Savageduck wrote:
On 2013-03-05 14:35:32 -0800, Rob said:
On 6/03/2013 1:08 AM, Floyd L. Davidson wrote:
Rob wrote:
The 70-300 is quarter the price. Half the weight 745gms/1570 gms

If that lens is satisfactory, then you have no need at
all for the new 80-400mm lens. But the 70-300mm is not
equal to the older 80-400mm AF-D lens, and is no where
near the same as the new lens.

I do have the 70-300 lens and find it light to carry
and stay mobile, running up and down a beach.

My old 80-400mm (bought in 2004 for $1400) has become a
dust collector and hasn't been a regular occupant of my
bag since 2009. The 70-300mm VR is a surprisingly good
value and performer, and the only areas in which the
70-300mm VR is not equal to the old 80-400mm is in the
80-400mm's unbelievably poor low light performance, slow
focus and the only performance benefit, the extra reach.
I certainly couldn't have made this capture with the 80-400mm.
http://db.tt/6SuM0WTp

Relatively what you say is true. The 80-400mm has the
advantage of a focal length range that extends to 400mm
vs 300mm and being about equal to the 70-300mm at 300mm.
For many purposes that has great significance, and of
course for many others it has none. The 80-400mm is not
exactly great in any way at 400mm focal length, but it
is nearly as good in the center of the frame at 400mm as
the 70-300mm is at 300mm.

The 80-400mm uses the built in focus motor, so the top
of the line models (such as the D2X, D3, and D4) would
see significantly less difference between the 80-400mm
and the 70-300mm compared to what would be experienced
by other bodies in terms of AF, particularly in low
light. That might color the experience of some users
compared to the experience of others.

Regardless of all of that, the new 80-400mm f/4.5-5.6G
lens appears to be more significantly better than the
70-300mm in every way than that lens is over the older
80-400mm in any way.

The biggest thing to note in the MTF curves for the new
lens is the match between the sagittal curves and the
meridional curves. To compare lenses, the lower value
of the two curves is probably the most significant. For
example the 70-300mm at 15mm from the image center has
an S30 value of 0.74 and an M30 value of 0.55, while the
older 80-400mm has S30 at 0.80 and M30 at 0.47. The S30
value is higher for the 80-400mm, but *what counts* is
that it's M30 is lower by 0.07, which is significant but
not huge.

On the other hand the new 80-400mm G lens has S30 at
0.73 and M30 at 0.74. Not only is that a very large
jump above the 0.55 of the 70-300mm, the fact that the S
and M values are so close indicates virtually no
astigmatism with the 80-400mm G.

In fact the 80-400mm G lens, at 20mm from the center
(basically this is in the very diagonal corners of a
full frame image) has S30 at 0.65 and M30 at 0.67, still
showing no astigmatism and being sharper than the 70-300
is even at 10mm from the center (M30 is 0.55).

*To put it mildly, the new 80-400mm G is a much sharper*
*lens than the 70-300mm G.*

It doesn't mean everyone will value that sharpness higher
than the 70-300mm when also accounting for weight and
cost. But there is little doubt that those who
seriously shoot sports and wildlife are going to snap up
this lens immediately.

--
Floyd L. Davidson http://www.apaflo.com/
Ukpeagvik (Barrow, Alaska)