It did give them time to tweek their marketing approach for sure (focus on weight, F8 AF, etc).
I certainly noticed that Nikon is highlighting the f/8 AF ability. But...I'd be very interested to know exactly how they implemented this. From the published information: "...the D4 maintains the power of the eleven central AF sensors, including one cross-type even if the combined open aperture value is f/8.
There are two possibilties:
- It's the sensor. They redesigned their 51-point sensor to include additional sensor lines for the f/8 AF, such that the center point is an f/5.6- and f/8 dual cross-type sensor, and the other 10 points have additional f/8-sensitive line sensors. Canon's previous 1-series bodies had a unique center AF point which had a dedicated f/8-sensitive single-orientation sensor.
- It's a firmware implementation. We know that Canon bodies which are limited to f/5.6 will try to AF and sometimes even do reasonably well with an f/8 combination that has pins on the TC taped (or a non-reporting 3rd party TC). Likewise, 3rd party f/6.3 lenses seem to AF ok on the f/5.6-sensitive sensors. So, Nikon may have simply tested the AF performance of lenses slower than f/5.6 on the D4, and enabled those points which gave decent results to AF with slower lenses.
Personally, I'm almost positive it's #2. The subsequent statement in their announcement was: "If the combined aperture value is between f/5.6 and f/8, you even have the power of fifteen central AF sensors available, of which nine are cross type sensors.
" I highly doubt the AF sesnor has individual points of differential sensitivity, such that the center cross point has additional f/8 lines, and the surrounding 8 crosses have additional f/7.1 lines or something like that.
Rather, it sounds like they saw the 1D X announcement with the lack of support for AF, tested the D4 models in development, found that they could get away with implementing f/8 AF for some of the points, slightly-wider-than-f/8 for a few more, and altered the firmware to make those points active with an f/8 lens attached. Unlike redeveloping the AF sensor, that
is something that could easily have been implemented for the D4 in the short time since the 1D X was announced (as could the H3/H4 ISO bumps).
More importantly, if Nikon's f/8 AF is a firmware implemetation using existing f/5.6-sensitive AF points, it's very possible that Canon could test and then implement something similar, even prior to the actual release of the 1D X. Perhaps not the same number of AF points, but at least some support for f/8 AF. Then again, even if they can
...will they? Previously, it made sense as a marketing strategy to drive people to buy longer lenses. But, from a competitive standpoint, matching Nikon's announced and touted f/8 AF capability may be more important...