What the human eye really sees

First topic message reminder :

Last weekend I finally completed a task that I set my mind to do 10 years ago.

For years I have been preaching about the optics of shooting: where should your eye be focused for optimal sight picture, railing against people who say you should focus on the sights, using an aperture to improve your depth of field, etc.  Well, I can finally show what I mean.

The human eye is about 1 inch in diameter, so around 25mm.  So I got a 24mm lens (close enough), and put it on my Nikon DSLR, so the camera is seeing about what my eye sees.  I then hung a target 50 feet away, I put the slide of a 1911 longslide on a tripod, aiming at the target, and I positioned my camera about 24" behind the rear sight, which is about how far my eye is from the rear sight.  I then set the camera aperture from about 3/8" diameter to about 1/8" diameter, which is about the size range of the human pupil.  I also included smaller apertures, which represent looking through openings on something like a Merit Disk.  These different apertures provide differing depths of field.  I took pictures with the camera focused on the target, and at a point between the rear and front sight, and at several positions in between, in steps of 0.25 diopters, which is the increment in power you get from eyeglasses.

Then I cropped the pictures to show just the sights and target, and assembled them in a grid, so for any setup, you can track up/down to compare focal points, or track left/right to compare aperture sizes.

And phooey, I just realized I cannot link to a pdf, but I don't want to retype this message.  So I'm going to post it as a teaser, and will return tomorrow to add a link to the pdf.  It's good.  I promise.

Added it below, before thinking to simply edit the original post, so I'll put it in both places: [url=https://www.dropbox.com/s/3cvu289yir12j8c/DOF3.01 comparison.pdf?dl=0]https://www.dropbox.com/s/3cvu289yir12j8c/DOF3.01%20Comparison.pdf?dl=0[/url]

My head is spinning around with all this calculating.  Kind of over the edge.

 I am 66, had cataract surgery and a lens implant. Some stigmatism is left but nicely corrected now. Before my surgery, using my Knoblochs, and various accessories my sights were razor sharp! Yes, the Knoblochs can be a great resource. eBay has some pretty messed Knoblochs without accessories, listed for $200. 

I am very pleased with my surgery and no longer need them, so if someone is interested?

GerhardGI am very pleased with my surgery and no longer need them, so if someone is interested?


Do you by chance have a +225 or +250 lens with them?

I can make Knobloch lenses in 2.25 or 2.50, however take a look at standard cheater reading glasses.  2.50 is a standard power that you can buy for $15 at any drugstore.