> So, my question is: Are the newer lenses made in such a way that the
> DOF is very, very shallow and the older lenses are not? Would the older
> lens be a better choice for general photography? There are times when
> I'd like the shallow DOF, but not always.
Les,
Older 50mm lenses have a longer focus scale, from infinity to close focus is
about 1/2 turn of the focus ring. The long focus throw gives slower and
more precise focusing, and means the focusing scale, and DOF marks are
wider.
Later manual lenses (AIS) and AF lenses have a shorter focus throw, from
infinity to close focus is about 1/4 turn of the focus ring. This means
focusing is quicker, but the compressed focus scale also means the DOF
lines are closer together.
Note that the length of the focusing scale has nothing to do with the actual
DOF. This remains the same for all 50mm lenses (with the same aperture)
DOF marks on manual lenses are color-coded. Colored numbers on the
aperture ring correspond with the colored DOF lines.
As for finding more manual lenses for your FM2n, it will not fit non-AI
lenses. Non-AI lenses can be recognised by looking at the aperture ring. If
the lower edges (edge closest to the camera) is even all the way round, it is
non-AI. AI lenses have a cam or ridge from the lower edge which connects
with the meter on the camera. Most manual AI lenses still have the "rabbit
ears" so they will meter on non-AI cameras.
If you are looking for a good portrait lens, the 105/2.5 would be the best
choice. I use the AIS 85/2 which is also good.
If you are looking for a manual 50mm lens to replace your current AF lens,
there are many options:
The AI and AIS 50/1.4 are good lenses, with the same optics as the current
AF lens. Sharpness is ok wide open, excellent from f2, but there is some
barrel distortion. Best if you need the speed.
AI 50/2 - old design but very sharp. No distortion.
AI and early AIS 50/1.8 - also a very good design.
Series-E and late AIS 50/1.8. Compact design which does not have the
recessed front element of the other 50/1.8 lens. Optically very good (same
as current AF lens). Mechanically not as good as other lenses - more
plasticy. Only focuses to 0.6m compared to 0.45m for others.
hope this helps,
ROland
