, one thing is the standard (SAFOX VIII), the implementation is a different story, and I doubt the implementation would be the same between the K10D and the K20D.

There is an obvious gain in IQ and dynamic range with the new sensor alongside nice new options, but presonally I don't see the use of Live View if the LCD screen cannot be tilted (Sony style...). Other than that, I'd upgrade in a minute

Cheers
02-03-2008, 10:35 PM   #19
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QuoteOriginally posted by Lucky Sky Quote
The higher AF speed on the K10D relative to the K100D is due to the K10D's batteries being of a higher voltage, yes? Are you thinking that the K20D's batteries will be of a higher voltage than the K10D's?
It's got nothing to do with battery voltage. The voltage available from either cell types can be stepped up or down as required and the motors can be designed to operate optimally at any chosen voltage, that's all simple engineering.

02-03-2008, 11:31 PM   #20
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We will not know until we see some reviews and start to get feedback from purchasers. Anything else IS speculation.....if you need any convincing have a look at the PMA'08 thread and read what one user of the K20D had to say about AF speed etc.

I accept fully the best guesses that are going on, but until it is on the market, you will all have to hold off with the "I told ya so's".

and Yes, Ben, we are spoiled.
Cheers
Grant
02-04-2008, 02:02 AM   #21
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QuoteOriginally posted by benjikan Quote
...snip...It is akin to judging a film based on seeing the posters...snip...I would like to think that we are intelligent enough here on this forum to wait until the finally released firmware version hits the stores before passing judgment on the K20D.

Man are we spoiled or what?

Ben
For some, it's the tool; for others, it's what the tool can do. And there's those for whom both the tool and the result of its use are equally valued. I tend to fall into this third group. So, like Stewart and some others, I'm underwhelmed by some specifications of the new tool (though I understand why Pentax might find it difficult to improve everything in one go, the way hardware junkies might wish).

On the other hand, the K20D photos I see Benjikan posting here and elsewhere suggest that this new camera can yield very impressive results, even before its firmware is finalized. The photographic result is what a photographer has to show for her/his use of the camera. The camera is just something you'll show off to a few friends and curious folks you encounter while on shoots. I'll stake more of my pride as a photographer on the shots I take, rather than what's on my camera strap, so long as the tool can do what I want it to.

Ben, your photos speak for themselves!
02-04-2008, 03:33 AM   #22
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QuoteOriginally posted by distudio Quote
It's got nothing to do with battery voltage. The voltage available from either cell types can be stepped up or down as required and the motors can be designed to operate optimally at any chosen voltage, that's all simple engineering.
Rob-
I'm not an engineer, so things of this type are not usually simple. Here goes:
Is not the voltage higher for the K10D's rechargeable lithium batteries than the K100D's lower voltage batteries of either the rechargeable NiMH or non-rechargeable lithiums? And doesn't this higher voltage in the K10D allow for a faster focusing motor?
You'll have to take it step by step: my copy of "Engineering For Dummies" is still not been unwrapped after Christmas.
02-04-2008, 05:49 AM   #23
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QuoteOriginally posted by Lucky Sky Quote
Rob-
I'm not an engineer, so things of this type are not usually simple. Here goes:
Is not the voltage higher for the K10D's rechargeable lithium batteries than the K100D's lower voltage batteries of either the rechargeable NiMH or non-rechargeable lithiums? And doesn't this higher voltage in the K10D allow for a faster focusing motor?
You'll have to take it step by step: my copy of "Engineering For Dummies" is still not been unwrapped after Christmas.
Sorry, as an engineer it's just hard not to comment. It's difficult to explain in few words but if you can bear with me.

I guess the easiest way to put it is yes both AA and L-ion battery systems differ in terminal voltage but if the host system is designed correctly this small variation can be accommodated such that there will be not be a performance deficit.

Where things get confusing is in the case of motors designed to drive heavy loads (such as a battery powered power hand tools). They do generally deliver more power as battery pack voltage is increased (and that's how they are marketed), however in this case the performance gain is primarily a function of the internal impedance of the batteries (the ideal battery will deliver infinite current however real batteries are current limited). Since power is a function of voltage x current if the current is effectively fixed the only way to increase power is to increase the battery voltage.

The AF motors in camera bodies just don't need to deliver the sort of power that would significantly constrain their design/operating voltage (as may be the case with powered hand tools). However when a system is poorly designed (like some of the early cameras which lack voltage regulation) battery voltage could affect motor speed (AF operation & shutter FPS) such that certain types of cells produce a marked increase or decrease in performance. Again this isn't just a function of cell voltage but of the cells internal impedance.

The biggest problem with the AA systems is that people can load them up with regular heavy duty or alkali cells, these really aren't suitable (due to their relatively high internal impedances) and performance will suffer noticeably relative to Ni-Cd, Ni-MH or Li/FeS2 (Energizer Lithiums). The beauty of a proprietary system (such as the L-ion battery in the K10D) is that there is limited variation in battery characteristics which makes it easier to design the host electronics.

I'm sure it's all as clear as mud now but as you can likely see there's a bit more to it than just terminal voltage, sorry again for the terse reply.

Cheers,


Last edited by distudio; 02-04-2008 at 05:59 AM.
02-04-2008, 06:20 AM   #24
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Rob, that was well put, and hardly what I'd think of as "terse." Good on ya!
02-04-2008, 06:43 AM   #25
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QuoteOriginally posted by benjikan Quote
Just wish to share a thought with all of you. There have been a multitude of Pentax and potential Pentax users critiquing the K20D. Now as far as I know, the only people in a position to do a review or comment on the camera are those that have actually used it. I find it quite amazing that there have been those who have slammed or praised this camera before it has even hit the market.
Amen to that! Talk about putting mouth into gear before engaging the brain!

QuoteOriginally posted by benjikan Quote
It is akin to judging a film based on seeing the posters. Look, I have used the camera. It is an incredibly versatile tool with features like multiple exposure to increase the dynamic range, custom lens calibration for up to 20 lenses and an incredibly good IQ up to 1600 iso and a usable 3200-6400 iso setting.

I would like to think that we are intelligent enough here on this forum to wait until the finally released firmware version hits the stores before passing judgment on the K20D.

Man are we spoiled or what?

Ben
Ben, I think you assume too much!

Intelligence? *********! Sorry, but I can't find a suitably polite comment to say! It does seem to been an even rarer commodity than even I (a curmudgeonly, cynical old B'ard) thought prevailed.

Like you, even having used a beta, I haven't made any final critique on the camera, but I look forward to doing so!
02-04-2008, 07:12 AM   #26
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QuoteOriginally posted by distudio Quote
Sorry, as an engineer it's just hard not to comment. It's difficult to explain in few words but if you can bear with me.

I guess the easiest way to put it is yes both AA and L-ion battery systems differ in terminal voltage but if the host system is designed correctly this small variation can be accommodated such that there will be not be a performance deficit.

Where things get confusing is in the case of motors designed to drive heavy loads (such as a battery powered power hand tools). They do generally deliver more power as battery pack voltage is increased (and that's how they are marketed), however in this case the performance gain is primarily a function of the internal impedance of the batteries (the ideal battery will deliver infinite current however real batteries are current limited). Since power is a function of voltage x current if the current is effectively fixed the only way to increase power is to increase the battery voltage.

The AF motors in camera bodies just don't need to deliver the sort of power that would significantly constrain their design/operating voltage (as may be the case with powered hand tools). However when a system is poorly designed (like some of the early cameras which lack voltage regulation) battery voltage could affect motor speed (AF operation & shutter FPS) such that certain types of cells produce a marked increase or decrease in performance. Again this isn't just a function of cell voltage but of the cells internal impedance.

The biggest problem with the AA systems is that people can load them up with regular heavy duty or alkali cells, these really aren't suitable (due to their relatively high internal impedances) and performance will suffer noticeably relative to Ni-Cd, Ni-MH or Li/FeS2 (Energizer Lithiums). The beauty of a proprietary system (such as the L-ion battery in the K10D) is that there is limited variation in battery characteristics which makes it easier to design the host electronics.

I'm sure it's all as clear as mud now but as you can likely see there's a bit more to it than just terminal voltage, sorry again for the terse reply.

Cheers,
Rob, you are absolutely correct in your analysis.

The challenge is that the AA batteried cameras have been designed around either CRV3 or AA lithiums as the primary power source, which deliver a constant voltage higher than 6v when under load, usually around 6.5v. The use of AA NiMH batteries usually means that, even with freshly charged units, they deliver around 4.8v under load, which in real terms means that for a given motors impedance the power that motor can deliver under those conditions is about 60%, this significantly affects the AF performance. If the system was specifically designed for only NiMH AA's, then the motor could be designed accordingly, but due to the variation of AA cell technology, there is just too much variation.

It is significant that Pentax have specified and supply AA Energizer (Li/FeS2) batteries with the K200D, I suspect that the performance using NiMH's will be significantly impacted, it will be interesting to check this out when I can evaluate a unit.

It can of course be argued that the camera should be designed around a 4.8v nominal supply and have regulators to control the voltage from higher voltage sources, however I suspect that the peak power levels encountered would mean fairly high power regulators and be wasteful of energy (heat) and also increase the current requirements and affect battery life/number of shots.

When using a proprietary battery system, the system performs in a much more predictable manner. That's why I eschew AA batteries and advocate the adoption of proprietary systems.

However I do concede that the best solution is to use a proprietary system with the ability to use AA's in an emergency. An easy way to do this with the K10D, for example, is to buy a 4 cell AA holder (or even larger cells) from a electronics store and have a flying lead to fit the external power socket and keep the batteries in your pocket. I find it just as easy to have a couple of spare cells and have a 12v charger in my car. I don't do long jungle treks away from power sources!
02-04-2008, 11:52 AM   #27
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Excellent Responses To The Non-Engineering Guy

Rob (Distudio) & Richard Day-

Thanks to you both for expanding on this battery subject. Let's see what I've gleaned in summary:

1) Rob.....nothing terse about your reply. Quite informative......thanks for your time and information.
2) Richard Day states that Lithium batteries can sustain a higher voltage under load longer than my AA NiMH Rayovac hybrids (which indeed are better than my older NiMH rechargeables).
3) If I wish for better AF performance, I need to stick with the batteries that will better maintain their rated voltage under load. But certainly no higher than what Pentax recommends i.e., no rechargeable Lithiums for a K100D.
02-04-2008, 02:48 PM   #28
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QuoteOriginally posted by distudio Quote
Sorry, as an engineer it's just hard not to comment. It's difficult to explain in few words but if you can bear with me.

I guess the easiest way to put it is yes both AA and L-ion battery systems differ in terminal voltage but if the host system is designed correctly this small variation can be accommodated such that there will be not be a performance deficit.

Where things get confusing is in the case of motors designed to drive heavy loads (such as a battery powered power hand tools). They do generally deliver more power as battery pack voltage is increased (and that's how they are marketed), however in this case the performance gain is primarily a function of the internal impedance of the batteries (the ideal battery will deliver infinite current however real batteries are current limited). Since power is a function of voltage x current if the current is effectively fixed the only way to increase power is to increase the battery voltage.

The AF motors in camera bodies just don't need to deliver the sort of power that would significantly constrain their design/operating voltage (as may be the case with powered hand tools). However when a system is poorly designed (like some of the early cameras which lack voltage regulation) battery voltage could affect motor speed (AF operation & shutter FPS) such that certain types of cells produce a marked increase or decrease in performance. Again this isn't just a function of cell voltage but of the cells internal impedance.

The biggest problem with the AA systems is that people can load them up with regular heavy duty or alkali cells, these really aren't suitable (due to their relatively high internal impedances) and performance will suffer noticeably relative to Ni-Cd, Ni-MH or Li/FeS2 (Energizer Lithiums). The beauty of a proprietary system (such as the L-ion battery in the K10D) is that there is limited variation in battery characteristics which makes it easier to design the host electronics.

I'm sure it's all as clear as mud now but as you can likely see there's a bit more to it than just terminal voltage, sorry again for the terse reply.

Cheers,
Actually that was pretty clear. I for one was disappointed to see AA's specified for the K200D. Having made the move to propretary and having found a cheap source of Hahnel clones for 12, I am very happy with the K10D. The K20D has longer battery life too (lower power CMOS) and uses the same batteries which I appreciate hugely.

Having used a K20D I can subjectively say that IMO, the AF is faster because it hunts less (even in the dark). Although the actual hardware in the Safox system has been carried over I dont think this is a bad thing (its has a lot of cross sensors and is actually very precise) but the algorithm for controlling the AF been improved apparently, especially for the SDM lenses that have less "slop" in the drive.

The early FW I used had other issues in very BRIGHT light, but the lens supplied had a serious centering issue so I dont want to draw too many conclusions. I reported this back to them.
02-04-2008, 03:00 PM   #29
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After handling the camera myself I made my conclusions and have stuck to them.

It's a great tool and with more latitude to do the things I want to shoot. Were there things I wanted to be better, sure who doesn't, but there is always something someone wants that it doesn't have.

Ben, your words are meaningful and I hope many take it at what it's worth.

BTW, speaking of AF, my beta version was hard to conclude much, but the continuous AF felt much better and the FPS was much more constant than the K10D. I need to bug someone and have them send me a newer K20D with a more finalized firmware.
02-04-2008, 03:19 PM   #30
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QuoteOriginally posted by codiac2600 Quote
I need to bug someone and have them send me a newer K20D with a more finalized firmware.
While you're at it, see if you can get them to send me one, too. ;-)

Will
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