Nikon 14-24mm f2.8 G: Replacement for the 24 TS-E?

Started Oct 25, 2008 | Discussions thread
OP cbnphoto New Member • Posts: 17
OK, here is an Example

Before moving on to an actual example, I'll just reply to your points:

wimg wrote:

No, not true. The big difference is that you can reposition the
optical axis of a TS-lens relative to the image and object planes,
while keeping the image plane in the same position. You can't do this
by cropping.

Actually, yes you can. There is no difference. A shift movement is nothing but a mechanical crop from a large image circle.

I think my reasoning is completely correct If you do not think
this is correct then try it and see!

You can be sure I have. This is why I own the TS trifecta. One of the
main reasons to go Canon.

I don't think you have. Unless, of course, you are describing some completely different setup to what I suggested in my original post.

And no, your theory is not correct, because you're shifting a
different part in this equation, namely the to be captured part of
the image plane rather than the optical axis. If this wasn't the
case, we would have never needed technical cameras in the first place.

My theory is very much correct w.r.t my original post as far as I can see. There are reasons for having technical cameras, but those reasons are different from the ones you are describing.

Take a picture of a tallish building with straight edges, with a
non-TS lens. Even if you manage to take a picture halfway the height
of that building, and especially if you use a WA or UWA, straight
lines will converge towards the edges and corners of the picture.
This is caused by the rectilinear design of lenses. And convergence
of lines is worse with (U)WA.

If we are talking about a rectilinear lens (and that is what both a TS-E and a standard WA non-fisheye lens are) then there is no convergence of lines if the lens is perpendicular to the plane being photographed. Actually, I'm not quite sure what you are getting at here. If lines converged towards the top or corners then either it would not be a rectilinear lens or it has not been pointed at the scene correctly.

The only way to get around is, is to shift the optical axis of your
system, i.e., use shift.

Or crop a larger image circle. Or crop from a normal image circle using a wider angle lens.

You could simulate this to a degree with a non-TS lens by tilting
camera and lens in the opposite direction of the convergence, IOW,
for a tall building down towards the ground,

No. In that case you would end up with lines that diverge.

but you'd need a small
aperture to compensate for this, and you might be lucky if you can
use half of the image, because the magnification of the "shift" of

"magnification of the shift"? I think you need to explain what you mean.

Give it a try and you will see what I mean.

Well actually, I went out today to do some other lens tests and to also compare resolution as indicated by my theory.

Perhaps you can use your expert eye and tell me which of the following two pictures is the result of cropping from a 17-40 image and which is a full-frame from a TS-E.

I'll post the RAW files once you give me your opinion and explain to me where the converging lines in the UWA image are (hint: there is one small difference - the 17-40 has more pronounced barrel distortion, but rather than being accused of tampering I have not removed this using the DPP distortion removal facility. All that was done was to crop from the 17-40 and to reduce the sized of both images for web display):

Do you realize, f.e., you can do macro with a WA TS and put the DoF
plane exactly where you want it? Just an example. I think you need to
explore the possibilities of a TS lens to really understand. Even
with buildings it is extremely useful. Imagine you can only stand
fairly close to the corner of a building and you want the whole front
to the left of you sharp, and have no converging lines straight up.
The only way to do this is use both tilt and shift.

Given that the 24TS-E has a ton of DOF there is little need to do this - unless you are standing within a few feet of the building, but in that case I doubt 24mm would be enough to cover the scene.

Anyway, you don't have to agree, of course.

I'm willing to agree, but only when I see evidence or have in front of me a reasonable theory!

But you're wrong in your
assumption that shift is the same as cropping.

As I said - you have two examples. Go for it. I'd be interested to know why you think I am wrong.

If that was the case,
we would never have had technical cameras or TS-lenses, just high
resolution film and sensors.

There are two reasons. Firstly the resolution is reduced because of cropping from a full-frame image. Secondly, and perhaps more importantly, such a lens allows you to frame it exactly at the time rather than having to do so later in PP.

Of course, things like the TS-E lenses are pretty limited compared to a large format lens with a full set of movements. There are plenty of reasons for such lenses to exist, but if we are talking 35mm and shift only then it looks like the Nikon 14-24 will bury the 24 TS-E if using a top-end body (21MP+).

Anyway, I await your reply.


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