Nikon maintains DSLR lead over Canon

In other words, IS/VR adds absolutely no real word benefit to WA lenses.
This leads me to part two of the problem. On WA lenses the optical element
needed for IS/VR correction is not designed to deal with barrel distortion
and other optical problems. After considering all the pitfalls and
*minimal* perceived benefits from IS/VR, the lenses manufacturers concluded
that it is technically and financially impossible to make a WA pro lens with
IS/VR. That said, we will never ever see a pro prime lens of 50mm and wider
with IS/VR.





Rita

 

I am kinda surprised that tables turned so fast, it will be
interesting to see if global figures follow same trend

Thanks for the link.

Sachin Garg [India]
www.sachingarg.com | www.c10n.info

 

Not surprising given Nikon's intro of the D80 and D40/D40x. Canon's 400D
falls short of the D80 in several ways, and Nikon's D40/D40x are at a
price point where Canon really has no competing product. Similarly, the
D200 beats the 30D in several ways.

Canon really needs to address the low to mid-range of the D-SLR lines.

 

But the geometry of the optics doesn't change, and there are huge
differences as a result of that. How close the object is matters as
well. For example, think of taking a macro shot. Shifting the camera
0.1mm vertically upwards will have a very large effect compared to the
negligible effect of shifting vertically upwards 0.1mm when
photographing a landscape. In the case of the landscape, and in
general, rotational movement is by far the most important. A very
small shift in the direction the camera is pointing will have a large
effect on the image.

Suppose for example you're using a lens with a field of view of 30
degrees, and suppose you wish to produce an image which is sharp at
300 ppi on a 10 inch wide print. The span of your field of view is
divided into 3000 pixels. So a rotational shift of 30/3000 = 1/100th
of a degree will move the image over one pixel, and you'd probably
have to hold it to within 1/1000th of a degree to keep the softening
of the image due to shake negligible.

 

It depends on the parameters of the IS, how it was designed, what it
was designed to do. Firstly it can only move so much before it hits
the edge. Secondly it has to ignore slow speed drifts otherwise it
will hit the edge when you move the camera to look at something else
and not recover before you've pressed the button. In other words there
will be a shutter speed below which it won't work, and that will
depend on its design.

 

There is "getting away" and then there is "getting away". With a wide
angle lens, at 1/125, using a tripod still makes a difference, if you're
enlarging enough. At 1/10 it makes a *big* difference; even if the
hand-held shot looks sharp, the tripod shot is sharper.

Why do you assume there must be any? Rita doesn't know what he's talking
about. (And is most certainly not female.)

 

Fair enough comment - I don't do very big enlargements.

I didn't assume - I said "might".

David

 

If you quantify them as I did above then roll about the axis of sight
has far less effect than yaw and pitch on the image. It has comparable
effects to linear position shifts.

It's not difficult to bound it with reasonable general maxima and
minima. Note too that for a given shakiness and strength of hands,
then the heavier the camera the more slowly it will move, up to a
maximum which is probably heavier than any hand-held camera unless
you're pathologically weak or shaky.

 

Sure, but what I'm wondering about is the relative effects of the three axes
of rotation. I think that yaw and pitch would have the greatest effects on
blur, and roll would have much less. But how to quantify them?

That's an interesting way of looking at it, but I'm not sure how useful it
is. In order to translate any of that into required shutter speed you'd have
to know the *speed* of camera movement (i.e., angular velocity) as well.
That I think would be difficult to arrive at, with the movement in human
hands.

Neil

 

As anyone who shoots a gun can tell you, there is a vast difference in
movement characteristics depending on how you control things like
breathing, your stance, you hand position on the camera/lens, etc.
Consistency is the key, once you've isolated all the variables.

 

I show a way how to compose w/o stopping down and you want to
saddle me with non-cpu nikkors and no D200 --- which, being a
Canon user, I have no need for?

-Wolfgang