My EOS 3 seems to get through about 30+ rolls of film when I am using it with 8 AA Alkaline batteries and my 300mm f4 IS lens - I am quite happy with this. When I put the 500mm f4.5 + 1.4x TC on i struggle to get 4 or 5 36 exposure rolls through it. This is usually using one-shot not AI servo and a mixture of manual and AF. Is this normal? Any advice on how I can extend battery life or do I just have to keep paying out? Is it worth getting rechargeable batteries?

TIA

-- Andrew Hardacre (andrew@jhardacre.freeserve.co.uk), September 28, 2001

Answers

Much bigger piece of glass to move around, more work required, hence less battery life.

-- (ratzlaff@ticnet.com), September 28, 2001.

Sorry, itchy trigger finger.

Try Nimh, Nickel Metal Hydride, rechargeable batteries (1.2 volts though, like NiCads, but last longer and much less memory effect than NiCads).

-- (ratzlaff@ticnet.com), September 28, 2001.

Another point to consider is the MF system. The 300 F4 IS has a true mechanical MF, whereas the 500 F4.5 uses the (now defunct) "original" FTM system, where the focus ring controlled the motor for MF. Thus MF is now putting a drain on the batteries also.

However, I'd check this out, because IS is well known for using battery power. Make sure you do the test with the same kind of batteries, in the same conditions (esp temperature).

-- Isaac Sibson (isibson@hotmail.com), October 04, 2001.

Maybe my trials will be over on Saturday as I have bitten the bullet and the 500mm f4.5 gets traded in for the 500mm f4 IS version. I am also going to see how much benefit I get from lithium batteries.

Andrew

-- Andrew Hardacre (andrew@jhardacre.freeserve.co.uk), October 04, 2001.