if i were to buy a Dynax 7D... IF!

[Magnus Wedberg]

It's got to do with the chemistry of the batteries... Lithium is the 3 element in the periodic table. It is very very light and small. For the same size of battery, u can pack more lithium ions (i.e. the charge carriers), hence the capacity is greater than either Ni-Cd, Ni-MH or alkaline batteries (which are actually zinc-carbon batteries).

You actually make even less sense ;-) The NP-400 is 1500MAh. A normal set of AA Ni-Mh is 2300MAh. This isn't chemistry, it's basic electronics. AAs have the (much!) higher capacity as well as only slightly lower voltage (7.2 compared to 7.4) so why should the AAs last /shorter/?

 

[UY79]

You actually make even less sense ;-) The NP-400 is 1500MAh. A normal set of AA Ni-Mh is 2300MAh. This isn't chemistry, it's basic electronics. AAs have the (much!) higher capacity as well as only slightly lower voltage (7.2 compared to 7.4) so why should the AAs last /shorter/?

The only reason I see is that AAs voltage might fall faster than NP-400 during use. In that case, even with higher capacity, it might not have enough voltage to power the body.

 

[Zerstorer]

I think so.... Energiser has lithium AAs and I'm quite sure that they are rechargeable... they come in a blue packaging as opposed to the silver for the titanium series, green for the Ni-MH series and red/black for the alkaline series....

Those are non-rechargeable lithiums. Have you seen a rechargeable lithium cell with a voltage less than 3Vs?

The chemistry of the 1.5V AAs are not the same as the rechargeable ones that come in voltage mulitples of 3V+.

 

[TME]

You actually make even less sense ;-) The NP-400 is 1500MAh. A normal set of AA Ni-Mh is 2300MAh. This isn't chemistry, it's basic electronics. AAs have the (much!) higher capacity as well as only slightly lower voltage (7.2 compared to 7.4) so why should the AAs last /shorter/?

The miiliamp rating alone is not sufficient to explain the life of a battery: You've got to factor in internal resistance and size of battery.

The NP-400 is of a larger volume (my estimate) than 6 AA NiMH which also suffer from greater internal resistance due to having 6 different points of contact.

So while the AAs have higher ratings, they spend more of that energy pushing against higher internal resistance, leading to a loss of energy and hence shorter battery life.

This is what I think... may not be true....

The part about packing in more lithium is true for same size comparison. Which is why lithium AAs from Energiser last longer than NiMH AAs from the same company... I forgot that the NP-400 is larger and that it has a lower rating...

 

[TME]

http://en.wikipedia.org/wiki/Lithium_ion_battery

http://shop.store.yahoo.com/greenbatteries-store/libafa.html

These might help...

 

[TME]

Those are non-rechargeable lithiums. Have you seen a rechargeable lithium cell with a voltage less than 3Vs?

The chemistry of the 1.5V AAs are not the same as the rechargeable ones that come in voltage mulitples of 3V+.

Yes I realised that after posting.... :embrass: the much higher voltage is a factor I guess...

 

[UY79]

http://en.wikipedia.org/wiki/Lithium_ion_battery

http://shop.store.yahoo.com/greenbatteries-store/libafa.html

These might help...

From the second link:

Are Lithium Ion batteries available in standard sizes like AA , C or D cell size?

No, Lithium-ion batteries are not available in standard sizes. We believe this is because it would be too easy for users to inadvertently put them in a charger not designed for Lithium-ion batteries creating a potentially dangerous situation. (If an alkaline battery is put into the wrong charger it might leak or even burst, but a lithium-ion battery put into a NiCd or NiMH charger not designed for lithium-ion, might ignite. Also, because Li-ion batteries operate at much higher voltage (typically 3.7V per cell) than the 1.2 to 1.5V of most cell batteries, designing a 1.5V lithium-ion cell would be expensive.

So there are no Li-ion rechargable AAs.

 

[Magnus Wedberg]

The miiliamp rating alone is not sufficient to explain the life of a battery: You've got to factor in internal resistance and size of battery.

The NP-400 is of a larger volume (my estimate) than 6 AA NiMH which also suffer from greater internal resistance due to having 6 different points of contact.

Li-Ion has (typically) higher internal resistance than Ni-Mh (which in turn has higher internal resistance than Ni-Cd). The contact points are unimportant; they can only impact /external/ resistance, in practice lower voltage or give bad contact, but the /internal/ resistance is how much current the cell can deliver in a specified time, and the contacts have nothing to do with that.

Li-Ion and Ni-Mh also have quite similar discharge curves. No, I'm pretty much convinced that the Minolta numbers are "marketing" ones designed to sell more of those super expensive NP-400 packs...

Recommended reading: http://www.batteryuniversity.com/

 

[TME]

Li-Ion has (typically) higher internal resistance than Ni-Mh (which in turn has higher internal resistance than Ni-Cd). The contact points are unimportant; they can only impact /external/ resistance, in practice lower voltage or give bad contact, but the /internal/ resistance is how much current the cell can deliver in a specified time, and the contacts have nothing to do with that.

Li-Ion and Ni-Mh also have quite similar discharge curves. No, I'm pretty much convinced that the Minolta numbers are "marketing" ones designed to sell more of those super expensive NP-400 packs...

Recommended reading: http://www.batteryuniversity.com/

I see... hmm.... it would be pretty expensive to experiment no?

 

[TME]

From the second link:

Are Lithium Ion batteries available in standard sizes like AA , C or D cell size?

No, Lithium-ion batteries are not available in standard sizes. We believe this is because it would be too easy for users to inadvertently put them in a charger not designed for Lithium-ion batteries creating a potentially dangerous situation. (If an alkaline battery is put into the wrong charger it might leak or even burst, but a lithium-ion battery put into a NiCd or NiMH charger not designed for lithium-ion, might ignite. Also, because Li-ion batteries operate at much higher voltage (typically 3.7V per cell) than the 1.2 to 1.5V of most cell batteries, designing a 1.5V lithium-ion cell would be expensive.

So there are no Li-ion rechargable AAs.

Yes it would seem so.... so we have to stick to Ni-MH...

 

[Del_CtrlnoAlt]

hmm how do you guys justify to your parents or gf that buying a DSLR is worth it? cos i have been changing camera almost once a year, from F717 less than 1/2 a year upgrade to F828, now going to get Dynax 7...

btw how much do you guys normally say the Dynax is worth? den the lens?

 

[deslim27]

hmm how do you guys justify to your parents or gf that buying a DSLR is worth it? cos i have been changing camera almost once a year, from F717 less than 1/2 a year upgrade to F828, now going to get Dynax 7...

Show them your picture.. if good, tell them it can be better if your have a DSLR.. if bad, put the blame on the camera's limitation, and tell them DSLR doesn't have those limitation.. :bsmilie:

btw how much do you guys normally say the Dynax is worth? den the lens?

Don't understand your question..

 

[downhere]

Hi I'm also looking to buy a Dynax 7D. Don't need to explain much really to your parents. Just bring them to CP or AP and show them side by side a 20D and a 7D. The feel and view of a 7D is way superior. I know. I'm trying to earn money for one.

View my website at Questions Answered for 7D

Haha we're in pretty much the same predicament.

I've done some lithium battery research before. Basically I would reccomend this. For flash, Ni-Cd will give you the fastest recharge times. For camera user Li-ion over Ni-Mh because Ni-Mh and Ni-Cd tend to lose charge quickly over time. Li also got higher energy density. The current draw of the camera is not very high, almost insignificant. I think if you compare the 7D and a Gameboy Advance SP, the gameboy definitely draws more current than the 7D, but it can survive on a smaller battery.

 

[sulhan]

Hi I'm also looking to buy a Dynax 7D. Don't need to explain much really to your parents. Just bring them to CP or AP and show them side by side a 20D and a 7D. The feel and view of a 7D is way superior. I know. I'm trying to earn money for one.

View my website at Questions Answered for 7D

Haha we're in pretty much the same predicament.

I've done some lithium battery research before. Basically I would reccomend this. For flash, Ni-Cd will give you the fastest recharge times. For camera user Li-ion over Ni-Mh because Ni-Mh and Ni-Cd tend to lose charge quickly over time. Li also got higher energy density. The current draw of the camera is not very high, almost insignificant. I think if you compare the 7D and a Gameboy Advance SP, the gameboy definitely draws more current than the 7D, but it can survive on a smaller battery.

Hiee Pals...

Well....with the presence of modern power management circuits like the buck/boost converters to step up and step down voltages and current control circuits.....Electronics devices gets to benefit by being able to stay longer on one single charge....low loss converter circuits nowadays has brought the consumer electronics very very far from those early generations....with better battery life....

Thanks to those circuit designers....

rgd,
sulhan

 

[-7-]

Hi I'm also looking to buy a Dynax 7D. Don't need to explain much really to your parents. Just bring them to CP or AP and show them side by side a 20D and a 7D. The feel and view of a 7D is way superior. I know. I'm trying to earn money for one.

View my website at Questions Answered for 7D

-OT for awhile-

:thumbsup: U r the man, Mr. DownHere... if some media guys see ur URL, sure u'll b famous and on the News

Cool guts u have, no joke.... actually, where do u get the idea of generating the fund from public through net huh?

 

[TME]

So downhere... did u get any money for your 7D?

Actually NSF pay these days quite decent... I remember I could save up enough for a fuel-powered R/C car when I was just a private (or corporal).... allowance those days was like $300.... and I gave my dad $50 each month...

These days if u are a specialist u get at least $500.... if u really passionate about photography and really save hard, (like $1/2 your allowance each month), u'll get to save enough in no time... that means, eat cookhouse for all meals, get haircut by SAF barber, dun book out except for weekends, no movies, no meals out, no entertainment for this period, dun use handphone except where necessary, no shopping, take only bus or MRT, no taxis, etc.... saves quite a bundle... trust me, I've been there before....

It can be done... anyway, what digicam did u buy? Why does it not suit your needs?

 

[ratboy]

So downhere... did u get any money for your 7D?

Actually NSF pay these days quite decent... I remember I could save up enough for a fuel-powered R/C car when I was just a private (or corporal).... allowance those days was like $300.... and I gave my dad $50 each month...

These days if u are a specialist u get at least $500.... if u really passionate about photography and really save hard, (like $1/2 your allowance each month), u'll get to save enough in no time... that means, eat cookhouse for all meals, get haircut by SAF barber, dun book out except for weekends, no movies, no meals out, no entertainment for this period, dun use handphone except where necessary, no shopping, take only bus or MRT, no taxis, etc.... saves quite a bundle... trust me, I've been there before....

It can be done... anyway, what digicam did u buy? Why does it not suit your needs?

Volunteer to get posted to Brunei for 6 months
High allowance, no place to spend
( if you don't gamble )
come back rich .....

further plus point... there very photographic scenery
every morning got foggy/misty fields

 

[TME]

Volunteer to get posted to Brunei for 6 months
High allowance, no place to spend
( if you don't gamble )
come back rich .....

further plus point... there very photographic scenery
every morning got foggy/misty fields

Dude, that is IF your unit can send you to Brunei.... and IF they have a need...

 

[downhere]

Yeah well.. I'm trying to earn on the side lah. No money yet. Decision is very much 7D for a user friendly cam ( I personally like manual controls, and I hate clicking menus.. looks really unprofessional and time wasting.) and 20D for a studio cam. Don't know which type of photography I'll do more.

I'm 1k away from a 7D. so it'll take 2-3 mths of NS (I'm a corporal) to get the money. And I'll miss the interesting christmas season which 7D will be damn useful for. Also Dec is the uni break so my friends can help out in studio shoots.

I might just shoot more film. It's served me well so far anyway.

Anyway NS not the place to make money lah. It's definitely serve country thing. I haven't made ANY money yet. So not much hopes lah.

Idea is not mine lah. Girls always post their wish list on amazon and some guys actually buy them stuff. Thought some ppl might wanna donate lor. Like if Bill Gates or something visits my site.

The best way to get minolta stuff is to work for KM at Sitex lor. 4 days should get enough for the new 17-35 I think. If they pay commission, I think getting a 7D also quite possible. Too bad I'm going overseas. Can't even visit Sitex.

 

[Flare]

Yeah well.. I'm trying to earn on the side lah. No money yet. Decision is very much 7D for a user friendly cam ( I personally like manual controls, and I hate clicking menus.. looks really unprofessional and time wasting.) and 20D for a studio cam. Don't know which type of photography I'll do more.

I'm 1k away from a 7D. so it'll take 2-3 mths of NS (I'm a corporal) to get the money. And I'll miss the interesting christmas season which 7D will be damn useful for. Also Dec is the uni break so my friends can help out in studio shoots.

I might just shoot more film. It's served me well so far anyway.

Anyway NS not the place to make money lah. It's definitely serve country thing. I haven't made ANY money yet. So not much hopes lah.

Idea is not mine lah. Girls always post their wish list on amazon and some guys actually buy them stuff. Thought some ppl might wanna donate lor. Like if Bill Gates or something visits my site.

The best way to get minolta stuff is to work for KM at Sitex lor. 4 days should get enough for the new 17-35 I think. If they pay commission, I think getting a 7D also quite possible. Too bad I'm going overseas. Can't even visit Sitex.

You know... have you ever thought of selling your photos?