Excerpt: I already own the DA* 60-250 and found that I wasn't getting the reach needed to capture birds in flight as well as other wildlife. I found this lens by chance on my local craigslist. At the price paid, I couldn't argue.
Excerpt: As I already owned a FA*600, and a DA*300 I bought this lens for a dedicated mission : an hand-holdable, lightweight lens for travel, birds in flight, and tricky approach of birds, with more reach than the DA*300 and better than a DA300 + a converter. It met 90 % of my expectations.
Pros: Sharpness stopped down, light and compact
Cons: CA, autofocus hunts sometimes, price on second hand market
Excerpt: As a 400mm lens, this is small and hand hold able. It is about the same size as DA*300/4. Image quality is excellent, but DA*300/4 is still a little bit sharper at f/5.6 and if you crop the image from DA*300/4 to the same size as from FA*400, it is difficult to see any difference.
Excerpt: The lens is quite light and very sharp when used at high shutter speeds or very secure tripod mount at lower speeds. It doesn't have the build quality of * lens, but the optical quality is in the same league.
Excerpt: This lens is very sharp and relatively light weight for its length. It is about as long of a lens for the 645D as I'd typically travel with (the length starts chewing up limited storage space in a backpack).
Excerpt: I recently bought this lens second hand to use with an adapter on my Pentax K-5 and I must say it does not disappoint. It is lightweight and can be handheld though it can be hit and miss even with the anti-shake as it equals 600mm on a fullframe equivalent.
Excerpt: This lens looks enormous when complete with its large lenshood but is surprisingly light for its size. It is very sharp at f5.6 and remains so until at least f16. However extreme care is required to get sharp images due to shake/vibration etc even when mounted on a good strong tripod.