Yoshizen's Blog

110 Pentax 24mm Lens (2)

I realized that the tiny toy like Pentax 110 camera’s 24 mm F2.8 lens appeared to be very critical lens.  What I mean critical is, as it was designed by the Pentax, aiming to achieve their 110 photo’s quality comparable to full size 35 mm, so the quality of the lens is very high —– and it’s requirement / the standard must be also high. 

In this blog, I’ve been plying with hundred of tinkering job, —– though, its standard is pretty casual.  I’m doing it in my kitchen, without having even an optical bench.  And I demonstrated that how the standard of the optics can be not critical. = typically like “Twisted lens” demonstration or  “F-Aperture control” kind. —– still I could manage those tinkering with good success.   So, when I adapted 110 24mm lens to Sony A7R body, I just made a hole in a Sony’s body cap and inserted the bottom of the 24mm lens then fixed it by Epoxi glue.  I thought, I’ve adjusted infinity very well (as A7R’s focus peaking works perfect) —– but later, I noticed that the focus was not even = left-hand side was a bit out.

110 Pentax(2)_DSC0481-003

110 Pentax(3)-002

Yet, the slant of the lens was barely visible = the lens may not off the straight perpendicular less than 1 degree —– though, lens was short focus 24mm, of which only 2mm of lens shift makes the focus from infinity to 0.35m.  It’s mean, even less than 0.1mm off-position on one side would spoil sharp infinity image. (Especially, here the lens is always fully open F2.8)

There was a funny paradox here.  24mm lens for 110 Pentax was a standard lens, = obviously, the lens for 110 Pentax was expecting to be used and worked as a standard lens.  But the same 24mm lens for 35mm camera was a very wide-angle. Therefore, while 24mm lens for Nikon was having distance scale  ∞, 3, 1.5, 1, 0.7 —m, 24mm lens for 110 Pentax has much finer scale  ∞, 8, 4, 2, 1.5, 1, —m,  and the focus seemed to be also quite critical.  (But, to fully satisfy those potential in the Pentax Auto 110 needs to have very delicate, fine handling while see the image in its small SLR view finder —– though, as the 110 body here was broken and I couldn’t see the finder image, I can’t tell if their aim to make hi-quality image was materialized by this system as a whole or not.


 

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