Jump to content
UltravioletPhotography

Informal Test of Two Asahi Takumars on a K5: 135/3.5 and 85/4.5


Andrea B.

Recommended Posts

Our member John Dowdy very kindly sent me an Asahi Pentax 135/3.5 Takumar to use and test for UV. I'm really excited to have that focal length for my UV kit. Thank you, JD !! 😄

 

Of course, cloudy blustery November weather and what we euphemistically call 'life events' prevented me from getting extensive testing done before I needed to leave on a trip to Colorado. But I was able to make some preliminary discoveries about the Tak 135/3.5.

 

I just got my Pentax K5 full-spectrum conversion back from Kolari Vision - an excellent conversion. For the record, I have a soft spot for all things Pentax because their black & chrome ME and later 'Super Program' were the film cameras I used for many years prior to the DSLR revolution and move to Nikon. So it's cool to have a Pentax body back in-house to use with my mini-collection of UV-capable Asahi Pentax lenses.

 

This would be the first time I had ever used any of my Taks on a Pentax body. Pentax makes a beautiful K-mount to M42 screwmount adapter so that all old M42 Pentax lenses can be retrofitted to Pentax DSLRs with no hit whatsoever on lens quality. And mating a lens to the correct body so that the lens flange focal distance is met provides infinity focus, something I have rarely enjoyed with my UV lenses except for the UV-Nikkor. (Aside: the F-mount Novoflex will go there, of course, but my copies seem to be very vignetty and harsh at infinity.)

 

For a reference lens I chose the Asahi Pentax 85/4.5 Ultra-Achromatic-Takumar, an extremely capable UV-Vis-IR M42 screwmount lens which ranks right up there with the classic 105/4.5 UV-Nikkor. It might even be a bit better because the UAT has no focus shift in any wavelength, while the UV-Nikkor does require a small focus readjustment in IR.

 

Here is a factual rundown on the two Taks being tested. Both are beautifully made. Pentax has always turned out fine lenses, imho. This older Tak 135 is particularly nicely constructed from alloy and chrome with very smooth double helicoids for the aperture preset and for focusing. If you hit the links, you can see photos of the two Taks.

 

Asahi Pentax 85/4.5 Ultra-Achromatic-Takumar

  • 1968-1975
  • M42x1 screwmount
  • 5 elements in 5 groups, quartz & fluoride
  • automatic aperture
  • minimum aperture of f/22
  • uncoated
  • minimum focusing distance .6m (1.9')
  • very sharp, no CA from 220-1000nm
  • Klaus Schmitt: http://www.macrolens...ObjektiveNr=239

.

Asahi Pentax 135/3.5 Takumar

  • 1957-1962
  • M42x1 screwmount
  • 5 elements in 4 groups (1,1,1,2)
  • aperture preset, dual helicoid
  • minimum aperture of f/22
  • uncoated
  • minimum focusing distance 2m (6.5')
  • bright, sharp, low to no CA in visible wavelengths
  • Frank Mechelhoff: http://www.taunusrei..._Takumar_e.html

.

There were many late-blooming flowers mid-November in my part of New Jersey, so I was able to gather up a little bouquet for testing which included a Rudbeckia. It's always good to have a known UV signature in a test whether it be floral or not.

 

And so -- there was my first testing difficulty -- that tiny late autumn bouquet combined with the 6.5 foot minimum focusing distance of the Tak 135. The flowers were going occupy only about 1/3 of the frame at that distance. What to do? No giant flowers with known UV signatures were available (...the giant sunflower heads of summer, for example, were long gone). But if I added an extension to the 135 to get it closer, I feared compromising the image quality and the exposure times. So I decided "oh well" - and set up the shot somewhere between 6.5-7 feet.

 

But now what to do with the Tak 85? It was designed to have a closer minimum focus of around 2 feet. Do I test and compare the two lenses at the same distance? Or do I test them each at their minimum focusing distance? Or do I test them so that the resulting paired photos show the subject at the same size in each photo? Me, I got no clue. So I planned to try all three scenarios.

 

For the first go-round, I decided to shoot the Tak 85 at the same 6.5-7 foot distance as the Tak 135 because I was afraid if I moved closer when using the shorter lens that I would interfere with the amount of UV light reaching the subject and thus again compromise the exposure time in some way. Exposure times are an important factor in telling us how capable a lens is for UV, so keeping the same amount of light on the subject did seem important.

 

Unfortunately, weather moved in and I was only able to perform that first testing scenario. However, it does answer the Primary Test Question: Can the Asahi Pentax 135mm f3.5 Takumar shoot UV? Read on to find out the answer.

 

Visible Autumn Bouquet with Asahi Pentax 135mm f3.5 Takumar

  • Pentax K5-broadband + Asahi Pentax 135mm f3.5 Takumar + Baader UVIR-Block Filter
  • f/11 for 1/160" @ ISO 160
  • Photo converted in Photo Ninja using a colour profile made for the converted K5
    with Color Checker Passport.
  • Minor edits in Capture NX2.

The Tak 135/3.5 is a very nice sharp lens. There's great detail captured here at 6.5 feet away. As a portrait lens it exhibits very nice background bokeh given that I was shooting at f/11. The photo was cropped in quite a bit, but held up remarkably well.

135_bouquetVisSun_110913wf_origPNres.jpg

 

 

Visible Autumn Bouquet with Asahi Pentax 85mm f4.5 Ultra-Achromatic-Takumar

  • Pentax K5-broadband + Asahi Pentax 85mm f3.5 UAT + Baader UVIR-Block Filter
  • f/11 for 1/320" @ ISO 160
  • Photo converted in Photo Ninja using a colour profile made for the converted K5
    with Color Checker Passport.
  • Minor edits in Capture NX2.

The Tak 85 is a very sharp lens although the background bokeh is not quite as smooth and pretty as that from the Tak 135.. The light was changing and I got an unusual light artifact on the edge of the glass vase intead of the aperture stars seen in the Tak 135 shot above.

85_bouquetVisSun_110913wfPNenlargedRes.jpg

 

 

 

Before you view the next two Ultraviolet photos, I would like to note that my standardization of the UV false colour palette for the Pentax K5 is not yet complete. Thus the two photos below do show slightly different false colour tints. This is irrelevant to the successful capture of the UV-signatures in both photos.

 

Ultraviolet Autumn Bouquet with Asahi Pentax 135mm f3.5 Takumar

  • Pentax K5-broadband + Asahi Pentax 135mm f3.5 Takumar + Baader UV-Pass Filter
  • f/11 for 6" @ ISO 160
  • Photo converted in Photo Ninja using white balance made from Labsphere 99% reflective standard.
  • Minor edits in Capture NX2.

135_bouquetUVBaadSun_110913wf_03PNcropRes.jpg

 

 

 

Ultraviolet Autumn Bouquet with Asahi Pentax 85mm f4.5 Ultra-Achromatic-Takumar

  • Pentax K5-broadband + Asahi Pentax 85mm f4.5 UAT + Baader UV-Pass Filter
  • f/11 for 1" @ ISO 160
  • Photo converted in Photo Ninja using white balance made from Labsphere 99% reflective standard.
  • Minor edits in Capture NX2.

85_bouquetUVBaadSun_110913wf_origPNcropRes.jpg

 

 

We now have an answer to the Primary Test Question: Yes, the Tak 135 can shoot UV, but it is a bit of a reluctant performer.

 

First there is focus shift to deal with. If you have first focused the lens in Visible light and then added the UV filter to the Tak 135, you must adjust your initial focus. If using Live View to focus, then a UV-LED is necessary to add more UV light to the scene as seen on the LCD.

 

And second, note the exposure time for this shot was 6" at f/11 for the Tak 135 in strong sunlight compared to the 1" exposure time of the UVIR-dedicated Tak 85 shot made in slightly less strong sunlight. (The weather was changing, remember.) Longer exposures can lead to noise in dark areas, and UV photos typically have a lot of dark areas. A UV-flash would be definitely necessary to get the best from the Tak 135 by bringing down the exposure time.

 

Now, from those exposure times, please do not make a conclusion that the Tak 135 is 6 times slower than the Tak 85. The most we can conclude here is that exposures with the Tak 135 are going to be rather longer than they would be with a dedicated UVIR lens. How much longer precisely? Well, that is not easily measured unless you shoot under very controlled conditions. (And I don't really think it is all that important to figure out.)

 

CONCLUSION: From examining the photographs, we can see that both lenses captured the UV-signatures, details and false colours of the flowers in the Autumn Bouquet. Ultimately that is what matters, yes? So, aside from a bit of focus shift and some extra UV-flash illumination to shorten longer exposure times, there's a good case to be made for the adding the inexpensive Asahi Takumar 135/3.5 to your UV kit. I'm certainly planning to use it!

 

UPDATE in 2023:  Refocusing between Vis and UV and IR is easy given the excellent Live View LCDs we have now. And there are converters which can appropriately make the small corrections needed to stack a set of UV/Vis/IR should you want to do so.

Link to comment

Andrea,

 

I am happy you like your "new camera warming" gift, may it serve you well!

 

On behalf of myself and doubtless other UV newcomers, you efforts to enlighten us are most appreciated and this comparison is a perfect example.

 

I suspect that Tak 135 was only reluctant to be compared to her more exotic cousin.

 

Thank you,

- John

Link to comment

I liked the way this older Pentax lens "draws", as they say. This is partly a subjective thing as we all do have our individual preferences for colour, contrast and bokeh in lenses.

 

It is standard practice to compare any UV-capable lens under test to one of the known standard UV-dedicated lens such as the UV-Nikkor, the Coastal 60/4.0 or the Tak 85 UAT. Then users of the tested lens will learn what they need to do to best use that lens. For example, as mentioned above, the Tak 135 needs good strong UV illumination to cut exposure times, so it is best used in really strong summer sunlight or with a UV-flash.

 

In the past I have tested a couple of lenses for UV capability and discovered that even though they can record UV under long exposures, the resulting photo seems to lack clarity or perhaps does not record a high level of detail. That was obviously not the case with the Tak 135. So while I termed it a bit 'reluctant', it certainly was not 'stubborn'. :D

 

I do hope to do more such comparative testing when I return from Colorado. I will include the Tak 35/4.0 and a couple of others in the next test shoot. And I also have a really early Takumar from the M37 days - a very tiny, heavy silver little thing. I have not yet been able to figure out its front filter size yet so I may have to hand-hold the Baader-U up to it. (Just got this lens in recently so I've drawn a blank on its focal length as I write this.)

Link to comment

No doubt a good benchmark comparison, I was merely extending the anthropomorphism. - :D

The comparison to your Tak 35/4.0 and their tiny silver auntie should be very interesting!

Link to comment

Great to see the results from your K-5

 

This is sort of off-topic, but have a look at the multi-exposure option on the K-5 (I used it on the K20D and it worked just fine), it's in rec. mode screen 2 I think. It means that if you need to use multiple flashes you can do so with the 1/180 s synch exposure for each one rather than having to use a slow shutter speed and make multiple flashes while the shutter is open.

 

Cheers,

 

Dave

Link to comment

There are more potential sources for errors when you do multiple exposures. Firstly, the risk of getting slight camera shake or tiny movements to offset positions; secondly, the camera's internal engine is different from film and it is quite common to see multiple digital exposures with striping or other repeated patterns. D200 in particular is prone to this but I've seen it with my Panasonics and the D600 as well. You definitively need to be able to set the camera to have autogain OFF if you do several exposure to be combined into a single frame.

 

There is an alternative that few seem to have tried, namely, using focus stacking but without any change in camera position. The advantage of course is that the focus stacking software is designed to realign minute shifts in position.

Link to comment
Bill De Jager
Thanks for doing this comparison, Andrea. I have the Tak 135 and some other lenses of similar vintage that I'm looking forward to checking and hopefully using. A quick check using a broadband mirrorless camera and a Baader UV filter a couple of months ago showed that various of these lenses let through a fair amount of UV, but that's not the same as taking actual photos and examining them closely for lens performance.
Link to comment

Thanks, Bill. I hope to return to this testing after I return home from Colorado.

I think that I am not happy with having to crop so much in the posted photos.

I don't think the photos show either lens to best advantage

because you are seeing such a small part of the original photo.

But, like I said, I ran out of time. :D

 

As Bjørn has often noted, you can sweat out a UV or IR photo with almost any lens

if you just expose long enough !!

It was definitely clear that the Tak 135 needed longer exposure times

because of its more complex structure of 5 elements in 4 groups

with none of those elements being quartz/fluoride.

But I liked the character of the Tak 135 so much that I'm eager to use it for some Visible shots, too.

And 6" exposures in strong sunlight isn't such a terrible record.

I've certainly seen worse.

 

Remember to look for those older, non-coated Tessar type lenses with 3 elements (or maybe 3 groups)

for some UV capability.

 

Truly, gentlemen, there is no substitute for a dedicated, achromatic UV lens.

But I most certainly do understand the financial considerations inherent in that statement.

The prices aren't pretty!

(And not all of us really need a dedicated achroUV.)

Link to comment

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
×
×
  • Create New...