[excanonfd]

Sell it on Dan, no point butchering a decent piece of glass. And do be more wary of LBA buys re compatability. A CZ Pancolar would probably have been a lot more affordable and a tad faster.

Yes, this probably is the best option but the temptation of owning the first CZ Ultron with a concave front element, successfully converted to a PK mount, might be too much to bear for some. After reading this thread the first time I eBay-ed for this lens - way beyond my wallet for a conversion project but since Dan already has the lens and seem to be able to afford the attempt, I'd say go for it. If it was my lens, I would definitely try it - but it all hinges on what's underneath the ring with the three screws. Can the lens function normally (focus and actuate the aperture) without the ring or not? I would go at least that far to determine whether the conversion is worthwhile or not.

Thanks,

[DanielT74]

...but it all hinges on what's underneath the ring with the three screws. Can the lens function normally (focus and actuate the aperture) without the ring or not? I would go at least that far to determine whether the conversion is worthwhile or not.

Thanks,

So... here we go - this is what's under the black bit with three screws. The black bit held aperture ring in place and allowed it to slide, and it also held the automatic aperture control mechanism, which also held the inner barrel from wobbling.

So the lens is in bits and we are contemplating whether we should go backwards or forwards...

Here are the pics - I suspect the folks here don't need much more comment.

The bits missing from the picture are the back plate with the three screws and the bayonet locking ring (my partner in crime took pics with them with his iphone and maybe he can upload them).

The challenge as we see it now is to attach a plate to hold the aperture ring in place and enable it to slide and also to stop the inner barrel from wobbling while focusing.

We were thinking of grinding off all but the base plate of the rear black plate and put it on together with the bayonet locking ring which threads onto it (and would allow infinity focus adjustment). Then put the pentax mount on the bayonet locking ring and somehow also attack a bit to go into the "thingie" on the inner barrel to hold it in place while focusing...

Any tips? I am beginning to think we are waay out of our depth here, especially seeing that we don't have any metalwork tools...

[excanonfd]

There's too much going on underneath the rear ring. I think your only option is to reassemble the lens back together and put it back on the market, especially since you say you don't have any metal working tools.

Thanks,

[jman]

hi all. a further pic:



in particular, removal of the tiny green screw at around 10 o'clock allows for the breech lock mount to be removed:


i think this is certainly a doable conversion if you had a few decent tools about. maybe even a dremel would get you most of the way.

firstly, the top of rear facing cover (section surrounded by the breech lock) would need to be cut off as it fouls on the camera body. if this were not the case, there would be no difficulty in this conversion. the only option is to cut it, as the lower section of the cover is integral to the aperture mechanism, and short of a lathe (and skill), it would not be possible to replicate.

the aperture release mechanism (which sets the correct aperture on shutter release) attaches to the removed section, so it not be retained. this is not a big issue as actuating it was never going to be possible.

however, besides aperture function, this mechanism also holds the lens assembly stationary while the focus rings is turned (note the vertical 'rail' in daniel's 4th picture). a similar rail will need to be fixed at another location. this would be the hardest part of the conversion.

finally, another mount would need to be fixed somehow. i think the best approach would be to directly fix a new mount onto the breech lock ring (as daniel mentioned). it would be a marginal fit, though the ring could perhaps be machined down if more room were required. this would also facilitate infinity focus adjustment.

all in all, i think this one's going in the too hard basket for us. if the required tools were at hand, it really wouldn't be that difficult, and while its a shame to destructively modify the lens, it is really of little use in the icarex mount.

perhaps daniel should donate the lens to me, as i think the adaption to sony nex would be a lot more straightforward .

[DanielT74]

Good to see you posting, Jman! Donation is not quite on the cards yet, I am afraid (maybe once you have succeeded in destroying the lens for good) but going back may be what we need to do, sadly...

No one seems to be particularly encouraging...

[DanielT74]

Well, we are a stubborn lot! So the latest battle-plan is to get a cheapish Tessar for Icarex in M42 mount and cannibalise the back bit for the Ultron, while putting the bayonet bit on the Tessar.

Anyone with an old fungus-ridden rusty Tessar preferably with oil on the blades? But it's got to be of Icarex variety (for any hope of fitting), like this:

[boisset49]

Hi
i have a tessar with TM(m42) mount and a ultron BM
Does somebody have exchanged the mount (or have links with pics)
thank you
(sorry for my english)
dom

[jman]

hi dom

yes, myself and daniel successfully converted the BM Ultron to M42.

It wasn't as simple as a straight swap, but wasn't hugely difficult. You will need to machine the tessar m42 rear mount to accommodate the larger diameter ultron rear element. I believe that is the hardest part, and you may need a machine shop if you do not own the required tools. also, for the circular component at the top right of this image:


you will need to use the tessar version (from memory), but it fouls somewhere inside the Ultron body where it needs to sit. I simply used a dremel to grind it back a little which seems to work fine.

I think daniel may have further pics/details of the work in progress.

john