These are very impressive photos from a home made rig.

Having tried and failed to get such a good view and picture of a bearded tit for many years over in norfolk, I have to say reading your comments I'm even more jealous. Lovely photo and great pose.

I can see why you would be pleased, I'd be very pleased with this shot.

Lovely series, it looks like you have your technique well sorted. 1,2,5 and 6 are the ones I like best.

I bought mine off ebay but you could try the people at srb-photographic.co.uk who have them in link

Thanks for that link. I've been looking for af tubes for pentax for as long as I've been into photographing dragonflies and butterflies. I often use auto extension tubes with my FA*300 F/4.5 to improve close focus. It would be so much easier with af tubes. Trouble is I normally use 65mm of tubes, oh well, can't have everything I guess. Although I see that KooKa also do a set of 20 and 36 tubes as seen here link perhaps srb will get them if I ask nice....

With reference to the af tests, this is what they say:
"Fnac lab was the first to having a measuring bench capable of simulating the displacement a subject at any speed from 0 to 300 km / hour, and anyone any distance. We programmed for two tests:
the first measurement the path a child trotting at 5 km / hour is triggered when it is 5 meters from the unit. The focal length is equivalent to 80 mm 24 x 36, well suited to this type photo. The second is triggered at 50 m from the subject moving at 50 km / hour, equivalent focal length 200 mm.
Measures burst position to obtain the distance to the first photo, but also how the unit is able to take, and where, and also how much are clear, what we symbolized by a color code in the graphical output of each device.

Green is good
Orange not very good
red blur"

Then this is the af info for the cameras you mentioned
Pentax K5II



Canon 700D


Canon 70D


So basically it is showing you how fast it can lock on to the child in the first line and how fast it locks on to the car and how many are good and how often it can take a good photo.
I don't know if this will help you in anyway to make your decision but the more info you have the better decision you can make? Besides it was fun to try and cut and paste this stuff in if it works!

Gedski and Steve (Gravelrash) thanks very much for those comments on my flickr stuff, much appreciated.
About the Canon 700D and the K5II have you seen the fnac.com report on the af of these? If not have a look at their pdf here link unfortunately it is in french but google translate does a reasonable job if you don't read french. Also the figures are reasonably self explanatory.
It's very difficult to say how this will translate into real life af with birds in flight and more consumer oriented lenses. I know my Pentax 55-300 is considerably slower to af than my canon 55-250 IS and that has an impact on tracking. Also I borrowed a friends canon 70-300 IS and that is also faster to af than my pentax 55-300. Any chance you could borrow or rent the kit to try out first? I tried to evaluate the af of the K5 and DA300 in a shop and high street and I just couldn't draw a conclusion on how it would perform for birds in flight.

What a great set, your fun commentary improves the viewing even more.

These are a very nice set, but number 3 does it for me, it just looks so balanced and the sky just top's it off.