Cost is always a consideration, and I've attempted to keep mine low
by NOT buying camera brand lenses. Tamron, Vivitar, Sigma have always
made good "third-party" lenses, Vivitar the oldest among that group,
I think. Tamron's 500 mirror is as good as or slightly better than
the Nikon of that era (according to Pop Photo review), and at half or
less the cost AND weight, at the time. During the SLR period, I never
tried Canon, opting first for Mamiya-Sekor and Olympus for film, then
Nikon for film, and being on limited budget, staying with low-end
Nikon digital D70... I started out in wildflower hunting and
photography, so wanted macro capability, which led to my choices.
I've found a smaller lens to be "best" of all worlds for most bird
photography, the heaviest of the small ones I've used being the 400mm
Sigma macro (5 ft min focus, at 3 lbs). Rarely even used its auto-focus
mode, since birds tend to not be the only thing in the view-finder...
I've used "macro" lenses since 1980 for both film and now digital
(their built-in 1.5x approx. multiplier factor a real boon), except
for the fairly recent acquisition of older version of Nikon 600, a
"slow" lens at 5.6, and close focusing to "only" 15 feet, but at a
quarter or less the price of the MUCH heavier and MUCH costlier f4
with auto everything... except auto intelligence! I bought Tamron
300mm 5.6 and 500mm 8.0 (mirror), both macros (4 ft and 6 ft min.
focus respectively), when they were "new" around 1980. I still use
them; still as sharp as the day I bought them. The Sigma I got in mid
1990's, but weighs more than the other two combined (around 3
pounds). Before there was image stabilization, I discovered that
removing center post from an old tripod, attaching to camera (or
lens, depending on how I wanted to balance it), then supporting the
post in my armpit (or across or under my forearm, now my preferred
method) gave me much better low-shutter speed capability, as well as
INCREDIBLE stability while following flying birds, since at least one
of the vibration angles is reduced to near zero while panning
[horizontal], the other [vertical] can be much reduced with the
tripod-post-arm... Secondary advantage is the ability to set it on
ground and by lying down and using elbows, make it as stable as if on
a 4-point tripod, or sitting on ground, rest it on knee and stabilize
it with arm to focus. Practice is the key - 30 years has made me more
comfortable with this than pushing a 5-10 pound tripod around,
limited by its height and distraction spent changing angles while
pan-focusing. I don't have to think about the tripod-post since it's
essentially an extension of my right arm, and if bird is not moving
and I can't at least sit down and use knee as brace, once focused, I
can brace the locking handle with my left hand and hip and fire
away...(the handle is reversed so it sticks out front, rather than
towards me as it would on tripod). And, the weight savings can allow
a one-pound flash unit to be attached for fill flash... I've been
able also to use a 600 5.6 manual Nikon lens, hand-held (!!!), to
shoot flying and stationary birds using my Konica-Minolta 7D, bought
for its internal IS... The whole arrangement weighs less than a good
tripod - but nothing beats a tripod for those super-sharp shots of
moderate to long distance objects... Anyway, the tripod-post (with or
without IS camera, and even with 600mm lens) is FAR superior to
expensive or jerry-rigged gun stock gadget, which limits the stable
point to the shoulder, assuming you have a large pectoral muscle to
brace it against which I do not, and it has no other limiting
factors, like having to have a trip release attached to forward
over-large handle... I can send anyone who's interested a couple of
photos of what I developed using the old tripod-post, showing the
400mm and Konica-Minolta [hence IS, with flash], all under 5
pounds... Hope this helps - Jim Greaves, Thompson Falls MT