Aero Ektar resuscitation effort

guardian · Joined: 18 Mar 2009 Posts: 1747

I'm writing this, more than anything else, to document my ongoing work. Still, I need all the help I can get so counsel of any nature is always welcome!

I saw this post yesterday by another forum member

http://forum.mflenses.com/kodak-aero-ektar-178mm-f2-5-question-t59627.html

and was reminded of my own 610mm Aero Ektar which I last tried to use to view a comet. I think it was in this century but I'm not 100% certain. Sadly the lens, badly clouded and loaded with fungus, was scarcely clear enough to be much good for that purpose. Nevertheless, I was for some reason inspired to take it out and begin working on it.

My Aero Ektar was originally purchased by my dad circa 1960 (I really don't know the actual year). It was, to say the least, not properly cared for over the years . . . . hence the fungus. And when an Aero Ektar gets fungus it's a lot of fungus. It's a large lens. The two front-most elements, with their aluminum mounting, weigh three pounds (1.36 kg). The front lens element is roughly 4 3/8 inches (about 110 mm) in diameter.

This was my first attempt to clear fungus. I had shopped for Ponds cream but did not buy. It is expensive. I read the Ponds cream ingredients list in the store and mineral oil was prominent. Going through my available substitutes, stuff already owned, I found some Keri Lotion which also listed mineral oil as the first ingredient. So I am trying the Keri Lotion.

This is a guess: It seems to me the fungus causes a hard calculus to form on the lens which the mineral oil softens, allowing removal. I don't really know if that's right.

Anyway, following disassembly I have been able to clean the front two elements of the Aero Ektar to where they are quite clear and, I believe, usable. Aero Ektars are very old lenses, from WWII. So I'm almost certain my lens is not coated. Still, I have an odd spot on the front-most element which almost looks like coating damage when viewed at an angle. Looking straight through the lens, though, the spot is not visible and I don't believe it is a problem.

The rear-most element of my Aero Ektar is another story entirely. It had by far the worst fungus. I was not able to separate the rear lens element from the aperture (which is huge), and I have not been able, either, to remove the element from its mounting. This makes working on the rear element more difficult. I have "lotioned up" the element a couple of times but the fungus, it appears, might have done permanent damage. Sad

I will continue to work on this.

My Aero Ektar is a true manual focus lens. Actually, everything is manual. There is no helical. You focus the lens by sliding one brass tube back and forth inside a second brass tube. The aperture works and is quite adjustable, but there are no f number graduations. It's all "seat of the pants". The entire experience is about as far from "point and shoot" as you can get. But it's an interesting lens just the same. I only hope I can clear enough fungus from the rear element so I can take a photo.

Oh! Yellowing. I nearly forgot. Yes, my rear element has the thorium thing going and is a gamma ray emitter. The yellowing, while noticeable, is not all that bad in my view. Plan is to expose the element to sunshine this summer in an effort to clear it. It's too bad the gamma radiation didn't kill the darn fungus!!

guardian · Joined: 18 Mar 2009 Posts: 1747

This post is intended to provide a brief update regarding this Aero Ektar project and also to ask a new question:

First, the update:

I have cleaned the front two elements of the lens fairly well, at least to where they are usable. The rear element has less fungus than it once did. Currently it is sitting outside, completely unshielded, in hope of catching some sun for a thorium yellowing cure. As I live in a rural area, I also hope it is not discovered and/or targeted by any of the many animals that roam freely hereabouts, including especially birds.

Now the question:

How does thorium yellowing express itself in your experience? My rear element has a mottled appearance, as regards the discoloration. Is the thorium yellowing you have experienced uniform, or has it expressed itself unevenly?

Aanything · Expire: 2014-05-30

I only had a couple of yellowed takumars, and the yellowed (brown-yellow actually) elements were always uniformly colored.

inombrable · Joined: 20 Mar 2012 Posts: 545 Location: Salamanca, Mexico

The yellowing of my takumar and pancolar lenses was always even on the elements.

guardian · Joined: 18 Mar 2009 Posts: 1747

Thanks, guys. That's what I was afraid of and, candidly, your responses make common sense to me.

I don't know why my lens is mottled: It could be coating damage unrelated to thorium. It could be something else. I am, in effect, endeavoring to raise this lens from the dead. It never will be perfect, but I already know it will be worth the effort.

We are getting some sun here now and I plan aggressively to cure the lens at every opportunity. It was a good day today, for example.

After the yellow is gone I will try to get to the bottom of the mottling . . if it remains.

David · Expire: 2013-01-25

I saw a 610mm Aero Ektar on eBay that had a non-uniform yellowing. It was darker in the center with uneven margins that tapered to clear. If that's similar to your experience, then it may not just be you. Maybe it has to do with either the group cement or the glass thickness. Both of those are just speculation.

For the dot on the front element, I think these are four-group, seven element lenses, correct? The front element stands alone but the other three groups are paired elements cemented. If that dot is in a cemented group, then maybe it's a cement issue? If you can't see it straight-on, then I would guess it's not super likely to impair image quality. I could absolutely be wrong about that being the lens design, by the way.

I've seen some photos taken with this online and even in imperfect condition it may have some uses.

You may also know of this site, but it has some interesting info about the lens' radioactivity. It's old, but maybe the author has additional information about the lens he could share. I don't know as I've ever talked to the guy.

http://home.earthlink.net/~michaelbriggs/aeroektar/aeroektar.html

Here's a guy who uses an f2.5 178mm Aero Ektar and speed graphic camera for his work. It's really, really excellent and shows off how well this lens family performs. I only share it because it shows that these can be used for other subjects than astro subjects (though with a 610mm with a 110mm front element that may be really unwieldy and difficult to manage.)

http://www.johndesq.com/graflex/grafgal.htm

Also, Flickr has a large collection of photos tagged Aero Ektar (probably different sizes, mostly 178, I'd guess) that are worth checking out. Some are NSFW, though, or I'd have posted a direct link here.

So the long and short of it is that this may have a second life for you as another type of lens, despite the really long focal length. On 4X5, 610mm is a 182.39 mm equivalent on 35mm (34X5 focal length X 0.299 for 35mm equivalent) and, though bulky, that could still make for some interesting landscape and scenery shots. I would imagine that the potential for miniaturization effects is pretty huge. Also, if the lens elements aren't perfect, it may be a good pictoralism lens.