That would mean the Sony and Nikon cameras would suffer from it as well!

That's known as a laminated beam and they would all have to be glued together for the full length to stop them deflecting. Also they wouldn't be round enough to spin smoothly

I wouldn't think tape would hold it and if it did it would be hard to do it without creases.

A bamboo pole is actually the best support. It's so strong (only bends when it's green) and very light. They use it for scaffolding in some countries lashed together.
Probably 5-10 US Dollars for an 8' length x 1.5 to 2 inch diam. Example

Rust-Oleum make some great spray paint for finishing things off in the studio.... they used to make a nice quick dry matt black, but I can only see satin and gloss now link

I've had similar shots from P&S. These were taken at f/2.4 a lot of P&S cameras have similar sized apertures.

The EXIF data is readable in Firefox with the Exif Viewer Add-On.
The light must have been really bad 1 sec at f/2.4 800ISO?

The K-5 has a problem with purple fringing and this can be seen in the first shot. I was surprised when I saw this on some shots I've taken. I hope they can fix that with a firmware update

Looking at the Flickr shot of the brass door handle it looks perfect apart from a bit of purple fringing in the wooden frame.

The Denon shot looks fine and the colour balance spot on
It's probably just a case of getting used to the camera and lens.

You could add a reversible painted background made from say two sheets of 6ft x 4ft x 1/8th inch ply on each side of say a 2in a 1in frame. This would be behind the roll of paper so that when it's rolled up you have a painted background.

That's up to you If I was building my own studio after seeing the high price of supports for paper rolls I'd be racking my brain for a DIY solution. Simplest would be shelf brackets and a bamboo pole, but suppose I want to be able to move it or there's nowhere to fix a bracket in which case I'd need some kind of stands

How about a DIY support for background paper (rolls) ?

There's something wrong with the two pictures you posted. The look like they've been taken with a 2Meg point and shoot If they are from jpgs you need to set the jpg size to 16M and the Quality to ****

The viewfinder looked small to me but it's OK now that I have put a KPS 1.3x magnifier on it. link

Lenstip are quite well known Quite a useful site

The 1.7x shot looks OOF. The right scaffold clip looks almost in focus.
Plus it might have a bit of shake.

Just measured the height from the tube to the top of the chimney with a pixel ruler on both shots and it works out 1.733x
So the 1.7x is about right.