I am still struggling with the concept of different mags with the same
extension and the sae focal length, but never mind!
Here are the markings for 20mm and 38mm, with the marked extension in mm
(which matches the physical distane between lens flanges):
70mm = 7x with 20mm lens
About 81mm = 3.5x with 38mm lens
90mm = 8x with 20mm lens
Very nearly 100mm = 4x with 38mm lens
110mm = 9x with 20mm lens
Piers
-----Original Message-----
From: olympus-owner@xxxxxxxxxx [mailto:olympus-owner@xxxxxxxxxx] On Behalf
Of Adam Long
Sent: 13 March 2004 20:38
To: OM list
Subject: [OM] 65-116 versions
>But the scales are specific only to the focal length of the lens in
>question - so it doesn't matter which version of the lens you use. And
>the 65-116 tube doesn't distinguish between the apertures
But it DOES matter which version of the lens you have! In my OM4ti
instructions it lists the mags as follows:
38/2.8 + 65-116 = 3.1X - 4.5X
38/3.5 + 65-116 = 2.5X - 4X
20/2 + 65-116 = 6.8X - 9.5X
20/3.5 + 65-116 = 5.8X - 8.3X
It seems the later lensheads are already a bit further from the film, giving
slightly higher mags. The focussing helicoid in them can then be used to
gain a little more extension/ magnification. So which is the tube marked
for?? From the picture in my OM1n brochure it looks like it is for the
earlier manual heads - making these tubes the older type! When Oly
redesigned the heads they must have dropped the markings to avoid confusion
between the versions. The tube pictured is also marked for the 80/4 +
close-up lens.
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