You've lost me a little. If the lens is PK-A, no adapter is required.
Can't help wondering if the lens was described incorrectly on ebay.

There are many dragonflies close to my home and I've spent many hours trying to catch them in flight. My mission has been to catch a head-on, in-flight like No3, sadly with no luck.
Knowing how hard this is, I am suitably impressed.
neville

Pleasure.

It is one of those rare occasions, where 'too good to be true' is not the case.

For long exposures I have found a wired release the handiest, especially for night. Quite simply because it is wired, I can't misplace it in the dark or fail to remember which pocket the IR remote is in.

Recently picked up an el cheapo one for my son link and quite frankly it is every bit as good as my more expensive one.

I use this for a K10D, but pretty sure it is the same for the K5. It is also compatible with many (all?) canons.

there is one on ebay now, if you are still looking

link

I thought this was exactly what the OP was doing, attempting to discover these differences'

To my feeble mind it would seem logical that a Pentax forum might be the best place explore the benefits of Pentax kit. Perhaps not? Surely to understand the benefit of one necessitates some discussion of the disadvantages of the other?
Brand loyalty is given by the very name of the site, we are after all 'Pentax users'. Being given an invitation to state why we are Pentaxians, would seem like an evangelical opportunity, but is regarded as potential treason!
Such silencing does nothing to diminish my opinion of the brand, but I suspect it does no favours for the credibility and perceived integrity of the forum.

I do not challenge the 'rights' of the site, or even the moderators prerogative powers, but I do question the wisdom.

I think I would suggest your friend also hires a decent tripod and radio/ ir remote control. He can then use the camera of his choice!

A 'mate' who can't trust you to use your equipment and give you 'professional' freedom, sounds like trouble to me. I would steer clear full stop. My guess would be that he would not be happy with anything you do and be hyper critical technically and artistically.
Might be easiest to have a small fallout now, rather than lots of acrimony later.

The price drop-down menu says pentax K and is £163.50. This would seem quite dear even if they were PKA.I guess you could always e-mail for clarification.

As stated the Jessops tubes are fine.

from what I can see these are K mount not PKA, ie no contacts. Certainly not autofocus.
I believe all they have is the linkage to stop the aperture down, that's all that is auto about them.
Seem pricey for a basic set of tubes.

Barrie, you share my first thoughts, but then I thought about spectacle lenses. In most ophthalmic glass the two faces are different, so could be regarded as having a right and wrong side. Yet in extremely rough and ready observations with my wife's specs, there appeared to be no noticeable difference which side I viewed from. I am fully aware of the flaws in my 'test', but it was this that set me wondering.

I do have the matched extension tube and there is no flare with this, but I never have problems with sensor flare when used in the macro range anyway. flare only presents a problem for portraiture and regular focusing distances.

Dr O. In the close focusing and macro range, flare only manifests at very small apertures and I tend to shoot wider than this too, so it is no problem. Here the flare normally only appears at apertures f16 or below. Yet at longer focusing distances I can get the flare at wider apertures and can be very noticeable by f8.
I echo all your comments about it's qualities and will continue to use it despite its limitations. However, 'knowing' this lens is my problem, as(like you report)flare doesn't show in all images even when lighting, contrast and other factors seem very similar.
For macro I feel I know the lens, but for portraits etc it seems less predictable unless I shoot f5.6 or wider.

thank you to both of you for your thoughts.