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The Compound is an old type shutter using an air-brake to control the speeds. When clean they are quite reliable and have the advantage over the older Ilex shutters of having a time setting independant of the speed setting so that you can focus without resetting the exposure time. They are also quite easily modified to provide for X-synch for strobe flash.
The old Ilex shutters are often found on older commercial lenses. If really clean they are acceptable shutters but should be exercised a couple of times before making exposures. They were intended to run without any lubrication. When they are lubricated they tend to be erratic. The cure is a carful cleaning.
All of these lenses are completely corrected for lateral color and were intended for color photography. Some Ektars were coated as early as 1940. These include the series of f/6.3 lenses marked "Eastman Ektar", which are the predicessors of the Commerical Ektar series. The early coatings were soft and applied only to inside surfaces.
Other early coated Ektars were the lenses made for the Ektra camera and for the Medallist. Other Ektar lenses were not coated until after about 1946.
Kodak had a very advanced glass plant and made their own optical glass. They developed commercially the rare-earth glasses discovered at the National Bureau of Standards and were one of the first manufacturers to use Lanthanum Crown glass.
Ektars are also among the earliest lenses to be cemented with thermo-setting synthetic adhesives rather than the traditional Canada Balsam.
Generally, an Ektar in good condition will have excellent performance even by current standards. Kodak quality control after about 1938, when Rudolph Kingslake took over the optical department, was excellent.
Kodak lenses from about this date on can be dated by the two letters preceding the serial number. They are a code for the last two digits of the years of manufacture. The code word is C A M E R O S I T Y standing for 1,2,3,4,etc. e.g. a lens marked ES-413 was built in 1947.
The Commerical Ektar was a series of f/6.3 Tessar type lenses intended for use on view cameras. Tessars have somewhat better performance at f/6.3 than when faster.
_All_ lenses sold under the Ektar name were highly corrected for color, especially for lateral color, which is sometimes known as chromatic magnification. In other words, the size of the images from different colors are the same size.
The Commerical Ektar series was sold as Eastman Ektars prior to about 1946. The earlier version was soft coated on insided surfaces, the Commercial Ektar is hard coated on all surfaces and bears the "circle-L" mark for coating standing for Kodak's trade-mark "Luminized".
Not all Ektars are coated. Most of the f/4.5 series, for use on press cameras, etc., were not coated until after about 1946 (I don't know the exact date Kodak started coating all its lenses).
Most Ektars for medium and large format are Tessar types, but Ektar was used as a trade-mark for a quality level rather than a specific design. For example, the f/1.9 lens for the Ektra and the Aero-Ektar are both seven element Biotar types, the 45mm f/2 lens for the Bantam Special is a six element Biotar. At least four other prototipical designs were used for Ektar lenses.
Undoubtedly, the quality of the coatings varied over the fifteen or so year period that Kodak continued to make lenses after coating was adopted. Unfortunately, according to my contact at Kodak, the historical material which would clarify this sort of issue has been buried away somewhere and is not accessible.
My statement about the coating of Eastman Ektars is based on statements made in a 1940 or 1941 Kodak lens handbook. This states that this series and the also the lenses for the Ektra camera were soft coated.
The quality varies depending on the vintage & purpose of Ektars... I realize that the original post was most likely about the LF Ektars, but many MF Ektars are on the market as well (sometimes sans their original cameras so one cannot tell without testing whether or not they cover 4x5...) Here is a brief description of just a few Ektars: Kodak Ektar 2/45 (for Bantam Special) 6 elements in 4 groups, covers 28x40mm negatives Kodak Ektar 3.5/100 (for Kodak Medalist) 5 elements in 3 groups, covers 2 1/4 x 3 1/4 (and 6.5x9 cm) Kodak Ektar 3.7/105 4 elements in 3 groups, covers 2 1/4 x 3 1/4 *** A very good lens, also used on the Precision enlarger. Sharp and contrasty. Kodak Ektar 4.5/101 and 4.7/127 4 elements in 3 groups, covers 2 1/4 x 3 1/4 and 3 1/4 x 4 1/4 respectively *** Also a great lens, esp. for 6x9 Eastman Ektar 6.3/8 1/2in; 6.3/10in; 6.3/12in; 6.3/14in 4 elements in 3 groups, these lenses cover 5x7 to 8x10in. The 14 inch covers also 11x14 at f/16 and below, but without much room for movements. *** Great, fully corrected lenses (coated!) Expensive, big and still very useful even today. All have a great circle of coverage and a very "sweet", "full bodied" shadow detail. The minimum f stop is f/45, whereas I'd prefer f/64 or even smaller for 8x10. Kodak Ektar 1.9/50; 3.5/50; 3.3/35; 3.5/90; 3.8/105; 4.5/135 (for Kodak Ektra) All cover (some barely) 24x36mm. Come in a variety of designs (even a nice triplet at 3.5/90) and their quality varies from lousy (1.9/50 esp. wide open) to superb 3.5/50, 3.3/35. Well, the Anastigmat was a separate line of lenses - essentially Tessars with the exception of the 6.3/105, 6.3/130 and 7.7/8in. Some notable Anastigmats were: 7.7/8in Covers 5x7 "process" lens, well-corrected for close-up work. Quite nice 5 1/2in, 6 3/8in, 7 1/2in, 8 1/2in, 10in and 12in - all f/4.5 Cover from 3 1/4 x 4 /1/4 to 8x10 (with movements) depending on the focal length. Fine lenses (great for architecture, as they don't display much linear distortions of any kind.) There were also Anastigmats for small format cameras (35mm, Bantams and Vigilants) Well after WWII, Kodak started tinkering with their lenses a lot, and the distinctions between many lens lines blur in the 50s. (The summary above describes the mid-to-late 40s status quo.) An additional note. Many prewar Kodak lenses were sold as Kodak Anastigmat followed by a number. It would seem from catalogue data that numbers in the "thirty" series, like K.A. No.33 are Tessars, those begining with 70 seem to be dialytes (four element air spaced type). Here are the numbers (actually in the Kodak catalogue, the numbers precede the lens name:) All data come from Kodak Reference Handbook, 1946 (practically unchaged from 1940-1946.) No. 31 Kodak Anastigmat f/4.5 5 1/2in (140mm) No. 32 Kodak Anastigmat f/4.5 6 3/8in (161mm) No. 33 Kodak Anastigmat f/4.5 7 1/2in (190mm) No. 34 Kodak Anastigmat f/4.5 8 1/2in (216mm) No. 35 Kodak Anastigmat f/4.5 10in (254mm) No. 36 Kodak Anastigmat f/4.5 12in (304mm) All appear to be Tessars (4 elements in 3 groups, 4 internal air surfaces) No. 70 Kodak Anastigmat f/7.7 8in (203mm) (Symmetrical, air-spaced, 4 elements in 4 groups, 6 internal air surfaces.) BTW, that's the one I like on a 4x5 VC the best (it will cover 5x7, but with 4x5 you'll sooner run out of swings and titlts, than go beyond its circle of coverage.)
They are famous lenses. The C.P.Goerz-American Optical Co. was originally the U.S. division of the German Goerz company which was important before the first world war. After the war the German parent was restricted in what it could make (by the German government) and in about 1926 was absorbed into the Zeiss-Ikon combine. The American division became an independant company and continued to manufacture the Goerz line. Goerz was the manufacturer of the famous Dagor lens. The designer of the Dagor, Emile von Hoegh, brought a second lens design to Goerz, a four element air-spaced type sometimes called a "dialyte". This became the basis for several Goerz lenses including the Artar. The Artar was designed by W. Zschokke and F.Urban in the late teens. It is an apochromatic lens originally intended for three-color graphic arts use. Goerz continued to make Dagors and Artars in the US gradually refining the designs. The Red Dot series of Artars came out in the early 1950's. They are an improved version of the older Artar and are coated. These lenses, although intended for close work, do very well at infinity. They are extremely sharp and generally have excellent performance. The original Artars were adjusted for best performance at 1:1 but the Red Dot series were adjusted for better performance at a distance and the image/object ratios vatied from about 10:1 to 1:1 depending on focal length and when it was made. Artar's cover a rather narrower field than a Tessar and your 9.5 should cover a 5x7. The field does not increase when the lens is stopped down. Optimum f: stop is f:22 This is a super lens.
Red Dots are apochromatic, they are also coated. The Artar was the most widely used process lens for decades. They were also widely used for color advertising work. Red Dot Artars in shutters are optimised for medium distance rather than 1:1 and should be just fine at infinity. I have a 19" Red Dot in a barrel and an old 12" Apo Artar in a dial set Compur. They are both extremely sharp lenses. Artars in shutters are rather more expensive than in barrels. My 19" in barrel cost $225 but that was a rather low price for it.
Coverage is limited to about 47 degrees at f/22. This works out to an image circle of 210mm for your 9.5" lens. This will just cover 5x7 with no movements so it will allow moderate though not extreme movements on 4x5. Unlike most modern lenses, the illuminated circle is larger than the sharp image circle, so you need to take some care that you don't exceed the coverage of the lens accidentally. John Sparks.
Goerz Amer. Optical Co. Serial #'s from Eddie Bolsetzian (former Goerz Tech.) Lens # 70001-140935 1902-1903 150000-190170 1903-1905 200941-224267 1906-1908 223775-226630 1908-1909 310001-315734 1911-1914 315735-320000 1914-1918 751240-756909 1927-1937 755300 1934 756910-765730 1937-1945 765730-771199 1945-1948 771200-780169 1948-1954 791500 ~1955 ser iii 61/2 #222788 1910 ser iii 81/4 #222836 1907 14" Dagor #190994 1905 19" dagor #757427 1938 ser iii 480mm #174429 1904 Artar 19" #396635 1922 artar 30" #751030 1926 first red dot artar #779612 oct 1953These are the dates passed to me, I make no claims about their accuracy. Michael Buchmeier
angle
off-axis 0 5 10 15 20 25 30 35 40 degrees
f/6.8 85 75 65 55 45 35 25 5 0 lines/mm
f/22 70 70 70 70 65 55 40 10 0 lines/mm
^diffraction lim^
f/64 30 30 30 30 25 25 25 20 10 lines/mm
^diffraction lim^
Corners of the film with this 7" lens are at: 4x5: 24 degrees
5x7: 31 degrees
8x10: 42 degrees
The astigmatism correction, done well in Dagors for the first time in
history, is interesting :
(table values are the difference in mm from the on-axis focal
distance, positive away from the lens)
angle
off-axis 0 5 10 15 20 25 30 35 40 degrees
sagittal
focus 0 0 -.2 -.5 -.5 0 +.8 +3.0
tangential
focus 0 0 0 +.2 +.3 +.2 -.8 -2.5
Larry Whatley
>Here's a surprise-- this old lens is surprisingly bad... and will >probably make surprisingly good pictures! (Can anyone tell me >specifically about this "5x7 Bausch - Lomb Tessar Series 1c Pat. Feb24 >1903 No 2448486"?) > >It has a field about the same as a Dagor (!) because the astigmatism >corrections are stretched out to cover more than 60 degrees, even wide >open. The problem is that the resolution falls to 5 or 10 lines/mm for >about half the field for the wider apertures. (One authority on fine >print resolution says a resolution of 12 lpmm in the _print_ is >considered to be truly "fine," by the way.) > >But... at apertures of f/22 and 32 this lens will cover its entire >plate with resolution of 40 lines/mm or greater-- it sharpens up very >nicely. Perhaps this old lens was designed on purpose this way to >cover this wide field angle, unusual for most tessars, with the fast >aperture intended just for focusing, not taking?I have one of these, it was on an old Agfa/Ansco view camera but is much older than the camera. Mine is S/nr. 3050646. It makes very sharp images. My guess as to date is based on the following clues: 1, It is a B&L not a B&L-Zeiss, makes it probably after the entry of the US in WW-1 (1914). 2, In 1927 the patent law was changed to require the actual patent numbers rather than just the date to written on products, makes the lens before 1927. 3, Patents are good for 17 years, 1903 + 17 = 1920. B&L may have continued to print the date on the lens rings after this. B&L was engaged in war production after 1914, they had the only credible optical glass factory in the US so got very busy. Best guess as to date therefore is 1918 to 1920. (Watch someone blow this closely reasoned argument to smithereens:-)) Mine is in a Wollensak Optimo shutter with marked speeds to 1/300 sec. This is an interesting shutter in which the shutter blades are double sided and turn through a complete 180deg when its tripped. When tripped again, they return. This permitted higher speeds than the usual oscillating blade variety but the effeciency at higher speeds wasn't too good, so the 1/300 may have been ligit for effective spped with the lens wide open when the thing was new. It makes about 1/50th now. This shutter dates from about the same period. This lens positivly amazed me when I first used it. Please note that even though its marked 5x7 the focal length is a little on the short side, about 180mm. It would be interesting to test more than one example to see if what you found is characteristic of the type or just an individual lens. It seems to me that B&L had some patents for modified Tessars themselves but I don't remember the dates. 1903 is the date of the Rudolph patent for the Tessar in the US.