So I went lens shopping, there was a guy with an advert for a heap of different lenses, one he had was a Sigma 100-300mm that would fit in well with my current collection and nicely cover some long distance stuff, like Moon rise videos, city landscapes, etc etc.
Anyways, he also had a "Formula 5" 400mm f1:6.3-22. Casing looked clean and well made, but it wouldn't focus and looked hazy, so he said "$20 ?"
Who'm I to turn down a potential bargain, or an opportunity to pull a lens apart and learn more about the insides?
So I strip it, found one of the elements was showing signs of having been 'cleaned' before, with either chemical contaminant, or a cleaner used that has reacted with the lens coating.
That element has been cleaned with some very gentle soap and cotton cloth that has been through the wash so many times that it's soft enough to use for lenses.
Put the lens together in same order, I can see through it and it focuses from 6m to about 10m, but not to infinity.
Swap the order of the two inner elements, I can do infinity, but not the close end, limited to about 20m at the marked 8m point.
Closer look at the threads shows original thread sealing compound on the inside of one thread, and the outside of another,... A ha,..
Flipped the inner elements mount, used the order for the inner elements that gave me the infinity focus, which turns out to be the correct order for the elements - flange - sensor alignment, and bingo - 6meters to Infinity,.... Sweet!
So, here's the test shots I did with the K-01 yesterday. No grading, no audio, no IS, plenty of heat haze warping.
Think I'll need me a new, longer, Rails & Matte Box kit.
Assuming I haven't screwed the upload and Vimeo doesn't mess it up..
As for the 100-300mm Sigma lens, that was $50, and looks to be sharper then my 28-200 Sigma.