A 400 mm lens is one of the most useful longer telephoto lenses.
It's ideal to photograph wildlife and larger birds. It has a size and weight
that still allows you to handhold it if you need to. It still offers good image quality
when combined with a 1.4× or 2× TC. A 600 mm is better suited for smaller
birds, but it typically costs five times as much with almost triple the weight.
Carrying a 600 mm over longer distances is not what you want to
do every day, especially when you have to carry all your other photo equipment
as well.
When Minolta released the Dynax 9 in 1998, they also released a few new lenses.
One of them was the 200/4 APO Macro G, a macro lens with a 1:1 maximum magnification
and 200 mm focal length.
When shooting at large magnifications (like 1:2 or 1:1) you get only very shallow
DOF, and you have to stop down to f/22 or more to get a few millimeters of
DOF. Consequently, exposure times become very long at these apertures.
You're often tempted to use flash in these situations, to get some light and
to stop motion. Using a regular flash unit is often not the best solution.
It's difficult to position the large flash unit to get light into the small
space between lens and subject. Furthermore, a single flash unit
results in harsh light from a single direction. By using two flash
units you gain much more control over the lighting situation. But again,
using two regular flashes, mounted at the end of long flexible bracket arms,
are uncomfortable to use. The center of gravity of these flashes is at the
end of a long lever, causing extra vibrations.
The solution comes in the form of special macro flashes.
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