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06-20-2007, 06:05 AM   #16
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The K100D and K10D have solid, stainless steel bodies. I have a Nikon owner here at work and he thought my K100D was just another plastic body, like his Nikon (can't remember the model, clearly a more prosumer dSLR). Then he held it and he instantly complained about how heavy it was. Then I showed him the internals from various review sits and he was like "wow, I didn't know they made such a cheap camera so tough!"

I think a lot of that has to do with the free floating sensor (Shake Reduction). It doesn't take much to mount a 1/1.8" -- let alone a measily 1/2.5" CCD. But doing the same with a APS-C sized sensor of 10-20x the weight requires a much more solid foundation. I'm an engineer, but a EE -- not a ME -- so I could be wrong in my assumptions. I'm much better at explaining issues with NiMH in the K100D (and why you should never use rechargeable CR-V3s in it).

06-20-2007, 06:49 AM   #17
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QuoteOriginally posted by benjikan Quote
Did you shoot in Raw or JPEG?

Due to the weather, I shot in both . . . have not had a chance to do pp but do not anticipate any problems . . .

Last edited by rprii; 06-20-2007 at 06:50 AM. Reason: added info
06-20-2007, 07:20 AM   #18
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Warning: thread highjacking.....

BJSmith said: "....(and why you should never use rechargeable CR-V3s in it)"

I assume you meant unregulated CR-V3's? or do you have a stronger opinion?
06-20-2007, 10:10 AM   #19
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Never use Li-Ion/Li-Poly in the K100D ...

QuoteOriginally posted by kmccanta Quote
Warning: thread highjacking.....
BJSmith said: "....(and why you should never use rechargeable CR-V3s in it)"
I assume you meant unregulated CR-V3's? or do you have a stronger opinion?
"Regulated" is still an issue. You can't change the inherent electric potential (voltage) properties of Li-Ion/Li-Poly. You're tempting fate with Li-Ion/Li-Poly in the K100D -- the CMOS and other microelectronic circuits (the motors will probably be fine, if not a tad more snappy) weren't designed for a battery that doesn't ever want to drop below 2x 3V.

I'll repost this response from another forum. It's 3/4ths through the thread here:
Pentax Forum: Batteries for Pentax K100D (and other K dSLR products)? -

I would NOT use Rechargeable CR-V3 Li-Ions in the Pentax K100D ...

First off, there are many aspects to Li-Ion (Lithium Ion), as well as Li-Poly (Lithium Polymer), that prevent them from being even sold at a 1.2/1.5V. In fact, today's commodity, rechargeable Li-Ion circuits don't like to drop below 3V (let alone a definitely deadly 2.7V) in general or they will fail to ever recharge again. A nominal voltage is 3.6V and a nominal charging voltage is 4.2V. It's not so uncommon to get a freshly charged Li-Ion/Li-Poly outputting over 4V! This is very different from "one-time use" Lithium batteries, which will never be recharged (and use different, chemical combinations).

Secondly, I have confused some people here on the "parallel" and "serial". A circuit of "parallel" batteries are independent, of their own electrical potential -- aka voltage -- and current is added, when discharging (output), or distributed, when charging (input). Because we don't want issues with one battery preventing the charging (or even discharging) of another, and we are not concerned with combining their electric potential (we are only delivering 1.2V to each battery), this is how we charge (always -- at least outside of any camera). Unfortunately, when we are discharging the batteries in output, we need to use a "serial" to add their electric potential together -- such as three (3) or four (4) batteries into a required 4.5 to 6V circuit. At the same time, any voltage drop -- which happens due to lack of current in just one battery -- will affect the entire voltage of the entire circuit, as all devices need to maintain the same current to deliver the same voltage. There is a point where the remaining charge over time -- Ah -- will be insufficient for the battery to deliver the required current. The more current required, the higher that "charge" in current-time is.

Side Note: Most point'n shoot cameras can get away with even two (2) batteries because they often use lower voltage mechanics, or don't need as much current to drive their smaller, less powerful 5-6V motors, so the voltage can be transformed despite the doubling of current from the batteries.

Third, today's CMOS circuits are well under 3V -- many approaching diode levels (0.8V, just above 0.7V). A lot of generic, very large scale integration is now at 1.5V (tolerable to 1.65-1.7V, because it divides from 3V (and up to 3.3-3.4V) perfectly. At the same time, many motors in SLR cameras, even today's dSLRs, are still 5V and require quite a bit of current (not enough to convert up from 3V). A common attitude is that "any 5V motor, or even TTL circuit, can take often take far more" -- yes, that is true. Unfortunately, commodity regulators that are designed for 6V, and driving the CMOS with a divider from that. If they are designed for 6V AA batteries, they are often designed with 6V being the "upper level," and 4.5V being the "lower level" as usage and drainage is expected. The regulator is designed for that range for the CMOS circuit (with many fractional regulators to keep the variance down), and most motors will work directly, even when you drop power a full 1.5V. Hence why you've got "snappy auto-focus" and 200 shots later, your camera is still working end-to-end, but not quite as snappy.

Stupid Thing To Do #1: You now through two (2) Li-ion/Li-poly 7.2-8.0V battery packs at the camera. Sure, motors will whiz fine'n dandy for the most part, and that 5V TTL logic probably won't blow either -- as someone stated, it can handle up to 9V. I've done this myself with 5V FPGA logic in the field. But that low-voltage regulator hates you. If you're lucky, it works for awhile -- maybe even months -- and it doesn't blow from the added current for the correct voltage. If you are unlucky, you either lose the regulator, or it's cheap enough it just over-volts your circuits. Even PC techs who overclock CPUs will tell you that sending 1.8-2.0V into a 1.5V CPU is often not possible on a majority of CPUs, only a minority will take that kind of volt. That's the equivalent you'll get if your regulators variance tops out at 6V and is being feed 7.2-8.0V (1/4). Ladies and gentlemen, make no mistake, the microcontroller+peripherial logic (like DSPs) are very, very complex logic that is into the millions of transistors, and much like CPUs of just a few years ago. That's why when da'camera sez it don't support those rechargeable CR-3V, it means da'camera has a regulator designed for a nominal 4.5-6V range, and all bets are off on a regular, nominal 7.2V input -- especially over time.

Stupid Thing To Do #2: Mix NiMH with Li-Ion/Li-Poly. NiMH melts. Alkaline melts. Lithium explodes! What's one of the biggest cause of Lithium exploding? Stress on, regular variance in or just a direct drop in voltage (especially reversed polarity, which can be a major issue here when the potential is significantly lower in portions of the circuit, long story). It's why they tell you not to charge your notebook computer on a plane (with an external battery or in-plane outlet), and the FAA is currently debating whether to allow notebooks to "plug-in" and charge batteries (a majority of explosions occur when the notebook is plugged -- and it's typically more than the CPU/GPU running hotter and being near the battery, but the charging process). Li-Ion and Li-Poly (which is much safer in design than Li-Ion, with some lifespan costs) have very complex circuits for regulation, especially from keeping the battery from dropping under 3V (and especially anywhere near 2.7V). But these circuits aren't perfect, and they fail, as anyone with batteries in Dells and other notebook vendors can tell you. You throw a pair of NiMH batteries in the circuit, which are topping at 3.0V at best, and down to 2.4V at worst, and guess what? The difference in voltage and variance in current drain is not good, as half the serial circuit could be delivering over 60% of the electric potential. Also not good when the Lithium is also heading south of 3.6V towards 3.0V at the same time, and current is varing greatly between them, especially as there is such a lack of convergence. A little transient here, a little transient there -- pop goes the camera, as in explosion (remember, those batteries are stored in a confined compartment)! Who cares about screwing up the NiMH batteries, they might just melt (and you're far more likely to have such a melt with the added volt-amps from the Li-Ion in the circuit) -- don't want to think what that Li-Ion battery is going to do the camera, possibly your eyes while it's panning in the viewfinder!

Will either of these two things surely happen? Probably not, or at least not immediately. You'll eventually wear out your voltage regulation or just the CMOS circuits over time in the case of "Stupid #1." As far as "Stupid #2," Li-Ion (and even more so, Li-Poly) has excellent, internal logic to regulate, and explosions are rare. So when mixing with NiMH batteries, you're far more likely to just see the NiMH batteries overheat and melt at some point than any Li-Ion explosion. And in most of the worst cases of rechargeable CR-V3s mixed with NiMH, the voltage will drop below 3V, probably even 2.7V as the circuit is being delivered as low as 2.4V from the NiMH (Li-Ion charges at least 4V), and just kill the battery much earlier.

But I still wanted to point these things out. I don't like to "tempt fate" when it comes to touchy CMOS ICs these days, and Li-Ion is the reason why I have an external Li-Poly battery on my notebook instead. Now if you want to have some real fun, we can talk about 7.2V fuel-cell. How hydrogen is getting approved for use at 30,000 feet is beyond me!


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