AFAIK the 400FTZ _does have_ a zoom head, as the Z letter in the FTZ
code implies.
Zoom head in flash means just that: that you can make the beam of
light wider or narrow, by pushing/pulling the head, or by means of a
button (if it's motorized zoom). OTOH, non-zoom flash emits always a
fixed beam of light, most usually to cover field of view of a 35mm
lens (with pentax it's wider in flashes like 280T and 400T, covering a
28mm lens). Of course snap-on adapters exist for almost any non-zoom
flash to make the beam wider or narrow.
Usually in modern flashes the motorized zoom head zooms automatically
when you zoom the lens (if it's an autofocus lens which can tell the
body what focal length it is currently).
Of course when you make the beam of light narrower the intensity of it
increases because a fixed power gets distributed to a smaller area. In
other words, if you photograph with a 100mm lens, and the flash's beam
covers field of view of a 28mm lens, lots of light gets wasted around.
However, this wasted light usually bounces of the room's walls filling
up shadows and making the illumination more pleasant on the
photograph (sometimes).
Therefore, when e.g. a flash is zoomed to 100mm it gains about 0.5-1
f/stop of light output over a zoomed to 35mm.
However, there are certain things to remember:
1) flash makers are LIERS. They state the GN (guide number = maximum
light the flash is able to output) for zoomhead flashes ONLY for the
MAXIMUM zoom head position! That's like if a car maker stated that
their car eats only 2 liters of gas per 100km, but forgot to mention
that on average, it eats 5 liters...
Therefore, comparing GN of zoom flashes with non-zoom flashes is
difficult. E.g.: 550FTZ has GN of 55(m) or 165(feet). Sunpak 3600DX or
Vivitar 285 have stated GN of 36(m) or 102(feet). That would seem that
the Pentax is much more powerful. Bulls**t! The Sunpak and Vivitar are
both non-zoom flashes and their GN is stated for 35mm lens coverage,
while the 550FTZ is stated for much more narrow beam, for 105mm
coverage. Actually, the 550FTZ is about similar in power as both these
flashes (or even slightly less).
Another example: AF330FTZ is stated at GN 33(m) or 99(ft). It would
seem it's just as powerful as the Vivitar and Sunpak mentioned above.
Bulls**t! AF330FTZ's GN is stated at maximum zoom, that's about 85mm or
so. If zoomed back to 35mm coverage, the GN would be around 20(m) or
60(ft)!!! That's lot less. Also the Pentax AF280T (non-zoom) is stated
at GN28m at 28mm coverage, so it's in fact more powerful than the 330FTZ...
The same goes on in Minolta,Nikon,Canon... all are artificially
inflated in their advertising and specs. Even Metz does this, but Metz
is more honest in their rating (instead of stating GN at maximum zoom,
they state it at 50mm zoom... However, the long accepted industry
standard was GN is measured at 35mm coverage).
So the stated GN doesn't matter much, the real GN at normal 35mm coverage is
much more useful.
The 400FTZ should have high enough real GN, probably about 30(m) or
90', that's only slightly less than 550FTZ.
2) Flash bouncing. I almost never shoot direct flash, I always (95%)
bounce it from ceiling or wall, as it makes much much more natural
looking photographs, without the red-eye and hot-skin, black shadows and other
unpleasant "flash was used" effects.
Therefore, zoom head is almost completely useless for me, as when
bouncing flash, one usually selects a wider coverage to have more
pleasant light as well. In bouncing flash, the most useful is raw
power at wide coverage setting.
The only occasion when I do direct flash is
a) I don't have any ceiling or walls near (like outdoors) - not
much.
b) I do fill-in flash. But for fill-in flash, I almost never use
full power, so I don't need the increase in power the zoom head
gives me at maximum zoom as I rarely use more than 1/10 of the flash power
for one burst.
***
As you see, lack of zoom head is almost no disadvantage, if all other
things equal (you can always put a wide or tele adapter on the
non-zoom flash yourself and have exactly same effect, ie increase of GN
with tele adapater/decrease with wide adapter).
The most important features to choose flash by are, IMO:
1) Tilt and Swivel (for bouncing the flash off walls or ceiling)
2) real GN (at normal coverage of 35mm or near it)
3) digital features if you have modern AF body (=AF asssist, etc...)
A flash with high GN but no ability to tilt or swivel it is imo
completely useless for oncamera shooting.
A flash with only tilt but no swivel is almost completely useless for
portrait orientation of the camera (verticals), as you can't bounce it
off ceiling (your only hope would be to find a nearby wall to bounce
it from wall, but that would make the direction the light comes from
change EVERY time you change from vertical to horizontal orientation,
UNPLEASANT in a series of photographs)
As I don't have any AF camera, I don't need digital features, just
plain TTL.
As you have an AF camera, I would go for a flash with digital
features, T&S, and reasonably high GN, which is (in Pentax) ONLY the
400FTZ or 550FTZ. The 330FTZ is useless as you can't bounce it. the
280T would be good but it's not digital (you could use in only in
plain TTL mode, nothing like second curtain synch etc.).
Or you could choose a Metz 32MZ or 40MZ which both have T&S, digital
features and reasonable GN (at least the 40MZ, the 32 is weaker as
it's real GN is around 24(m)), but I doubt you would be able to find
the 40MZ at any price close to the 100$ for 400FTZ (it usually goes
for around 1.7 - 2x as much here)
. Sunpak makes some pretty powerful flashes, including superb models
with TTL, T&S, and really high GN of 36 (at 35mm coverage!), which is
as high as hotshoe flashes go (no hotshoe flash I know has higher
GN than 35-38 at 35mm coverage, including the nikons and canons), but
unfortunately, all the sunpaks offer only plain old TTL without any
digital features.
Hope this helps :)
Also, please bear in mind this is my opinion, depending on my flash
usage. Others' mileage may
vary.
Frantisek
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