Cotty wrote:
On 19/1/06, Adam Maas, discombobulated, unleashed:
Which assertion? The one that Full-frame sensors are extremely sensitive
to edge performance and consumer lenses generally underperform on FF
because of that? That's well documented in reviews of pretty much every
FF camera of the last few years. There's a reason Canon introduced a new
L lens just for the 5d, and it is simply that the 28-135 IS shows its
warts on full-frame.
Or that the 1.3x crop cameras are more susceptible to edge performance
issues than 1.6x crop cameras. That's simple geometry. If the camera
uses more of the edge, it will be more susceptible to issues with edge
performance. Digital is generally more sensitive to lens performance,
even with 1.6x cameras.
'That's well documented' does not answer the question. Let's see your
resources, or let's see your tests. There's plenty of wind on this list,
and plenty of pixel peeping. Nobody look at the damn pictures any more??
Cheers,
Cotty
Here's some on Canon's L glass:
http://www.dpreview.com/reviews/canoneos5d/page22.asp
That shows definite vignetting/fall off on the 5D that doesn't exist on
the 20d (As the problem areas are off the sensor).
Another example, this one on a EOS 3, with the EF 28-105 f3.5-4.5 USM II
wide open at 28mm on Acros 100:
http://www.flickr.com/photo_zoom.gne?id=85917538&size=l
This shows off distortion that would be out of the frame on a 1.6 crop
camera and possibly on a 1.3 crop camera. This is my own shot btw. The
full resolution scan shows mild CA and distinct softening at the edges,
but it's not particularly visible on this shot because of camera shake.
On a 5D, which is more sensitive to edge performance than film is (For
the reasons Rob noted in his response to me) I'd expect this zoom's
weaknesses to be more apparent. Don't get me wrong, considering the
cost, the 28-105's a great lens (I'd consider it at twice the price) but
I'd hesitate to use it on a 5D unless it was stopped down and not at the
wide end of the zoom. The 28-105 is pretty comparable performance-wise
to the 28-135, it just lacks IS and the extra length on the tele end.
-Adam
