Why you DON'T need a tilt-shift lens--an article by me published in UK's Photo Blog

Started Mar 3, 2011 | Discussions thread
JensR
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Re: Jens - new start Part 3
In reply to Gerry Winterbourne, Mar 9, 2011

Hi Gerry!

Hi Jens. I think this may be the last of my items here: if I've convinced you that's fine; if not I think we have to follow Cindy's idea and agree to differ.

Of course you have not convinced me and I am sad that I have not convinced you.

In Part 2 I showed how the straight-stays-straight merge pulls the format away from square to rectangular (I'm talking about the shape of the white area bounding the photo, not the irregular shape of the photo itself).

I'm not sure why the canvas is now important. Had you taken more shots at the respective region, the remapped image would look very differently.

In my earlier post you objected that in my non-straight comparison shot was just stretched vertically. The point of the merge comparisons is to show that your logic was back-to-front: it's the UWA/straight treatment that introduces the squeezed distortion and all I did was remove it.

Wait? You mean the shot of the bedroom, where you scaled the height and added distortion to make it look like what you imagine it has to look?
Well, I still very much object to that procedure.

You also argued somewhere that UWAs are somehow special in the way thay treat shapes. This time I throw the challenge back to you: see if you can find a series of shots at different focal lengths that show a clear boundary between "ordinary" effects and "special" ones.

That's very likely not what I said. I described the difference between rectilinear and fisheye lenses - both in the (U)WA range - with respect to angles and areas.

Even if I said that, this would in no way imply that there is a strict cut-off (and of course there is not).

What I did say is that UWA lenses are fascinating (or special or weird or interesting) because they allow an angle of view that our eye does not. But it should be obvious that if an 8mm lens is extremely adjective , a 16mm lens will be mildly adjective , a 28mm lens will be "normal" and an 800mm lens will be extremely reverse adjective .

I don't believe you will be able to. All the logic I can apply to the situation is that the effects we are discussing are the same in kind at all focal lengths.

Of course - I said so much in reply to your other post, where you said UWA distort and cannot be trusted.

They increase with increasing AOV and every individual will have an opinion about where the increasing amount reaches the limit of acceptability.

Yes.

Moreover, a single person is likely to set the limit at different AOVs depending on the subject: I'd expect most people to be more tolerant in general landscape shots than in architecture.

The difference is not so much landscape or architecture, the difference is in distance and the percentage of overall angle of view covered by the subject.

If I'm right, the fact that the limit can move shows that there is no clear cut-off.

No one contested that, so it proves nothing.

So, while enjoyed our banter, may I suggest that for next time, we use the quoting functionality to address and readdress specific arguments and counter-arguments. Even if this might run into word-count limits, I feel this is in the end a more effective way of discussing a point.

In closing, my points still are:

Perspective does not bend lines.

Entasis and lean exaggerate the impression of a tall and mighty structure and do not compensate perspective.

Cheers
Jens

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'Well, 'Zooming with your feet' is usually a stupid thing as zoom rings are designed for hands.' (Me, 2006)
'I don't own lenses. I pwn lenses.' (2009)
My Homepage: http://www.JensRoesner.de

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