[Rnovo]

A friend just lent me this lens for testing. I searched everywhere (?) for some information on what the 2x conv. 1:1.5 and 1:3 scale really is (beyond just being the classic 2x converter...?) - is there such a thing as a user guide or manual on that lens?
Furthermore, there are lots of small spiderweb-like blotches all around the centre piece that appear to be on an inside glass (mirror?). Are those signs of fungus or signs of some sort of "old age"? I'm not seeing anything in particular on test shoots...?
Thanks for any pointers.

[ripit]

It would be helpful if you could post a pic of the problem but yes that sounds very much like fungus. You can also google lens fungus and click images, to get many examples. Then you can see if any look like what you have. Depending on where the fungus is and how bad it is, you are more likely to have a loss of contrast and sharpness than to have something visible on the image. I have cleaned fungus out of a hand full of lenses and was not really happy with the results. You will end up with a functioning lens but the image quality may be degraded. The fungus can produce acid that etches the glass. Of course it depends on how bad the fungus is. I have heard of others cleaning it and getting a lens they were happy with.

This tells a little about the teleconverter

http://www.adaptall-2.com/brochures/SP_500mmF8/SP_500mmF8_page2.jpg

[hoanpham]

Samples are here:
https://www.pentaxforums.com/forums/lens-sample-photo-archive/174584-tamron-5...s-samples.html

these web can be fungus.

[Stone G.]

A friend just lent me this lens for testing. I searched everywhere (?) for some information on what the 2x conv. 1:1.5 and 1:3 scale really is (beyond just being the classic 2x converter...?) - is there such a thing as a user guide or manual on that lens?
Furthermore, there are lots of small spiderweb-like blotches all around the centre piece that appear to be on an inside glass (mirror?). Are those signs of fungus or signs of some sort of "old age"? I'm not seeing anything in particular on test shoots...?
Thanks for any pointers.

Tamron Adaptall user guides/manuals aren't particular detailed. But YES, you can find it (pdf-file) via my download page:

PhotoDocs

(The deep link is here (if it works): Manual: Tamron SP Model 06B and Model 55B - Owner's Manual (1982) - lhe latter is in most respects identical to the 55BB)

[Stone G.]

some information on what the 2x conv. 1:1.5 and 1:3 scale really is

I should add: These figures mean that at the closest focusing distance you will have a 1:3 reproduction scale with the les alone and a 1:1.5 reproduction scale with the lens + a 2X teleconverter, such as the matching Adaptall-2 SP 2X Model 01F converter.

[Rnovo]

Thanks all, and Stone G. I saved your PhotoDocs because there are interesting manuals there - thanks. I was able to get the Adaptall-2 manual from the same friend and I was getting ready to scan it and post it for any out there that might interested but its in your list!
I'll post an image of the lens problem tomorrow.

[Lloydy]

Cleaning fungus from a mirror lens can be difficult. I have a Canon FD 500 mirror that is fungused which a friend of mine offered to clean. He's an optical technician working for the Army who cleans and repairs weapon sights and night vision stuff, so he knows what he's doing. He uses cold cream to remove fungus, but if it is stubborn some gentle rubbing is required. On the Canon mirror surface he tried a very tiny area that would be under the clamping area at the edge, and out of sight, and the mirror finish was so fragile it took the shine off with a gentle rub using his finger. This was on the front of the mirror, not the silvered back - there is a coating that once damaged would make the surface flat, if that makes sense? So he just coated the mirror with cold cream and washed it off, which removed most, but not all the fungus.
The optical elements were fine after cleaning, and the mirror is still useable. But that was only down to his skill and experience, he knew some optical mirrors would degrade just from touch and leave permanent fingerprint patterns on the surface.
My Canon works fine, even with the remaining fungus which is easily visible. Nobody wants fungus in a lens, but very often the degradation of the image is so minor the lens is best left alone. but if fungus has etched the optics and especially the mirror, it's wrecked.

The Tamron 500 is one I've been looking for, and actually bought a few weeks ago, but I had to return it as it was badly decentered and wouldn't focus on anything. I was a bit gutted, it looked in great condition and was the right price. I guess it was the 'right price' for a reason.

[Just1MoreDave]

I cleaned my 55BB and the fungus was not on a delicate surface. It was about a ten minute job.

[Rnovo]

Thanks for all the comments and the fungus - or whatever it is - does not seem to interfere with the quality of my images (?). Here are some results and my first ever full moon shot and one the day before where the craters are clearly visible. No wonder this type of lens is called a "moon lens"!
One remark though, she's a real b.... to focus, boy! I ended up focus bracketing even though I used a cable release and mirror lock up + 2 wrist exercise weights hanging from the tripod! I still had to use a good sharpener like NIK software as regular PS USM was not good enough).The tripod mount on the older 5BB must have been handy...
Just1moreDave, I sympathize with you because I found that this lens is near impossible to focus properly and it might even be a problem with it (?). The posted images - taken with my K5 which is OK on focus - use strong sharpening to make them look good, I think.

[Stone G.]

One remark though, she's a real b.... to focus, boy! I ended up focus bracketing even though I used a cable release and mirror lock up + 2 wrist exercise weights hanging from the tripod! I still had to use a good sharpener like NIK software as regular PS USM was not good enough).The tripod mount on the older 5BB must have been handy...

Mirror lenses are notoriously more tricky to focus. That's because you have the relatively large central obstruction and use the outer beams hitting the lens to form your image. So, focusing will always be critical. When I use my mirror lens on a tripod, I have found that live-view with 8-10X magnification comes in really beneficial.

Of course, older lenses may also have taken some rough handling over time and may happen to need re-collimation. I know that there are a few enthusiasts here and there that may perform such collimation. Anyway, If you haven't discovered it already, I suggest that you visit the Mirror Lens Club to see, what can be done with these lenses:

https://www.pentaxforums.com/forums/lens-clubs/71775-mirror-lens-club.html

Secifically regarding your Moon photos: Firstly, congratulations with your first achievements! Secondly, photos of the Moon are so sensitive to atmospheric turbulence (aka 'seeing') that post-sharpening will indeed be required in many cases, unless the atmosphere is exceptionally calm and the Moon high in the sky, where you shoot through a minimum of air. Stacking (for example in Registax - freeware) of some 5-10 exposures will be the best, although also a more laborious route to post-processing.

Here's a small animation, based upon 3 frames recorded over less than 1 second, I have made to illustrate the effect of poor seeing and stacking:

[Rnovo]

Great suggestions, Stone G., I'll visit the site and give this a last try tonight - until next time around for 1/4 moon shots!
I didn't stay up until 1AM this morning when the moon was at it's highest - and I should have, as you say - for the reasons you mention...!
Great way to show the moon - I like that!
Thanks again.