[dadipentak]

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The 1000mm lens would have to extend on the focus travel by 500mm to focus at 3M. This is probably about 10 sets of macro extension tubes screwed end to end to get a rather unweildy 1.5m long 1:2 macro. I might be usefull for filling the frame with a particularly shy butterfly though

Then there's the question of whether any light would survive the journey.

[MattGunn]

Then there's the question of whether any light would survive the journey.

With the lens set at its maximum aperture of f/8 the effective working aperture would be f/12 so some light would get through but the subject would need to be pretty brightly lit in the forst place.

[Ben_Edict]

The 1000mm lens would have to extend on the focus travel by 500mm to focus at 3M. This is probably about 10 sets of macro extension tubes screwed end to end to get a rather unweildy 1.5m long 1:2 macro. I might be usefull for filling the frame with a particularly shy butterfly though

Yes, but only those pinned into an album, as you'ld need endlessly to turn the focus ring...

Ben

[MattGunn]

Yes, but only those pinned into an album, as you'ld need endlessly to turn the focus ring...

Ben

So true. Also depth of field wopuld be about 3mm so even pinned to an album it would be difficulty to get it all in focus. I never said it was practical, only possible. This is obviously why macro lenses stop at around 200mm. Anything longer would be un-usable.

[Paul Ewins]

I guess I'm chiming in a little late, but I'm new on the forum. I've got the SMCT 500/4.5 (and it's predecessor the Tak 500/5) and have just acquired an SMC 1000/8 which I suspect is the one xjjohnno rejected .

First up, comparing the photos of the modified 500/4.5 mount to my own SMCT version it looks like the entire end has been cut off, as mine has a 2mm wide smooth section after the narrow milled ring which appears to be missing on the modified version. FWIW apparently the conversion to Nikon mount was quite common as some of the photo agencies in the US which had used Spotmatics swapped over to Nikons. It was cheaper to convert the 500s than sell them and buy the Nikon equivalents.

Second, the adapters from the 500/4.5 and 1000/8 do appear to be functionally interchangeable. As you can see in the picture the M42 version is longer, but the distance from the breech mount on the lens to the body mount is the same and they do appear to fit on either lens. The M42 mount has a 49mm filter thread while the K mount has a 52mm filter thread. The K mount rotates at 90 degree intervals while the M42 version is fixed. As you can see by the other photo the k mount is similar to the 6x7 -> K converter. I don't think you could convert one into the other but they do appear to share some parts.

[xjjohnno]

Gidday Paul, good luck on getting the lens cleaned up. Looks like Aus Post has been getting a bit of trade from that lens moving backwards and forwards from Byron Bay. The first thing I did when it arrived was give it a decent airing. The musty stench when I opened the case was very strong and the case was left open while it was in my care.

[Paul Ewins]

It should be doable, none of the elements are cemented together. I wouldn't normally buy a lens with fungus, but a 1000/8 is rare enough to be worth it. The last lens I had cleaned was a 400-600 reflex zoom and that came up a treat, so I'm pretty confident that the repair guy should be able to handle it.

[MattGunn]

Paul that picture of the M42 mount is really usefull for comparing to deadwolfbones modified one. However it relveals that deadwolfbones mount has been modified more then I had though and it looks like everything beyond the second knurled section has been removed and replaced.

Deadwolfbones: Based on this new information I think your best option would be to get someone with a screwcutting lathe to make a new section to replace the whole of the bit you unscrewed. This shouldn't be all that complicated and would ensure tht you can get infinity focus etc again. If you get it made so that the section if about 1.5mm shorter than the current one you should be able to go slightly beyond infinity. The F mount flange focal distance is 1mm greater than pentax so by changing from F to K mount you gain 1mm straight away. Removing an additional 1.5mm will give you 0.5mm to spare just in case measurements / estimations / calculations are a bit out. It is possible that the bit you unscresed could be converted to M42 or K mount, thus doing away with the need for screwcutting, but I can't tell without examining it more closely.

Paul Ewins: I really dont think fungus (as long as its not too far advanced) is such a big problem as everyone makes out. I'm sure you will end out with at least a perfectly usable lens and provided the fungus has not attacked the coatings then it could end up imaculate again. I have obtained some of my best lenses by bidding on fungus infected ones no one else wants and cleaning them myself. Good luck with getting it repaired.

[Blue]

Based on what Paul has said, I'm guessing there was a 3rd party company that was selling conversion kits for these things. This lens had a long run in its various incarnation up until about 1989.

[deadwolfbones]

So I got the lens back from Eric today, and as expected it looks fantastic. He cleaned the elements, fixed the loose light baffles and the screw that was rolling around inside, and re-adjusted the focus.

Here's the really interesting thing...

The first thing I did when I got it back was go to inspect the mount for the umpteenth time. The converted Nikon mount bit was harder to get loose this time than it had been in the past, so I applied some extra pressure. Shockingly, the F-mount adapter came off quite easily, revealing that it's simply a T-mount to F-mount adapter on a Vivitar 52mm reverse adapter ring. All I need to do is buy a T-mount to Pentax K-mount adapter and it should work fine (albeit with infinity focus still futzed up a bit). It's like Christmas!

edit: or accept Monochrome's gracious offer of a freebie.

[philbaum]

So, uh... I may have just done a very foolish thing.

Was cruising eBay tonight (yes, the beginning of all bank account-crippling stories...) and came across this auction:

PENTAX ASAHI TAKUMAR 500mm TELEPHOTO LENS MUST SEE !! - eBay (item 270448120945 end time Aug-26-09 22:26:56 PDT)

Of course, the first thing I noticed was that the listing said 500mm f/4.5, while the pics clearly show a S-M-C 1000mm f/8.

I sent the seller a question asking for clarification on the lens identity and the condition of the internal elements, but then I got to thinking...

If I wait for the seller to respond, there's a pretty good chance someone else is going to take a gamble and snap it up. And even if it is the 500mm f/4.5, that's a pretty damn good price (especially w/ Bing cashback, etc). And on the off chance it's really the S-M-C 1000mm f/8... well... what a deal!

So I jumped.

LBA, story of my life.

Yes, you did a very foolish thing, but thanks for taking the temptation away from me :-) What a beautiful lens - the case alone is probably worth $250. Great find

[Ben_Edict]

The first thing I did when I got it back was go to inspect the mount for the umpteenth time. The converted Nikon mount bit was harder to get loose this time than it had been in the past, so I applied some extra pressure. Shockingly, the F-mount adapter came off quite easily, revealing that it's simply a T-mount to F-mount adapter on a Vivitar 52mm reverse adapter ring. All I need to do is buy a T-mount to Pentax K-mount adapter and it should work fine (albeit with infinity focus still futzed up a bit). It's like Christmas!

What I still do not get is, how it comes, that you got a T2 thread on that rear section. If the whole section is part of a replacement kit, ending in T2 to facilitate adaption to almost any camera, then it should reach infinity focus an all cameras using the T2 adapter. Could it be, that simply somebody forced the T2-Nikon-F adapter on the original M42 threads? With force this is possible. And adding then a T2 adapter to the original M42 threads would ofcourse throw infinity focus off.

I guess there are others here with the original M42 rear section. It would easy just to measure the overall length of this rear section from the mount on the lens side to the end of the M42 threads. Then you can compare your rear section and see, whether it is really too long. If so, go to your next metal workshop and let remove the extra millimeters on a lathe. They can cut an M42 thread then and you can use the standard PK adapter with that and reach infinity focus as intended.

Ben

[deadwolfbones]

I'll take some shots when I get home of all the various parts disassembled and together, to give you an idea of how it all fits together. I don't quite get it myself, either, and I'm looking at it.

edit: just had another look at it... though I can get the T-to-F-mount adapter off of the Vivitar adapter, I can no longer get the Vivitar adapter off of the 52mm ring (which is all I was able to remove previously). I'll try it later with a vise and see if I can get it loose, but my impression is that someone machined the mount end off of the bottom portion of the right-hand tube in this image, just above the lower grip ring: https://www.pentaxforums.com/forums/attachments/pentax-slr-lens-discussion/43...-f-8-m42_k.jpg

[monochrome]

All I need to do is buy a T-mount to Pentax K-mount adapter and it should work fine (albeit with infinity focus still futzed up a bit). It's like Christmas!

edit: or accept Monochrome's gracious offer of a freebie.

PM Sent - waiting for your mailing address to forward the adapter with my compliments - this has been a really fun thread to read and learn from.

Here's a link to the pix of the adapter from earlier in the thread Vivitar Series 1 T-adapter for Pentax K

[deadwolfbones]

Thanks much, Paul!