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Aetna Rokunar 300mm f5.6
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PostPosted: Mon May 24, 2010 3:23 pm    Post subject: Aetna Rokunar 300mm f5.6 Reply with quote

Just picked this one up today, an Aetna Rokunar 300mm f5.6. It came to me with an inoperable aperture, a loose barrel, and no set screw in the tripod collar. But for once, the right mount!! Very Happy

I've already fixed the aperture (a stuck stop-down mechanism), as well as the barrel (three loose set screws behind the tripod collar, accessible through the tripod socket).


I don't know anything about this lens, so I'll describe it. It has a built-in sliding lens hood that is quite large:


.. and it extends a considerable length when you focus it.




The close focus is quite close, somewhere in the range of 1 to 1.5m. It gives dim blueish reflections off of the front element, so I believe it is multi-coated, and it was made in Japan. The Nikon mount is permanent, and is not a T-mount.



With the lens and hood collapsed, it is the same length as my 30cm (300mm) Minolta TELE ROKKOR-QD, f/5.6, but the Minolta is narrower and noticeably lighter. The Aetna appears to have better coatings than the Minolta, and focuses much closer (1.5m vs 4.5m). The Minolta is a preset lens, while this Aetna is *not* a preset.


Other than that, I don't know anything, and the search is turning up results for much older Aetna lenses. Does anyone know anything about this particular model, or Aetna in general during this time period?

Thanks. Cool


PostPosted: Mon May 24, 2010 3:40 pm    Post subject: Reply with quote

Aetna was a brand name used by a US importer that at one time also used other well-known trademarks either by themselves or in conjunction with Aetna - "Rokunar", "Coligon", etc.

Just about everything was sold under this brand/brands, so there is no way at all to tell what you have without a picture.


PostPosted: Mon May 24, 2010 4:37 pm    Post subject: Reply with quote

That's a carbon copy of the Tamron Adaptamatic 300/5.6 and some of the earlier Adaptall 300/5.6 designs. So it's a Tamron basically!


PostPosted: Mon May 24, 2010 4:51 pm    Post subject: Reply with quote

luisalegria wrote:
Just about everything was sold under this brand/brands, so there is no way at all to tell what you have without a picture.


I put five pictures in the original post... are they not working?


PostPosted: Mon May 24, 2010 5:06 pm    Post subject: Reply with quote

ManualFocus-G wrote:
That's a carbon copy of the Tamron Adaptamatic 300/5.6 and some of the earlier Adaptall 300/5.6 designs. So it's a Tamron basically!


Wow, good eye! Shocked

I found the match on adaptall-2.com: (edit: now adaptall-2.org)








I suppose this means that it is a decent lens then? Very Happy


Last edited by Scheimpflug on Fri Jul 16, 2010 1:49 am; edited 1 time in total


PostPosted: Mon May 24, 2010 5:14 pm    Post subject: Reply with quote

Several people here have seen good results with theirs, although my example was pretty crappy to be honest!


PostPosted: Mon May 24, 2010 5:34 pm    Post subject: Reply with quote

No, I didn't see your pictures, I don't know why. Perhaps my work internet settings are interfering. I do see Scheimpflugs pictures though.

I also have this Tamron. I find it excellent, its my favorite 300mm at the moment.


PostPosted: Tue May 25, 2010 12:38 am    Post subject: Reply with quote

Nice buy Scheimp! I have a 135 adaptamatic. You know pictures from this lens are expected! Very Happy


PostPosted: Tue May 25, 2010 4:08 am    Post subject: Reply with quote

ManualFocus-G wrote:
Several people here have seen good results with theirs, although my example was pretty crappy to be honest!

Well, that's good to know... I guess. Very Happy What sort of problems did yours show? Also, were you testing yours on the 5D?


luisalegria wrote:
I also have this Tamron. I find it excellent, its my favorite 300mm at the moment.

Great news. Cool Do you use yours on your Pentax DSLR or on your film bodies?


I'm wondering if there was just a lot of sample variation between these lenses, or if the full-frame vs digital crop usage makes the difference... Either way, I'm happy to learn that it is a Tamron as opposed to a complete no-name lens maker. Wink


PostPosted: Tue May 25, 2010 4:20 am    Post subject: Reply with quote

mo wrote:
Nice buy Scheimp! I have a 135 adaptamatic. You know pictures from this lens are expected! Very Happy


Yep, I'll try to get some test shots. Cool

I think that with any new lens, you pretty much have to take it somewhere and leave the rest of your lenses behind for a bit. Just walk around with it and get a feel for the characteristics. Otherwise, if you don't know what it is good at (and what it is NOT good at), you won't ever know when to take the lens or when to grab it out of your bag. Wink


I'm still not entirely sure when I will use this one, to be honest... For flexibility in normal use, the D40's kit 18-55 combined with the Vivitar series 1 70-210 is very hard to beat... I've been looking forward to finishing the modifications on my 300mm preset Minolta, as it's size & weight would make it much less intrusive as an "extra" lens to carry around... This Aetna might be a better lens (who knows, haven't tested either one yet), but it's weight and bulk might be too much to carry around for general use unless I leave the 70-210 at home... We'll see what happens. Very Happy


PostPosted: Sat May 29, 2010 7:46 am    Post subject: Reply with quote

mo wrote:
You know pictures from this lens are expected! Very Happy


Ok, here they are. Cool

This lens has absolutely exceeded my expectations. Shocked I put it on the D40 and took it out on a cold overcast afternoon (just starting to snow) and shot at ISO 400 & 800 while shivering, and this is what I got. Very Happy


ISO 400, 1/400 second, f/8. Test of infinity and close focus abilities:




ISO 800, 1/200 second, f/8. I wanted to see how easy it was to focus smoothly, so I picked a moving chairlift as my subject. I took 6 shots as it came toward me, and 4 of them turned out. Surprised


And finally, a 100% crop. ISO 800, 1/200 second, f/8.



I'm thoroughly impressed. It may not be the most practical focal length, but it will be hard to leave this one at home now that I know what it can do. Wink


PostPosted: Sat May 29, 2010 10:59 am    Post subject: Reply with quote

Nice surprise.

I am afraid it would be just too heavy on my G1, in fact the Vivitar Series 1 70-210/3.5 is.


PostPosted: Sat May 29, 2010 11:53 am    Post subject: Reply with quote

revers wrote:
I am afraid it would be just too heavy on my G1, in fact the Vivitar Series 1 70-210/3.5 is.

You have the v2 Tokina version of that lens, right?

I have the v3 Komine version, and this 300mm feels a bit lighter when you lift them side-by-side. When you use them though, the difference is more pronounced - the Vivitar feels much heavier.

It's hard to describe, but I think it comes down to the fact that with the Vivitar, you really don't have anything solid to hold on to - everything moves, and in multiple directions. So when you hold the Vivitar, you *have* to hold the camera to help support the lens. With the Aetna, the focus grip only rotates, it doesn't slide, so you feel like you can support more of the lens weight with your left hand, especially when pointing the lens at larger angles up or down. The lens also has a tripod collar, which you can hold on to, or use with a tripod. Wink

The weights are all relatively close:
Vivitar S1 70-210 v2: 710g
Vivitar S1 70-210 v3: 860g
Auto Tamron 300: 795g
... and I assume that this Aetna is slightly lighter than the Auto Tamron 300mm, as the mount is non-removable and there is no auto/manual switch. So it might actually be pretty close to the weight of your Vivitar. Wink


PostPosted: Sat May 29, 2010 12:48 pm    Post subject: Reply with quote

I've also got the Tamron version of this lens. Admittedly I was never really happy with it. I've not yet tried it on my K7. Maybe I'll have to give it another go. I did find it has really bad PF wide open, and I just didn't find it that sharp. Maybe I'll have better results on K7.


PostPosted: Sat May 29, 2010 1:57 pm    Post subject: Reply with quote

"You have the v2 Tokina version of that lens, right? "

That is correct.

After seeing your shots it this thread I went out this morning & tried something similar. See my post Sears 80-200/4.0.


PostPosted: Sun May 30, 2010 2:50 pm    Post subject: Reply with quote

eccs19 wrote:
I've also got the Tamron version of this lens. Admittedly I was never really happy with it. I've not yet tried it on my K7. Maybe I'll have to give it another go. I did find it has really bad PF wide open, and I just didn't find it that sharp. Maybe I'll have better results on K7.


You should give it another shot, and make a thread for some samples. Cool


I haven't done any tests with mine wide open, but I didn't find any real fringing problems at f8. The D40 doesn't correct CA/PF, so I know it isn't being processed away. I will have to wait for a sunny day to test some higher contrast edges to see how it does, but so far it looks like fringing is pretty well controlled.

Mine certainly seems to be plenty sharp too. I have to adjust the focus carefully, as it will focus just a touch past infinity. So if I just turn it until it stops, I won't get a sharp photo. But just a fraction of a turn before the stop, the focus confirmation lights up and the shot is good. Cool


Here's another sample. ISO 400, 1/250 second, f/11


That mountain is about 9.5 km (~5.9 miles) away, and the snow you see is the snow that started falling during my first test a few days ago. Cool


PostPosted: Sun May 30, 2010 6:02 pm    Post subject: Reply with quote

Scheimpflug wrote:
ManualFocus-G wrote:
Several people here have seen good results with theirs, although my example was pretty crappy to be honest!

Well, that's good to know... I guess. Very Happy What sort of problems did yours show? Also, were you testing yours on the 5D?


Hello

I shot that lens on a variety of cameras, but mostly my Sony a200. The lens was soft until f11 and got thrashed by other 300mms, especially my Soligor 300/5.6. Your copy looks good however Smile


PostPosted: Mon May 31, 2010 6:01 am    Post subject: Reply with quote

Scheimpflug wrote:
The weights are all relatively close:
Vivitar S1 70-210 v2: 710g
Vivitar S1 70-210 v3: 860g
Auto Tamron 300: 795g
... and I assume that this Aetna is slightly lighter than the Auto Tamron 300mm, as the mount is non-removable and there is no auto/manual switch. So it might actually be pretty close to the weight of your Vivitar. Wink


So I put both lenses on our cheap mechanical kitchen food scale (0 to 1000g readout). The Vivitar came in at ~865g, so the scale is pretty close! Cool I then put the Aetna on, and got a reading of ~775g. So this lens does appear to be slightly lighter than the Auto Tamron.

I should point out that I removed both caps from both lenses before weighing, and I left the clear filter on the front of the Vivitar. Also note that my Aetna is still missing the screw/knob that locks the tripod collar rotation. Our kitchen scale was really cheap, so the actual weights may vary. Cool


PostPosted: Tue Jun 01, 2010 5:37 am    Post subject: Reply with quote

I'm starting to think that perhaps this lens is NOT a direct copy of the Adaptamatic Auto Tamron... or any of the Tamron 300mm f5.6's for that matter. I've been comparing the versions, and mine just doesn't match up. Confused


So here's mine, the Aetna Rokunar 300mm f5.6:



.. and now let's look at the Tamrons. First is the Auto Tamron, with the Adaptamatic mount, model 670Au:

http://www.adaptall-2.com/lenses/670Au.html
(edit: now http://www.adaptall-2.org/lenses/670Au.html)


followed by the early (transitional?) Adaptall version (posted on the forum here by member dab63, but not listed on adaptall-2.com):

http://forum.mflenses.com/silver-tamron-300mm-f-5-6-adapt-a-matic-or-adaptall-t23757.html


followed by the Adaptall version, model CT-300:

http://www.tamron.co.jp/data/old-lens/ct300.htm


followed by the Adaptall-2 SP version, model 54B:

http://www.adaptall-2.com/lenses/54B.html
(edit: now http://www.adaptall-2.org/lenses/54B.html)



Comparisons:
  • The Aetna has the most visual similarity to the Auto Tamron.
  • The presence of a tripod collar on the Aetna matches it with the Auto Tamron and the early Adaptall.
  • The Aetna's focus/DOF "tree" is a diagonal fan-out style, matching the Adaptall version of the Tamron, but not the Auto Tamron or the early Adaptall.
  • The Aetna has 62mm filter threads match the Auto Tamron and the early Adaptall, but not the Adaptall or Adaptall-2 SP models (58mm).
  • The Aetna's focus grip moves away from the mount when focusing, which matches everything except the Adaptall-2 SP.
  • The Aetna's close focus distance is around 1.5m, and the lowest marking on the focus ring is 1.7m. The minimum focus for the Auto Tamron is 2.5m, and remains 2.5m for the Adaptall version. The only Tamron with a closer close focus is the Adaptall-2 SP at 1.4m.
  • The only Tamron to get consistent good reviews for optical quality is the Adaptall-2 SP.
  • The Adaptamatic has 4 elements in 2 groups, the Adaptall has 4 elements in 4 groups, and the Adaptall-2 SP has 6 elements in 5 groups. Looking into my Aetna through the mount side under a bright light with the lens cap on the front, I can see 5 reflections and a possible tiny tiny sixth.



... So what do I have? Question Is this perhaps not a standard Tamron lens, but maybe a "clean-up" batch to make use of parts left over from other lens designs? Question


Last edited by Scheimpflug on Fri Jul 16, 2010 1:51 am; edited 1 time in total


PostPosted: Tue Jun 01, 2010 7:14 am    Post subject: Reply with quote

Interesting. Please note though, there were at least two versions of the Auto Tamron (Adaptamatic). Mine looked very similar to yours with the same focusing barrel.



PostPosted: Tue Jun 01, 2010 8:01 am    Post subject: Reply with quote

That Aetna looks like the Adaptamatic version indeed, and I would be surprised if it had a different optical layout, all the other important bits like the focusing helical and aperture mechanism are in exactly the same places as with the Adaptamatic. This all would be different with different glass. The differences vs the Adaptamatic are purely cosmetic. The Adaptall-style DOF scale is a case in point.

I bet this lens was yet another transitional type dating from the early 1970's, when the Adaptalls were coming in, made up possibly from existing bits but certainly from existing Adaptamatic tooling.

There were many undocumented variants it seems, especially those fixed mount types made for third parties. I even have lenses labelled by Taisei (Tamron) that have absolutely no relation to the "known" types.

As for performance - I have absolutely no complaints against my Adaptamatic, its one of those lenses that manages to almost focus itself.


PostPosted: Tue Jun 01, 2010 8:14 am    Post subject: Reply with quote

Luis - what do you think about the large difference in the minimum focus distance? That is pretty much the only piece I can't explain as a cosmetic change...


PostPosted: Tue Jun 01, 2010 6:21 pm    Post subject: Reply with quote

I can't explain it either. I can only speculate. Possibly the helical in the basic Adaptamatic design of this lens has some additional travel available that is limited by a stop - not an unusual situation. For whatever reason - competitive feature bid against a rival maker ? - this one made for Aetna was given closer focus capability, maybe as simply as moving the stop and permitting some more rotation on the helical.

Whatever the explanation, the sum of all the features says "Tamron Adaptamatic" to me.


PostPosted: Sun Sep 12, 2010 1:45 am    Post subject: Reply with quote

My copy, M42.





PostPosted: Sun Sep 12, 2010 10:30 am    Post subject: Reply with quote

Thanks, visualopsins! That makes two... up until now, I had only know of mine, and I hadn't seen any like it on ebay or anywhere else. Wink

There are some slight differences, such as the chrome trim around the grip on mine, and the fact that mine says "AETNA ROKUNAR" while yours says "AUTO ROKUNAR"... but otherwise they appear to be identical! And now, I know what kind of knob to look for for the tripod collar set-screw. Cool

It is interesting how different the serial numbers are... 296xxx vs 693xxx.