> Date: Sun, 29 Nov 1998 12:24:37 -0800 (PST)
> From: Rolland Elliott <[EMAIL PROTECTED]>
> Subject: Why does anyone need a 28-70mm AFS lens? [v04.n141/2]
> Message: 2
>
> What applications and subjects would justify the use of a 28-70/f2.8
> AFS lens? Does anyone really need a silent wave motor at these focal
> lengths? At two to three times the cost of the current version?
> Maybe I'm just being pessimistic, but I don't think this new lens is
> going to focus that much faster then the old versions made by Nikon
> (or Tokina or Sigma), expecially on a professional body like the F100
> or F5. And as far as noise is concerned doesn't mirror slap and the
> motor drive cause a lot more noise then the AF motor?
>
Rolland,
I think there are a couple different issues buried/entangled in
your paragraph above.
First, let's just examine the technology -- AF-S, or "Silent Wave"
motors in the lens. It provides several improvements over the
screw-driven lenses;
o Speed. Most people fixate on this, for obvious reasons.
o Silence. Yes, things like mirror movement, shutter movement,
and film advance all also contribute to the overall "noise" of
taking a picture. Reducing the total noise output -- which is
very desireable in many different applications -- can be achieved
buy reducing each of the contributors in turn.
So, Nikon has been working on ALL those factors: we heard the
mirror box was redesigned in the F5 to reduce vibrations; we
see that there is some sort of "floating mechanism" in the F100
to reduce (shutter?) noise; the pro cameras have an additional
film advance and rewind mode for more "silent" operation; and
now AF-S quiets the AF. All these things taken together make
a great improvement in the quietness of operation.
o Instant MF-override. As great as AF technology is today, and
that includes all the multi-spot AF sensors that exist in the
F5, F100, and several EOS bodies, sometimes you need to grab
the reins - so to speak - and say, "NO! Focus HERE!"
If you're not in a hurry, the button/clutch mechanism Nikon uses
on some of its lenses is okay. But if every millisecond counts
as a once-in-a-lifetime event unfolds before your lens, *I*
certainly don't want to be fumbling with the clutch ring (on the
1-touch 80-200/2.8, it's a real PAIN, and we've already discussed
here that there is a lag in engagement when switching between the
two modes) -- I just want to reach out, grab the focus ring, and
take the picture. It's that simple w/ AF-S.
o Battery consumption. I don't have the numbers to prove it, but
my gut reaction is that the motor in the lens sucks less power
than the screw/gear mechanism ... more obvious w/ longer lenses,
but I would suspect even a mini-beast like the 28-70/2.8 will
benefit.
Now, none of this has anything to do with the COST passed on to
the consumer. The word "justify" you use probably takes into account
this factor, and each person will have to decide for themself. This
particular lens is probably a great PJ lens for its focal length;
but it is made even more valuable by the benefits listed above,
thanks to AF-S (if I were to rank them highest to lowest importance,
it would be Instant MF, Silense/Speed, battery). But that's only
my guess as I'm not a PJ.
I'm gonna save my pennies for it (and the F100) simply because it's
QUIET. My fiancee' has an EOS A2 and several USM lenses. The ONLY
thing I covet is the wonderful near-silence with which she can take
pictures (on the EOS digest there was a discussion about this recently,
and many folk believe the A2/5 is the quietest AF SLR out there).
I've rambled a bit. I'm not trying to convince you, Rolland, that
this is the technology for you. But I firmly believe it is quite
valuable to a wide range of pros, and desireable to even more.
Regards,
Chris
--
| Chris Somers
Want to make God laugh? | Rise Technology
Tell Him your plans. | www.rise.com
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