[kypfer]

Something else I learned from delving into this, is that, correct me if I'm wrong, but the Tamron 2x tele converter itself is, mostly kinda generic, & not camera specific. Sometimes people will list them on the auction site as "for Pentax" or "for Nikon," etc... But it is my understanding that the tele converter is not camera specific and works with many different cameras. It's the Adaptall-2 that is camera mount specific....

Depending on your point of view, any third-party tele-converter could be reasonably considered to be "kinda generic", certainly as far as the optics are concerned, only the mount fittings and mechanical aperture linkages will likely be different to suit each range of cameras.
Tamron (along with the Vivitar TX mount and a couple of others) simply took this concept one step further and made the just the mount camera specific, in one stroke reducing their production overheads whist offering their customers the welcome opportunity to move from one camera manufacturer to another without having to replace all of their lenses (I did this several times!)
Fortunately for those who "know what they're looking for", many eBay sales are poorly described, allowing welcome opportunities to accrue desirable items for low prices

[longbo]

Further to my previous comment about using a Adaptall x2 rear-converter with a Tamron 55BB Mirror lens, i've got 2 comparative images for comment.


They are of a neighbour's chimney at about 100m distance, taken with my K3-3. The first one is with the 500mm mirror lens alone and the second using the 500mm lens plus the x2 Tamron converter - I've adjusted the crop in Photoshop so that both appear the same physical size.


I can't see much difference in the two shots, which would indicate that the converter isn't giving a better image, but it's not worse either? [The doughnuts to the left of the chimney are from some tree branches, much closer to the camera]

I'd welcome comments.

[kypfer]

Further to my previous comment about using a Adaptall x2 rear-converter with a Tamron 55BB Mirror lens, i've got 2 comparative images for comment.
I can't see much difference in the two shots, which would indicate that the converter isn't giving a better image, but it's not worse either?

Looks good … would certainly indicate that the X2 isn't degrading the image to any noticeable extent, also that the lens is doing a good job in the first place.
It also demonstrates how hard you can crop an image from the K-3iii and still get a useable image!
In theory, it'd be nice to have a direct comparison with something a bit more modern, the 150-450mm for instance, but it looks to be a good value combo for those instances where a/f isn't really necessary

[wadge22]

I'll hold out and get the 01F tele converter in the States though....

There are 01F and 140F teleconverters in stock at KEH (in Georgia, USA) right now.