Asahi 85mm f/4.5 Ultra-Achromatic-Takumar

[Andrea B.]

INCOMPLETE

 

Asahi 85mm f/4.5 Ultra-Achromatic-Takumar

 

Manufacturer: Asahi Optical Co., LTD, Tokyo, Japan

Lens Label:

Currently Manufactured: No

Note: There are 2 models. And we need to look up the history.

 

Lens Type: short telephoto, manual focus, aperture preset

Lens Design: 5 elements, 3 fluorite + 2 artificial quartz

Focal Length: 85 mm

Aperture Range: 4.5, 8.0, 11.0, 22.0

Correction: 220 - 1100 nm

This lens could be focused in Visible light prior to adding a UV-pass or IR-pass filter. In digital Live View, focus can usually be made on screen if the aperture is set wide open.

 

Format Coverage: 29°

Minimum Distance: .6 m = 2 ft

Magnification:

 

Mount: M42 x 1 screw mount

Helicoid: Yes

Flange Focal Distance (FFD): 45.46 mm

The lens can easily be used on any camera with an FFD shorter than 45.46 mm by means of a mount adapter.

Front Filter: 49 mm

 

Sharpness:

 

Transmission:

Our member JMC has kindly provided us with a comparison chart for the Big Four dedicated UV lens. 

This topic's UAT lens is the green line.

[dabateman]

This is one of my favorite UV lenses.

But oddly it may (or my copy at least) has a hot spot at 254nm. Will see if I can prove this definitively. This is why film and digital UVC will loose contrast with UVC imaging.

Yes UVC imaging is rare, but so is this lens.

[ulf]

A very rare and normally expensive lens.

 

Someone got lucky here a few years ago:

https://buyee.jp/item/yahoo/auction/r249496142?conversionType=search_yac_browsing_hisotry_list

 

I found this listing one week after it ended.

If the winner was ignorant of the real value I could have won auction.

[lukaszgryglicki]

This won't focus at infinity on Nikon, right? (flange distance 46.5 mm) - it has M42 flange distance 45.46 (so 1mm + adapter width short). Can anybody chekc on Nikon body and tell me how far from infinity can I focus? At f=4.5 and at f=22?

Would be great to know this....

 

[colinbm]

Are you not able to use a shorter helicoid ?

 

[lukaszgryglicki]

No helicoid at all, I have only Nikon F bodies (DSLRs) - it's mount flange distance is 46.5mm - already more than M42 standard. I know some lenses work "anyway" - usually longer ones - stopped down or those which can focus "beyon infinity". This is just a request - if anybody have that lens and any Nikon-F body - please try to mount and report how far can I focus - just asking, I know it's probably impossible to get that answer...

[colinbm]

Sorry, I was mistaken, I see you are using a DSLR..

[Doug A]

2 hours ago, lukaszgryglicki said:

No helicoid at all, I have only Nikon F bodies (DSLRs) - it's mount flange distance is 46.5mm - already more than M42 standard. I know some lenses work "anyway" - usually longer ones - stopped down or those which can focus "beyon infinity". This is just a request - if anybody have that lens and any Nikon-F body - please try to mount and report how far can I focus - just asking, I know it's probably impossible to get that answer...

@Andrea B. has the UAT and a Nikon DSLR. She also has other cameras and may never use the UAT on the Nikon DSLR.

 

Wonder if UV Quartz tele lenses focus past infinity like many lenses do?

Good luck,

Doug A

[lukaszgryglicki]

If this one do, it may be usable on a Nikon DSLR, would be great if @Andrea B. can check this in some spare time and let me know - I can buy this lens a bit cheaper than UV-Nikkor or Coastal Opt.

[dabateman]

No infinity. 

Tested the UAT on a Nikon DF with a really slim m42 adapter.  The best is about 20 feet.

It also works on a Pentacon film camera, but best was about 12 inches. I used it for my Kodak portra film tests.

I can see if I can do a more controlled test with a tape measure later. 

[lukaszgryglicki]

OK, 20 feet makes no sense for my use, I wanted landscapes too. Thanks, that filters this lens out.

[nfoto]

Never underestimate what a Dremel judiciously applied to a lens can do in terms of adaptability. Over the years, with help of friends, I have modified Leica, Exacta, Olympus, Canon, Petri, and Pentax lenses to work with F-mount and usually been able to keep inifinity focus.

 

Of course using morrirless cameras adds more versatility thanks to their much shorter register distance compared to DSLRs. However, sometimes a DSLR is the preferred tool for the job. Then the Dremel might come into play.

[Andrea B.]

I used my UAT on a Pentax K5 with beautiful results.

Now I will use it on the Lumix S1R.

The UAT is not useable on a Nikon DSLR.

[JMC]

Here's the transmission data for the 85mm Ultra Achromatic Takumar (UAT) between 280nm and 420nm, and how it compares with a few other UV lenses - Rayfact 105mm, UV Sonn ar 105mm, and Coastal Optics 105mm. The dip at 310nm is real, as I see it each time I measure this lens, and I presume this is down to something specific to the CaF2 that they used.

[Andrea B.]

Jonathan, thank you for this contribution. It is greatly appreciated.

I had a manufacturer's transmission chart for the UAT. But sometimes manufacturers are a bit optimistic. 

 

The UAT seems to be a bit "bumpy" in the UV, doesn't it? I wonder if that has anything to do with the model type? 

The Sonnar looks better than I thought it was, seeing it in comparison like that.

 

 

[Stefano Rosoni]

On 10/13/2021 at 2:03 PM, lukaszgryglicki said:

This won't focus at infinity on Nikon, right? (flange distance 46.5 mm) - it has M42 flange distance 45.46 (so 1mm + adapter width short). Can anybody chekc on Nikon body and tell me how far from infinity can I focus? At f=4.5 and at f=22?

Would be great to know this....

 

You can calculate the maximum focusing distance with the optical formula: 1/p + 1/q = 1/f (f is the focal length of the lens, while p and q are the two distances between the lens and the sensor and between the lens and the subject).
In any case, using ordinary M42/Nikon adapters and without a special negative lens (which some adapters have, but at the risk of losing optical quality) you will never go to infinity with a Nikon camera, and maybe you could touch it with the tips of your hair using the depth of field according to the table of hyperfocal distances. There are programs for windows computers that calculate it and plot it. However, if I were in your place, I would get a used Pentax or Canon full frame and full spectrum body, with the greatest dynamic range possible (you can see https://www.dxomark.com/ for orientation). 

[lukaszgryglicki]

No longer an issue, I've switched to mirroless with a lot shorter flange distance (Fuji GFX) and that MF mirroless has a lot of adapters, including M42. I also have UV-Nikkor now, so don't need this lens anymore (but I would buy if I see it cheap somewhere :P).