On May 19, 2005, at 7:50 AM, Derby Chang wrote:
A few weeks ago, I noticed that the istDS AF did funny things in low light with my 85mm/f1.4. Occasionally, the camera wouldn't fire, even though I thought it was in focus (on a manually selected zone). It wouldn't even bother to hunt. A little while later, it would be fine. And then it would hunt on a perfectly brightly lit zone. I thought this was because of the lens.
Tried it with the 77mm LTD tonight. Worked fine for most of a 1GB card, then started doing it on the second card.
D'oh. I think I know what it is. Once the batteries are partially depleted, and even though the rest of the camera fires fine, the AF seems to be a bit sensitive to the power levels. Of course after a while the batteries recover if I go for a while without shooting.
I'm using two sets of Sony 2300mAH NiMH's. I think I might buy a few more.
NiMH batteries seem to have somewhat variable power delivery characteristics under load. I use them too (Power2000 2400mah AAs), but I always keep a set of either CRV3 or AA Lithium disposables in my bag as backup.
I'm considering carrying just the AA lithiums for my upcoming trip ... four-five sets will cost me $40, last 1000-1500 exposures each, and the package will be both lighter and smaller than two sets of NiMH AAs plus a 1.5hour fast charger setup. It will also get smaller and lighter as the trip proceeds.. and not having to worry about or fuss with recharging would be a bonus. I could get more while enroute as well.
5000 exposures should be enough for a three week trip, ya think? !!!
Godfrey
