Dear Mr. Backyard Exmoor Mechanic WhoWhipsALot
I have frantically searched for an answer to a mystery. Every time I utilise the outer left autofocus sensor of my tool I seem to nail focus. I am getting very nervous over this because it happens even if my target lurkes in an less than optimally lit situation...say a back yard.
Can you enlighten me on this issue? Will a pure magnesium target help or is polycarbonte, a.k.a. plastic, be better?
The other reason I write you is that I'm planning to buy another lens. Two options are emerging, one is a beautiful all magnesium alloy 500mm f/5.6 catadioptric type lens hand made in Japan, the other is a 500mm/f/4 true apochromatic Canon lens from a factory just opened in Thailand. Although the latter will probably suit my needs best, my concern is that the lens made in Thailand, with its polycarbonate/kevlar outer shell, will be inferior due to lack of skilled workmanship.
Please exmuse me if you find this too trivial to answer but I ass ure you, any reply from you will be highly appreciated...so to speak.