Fast LF lens

[David M]

I recall someone wanting a fast LF lens, but can’t recall who. There’s one on EBay listed as:

“Cooke 6 3/8 Inches F2.5 Anastigmat Large Format Lens. English TTH Series X 5x4”

I have no interest in it and I know nothing more about it. It merely popped up in my in-box. Hope it’s useful to someone.

 

[Analogue & Light]

I recall someone wanting a fast LF lens, but can’t recall who. There’s one on EBay listed as:

“Cooke 6 3/8 Inches F2.5 Anastigmat Large Format Lens. English TTH Series X 5x4”

I have no interest in it and I know nothing more about it. It merely popped up in my in-box. Hope it’s useful to someone.

That COULD have been me as I posted a wanted thread recently. Thank you, I was offered an Aero Ektar from a friend at a very reasonable price. My Speed Graphic arrives tomorrow.

 

[Ian Grant]

I recall someone wanting a fast LF lens, but can’t recall who. There’s one on EBay listed as:

“Cooke 6 3/8 Inches F2.5 Anastigmat Large Format Lens. English TTH Series X 5x4”

I have no interest in it and I know nothing more about it. It merely popped up in my in-box. Hope it’s useful to someone.

There was one at my house on Saturday, that focal length is for quarter plate..

Ian

 

[AnalogueWendy]

There was one at my house on Saturday, that focal length is for quarter plate..

Ian

May be a little different, Ian. Mine is only 70mm dia across the back filter holder. Does not look quite the same . It might cover 5x4 . . . I wonder how Real Camera company tested it.

 

[Ian Grant]

The TT&H Cooke data is the 6.375" f2.5 is for quarter plate, and the 7.75" for 5x4. The issue here is the circle of illumination will be much larger than the manufacturers image circle which is of acceptable sharpness. You have to allow for rise/fall etc.

The faster the lens with a triplet (or Tessar type) design the quicker sharpness fall off away from the lens axis. So for quarter plate Cooke sold the Series II f4.5 5¼". or longer.

I'll ask Jeremy when I next see him In practice coverage increases with extension for say portraits so it's likely OK on 5x4.

Ian