When it comes to digital photography with Nikon DSLRs I'm always reminded of the saying "reformed, always reforming" . . . just as I get something in my head, I change cameras and struggle to master all the controls on a new one.
I am going through Thom Hogan's D300 book and thinking about 1) exposure metering, 2) AF area mode 3) AF mode: continuous versus single server focus and 4) AF area and how these best relate to UW photography. The problem, it seems to me, is that all these factors are NOT independent in the D300, but one choice in one area may affect your choice in another. I was wondering how other Nikon users use these factors to their advantage (or disadvantage)?
1. Exposure Metering: Matrix versus center weighted versus spot.
It seems to me that Matrix is probably out for underwater use as the database Nikon uses expects topside pictures of some sort. The one exception would be matrix and single area focus mode as the camera heavily weights the exposure towards the single user selected focus area. But it still seems to me that the database might bias the exposure in a way that is unsuitable for underwater . . . yes or no or maybe?
Center weighted seems like a good choice, though as I understand it, the center weight doesn't follow the focus but is a circle in the middle of the focus area. Hence if one moves the focus (single focus mode or in single focus servo) one could move the focus outside the area of the centrally weighted focus area. Or, perhaps one could increase the size of the central weighted focus area from the default of 8.
Spot metering follows the focus point whether fully user selected (single servo and or single area focus) or camera selected (continuous servo or dynamic area focus). This seems like it is the best choice as the camera will meter the subject of the picture in favor of the surrounding area.
2. AF Area mode
Auto area AF seems to be a bad choice for underwater as the camera may have a very difficult time figuring out the subject.
Dynamic Area Autofocus seems to be a good choice, particularly since there is always movement. The camera starts with the user chosen AF point but moves it IF the subject under the chosen AF point moves.
Spot Autofocus: ? bad choice as one has to continually move the autofocus point. Easy on land, hard underwater.
3. Auto Focus Mode: Continuous versus single servo: I have used continuous most often, though in the D200 it ate up the battery, though the D300 seems to be better with battery life. With continuous the camera will decide the actual autofocus point in matrix or dynamic AF mode, I think.
4. AF area. The camera allows for 9, 21 or 51 spots (also 51 with 3D, which takes color into account). Seems to me that 9 or 21 would be the best choice. Any opinions?
So it seems to me - knowing one size never fits all but I like the KISS principle underwater - the best choice would be spot metering, dynamic autofocus, continuous servo, 9 or 21 AF area as a primary choice for macro and perhaps center-weighted, dynamic auto focus, continous servo, 9 or 21 AF area for wide angle.
Thoughts? Thanks in advance. This stuff makes my head hurt sometimes.
Steve Dingeldein