Saturday, June 18, 2011

Yellow Dot Clue for Aero Ektar Aficionados

Put this post in the arcane category: You have to be one of the possessed people who have latched onto the Kodak Aero Ektar and other big eyes to appreciate the meaning of this. Here is a plate for a very large aero lens, a giant 48 inch f6.3 mass of glass too heavy to even lift.

But the label with its dot is interesting. If you read it normally, left to right, it almost looks like you could read it as "48 inch f/6.3 for 9 inch X 18 inch camera telephoto type I-class B DAY NIGHT temperature compensated USAF spec No..."

Notice that the dark dot is violet or purple. The two in this context seem to me to indicate the use of the lens, in this case day and night. Sunny/Cloudy? I don't think so, and cannot come up with another plausible interpretation of the dots.

Therefore, the famous yellow dot, so cherished by those who pay extra for it in their Aero Ektar hoods, might indicate "Daylight Use".  What would be different from night use? In darkness, the Aero Ektar was used with flash bombs to illuminate the scene of night bombings.

Do we now know that the yellow dot means? Comments please.

I grabbed this image and cropped it, taken from some other online post that I cannot find, to provide a proper attribution, at the moment. Here is another Aero Ektar and some earlier speculations about the meaning of the dot.


Anonymous said...

There is no difference in the coating afaik but the yellow day designation makes sense.

Anonymous said...

If yellow means daylight, violet night, then I suppose the two dots could mean that the lens is suitable, meets specs for, both wide open and stopped down operation. A yellow dot could mean it is suitable for stopped down operation only.

Bob Crowley said...

Now it seems to me that the colors here could mean "Hot/Cold". It would not be redundant, because the lettering does not say what temp. Hot and cold temperatures could be expected in flight applications, especially where the mission might start after idling on a hot tarmac, then ascend to 40,000 feet, or more, for reconnaissance.

Anonymous said...

I came across this blog, in searching for the history of Ektar lenses, being from one of the factories, long ago. I remember the dots, and yes, a yellow dot generally meant it was good in bright daylight, as you seemed to have guessed.

Anonymous said...

A yellow dot could mean selected for stopped-down daylight use, over other lenses that performed better wide open. It might even have been a way to pass a lens that would fail the full open MTF. Later in the war, and after, higher altitude daylight runs became more common.

Anonymous said...

If yellow dot means it's good for stopped down shooting. Then people are paying extra for lover quality Aero Ektars for wide open shooting :)

At least it's not coating related, as i have had 15" wolly tele that was not coated at all, but had yellow dot.