On 2010-06-10 13:27:41 +0100, Peter said:

"Pete" wrote in message
news:201006101320053118-availableonrequest@aserverinvalid...
On 2010-06-10 12:43:10 +0100, Peter said:

"bugbear" wrote in message
...
Dudley Hanks wrote:
http://www.blind-apertures.ca/Latest...orAnderson.jpg (full size)

http://www.blind-apertures.ca/Latest...ersonSmall.jpg
(fast loading)

Visited City Hall this morning and brought along the SX120 in order to
see how it works at full zoom.

Took this pic from the back of the room, handheld at 1/100 sec (360mm).

I'm sure you will find a bit of camera shake, but I'm really interested
in how the barrel distortion appears, ditto for purple fringing...

Appreciate anything you can tell me.

Barrel distortion can be trivially post corrected.



Is that barrel distorting, or a curved wall?

Distortion at full zoom is pincushion.

true

Here it is offset by the curved wall and is barely detectable towards
the top left corner.


I didn't notice the pincushion, but thought bugbear might have been
confusing the curved wall with barrel distortion.

Oops! The tone of my post wasn't meant to be corrective or pedantic.
Sorry to all.

The pincushion distortion is very slight. I confirmed it by rotating
the picture in an editor and checking along its grid lines.

I have to be overly sensitive to barrel/pincushion distortion in most
of my photography. Horizontal tilt correction is equally important and
causes me endless grief, especially when the vanishing point is outside
the frame.

--
Pete