Aero Ektar Diferent serial number betwen front and rear element.

[southman81]

Hello there.
I recently got an great kodak aero ektar 7" F2,5.
The focusing wide open is a bit hard, but it is logical in that kind of aperture.
The problem is that when it is wide open, even focusing in infinity is a little blury, i dont know if this happend in all aero ektars or just in mine.:confused:
Then, looking quite hard, i found that te rear element has a diferent serial number to the front element. (I can`t remember right now, but one is EE ans the other EM (1944-1943)
So, set the ektar to infinity, and put it wide open, can i find a good sharpen image? Or it is normal that i find a bit blurry image on my ground glass?
Regards. And sorry my english.:)

[jackpie]

Southman81 are you familiar with the use and focusing of Large Format cameras? I ask this because you say "set the ektar to infinity" which I find strange. The only explanation for this phrase I can think of is that you are using a Speed Graphic that has been setup for use with the Aero Ektar. But if it had been setup correctly it should focus just fine.


Sorry I can't help you with the specifics of Kodak Aero Ektar serial numbers.

[Steven Tribe]

These are old military lenses where depot staff had dozens of sets to clean, maintain and decommission when necessary. It is quite likely the lenses were swapped between mounts - on purpose or by accident.

[southman81]

jackpie, yes, the ektar is on an aniversary speed graphic, when i mean set to infinity, i mean on the GG, not in the telemeter.
But when i focus on the GG, even with a lupe, is strange, i can´t find a nice sharp image, when i focus on (let say a tree) is quite a ghosty image, like a thin blur on it.
Only happend of couse at f:2,5, the question is if this happend on all aero ektar or just in mine.

Steven Tribe Thnaks a lot, nice tip to have in mid, that can explain this mistery.
I think that this diference don´t disturb the lens image quality.
Best regards

[jackpie]

The lens should be able to focus sharply. A fast lens like this is usually regarded as easier to focus than slower lenses. The reason for this is that it projects a bright image on the ground glass and the shallow depth of field makes the exact focus point more obvious.

The lens should focus at infinity at a distance of 1 focal length away from the ground glass. This is measured from the nodal point of the lens, which for this lens will be about in the middle of the barrel. As the focal point gets closer to the camera the distance between the lens and the ground glass gets longer. When the lens is focussed at a point 2 x focal length in front of the lens it will be 2 x focal length away from the ground glass.

Practically you should try this. Postion your camera so that it is pointing towards a long object that is receding towards the distance, ie a fence, or wall, or road etc. Move the front standard so it is 7 inches from the ground glass and open the aperture fully. Check for focus. If you can't get any part of the object in focus then extend the lens ground glass distance looking for focus. As you extend the lens you should see the focus move towards you along the fence or wall.