Wednesday, February 22, 2012

f2.5 Aero Ektar Lenses




There are quite a few versions of the coveted Kodak Aero Ektar lenses.  Here are the two most common versions: The 12" f2.5, weighing 7.3 Kg/16.1 lbs is on the left. It sports two dots, one yellow, one purple, and was made in 1953. Perhaps it was used to spy on Iron Curtain countries during the Cold War.

In the center is the much more common f2.5 7" version, with a weight of 1.45 Kg/3.2lbs. There are lots of these around from WWII. This example was made in 1944, about three years after Aero Ektar inventor George Aklin's 1941 patent.

To the right is a far rarer, and more desirable Aero Ektar with a very much slimmed down mount as supplied by Kodak in 1951, making it one of the later versions of this useful lens. It weights a "mere" 1.2 Kg/2.8 lbs, and has a slim aperture ring, a much slimmer front hood with the indicia placed at the periphery, and appears to have a hard coating.  This also sports the two dots, one yellow, the other purple. It has a manufacturing date of 1950.

These were very expensive to produce. Kodak took a great deal of pride in the Ektar lenses, and today they are still among the sharpest.  Our masthead of the Charles River and trees was shot on Type 55 using an Ektar lens, and you can view it with a microscope and see every leaf, so sharp it is.

All of these are quite well made and thick lenses of the double Gauss design, with rear elements comprised of mildly radioactive thorium glass that, over time, produces color centers at the molecular level responsible for producing a reversible yellowish or even brown cast to that element. The physics of color centers has been studied in crystals and other optical substances and this sub-micron change to the actual structure of the molecules can be brought on by gamma radiation and reversed by exposure to UV. Read Micheal Brigg's emphatic, and excellent treatise on Aero Ektar radioactivity.

Online there is this un-named shot of an even later Aero Ektar having a sort of hybrid mount. Like the distal end of our slim Aero Ektar, above, this version uses a peripheral beauty ring too, but retains the more massive aperture ring. It has a manufacturing date of 1960. One wonders what Kodak was up to during the peak of the cold war, and how many of these were made.

The lenses shown are of the same design, just scaled up (or down) depending on the focal length.  There are other longer and shorter focal length Aero Ektars too, including a 6" f2.5 version, and slower, longer versions that are not often much sought after, but show up on ebay frequently.

People love the mysterious dots, so here is more about the dots, here, and even more here.

Even more from Aero Ektar inventor, George H Aklin....Click Here


Aero Ektar Patent

Saturday, February 18, 2012

Friday, February 17, 2012

Bob's Leitz Microscope

Monocular biological microscopes are not very common today. The curve and style of this 50s era Leitz is well captured with New55 FILM.

Bouquet of Wires

Ted McClelland's pod still life test shot done with New55 FILM as he gets up to speed with the mechanics of the pod, sleeve and insert which all have to fit, be straight, with well attached clips and of the exact size to fit into the 545 holder, all accomplished in this photograph.

Sunday, February 12, 2012

Tobias Feltus and Rachel Rayns on New55

Edinburgh: February 8, 2012:  Artists Tobias Feltus and Rachel Rayns recent collaborations include the first uses of New55 FILM in Europe, marking a milestone in the progress to bring 4x5 instant film back to photographers.  Rayns, noted for her self portraits, experimental motion pictures, and the highly visible "Soup Lab" posed for this portrait in a portrait for artist and photographer Tobias Feltus of Edinburgh, Scotland during a visit there.

"We got one decent shot out of the five" remarked Tobias Feltus, who is part of the New55 group and is recommending improvements. "The pods are too full, and we could only get them in [to the 545 holder] by opening it first." he remarked.

Despite this, the New55 negative yielded a photograph showing Rayns and one of her trademark expressions on The Impossible Project film.

"We have a way to go", said Bob Crowley, who has financed New55 to-date. "The progress has been good, and there is no reason we cannot produce this film without defects in the future if we have adequate financing."

Friday, February 10, 2012

Mind the gap - again

Yesterday, Ted McClelland of 20x24 performed some experiments, of which this is one, showing the effect on the negative of too-thin a reagent gap, and what happens.

In the upper left, there is sufficient gap for smooth and complete processing with no solarization after pulling either. On the lower right, the mottled appearance is where the reagent was exhausted before the process was complete, resulting in an uneven appearance.  All this matters to the construction of the pod, and the rails.

The difference between these two areas in terms of thickness is slight, perhaps a tenth of a mm, or less.

Other artifacts that look like little wings if you zoom in close are the receiver sheet top coat pulling away from the substrate. This happened, I think, because we over humidified the receiver, which has been severely curling on us due to the very dry weather.

Summer was a better time to build New55. Our lab is not climate controlled, and there is no way to humidify it.