Graflex.org

[Murray@uptowngallery.org]

There are two Ektars that are Heliars; the Kodak Medalist's 100/3.5 and IIRC 105?/3.7

The 101 I think is an anastigmat, and I heard someone claim it was a Tessar. I believe if I remember what Kingslake said, that an anastigmat is 3 or more elements, highly corrected.

So a Tessar may be an anastigmat, and some triplets COULD be. No one seems to call planar (modern symmetrical 6 element) lenses anastigmats...it seems at some point a boundary of lens definitions was drawn.

So, I am wondering if someone can clarify WHAT the 101/4.5 Ektar is. DOES it need to be stopped down for sharp corners like most normal A.O.V. triplets and Tessar variants.

The Heliar 100/3.5 (in my Medalist) seems sharp corner-to-corner wide open and the manual doesn't seem to warn you about stopping down...

What should I be aware of on the 101/4.5 in that regard on the Mini Speed I just got?

Thank you
_________________
Murray

[Dan Fromm]

Old question, Murray. Ektar is a trade name, means "our best in this focal length-maximum aperture combination," has no implications for design.

The 101/4.5 Ektar is a tessar type. The 100/3.5 and 105/3.7 Ektars are, as you said, Heliar types. Tessars are anastigmats, not all anastigmats are tessar types.

I have a couple of 101/4,5s, had a 105/3.7, and recently bought another 105/3.7 that I haven't used yet. I sold my first 105 because at the apertures I shoot -- no wider than f/8, usually f/11 or smaller -- it was less sharp everywhere in the frame than the slightly better of my two 101s. This is consistent with Chris Perez' results.

That said, the slightly better of my 101s is slightly less sharp in the corners than in the center at f/16.

[clnfrd]

I have no formal training in this topic, just the school of hard knocks. That having been said, I know that some lenses were labeled "Anastigmat". However, in my primitive up-bringing, anastigmat was a generic term that referred to the fact that the lens was corrected for astigmatism...that is, it would produce images without distortion, i.e., around the edges and in the corners.. Thank you...no applause, please..just throw money. Fred.

[clnfrd]

P.S. My 101mm Ektar, in its Kodak Synchro-Rapid 800 shutter, however many elements it has, is my sharpest lens, usually used at ƒ11 or smaller. Fred.

[Dan Fromm]

Fred, for years my 101/4.5 Ektar was my gold standard. After careful testing I've concluded that my 4"/2.0 Taylor Hobson Anastigmat (there's that word again) is a little better, especially in the corners. One could be very happy with either. The Ektar, which is much smaller and lighter and in shutter, is easier to live with.

The Taylor Hobson is, by the way, a 6/4 double Gauss type. As I told Murray, all tessars are anastigmats but many anastigmats are not tessars.

Cheers,

Dan

[tsgrimm]

I don't make large photos, >8x10, most photos I take are just for reference; so top flight lenses are not too important to me, but for those of you that do make large photos check out the link below dealing with Kodak lenses.

http://www.prairienet.org/b-wallen/BN_Photo/KodakEktarsIndex.htm