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08-13-2008, 04:14 AM   #31
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The only explanation of the double-aperture markings on the aperture ring is that the ring will turn to the right, rather than the left, on different mounts. (F, M42, FD, OM, MD?)

08-13-2008, 05:14 AM   #32
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QuoteOriginally posted by ftpaddict Quote
The only explanation of the double-aperture markings on the aperture ring is that the ring will turn to the right, rather than the left, on different mounts. (F, M42, FD, OM, MD?)
Must be the case.
08-13-2008, 05:58 AM   #33
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That's obviously different than my f/2.5, and looks smaller than the 2.8 I've ogled at the camera show. Meaning there's at least three versions of the TX 28 that I know of.

The aperture markings going the other direction are used for certain other camera mounts, where the thing turns in the opposite direction. All in all a less elegant solution than what Tamron managed with their Adaptall.
08-13-2008, 11:33 AM   #34
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Here are some grab shots from today with the 28mm. All have been processed with my usual work-flow. At first I thought there was something wrong with the lens but then I realised it was glare and reflection. This lens needs a hood. Nonetheless I walked about town to get some shots.

Flower Garden

At f/8. Saturated colours.




Rainy August

f/11 methinks with hyperfocal distance set (easy to do with the scale markings). Overcast day so slow shutter. Colours again seem vibrant and spot on. No colour temperature adjustments done here or elsewhere in this series.

Not a great brick wall for brick wall distortion testing.




Heineken Cup

I happened upon some sports stars doing a book signing. Mad crowds and police guarding the line-up. So I went down the back stairs and hung out with the press photographers and their giant full-frame digitals. They didn't even notice me manually metering.

Taken at f/4 maybe. Indoors and slooooow shutter. I pumped the contrast on this quite a bit.




Trinity Lion

Testing wide-open at f/2.8 and focus as close as possible. The clarity is nice and the bokeh smooth enough considering the ugly background. It won't win any prizes but won't embarrass you either.



08-13-2008, 02:38 PM   #35
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QuoteOriginally posted by ftpaddict Quote
The only explanation of the double-aperture markings on the aperture ring is that the ring will turn to the right, rather than the left, on different mounts. (F, M42, FD, OM, MD?)
Correct. I know Nikons from the period go the opposite of Pentax and I think either Canon or Olympus did also.
08-19-2008, 01:56 PM   #36
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QuoteOriginally posted by rparmar Quote
The Mount Lock



The locking mechanism for the TX to k-mount adapter. I believe one has to unscrew this protective cover, depress the tab, and then remove the adapter. There's no chance of this happening unexpectedly!
Actually, you don't have to unscrew anything. Push the tab in and twist, and the mount frees. An accident would have to be pretty complex for this to happen unintentionally.

I just received two TX's - the 200/3.5 and the 90-230. I had to take that second lens as part of the package and I'm sure I'll play with it too. I paid a total of $23 so I guess I broke my $10/lens rule...

The damnest thing though: now I have 3 TX M42 mounts, and each one is different! The one with the 28 has a proper A/M switch. The one on the 200 has a metal push button, one that sticks out like a long thumbtack! In other words, no "M" mode. Big deal, I use it on the Fuji and Spottie, and if I want it on the digital I'll use the one from the 28. The mount is labeled 'cs' if I remember right.

I thought the one on the zoom would have an A/M - it has a knurled, curved bit that looks like you should be able to move it sideways. And the letter M next to it. But no, it pushes in to stop down the lens...

Both lenses are very solid chunks of metal, serial numbers start with 37, and they both have tripod bushings. Haven't had much chance to try them out, though I did take the 200 out around midnight for some moonshots. It's funny, I had to keep my finger pushing that thumbtack thing to stop the lens down. Pics came out with good detail though.


So, who bought the TX K mount off ebay for $32? This could get as bad as the adaptall K-A situation
08-21-2008, 03:34 AM   #37
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The more I use the TX 28/2.5 the more I like it. I now think it at least equals if not exceeds the Takumars in resolution at middle distances...and focuses much closer. And the funky aperture makes for some interesting bokeh and highlighting.

TX 28mm f/2.5, K100D, spritzer bottle :






To see one large size (1300x1300):
http://www.flickr.com/photos/nesster/2783142983/sizes/o/in/photostream/
08-21-2008, 06:31 AM   #38
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Wow, that is some funky bokeh shapes!

08-22-2008, 05:13 PM   #39
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When I saw the aperture shape from f4 to f11 in my T2 lens I thought someone had done a home repair and put the blades back in upside down or something - I am glad to see that this is the stock configuration
Image taken with my newest lens the K2 (viv close focus 28).
08-23-2008, 06:12 AM   #40
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Actually I have seen that sort of blade shape... somewhere on one of my Pentax lenses. But I have never seen it show up in OOF highlights so distinctly!
08-23-2008, 11:28 AM   #41
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Heh heh, that's why I subjected the poor spider to the spritzer, I wanted to make use of that iris shape.

The 200/3.5 and 90-230/4 turned out to be T4 lenses, not TX. So I did a little photo essay:


T4 and TX mounts compared. These are the naked lens rears, the TX is in the middle, and it's a 28mm vs. the two teles so it has the lens element sticking out.

Each has the same tab - you push the little metal tab in and turn the collar in the O direction to release the mount. Re-attaching it, the collar is ratcheted and locks in place.

The TX has additional linkages available via the mount to permit open aperture metering. Note the little ears where the white arrow is pointing to the left on each lens - this is the aperture ring sensor and it lines up with the arrow when the lens is set to f/5.6. Which is why that aperture is in a different color - you set it there to attach a mount.


T4 TX T4 on Flickr - Photo Sharing!

These are the mounted lens rears, the TX is on the right, mounted on a T4 200mm lens.


On the web, it is said that you can mount a TX on a T4 lens, but rarely the other way around. Well, I managed to mount the TX on the 200mm T4, however I only got f/4 instead of f/3.5. So it can be done, with limitations.

The PX = pentax screw mount is a bit frustrating, it has a knurled knob that does NOT lock into place for manual operation (ie. on a K mount converter). I can still use it on the screw mount bodies though.

The CS mount in the middle is a mystery - what does CS stand for? It has a big push pin (you can see it at 5 o'clock) that closes the aperture. I'm using a hair bungee to hold it closed when I use this mount on the K100D. Otherwise it is just a M42.

The P/ES is a TX mount, a perfect reproduction of the SMC Takumar mount.


T4 Tx PK CS PES on Flickr - Photo Sharing!

The rear of the mounts, unmounted.


rear px cs pes on Flickr - Photo Sharing!

The front of the mounts, ie. where the lens goes. You can tell the TX because it is the one that says TX on it. You line up the white arrow to the same on the lens, then tighten the ratcheted collar.


front px cs pes on Flickr - Photo Sharing!
09-28-2008, 03:12 PM   #42
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Hi Guys,

Just stumbled onto this thread via Google so joined up with your group. I am a user and avid collector of the T4-TX series lenses. Several years back I wrote a web page on the T4s. You can see it here.

T4 For Two

Since then, I've acquired all of the T4s (I think) and am closing in on all of the TXs. There are some interesting variations, as you've discovered in this thread.

In regards to the CS engraved on some of the M-42 adapters, I speculate it stands for Contax S or Contax Screw. The East German Contax S of 1949 being the first camera in series production to use the M-42 screw mount. It is found on screw mount lenses that originated at Tokina. That list includes Soligor, Sears, Lentar, Focal, Ricoh, Mamiya/Sekor and others.
09-28-2008, 03:14 PM   #43
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QuoteOriginally posted by casualcollector Quote
Hi Guys,



T4 For Two
One of my favorite pages on the net, thank you!

And thanks for the explanation of the CS... makes sense.

Welcome aboard!
09-28-2008, 03:54 PM   #44
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Very cool page. Amazing research there.
09-28-2008, 04:25 PM   #45
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QuoteOriginally posted by rparmar Quote
Very cool page. Amazing research there.
Not so much research. More like a bit of experience and a bunch of hunches. Some of that information I would go in and change now, if I could. I am no longer a subscriber to that internet provider so I can't change it. Luckily, they haven't taken my site down to make room for something else. I'll move it when I find an affordable alternative.
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