Hi,
I did some research but still some things remain opaque. From K-5 II(s) news-release:
Quote: The K-5 II features a newly developed, highly sensitive SAFOX X AF module. Thanks to the unit’s high-sensitivity AF sensor, which performs brilliantly in low-light conditions, this new module offers a broad AF working EV range (-3 EV to +18 EV). SAFOX X can work with luminous flux based on F2.8 levels in addition to that of F5.6. This increase the AF accuracy drastically when using with very fast lenses coupled with an upgraded AF algorithm, it delivers exceptional AF performance, including such useful features as a select-area expansion function, which automatically tracks the subject even when it moves away from a pre-assigned select point by assessing distance data collected by neighboring focus sensors.
1.
new module offers a broad AF working EV range (-3 EV to +18 EV)
- Does the range depend on the brightness of lens used? I mean, having 1.4 or 4.0 lens which one will focus at -3EV? Another question is T-value. If, for example, one is has T/2.9 and another is T/3.2 (both marked as f/2.8) will the first one focus better in dim light?
2.
SAFOX X can work with luminous flux based on F2.8 levels in addition to that of F5.6.
- as I understand, new, bigger and brighter lenses are used in new AF module. Is it true? If not what does it mean physically? Why does it mean that only 2.8 and faster lenses will gain some benefit (I read it more than once on the forum)? Wouldn't all lenses gain some benifits because now AF system uses more light (or more sensetive sensors)? Will it increase the range of usable apertures from f/8 to, say f/11? Which AF points got the improvement (center, 5, 11) compared to K-5 AF?
3. i
ncluding such useful features as a select-area expansion function, which automatically tracks the subject even when it moves away from a pre-assigned select point by assessing distance data collected by neighboring focus sensors
- is that feature for AF-C only? Say, if I use AF-C with automatic AF point selection, why if 'subject moves away form pre-assigned' don't just use another AF point? Am I right in understanding that the feature works only for AF-C plus single AF point mode?
I do believe that the new AF system is better in practice, what I want is understanding of technical details and help in decrypting that quote from news-release.
Thanks in advance.