All that being said, the '468-II has been easy to use and certainly powerful enough for my needs. It's a TTL flash, but not "iTTL"..
FWIW, if it does automatic TTL on a current Nikon DSLR, it definitely is always iTTL. Nothing else can work. Todays Nikon digital camera only does iTTL.
What the 468 seems to do is TTL instead of TTL BL metering mode (which the camera meters this way, the flash does not meter it, but apparently some flash firmware triggers one mode and some the other). In contrast, the 565 does TTL BL on Nikon. These two work differently (that is to say, the camera meters them differently).
(I do know better than to continue, since no one today wants to know anything, but I tend to enjoy details)
History has made the terms be really confusing, TTL has at least three meanings now.
Meanings in this way:
For Nikon: (Canon has different names and different systems)
TTL means
Through The Lens metering. not necessarily even flash metering. It is a general term, meaning meter sees the same view and area that the lens sees. For flash, it also means automatic point&shoot flash.
Film camera TTL was this automatic metered flash system, metered though lens (as opposed say to Manual flash mode).
First Digital models (D1, D2, etc) required big changes, called D-TTL
Subsequent digital models revised and improved and now do iTTL.
All are different, all are incompatible with each other. All are automatically metered flash, all are generally called TTL (Through The Lens metering), but film TTL, and D-TTL and iTTL are all very different and incompatible systems.
But yes, current iTTL digital does generic TTL
Through the Lens metering of flash.
In fact, iTTL TTL has two metering modes,
TTL and TTL BL (metering is done by the Nikon DSLR camera).
This TTL metering mode meters the flash without regard to any ambient. If in bright sun, then you get two proper exposures, sun and flash, so when added at the sensor, the subject is overexposed one stop (2x). We know to set about -1.7 EV flash compensation then, for it to turn out well. Indoors in dim light, no such concern.
TTL BL takes the bright ambient into account automatically, and in bright sun, TTL BL does that compensation automatically, and will back off the flash power maybe 2 EV, or it comes out about right automatically, without our manual compensation (called Balanced Flash). Automatic compensation (due to ambient). We can still also manually use Flash Compensation too, when necessary tp tweak exposure.
Some Nikon flashes (SB-600, SB-800, SB-900) have a menu to select TTL or TTL BL. Nikon is a TTL BL system, but a TTL menu can override. Spot Metering also overrides, changing TTL BL to be TTL.
The menus all say TTL generally, but they mean iTTL today, and may mean TTL or TTL BL.
Flashes like the SB-700 or SB-400 have no menu like that. Their TTL menu setting only causes camera to meter TTL BL by default (unless Spot Metering, which is TTL then). Also the camera internal flash TTL mode is TTL BL, also the Commander TTL menu is TTL BL (unless Spot metering, which is TTL).
So either of TTL and TTL BL (metering modes) may be selected by a TTL menu (general automatic flash) which will do iTTL (current digital DSLR).
It can get confusing, and maybe we are not interested, but regardless of our interest, we certainly can get very different flash results depending on this mode our flash will cause. It is good stuff to know what is going to happen. I would say that indoors, TTL BL often routinely needs +1 EV flash compensation to avoid being too dark. TTL probably does not. Either way, we have to watch, and do what we see we need to do.
