[Spamer]

Hi Tamron fans,

I am a new member of Pentax Forums and have been scanning the posts in the Tamron club and found some interesting information. However various searches of the thread have not shed any light on my question/problem.

I have 4 Tamron lenses (an SP 500mm mirror [55B], an SP 90mm [52B] - my favourite lens, an SP 28-80mm [27A] and a 70-210mm [46A]), 2 x Tamron 2x teleconvertors [01F]. The 27A and the 46A were bought decades ago for use with my Ricoh XR-X 35mm cameras. The 55B, the 52B and the 2 01Fs are recent purchases after rediscovering my interest in photography as my daughter is now studying "Digital" photography in college. (We now have a K-30 and my XR-Xs.)

My question/problem is related to the 2 01F TCs. One is crystal clear and appears to do its job very well. The other seems a bit hazy when inspected with a magnifying glass and held up to the light, and is obviously not as good as the other from viewing test shots. The bad one does not appears to be suffering from fungus, just general muck and dust.

I am considering de-glassing the poor 01F TC for use as an extension tube. Does anyone have experience of doing this? What is the difference between using a 01F and a de-glassed 01F (or a 18F - almost the same as a de-glassed 01F except for a few mm), in terms of DOF and IQ for macro work (glass - no glass must make some difference!)?.

Also the glass in the 01F appears to be glued in - is the glass difficult to remove? (I have de-glassed a Teleplus MC4 KAX 2x TC, which had some fungus, to make a 23mm extension tube. That was easy.

Both 01F TCs were picked up at a camera stall at a local market, very cheap, £7 for the good one and £5 for the duff one. So possible waste of money is not a problem.

I apologise for the length of this post. Any help/advice would be appreciated.

Mike

(the PEAK half of zhang_peak, ZHANG is my daughter Yasmine)

Zhang welcome. I don't have the expirience of deglassing 01F, but I saw one without glass on eBay. The seller wrote that it works just like 18F extension tube. I don't see anything wrong here. Actually I have two 18F extension tubes and must say that because it was designed special for 52B(b) tamron lens it has non movable fitment. So when you're trying to attach it to some slower lens (my 19AH for example) it does not fit correctly. The 01F fitment is free to move so it should be the better solution. But actually I doubt that you will use the 18F or deglassed 01F with something else than your 52B since it's the exact macro lens.
I can only tell you "good luck" here. It should work as you think. My 01F has damaged coating, but it seems that I had more luck and it does not affect image quality.

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Last edited by Spamer; 10-23-2013 at 04:29 PM.

[pacerr]

If you have a poor quality 01F it will be most useful as a de-glassed extension tube. I have done that myself.

H2

[Jean Poitiers]

If you have a poor quality 01F it will be most useful as a de-glassed extension tube. I have done that myself.

H2

Guess what's now on my "to do" list ... Salut, J

[Jean Poitiers]

My experience with "slight" fungus is that I do not notice any degradation in IQ usually, so it is not worth opening the lens up. Even if you can figure it out may do more damage than good (if it aint broke, don't fix it). Much depends on where the fungus is. Front elements: less effect and more readily accessible for cleaning. Deep/rear elements: bad juju
I have a 19AH which has pervasive "light" fungus on a number of elements through the lens and this has clearly lower contrast (in the project box....). Conversely the first adaptall lens I bought, a 23A, has what looks like pretty heavy fungus on the element by the iris, but I cannot really say I can see much effect.
A votre disposition...

Salut marcus ... thanks for your post and sorry for my slow reply ... busy, busy times ...

Still have not decided about the 26A, and I, too, have a 19AH with a bit of fungus ... have not shot with it yet; picked it up at my thrift store for 3€ with a Nikon mount (previously posted I think) ... I'd like to service it but the tolerances to me are already quite tight, and this lens has been dropped with a dent on the outer and inner barrels ... thus, mission impossible IMHO ... here's an image. I doubt if anything will be visible with such "little" fungus ... Salut, John

[kacansas03]

Salut marcus ... thanks for your post and sorry for my slow reply ... busy, busy times ...

Still have not decided about the 26A, and I, too, have a 19AH with a bit of fungus ... have not shot with it yet; picked it up at my thrift store for 3€ with a Nikon mount (previously posted I think) ... I'd like to service it but the tolerances to me are already quite tight, and this lens has been dropped with a dent on the outer and inner barrels ... thus, mission impossible IMHO ... here's an image. I doubt if anything will be visible with such "little" fungus ... Salut, John

Wow that lens hit hard. I see deformation on 2 areas of the barrels plus deformation what looks like an inner thread ring not just the filter thread. on the other hand it doesn't seem to have too much fungus but only you know what kind of IQ you are getting from the lens. Good luck with your projects!

[Jean Poitiers]

Wow that lens hit hard. I see deformation on 2 areas of the barrels plus deformation what looks like an inner thread ring not just the filter thread. on the other hand it doesn't seem to have too much fungus but only you know what kind of IQ you are getting from the lens. Good luck with your projects!

Salut kacansas03,

Yep ... it took a real good shock there ... I have tried to loosen the inner retaining ring, but it's hopelessly stuck IMHO... I need to go out and shoot with it and I will report back when possible ... just not enough time to do all ... Later, J

[pacerr]

I have tried to loosen the inner retaining ring, etc . . .

Jean, a coupl'a tricks:

- The concentricity of outer barrel shells isn't necessarily a functional problem if it doesn't jam or rub too much. Sometimes you can simply cut away a portion of the rim to free the barrel to rotate. Sort'a like extracting a tooth! A side benefit is that if it's in a filter thread that may relieve some distortion stress and allow the remainder of the threaded rim to return to a useable form -- and even accept filters if desired.

I've had some small success using a section of a empty filter ring as a mandrel(?) to press out dents in lens filter threads using needle-nosed Vice-grips as a pressure tool. The threads self align on the inside of the barrel and a metal-backed leather strip provides support on the outside of the rim. A poor man's DIY filter thread vice.

H2

[marcusBMG]

and I, too, have a 19AH with a bit of fungus ... have not shot with it yet; picked it up at my thrift store for 3€ with a Nikon mount (previously posted I think) ... I'd like to service it but the tolerances to me are already quite tight, and this lens has been dropped with a dent on the outer and inner barrels ... thus, mission impossible IMHO ... here's an image. I doubt if anything will be visible with such "little" fungus ... Salut, John

Bonsoir Jean et al

Now the fungus I can see in your pic thats what I call light fungus and I shall suggest that there will indeed be no discernable effect on IQ - but is that the only fungus....? I just spent a few wasted minutes holding my 19AH to the light and trying to get a worthwhile image of the fungus deep in the lens. It sure does catch the light I can see why its effecting IQ

By coincidence I have also just been in the garage straightening out the filter ring on my smc 50mm. Pic shows the essential tool for me; Its a piece of hardwood I shaped, then I used "chemical metal" (a hard type epoxy) to make it a perfect mould of the lens barrrel profile. I used floor wax to stop it sticking - worked (just!!) Apropos pacerr's advice I have to say I had little success with squeezing/gripping techniques. What worked for me was laying the lens in the "mould" and using another pencil like piece of hardwood as a tamp with a light hammer. The wood is soft enough not to ruin the thread but hard enough to straighten the ring. IMO only st like this is going to have an impact on those dents the metal is too thick.
Bonne chance with that one!

[marcusBMG]

I have ben enjoying myself lurking on the Conwy quayside with my lately acquired 300mm f5.6, trying to catch snaps of the the maurauding avain fauna...



But thats an adaptamatic you cry. Well I shall reason that its the same apart from the mount as the first version adaptall CT300 so let it in... pleeeese

I am acquiring an increasingly favourable impression. Crop and resize, bit of sharpen to compensate otherwise just off the card at f5.6.

[g026r]

I've got an issue popping up with my PK/A adapter. Curious if anyone has had it happen before, and if they know of a solution:

Was taking some longer exposures the other night, and noticed that anything taken at f22 was overexposed. Pressing the optical preview button and looking at the lens under a bright light, it appears that it's not stopping down all the way if the aperture is set to f22 from the camera body. (If the aperture ring is set to 22 rather than AE, then it stops down fine.)

I rarely use apertures that small and I have a workaround, so it's not a huge issue, but it's still somewhat annoying.

[Jean Poitiers]

Jean, a coupl'a tricks:

- The concentricity of outer barrel shells isn't necessarily a functional problem if it doesn't jam or rub too much. Sometimes you can simply cut away a portion of the rim to free the barrel to rotate. Sort'a like extracting a tooth! A side benefit is that if it's in a filter thread that may relieve some distortion stress and allow the remainder of the threaded rim to return to a useable form -- and even accept filters if desired.

I've had some small success using a section of a empty filter ring as a mandrel(?) to press out dents in lens filter threads using needle-nosed Vice-grips as a pressure tool. The threads self align on the inside of the barrel and a metal-backed leather strip provides support on the outside of the rim. A poor man's DIY filter thread vice.

H2

Bonjour H2,

Thanks a lot ... not a bad idea at all ...

Oh, and did I mention that I just bought a third 19AH out of Belgium for a good price ... made a "low-ball" offer and it was accepted ! Awaiting the lens now ... will keep you (all) posted ... here's the dented 19AH when I got it from my thrift store, with my good 19AH to the right of it.

The "3" on the filter was the price of the dented 19AH ... THREE EUROS with a Nikon mount plus rear cap & the filter itself ... the Nikon FG-20 was only 5€ and I gave it to a French friend that's a D700 "prime" shooter guy with his own wet dark room ... gave it to him in return for a MV-1 with a M 50/1.7 that he had given me earlier ... Salut, J

[Jean Poitiers]

Bonsoir Jean et al

Now the fungus I can see in your pic thats what I call light fungus and I shall suggest that there will indeed be no discernable effect on IQ - but is that the only fungus....? I just spent a few wasted minutes holding my 19AH to the light and trying to get a worthwhile image of the fungus deep in the lens. It sure does catch the light I can see why its effecting IQ

By coincidence I have also just been in the garage straightening out the filter ring on my smc 50mm. Pic shows the essential tool for me; Its a piece of hardwood I shaped, then I used "chemical metal" (a hard type epoxy) to make it a perfect mould of the lens barrrel profile. I used floor wax to stop it sticking - worked (just!!) Apropos pacerr's advice I have to say I had little success with squeezing/gripping techniques. What worked for me was laying the lens in the "mould" and using another pencil like piece of hardwood as a tamp with a light hammer. The wood is soft enough not to ruin the thread but hard enough to straighten the ring. IMO only st like this is going to have an impact on those dents the metal is too thick.
Bonne chance with that one!

Salut marcus,

Thanks a lot for your post ... this 19AH is in the "project box" and your technique sounds interesting ... thanks again for the advice ... I really need to go out and shoot with this dented/fungus 19AH to see what it does in real life ... will keep you (all) posted ... A+, J

[dms]

(go26r) possibly the PKA adapter is not properly showing the f/stop when fully open, and then every f/stop below will be off by the same amount. A problem that happens pretty often (I gather) is the wide open f/stop registers as f/4 when in fact it's likely f2.5 (or f2.8 or whatever). I have this on one of my PKA adapters. But I don't recall/not sure if that then causes it to overexpose (I usually shoot in M mode and use the lens aperture ring).

[g026r]

(go26r) possibly the PKA adapter is not properly showing the f/stop when fully open, and then every f/stop below will be off by the same amount. A problem that happens pretty often (I gather) is the wide open f/stop registers as f/4 when in fact it's likely f2.5 (or f2.8 or whatever). I have this on one of my PKA adapters. But I don't recall/not sure if that then causes it to overexpose (I usually shoot in M mode and use the lens aperture ring).

It's registering lower stops. Though now that I think of it, it might be showing 2.4 as the widest aperture rather than the actual 2.5. (Which would suggest that the ring or the tabs that slot into it are misaligned.)

[marcusBMG]

I've got an issue popping up with my PK/A adapter. Curious if anyone has had it happen before, and if they know of a solution:

Was taking some longer exposures the other night, and noticed that anything taken at f22 was overexposed. Pressing the optical preview button and looking at the lens under a bright light, it appears that it's not stopping down all the way if the aperture is set to f22 from the camera body. (If the aperture ring is set to 22 rather than AE, then it stops down fine.)

I rarely use apertures that small and I have a workaround, so it's not a huge issue, but it's still somewhat annoying.

Can you do some test pics: ideally of a uniform surface under even consistent light. Need to distinguish the normal variance of exposure on a pentax from what you are seeing - seeLowell Goudge's graphs.

https://www.pentaxforums.com/forums/6-pentax-dslr-discussion/86746-accuracy-k...42-lenses.html

If you are indeed suddenly getting a large exposure discrepancy at f22 for me thats almost certainly a mechanical issue with the mount.