Photo's with Calcium Fluorite and Other unusual Lenses

[Brian Sweeney]

Calcium Fluorite sounds like something that should be in Tooth Paste.

Calcium Fluorite and Quartz are used in optics that pass deep UV and into Midwave Infrared. They are highly color corrected, deemped "Super-Achromatic" and "Ultra-achromatic", meaning they are color corrected for four or more wavelengths. The Pentax 85/4.5 is such a lens, and is in standard M42 mount with an automatic aperture. Stick it on a regular Pentax screw mount SLR and off you go.

Best of all, it makes pretty colors and has nice Bokeh.

Wide-open on the Fujica ST-801.

http://www.ziforums.com/picture.php?albumid=164&pictureid=1552

http://www.ziforums.com/picture.php?albumid=164&pictureid=1550

http://www.ziforums.com/picture.php?albumid=164&pictureid=1549



Not bad colors for a 40 year-old uncoated lens.

[Brian Sweeney]

Have an unusual lens made of some strange material? How about posting some shots here. I used to have some Zinc Selenide optics. But they were not for the visible spectrum, and that was 25 years ago..

[squinza]

I knew of the Nikkor-UV 100 macro lens, for UV and IR photography, but I've never heard of your Pentax 85mm. Interesting, I'll google a little :-)

[Mackinaw]

I've got an old Canon FL-F 500mm F5.6 lens sitting in my closet. This is the fluorite lens Canon made for their SLRs' back in the 1960's/1970s'. Haven't used it in years being that I'm a rangefinder guy. Still, it does take excellent photos.

Jim B.

[kds315]

Hi Brian, great to be in contact again! Wonderful autumn shots!

If you follow the link in my footer you'll find stuff for hours to go through...

P.S.: broad band coating IS possible for 200-1100nm btw. and 800nm is
just NIR (near infrared; visible light is to 700nm)

[mabelsound]

That Pentax lens is a real rarity. Brian, do you have any photos that illustrate the difference in color rendering between it and a normal lens?

[kds315]

This is it, the fully corrected Ultra Acxhromatic Takumar 4.5/85mm

http://www.macrolenses.de/bilder/IMG_8835_wp_b.jpg

[hans voralberg]

Huhm wonder where I could get my hand on this baby!

[radiocemetery]

See:

http://www.pentaximaging.com/files/manual/ES.pdf

The Pentax lens above uses no glass, only flourite and quartz. You will need to scroll down to see the lens listings

[kds315]

That Pentax lens is a real rarity. Brian, do you have any photos that illustrate the difference in color rendering between it and a normal lens?

I have recently made a comparison test of the famous Pentax 1.8/85mm and the Ultra Achromatic 4.5/85mm here:
http://photographyoftheinvisibleworld.blogspot.com/2009/08/test-pentax-smc-f1885mm-vs-ultra.html

[Brian Sweeney]

Klaus, I thought you might see this thread!

I was mistaken on the color-correction range for this lens. The transmission for Calcium Fluorite extends from ~0.2um to 7um. This lens was in an old spectrascope, relied more on transmission than color correction.

[oftheherd]

See:

http://www.pentaximaging.com/files/manual/ES.pdf

The Pentax lens above uses no glass, only flourite and quartz. You will need to scroll down to see the lens listings

One on ebay now. I don't know if this is a normal price range. One never can be sure unless one is experienced at watching, buying, or selling.

http://cgi.ebay.com/Pentax-M42-4-5-85mm-Ultra-Achromat-Takumar_W0QQitemZ230397506279QQcmdZViewItemQQptZCa mera_Lenses?hash=item35a4c2f2e7

Certainly some interesting results as shown by kds315. Thanks for those photos. Most of us would have no clue without seeing something like that.

Thanks to you too Brian. It is always interesting to see your posts. Interesting and educational. I couldn't help but notice you used an ST 801. Nice camera, although I prefer the ST901 most of the time. Do you prefer that over the Pentax M42 mount cameras, or was it just close at hand? I think it would be a little smaller than most of the Pentax M42s.

[hans voralberg]

Here's the Canon 500/5.6 Flourite converted to Nikon mount, anybody have a sample from this lens?

http://cgi.ebay.com/Canon-FL-F-500-5-6-Fluorite-11102-Nikon-SLR-MT-Rare_W0QQitemZ370262400339QQcmdZViewItemQQptZCamer a_Lenses?hash=item56355bdd53

[Brian Sweeney]

I couldn't help but notice you used an ST 801. Nice camera, although I prefer the ST901 most of the time. Do you prefer that over the Pentax M42 mount cameras, or was it just close at hand? I think it would be a little smaller than most of the Pentax M42s.

I fell into the ST801 at a good price. It is the same size as a Nikon FG, and even goes into the CF-18 case for it. I need to remember to hunt for an ST-901. I also have the older ST701, but the meter is dead on it.

The price shown for the lens seems very high. Keep an eye out for surplus spectroscopy gear.

[Harold Gough]

I can't find a reference now but an article (Amateur Photographer) about the history of lenses (cameras and microscopes), in recent years, warned that old fluorite lenses naturally slowly degrade. I believe it said that they became fogged.

The following are more general but may be of interest;

http://www.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=000AzP (http://www.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=000AzP)

http://cpn.canon-europe.com/content/infobank/lenses/fluorite_aspherical_and_ud_lenses.do (http://cpn.canon-europe.com/content/infobank/lenses/fluorite_aspherical_and_ud_lenses.do)

http://photo.net/canon-eos-digital-camera-forum/00E07w (http://photo.net/canon-eos-digital-camera-forum/00E07w)

[Brian Sweeney]

I've not noticed a problem with this lens, and it is ~40 years old.

The Salt lenses in the lab Degraded, and basically disintegrated. Moister gets them. Wish I could have tried them out.