The Vivitar 2x Macro Focusing Teleconverter: More Than A Gimmick

I came across this Vivitar 2x Macro Teleconverter in the local camera shop years back and thought it looked pretty interesting. Against my usual judgement, and because I needed to spend a few extra dollars to get a deal on something else, I picked it up. It was only recently I began playing with it and upon discovering it's very capable nature, I did some web crawling and found it has quite a following (and for good reason it seems). So I figured, what better way to see what it's capable of, than compare it to a couple of my favorite manual focus macro lenses? The Kiron 105mm and the Tokina 90mm (Vivitar Series 1 90mm could be also considered as they are optically very similar).

I have not used a ton of optical adapters in my life. This is due, in part, to a commonly held photographic tenant that says: adapters, teleconverters, or any optics placed between your lens and the camera will degrade image quality. If you are unfamiliar with this concept, consider this: Prime lenses, lenses with a single focal length, are designed for a fixed angle of view (e.g. what you will see in the frame). And to this day, no lens exists that is devoid of all optical aberrations. These greatest lenses we have still have aberrations, albeit far less prominent than their average counterparts. To complicate things, consider the zoom lens. Zoom lenses introduce new problems because now we are attempting to do the same thing as mentioned above, across a range of focal lengths, which inevitable taxes the design even further. Inevitably, we find more aberrations in zooms (Though again, there exist some AMAZING zoom lenses, that is to say, the output still looks amazing for printing and even enlargement, so we are still speaking in relativities). Now consider the adapter, be it a teleconverter or macro adapter, or what have you. This optic, especially those from third party manufacturers, attempts to accept the image coming from a range of optics (designed by different companies), and manipulate it (increase magnification, etc.). The adapter must do this despite already present aberrations from the primary lens AND try not introducing too many more aberrations. Because of the introduction of more glass into the formula, we already lose some light (stops). Tell me that's not a tall order.

But, as I say, keep in mind, the relativity of this concept. All lenses have aberrations. And yet, everyday we make and see amazing imagery coming from these lenses. The key is understanding each lens' strengths and weaknesses and using them appropriately. And thus, we come to the point of why I bother pixel-peeping and writing. It is quite simply, to answer the next, and more oft asked questions, 'How much is the image degraded? Does the optic enable me to capture something I would otherwise not have been able to record, and with acceptable enough quality to match my desired output?" This answer will inevitably be different for everyone and again, I stress, the whole purpose I write is to share my findings, and let you decide (though I obviously throw in my 2 cents!).

Setting the Stage

Recently, my wife asked me to photograph jewelry she made, to begin listing it on etsy. I decided on a backyard shoot, in the grass. I naturally grabbed a beer first (given the weather, a New Belgium's Summer Helles seemed appropriate!), my favorite macro lens, the Tokina 90mm f/2.5 and begun making images. I had also recently been conceptualizing a post about this Vivitar Macro Adapter and realized this would also be the perfect opportunity to explore the adapter's capabilities. After completing the 'job', the day was simply too gorgeous to go inside and I began tinkering (montage to the day pictured above). Using a piece of her jewelry as my subject, I grabbed my Kiron 105mm f/2.8, the Tokina 90mm f/2.5, and the Vivitar 2x Macro Focusing Teleconverter which I attached to my Nikon Series E 50mm f/1.8.

Also, I have begun using a GGS Swivi LCD Viewfinder to achieve critical focus. I cannot recommend one of these more! For me, it functions in several ways: Most importantly, I found I was having trouble achieving pin-point accuracy of focus, especially when using larger apertures (shallow DoF). This finder enables me to use the live view mode, zoom into my images to find precisely where my focal plane is, in my frame, even in bright sunlight. I will likely be reviewing this further in the future.

Specifications
Source: The teleconverter's user's manual.

Optical Construction: 7 elements, 5 groups
Coating: Multi-coated for increased light transmission
Diaphragm Coupling: Fully automatic
Weight: 282g (10 oz)
Length: 44.2mm (1.74")
Max. Barrel Diameter: 66.1mm (2.6")

Manufacturer: It seems to be suspected that Kenko-Tokina was the producer of this optic, and a few variations in branding have been reported, though all seem to be the same 7-element optical formula.
Other Brandings: Teleplus, Panagor

As a 2x teleconverter, this optic doubles your focal length and reduces light transmission by 2 stops. So in the case of this article, my Nikon Series E 50mm f/1.8 becomes a 100mm f/3.5. Macro reproduction can achieve 1:1 with this teleconverter.

Build and Handling

This little adapter feels solid in the hands, and the focusing helicoid turns smooth as butter. It appropriately harkens back to the solid lens builds of it's day. Overall, it is a pleasure to use.

Disclaimer

I want to emphasize that this article is about my experience with this optic. As with any optic, so many factors can contribute to skewed results. Consider that element is amplified ten-fold with the Vivitar Macro Teleconverter since it is an adapter, to be used in conjunction with so many other lenses. Someone using a different lens (than the Nikon Series E 50/1.8) will likely have a completely different set of results. That is, in some ways, the exciting nature of the optic. Experimentation!

Comparison

The following is the full frame I opted to use to do my comparison. I found a busy log, and place the shiny bracelet on it. It is, indeed, a cluttered shot (and this is the point). For me, the frame was about finding a frame that contained depth, lots of detail, and a range of highlights and lowlights. There will be some differences in lighting as the sun did pass behind some clouds now and again, and because of the varying focal lengths, the magnification of the subject within the frame will shift slightly (though they are pretty close). Also, I noticed the focal plane is shifted ever so slightly between images, though it shouldn't be difficult to see where focus is and assess accordingly. The full image is reduced resolution, but all crops are 100%.

Full Image

Wide Open Crop (Near Center)

Wide Open Crop (Off Center)

Crop @ f/5.6, f/5.6, and f/7.1 (Near Center)

Crop @ f/5.6, f/5.6, and f/7.1 (Off Center)

For this comparison, I only posted the results wide open, and then stopped down 2 stops to summarize my findings as I look at the results with all apertures. Wide open, using the Series E 50mm, the image quality suffers from some massive issues. It looks downright terrible (to me). Significant chromatic aberration is evident, some serious coma is occurring out at the edges, the bokeh is awful, sharpness across the frame is laughable. It's poor. But, no kidding, as soon as I stopped the lenses down to f/4 (and effectively f/5 for the Vivitar), the Vivitar quickly began falling in line. And by stopping down 2 stops, to f/5.6 (and f/7.1 effectively for the Vivitar), we can see the teleconverter/50mm combo becoming an actual contender, or at least an optic worthy of comparing.

Here is another impromptu comparison between an image I made, of a little bug on a leaf, first with the Tokina 90mm and then with the Vivitar/50mm combo. The framing is different, the plane of focus is slightly different, but again, consider it for what it is.

Bug on a Leaf

Tokina 90/2.5 (1/400 @ f/5.6)

Bug on a Leaf (crop)

Tokina 90/2.5 (1/400 @ f/5.6)

Bug on a Leaf

Nikon Series E 50mm and Vivitar 2x Macro Focusing TC (1/320 @ f/10 effectively)

Bug on a Leaf (crop)

Nikon Series E 50mm and Vivitar 2x Macro Focusing TC (1/320 @ f/10 effectively)

Conclusion

Clearly the Vivitar 2x Macro TC is capable of producing some impressive macro results, technically speaking. I mean, for a TC I am very impressed and pleased to own it. I love the concept of experimentation and will definitely be trying it with my other lenses.

But where I find issue with this TC is simply it's lack of robustness. In order to get solid results, many variables must be accounted for. The user must have a proven lens to mate with the teleconverter. He or she will likely need to stop the lens down a bit to achieve significant results which means losing even more light than the 2 stops this 7-element TC already absconds with. So any f/1.8 or f/2.8, which becomes an f/3.5 or f/4 just by attaching the adapter, becomes an f/7.1 or f/8 once stopped down to the sweeter spot. That means we need to have a fairly well illuminated subject to be able to capture sharp images devoid of any camera shake (and the use of a tripod becomes all the more important, which isn't necessarily convenient).

I bought this TC for something like $30. I bought my Nikon Series E 50/1.8 for nearer $40. Glancing on eBay, I see many of these TCs for sale, for around $40+. So consider, we achieved the image quality above for ~$70.  In my experience, I have found plenty of macro lenses for around this price. Heck, an old Nikkor 55mm f/3.5 would run you the same price as the adapter sometimes. The occasional Vivitar 90mm f/2.5 (Komine made version) will go for between $75-150. The point I am making is, you can find a dedicated macro lens that will likely outperform this adapter (plus whatever you stick it to) for around the same price or slightly more (or less if you really find a deal!).

BUT, all that said, should you happen into one of these, for the right price, let it not be said, it is a poor optic. Quite the contrary, this little TC can enable you to capture some very beautiful, high-magnification images.

Other Sample Images

Dandelion

Nikon Series E 50mm with Vivitar 2x Macro Focusing TC @ effectively f/7.1

Dandelion (crop)

For fun, I threw the Tokina 90mm f/2.5 with it's matched macro extender on the Vivitar Macro Teleconverter and in conjunction with an off-camera SB-600, captured a few images of this little jumping spider that appeared on my windowsill.

Jumping Spider (cropped)

Tokina 90/2.5 with 1:1 Extender and Vivitar 2x Macro Focusing TC @ effectively f/22 (-3 stops)

The image above is a crop, has some post-processing applied and some sharpening because of it has been resized down using the 'bi-cubic sharper' setting in PS. Still, after using both the Tokina 90mm macro extender and the Vivitar Macro Teleconverter, I was able to really get in tight (while still maintaining 8-10" of working distance, with this jumping spider. As can be seen, chromatic aberration is present but I am still very impressed.

Resources

Pentax Forums thread with a good amount of user input on this TC:
http://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/27163-vivitar-2x-macro-focusing-tele-converter-definitive-thread.html

The Chens blog - write up with User Manual!
http://mailch.blogspot.com/2012/08/the-users-review-vivitar-2x-macro.html

Another User's Write-up
http://www.nicobastone.com/Vivitar_2x_Macro-Focusing_Teleconverter.htm

Manual Focus Lenses forum post
http://forum.mflenses.com/vivitar-2x-macro-focusing-teleconverter-t40765.html

Century Precision Optics Tele-Athenar 1000mm f/5.6 - Part II Performance

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The Test

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Click HERE to read Part I if you're lost...

For a little scale as to what 1000mm looks like, here is the test scene through a 50mm lens on a full-frame camera (D700). The turquoise box is the field of view of the 1000mm lens.


Performance

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For fun, I threw in a crop from the key image made with the Nikon 50mm f/1.4 at 100%. Due to posting size restrictions, for the time being, I have posted the Century results at full-frame in a reduced size. Full size from the D700 is 4256 x 2832 pixels.

Nikon 50mm f/1.4 AF-D

Crop @ f/8

+

Century Tele-Athenar 1000mm f/5.6

f/5.6 (wide open)

f/8

f/11

f/16

f/22

f/32

f/64 (sorry about the birds!)

Analysis

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The Century Tele-Athenar 1000mm f/5.6 does not perform extravagantly wide open. In it's defense, most lenses do not. I do not know what kind of specs were required of this lens when it was designed but it appears it will have to be stopped down to be used for anything more than an enormous spotting scope.

Chromatic Aberration - In high contrast situations, this lens definitely exhibits some serious CA.

Vignetting - Clearly on a full-frame DSLR, the Tele-Athenar 1000/5.6 has some severe vignetting wide open and diminishes as stopped down but is present all the way through f/64.

Sharpness - This lens resolves quite well especially considering that at 1000mm many more factors come into play than at say 300mm such as weather, temperature, atmosphere, etc. Wide open the lens is soft but f/8 isn't too bad and f/11 is great. I think optimal aperture is actually around f/16 or f/22 with this lens.

Distortion - I don't see any noticeably severe distortion.

Contrast - The sample images have been aided by a slight curve in post process. The lens appears to produce good contrasty images but not as contrasty as my *ED Nikon glass. Also flare may have been a factor given the extremely bright day.

Flare - I used this on an overcast day and achieved some very nice, contrasty images. However, in this test on a very bright, sunny day, the lens produced slightly less contrasty images. The lens possesses an ample hood for protection against stray rays so this may have been due to atmospheric conditions.

Color - Images seemed to come out a bit dull in color. No especially beautiful rendering.

Bokeh - Possibly due to the number of aperture blades, along with the immense focal length, one can achieve some beautifully soft bokeh with this optic. I will work at getting some samples of this soon!


The Wrap-Up

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The Century Tele-Athenar 1000mm f/5.6 is hardly a practical lens. At best it's a novelty, if not simply an anchor. I love it nonetheless. I suppose it's more for the pure shock factor of putting this on a tripod and pretending to be serious. The lens is capable of some very sharp images at smaller apertures.

It probably would make no sense to make a recommendation here, seeing as few will ever come across one of these. But in the off-chance you do find one, above provides a good sample of what you can expect and make your offer accordingly. I had a hawk flying overhead and attempted to "bird" with this lens. HA! That was a challenge!

Next stop with this lens? The Moon!...on the GF1...with some TCs

Century Precision Optics Tele-Athenar 1000mm f/5.6 - Part I

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The Century Precision Optics Tele-Athenar 1000mm f/5.6

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You may recall I found this lens a few weeks back via an ambiguous, local Craigslist ad. This lens is huge. Measuring 38" from the tip of the hood to the camera mount, the lens weighs over 15 lbs. (Some of that weight can be attributed to the heavy metal brackets on which this lens was originally mounted.). Although I didn't initially know anything about the lens and had no idea if I could do anything with it, as Rick from Pawn Stars often enthusiastically declares, "I wanted it!" A couple text messages and less than an hour after discovering the ad, I was driving home with this thing in my backseat! I took the gamble and now I needed to know 3 main things:

1. Some History - Where did this lens come from? What was it used for?
2. Optical Capabilities - How can I adapt this for use with my DSLR? Is it possible?
3. How to Mount - If use with a DSLR is optically possible, I need a means to mount this lens on a tripod.

The Search for Info on Century Tele-Athenar Lenses

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I contacted Schneider Optics, the company who purchased Century Precision Optics and asked them for some information on this lens. Schneider was surprisingly prompt in responding (A stark contrast to my attempts at getting info from the Tokina corporation) however, they had very little info to give. Even what the rep did have to tell me seemed more like speculation than fact. I also asked around on the Manual Focus Lenses Forum and one user, cooltouch (Michael), seemed to have more info and be much more confident than the rep from Schneider.

The rep basically said:

The Century Tele-Athenar 1000/5.6 was most likely contracted by the military and probably about 10-15 years old putting it around 1995-2000. Originally it probably sold for more than $4k and was a special order lens.

That's it. Despite my numerous questions, that's all I got.

Michael on the other hand had quite a bit more to help me out. He says:

"If the lens is white, it was military-contracted. If it's black, it probably wasn't. But it probably was used in the movie industry. CPO sold most of their optics to the movie industry and the military. Back in the 60s, photographers got wind of their optics and began requesting a line for 35mm still photography. CPO came out with the Tele-Athenar II line for still photographers. The main difference is the TA II's barrel does not rotate when the focusing ring is turned. The lens should also say it's a TA II if it is indeed one.

As far as its age, 10- 15 years ago is probably too young. I got the impression from talking to Bill Turner that, even though they still showed the TA lines in their catalog, they rarely sold one anymore, and this was the early 90s. So it's possible, but not all that likely that your lens is that young.

...
Anyway, according to my records, the 1000mm f/5.6 is a Tele Athenar and not a Tele Athenar II. It was made for movie work primarily and not specifically for 35mm photography. However, I don't see why it wouldn't work. I imagine it will take killer photos of the moon, for one thing."

Thanks Michael! Essentially this is good news! This lens can be used on modern DSLRs since they were used for cinema, a similar application. I have heard stories about some of these old large lenses being discovered but turning out to be very special purpose lenses. One user from MFL, nemesis101, was telling me of a lens he found long ago that turned out to be for aerial spotting duties with a minimum focusing distance of 3 miles!

As always, I will keep this section updated as more information surfaces.

Adapting The Lens For Use With A DSLR

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Optically it's possible to use the lens. Now I need to figure out what parts are necessary for that adaptation. The lens was handed off to me with a rear mount that looked like this:


A seemingly arbitrary sized thread and an empty filter slot. In contacting Schneider, I found out this thread is a proprietary mount that was utilized by CPO on their Tele-Athenar lenses. Fortunately, the mount is still used today on some of their newer products! So the company had the parts for me to order. To use this lens on a DSLR, you need the following part:

0TM-00TC-00 (those are zeros) - Century Interchangeable to T-mount Adapter

Then you just need the correct T-mount for the camera with which you want to use this lens. They even had the 2"x 2" filter tray.

Issue #2 down. At this point I was leaning the lens on a deck post, while awkwardly attempting to support the back end and focus at the same time with an extremely narrow field of view. I think I'm going to need a tripod mount...

Mounting the Century 1000/5.6

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The lens originally had two large metal brackets attached this to whatever rig it had been designed for. Structurally, it seems to me, it makes the most sense to start from these for a sturdy tripod mount. I began by gluing several 8" x 12" PVC boards together.

Next, I trimmed the boards to an even block.

Then the shaping began.

The process was pretty much just a lot of cutting, drilling, and sanding. Eventually I hope to really smooth everything out and paint it black. For now though, I was too anxious to use it. There's no sense in taking it to the final product if it doesn't work so I had to test it!

Objective 3 complete. Finally time for testing!

Specifications

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Focal length: 1000mm
Angle of view: 2.1º
Max. aperture: f/5.6
Min. aperture: f/45
Elements/Groups: unknown
Dimensions: 38" L
Aperture blades: 20

Performance

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Click here for the performance review of this lens: Century Tele-Athenar Part II!

A Second 1000/5.6 Found! John Maycock shares his experience with this behemoth.

Tamron SP 200-500mm f/5.6 31A

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While this lens isn't "rare", it isn't exactly in ready supply either. While exploring Tamron's Adaptall-2 line-up in effort to find an inexpensive alternative relative to the premium name-brand glass, I continually saw mention of the Tamron SP 200-500mm f/5.6 31A but infrequently found any actual results. Mostly people just commented on how large of a lens it is. Having originally retailed for over $1000, I think it is time we had a little more info than this.

Aesthetics/Ergonomics

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I have to say this lens was somewhat of an impulse buy. I have no idea what they typically cost since I haven't been on the lookout for one. I just saw one ending on eBay one day, in great condition with what looks to be nearly all of the original accouterments. After having sold another lens and having the money sitting in paypal I reasoned I would just pick it up and give it a try since I wasn't finding much online. Then resell it after I am finished, should it not turn out to be Tamron's best kept secret. Spoiler alert: it isn't.

That may sound harsher than I intend since this lens isn't a poor performer, just not amazing. But I am getting ahead of myself! We will get to performance.


First impressions of this lens are in agreement with what I have found online: this lens is a beast.
Being a non-IF (internal focus) zoom lens with such a broad range, this kind of size is inevitable. The built-in hood is great, though this adds another 4" to the length. The physical length of this lens goes from 14" fully compact, to 20" completely extended and hooded.

The overall look and feel of this lens is nothing short of Tamron's best Adaptall design. A solid 6 lbs. of metal and glass. I love the all-black semi-gloss finish. All lettering and info is engraved into the lens barrel. Hints of Tamron's signature turquoise color appear in the distance scale lettering. The barrel sports Infrared scales for 200, 300, and 500mm focal lengths. The 200-500mm f/5.6's front filter is a massive 95mms but the lens is also equipped with a rear 43mm filter tray. Due to the size, the lens was designed with a tripod foot which does rotate 360º. I have read, and do agree, the tripod mount is further back than it should be. Even with a camera mounted, the lens is pretty front-heavy.

Using this lens, I also quickly realized another drawback to the non-IF design of this particular lens. When focusing the lens, (Anywhere from 200-500mm, focal length doesn't matter because that action does occur internally) the front portion of the lens rotates. For one thing, if you were to use a polarizing filter, it would need to be adjusted accordingly as you focus. But secondly this means anytime you are focusing upward, holding the lens at a high angle (and I mean nearly verticle), the sheer weight of the front of the lens creeps back down (toward the infinity focus position). I will say however, this lens manages to stay in place to a pretty severe angle. I assume this will all be dependent on the condition of the lubricants in your particular lens.

Accessories

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Accessory-wise, this lens originally sold with a large faux-leather case (L-40) with a red fabric lined interior and foam inserts fitted to the lens. There is also an accessory compartment in the case to accommodate a teleconverter, strap, additional filters/trays, etc.. I do not have the original Tamron 95mm protective filter for the front of the lens and boy are they hard to come by! The lens also came with a cheap fake leather lens cover for the front which is black felt-lined on the inside (which I did get).


Specifications

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Focal length: 200-500mm
Filter thread: Front 95mm, Rear tray 43mm
Min. Aperture: f/5.6
Max. Aperture: f/32
Angular field of view (diagonal): 12º-5º
Elements/groups: 14/10
Maximum magnification ratio: 1:3.52 (500mm @ 8.2' [2.5m])
Multi-Coated: Yes, BBAR MC
Min. focusing distance: 8.2' (2.5 m)
Length at ∞: 14.4" (365 mm)
Maximum barrel diameter: 4.1 " (105mm)
Weight: 6.1 lbs. (2780 g)
Lens hood: Built-in
Mount: Adaptall-2
Manufacturer designation: 31A

Above, the optical diagram is from Adaptall-2.org.

While this lens is an SP (Super Performance) lens, it does not have any LD (low-dispersion) glass in it. This was to keep costs low since the lens was intended to compete with premium brand lenses but cost the consumer less. Also, regarding the "BBAR MC" designation. From what I am finding online, it seems BBAR may stand for "Broad-Band Anti-Reflection" and then MC obviously "Multi-Coating". Either way, all Tamron's Adaptall-2 line listed in the 200-500mm's brochure were BBAR.

Performance

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So who cares about all that stuff. Is the lens any good optically? Well I'll tell you what, I care about all that other stuff. But agreed, I think it is important that we understand if this lens is worth its weight optically too.

Since the time I initially got this lens, I haven't had a whole lot of time to get out and use it for birding or various other long-range activities for which it was designed. But I did a fair amount of image comparison which should suffice to at least show what this lens is capable of.

Here I had the rig mounted on a sturdy tripod. I used a D700 @ ISO 800 to ensure high enough shutter speeds so I was not affected by camera shake. The sun was at my back to the left. I cropped these images and enlarged them by about 50% so that you can see the pixels. Only a hair of sharpening to combat the web softening images slightly when posted here. All images were made in RAW.

200mm

Below is the key image made of the Clark Bridge in Alton, IL @ 200mm.

f/5.6

f/8

f/11

f/16

f/22

f/32

500mm
Here is a key for that same Clark Bridge @ 500mm.

f/5.6

f/8

f/11

f/16

Beyond f/16 the wind began affecting the shots. Being out by the river, the winds can get pretty intense.

Analysis

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As always the lens shows slight softness wide open but is still pretty sharp! I am impressed with the sharpness of this lens at both 200 and 500mms. Center sharpness as well as corner sharpness with this lens is quite acceptable.

As far as contrast, I would say the lens again performs well. These shots aren't the best examples to show contrast but I assure you from other use with this lens, you will not be disappointed with the rendering of a scene!

Flare doesn't appear to be much of an issue, nor does any concern for stray light affecting the image. The built-in hood provides copious coverage.

Now to address the issue that plagues the Tamron SP line, Chromatic Aberration. CA seems to be the biggest downfall of even Tamron's best LD lenses. While this lens has no LD glass, it is designed to compensate for CA in other ways. Nevertheless, CA is quite visible even at f/8. The best way to handle this issue is either to avoid shooting in situations that produce CA (extreme high contrast) or deal with it in post.

Recommendations

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Since the introduction of this lens in 1984, the industry has made leaps and bounds toward better zoom technology. The 31A is pleasantly sharp wide open and performs quite well beyond that. However the CA can be a bit much at early apertures and the effort to keep your zoom/focus in check can prove a bit of a challenge, especially in fast paced environments. While I love the build and look of this lens, the reality is that it isn't very practical by today's standards. The Tamron SP 200-500mm f/5.6 31A is a great choice if you need sharpness and zoom for a low price. Also the adaptall feature allows you some portability in between systems if needed. I haven't tested the newer Tamron 200-500mm f/5-6.3 Di AF but I imagine it is a much more manageable lens (also nearly 3 times as expensive). There is a Tamron 200-400mm f/5.6 D AF that costs a little less than this adaptall actually (as of 10/2010) but I have heard nothing about it. The Tokina 400mm f/5.6 AT-X and the 80-400mm f/4-5.6 may be other options and can be had for around the same price as this adaptall ($300-400). Both of which have AF and are considerably lighter. But I know little about their performance at the long end which tends to be where these zooms struggle.

Plain and simple, the ability to get similar zoom, same f# or faster, and AF for the same price as the 31A makes buying this lens more about nostalgia for well-made Adaptall lenses than anything else. If you can afford to take your time and are just looking for a sharp 500mm that can double as a weapon, all for one low price, here it is! Optically, it's no slouch, but technology has moved quite a bit beyond this.

Links/Resources

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NEW!! - I received the owner's manual with this lens and have scanned it into a PDF document.
Click HERE to download the User's Manual for the Tamron SP 200-500mm f/5.6 31A
Adaptall-2.org (mirror site of the previous adaptall-2 site) - Tamron SP 200-500mm f/5.6 31A

Here's link to Pentax Forum's profile on this lens.