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Forum: Pentax Q
07-03-2019, 07:43 PM
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This is a great idea for a CS mount. That "#3 adapter" does seem to have gone scarce on ebay, at least from sellers willing to transact with USA, but I did find and purchase a few on AliExpress.
m1zeng C Mount 16mm cine/film cctv Movie lens adapter to Pentax Q P/Q PQ Q10 Q7camera
Depending on the width of the CS lens' flange in front of the CS lens' threads, and 'how far rearward' the focus/ aperture/ zoom collar(s) are on a particular CS lens that you want to use, you wouldn't necessarily have to shave off the whole front of the "#3 adapter"- a recessed area of sufficient diameter to "fit" the flange of the CS lens, 5mm "deep" from the original front surface of the adapter, but leaving in place the rest of the outer area, could work. That way you'd still have the outer grip area, and it would to some degree give a bit more support/ protection to the thread/flange interface. I have a metal lathe (though my skills with it are still a work in progress) and I hope to give a try at making such an approach after my adapters arrive, and when I get a chance to fire up the lathe.
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Forum: Pentax Q
07-01-2019, 08:22 PM
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I need to get out and use my Q more, I get too busy with work and other things in life, but I find it fascinating how the Q opens up such opportunities to experiment with lenses at both the extreme wide and extreme telephoto ends of the spectrum. I have a couple of low cost mirror lenses inbound, one a 300mm and one a 500mm. Not sure yet how the optical quality of the mirror lenses will fare when subjected to the Q's crop factor, but it will be interesting to see. I already have an optically very nice Fujinon 'machine vision' TF2.8DA 2.8mm lens- it doesn't fill out the full Q sensor in the corners but seems from some initial brief testing to be very sharp. From the Theia 1.7mm on the one end being 9.5mm at 35MM equivalent to the 500mm mirror being 2800mm at 35mm equivalent (or even the 300mm mirror being 1680mm 35mm equivalent), it is "way out" that one camera can accept lenses that have such range at both extremes, and also that it can still amount to a modest lightweight bagful in order to have the 'official' Q lenses plus some of these extreme options.
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Forum: Pentax Q
07-01-2019, 08:12 PM
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Glad this idea might help open doors for people to use CS lenses. There seem to be more affordably-priced CS lenses on ebay than C lenses, both because a lot of modern CCTV seems to have gone to CS, and also because no other camera other than the Q has a flange distance short enough to be able to use either CS or D lenses.
The Theia is a really weird lens, in an interesting way. Some proprietary technology that they use allows a relatively non-fisheyed ultrawide lens. 1.7mm at the Q's 5.6 crop factor would be a 9.5mm equivalent for a 35mm format comparison, and the idea of a 9mm non fisheye lens is pretty wild. I think I remember when I was hand-holding it in front of the camera opening that I saw the edges of my feet, even though I was standing up and pointing it forwards. I am not sure the resolution will be terrific (the model I have is one of their economy-line ones)((I think I got it for about $40 on ebay, open box, spotless, but the list price is far, far higher) but it will be fun to play around with. They do have some higher resolution models but I haven't come across one of those yet at a good price.
The model that I have - SY110/MY110 Ultra wide ? Theia Technologies
overview of their ultrawide non-fisheye tech and models: Ultra wide angle lenses ? Theia Technologies
simulator Calculator ? Theia Technologies
I have no connection with the company - I just like experimenting with oddball stuff
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Forum: Pentax Q
06-30-2019, 09:29 PM
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I've been interested in trying some CS lenses on my Q, including an ebay-acquired Theia SY110M 1.7mm F1.8 that I bought a year or two ago but haven't adapted yet (my projects outstrip my time). No typo, truly 1.7mm, and apparently the company has some patented way of doing things that eliminates or at least minimizes barrel distortion. Judging by hand-holding it in front of the Q's flange, not sure the image quality will be stunning, but I am hoping that was partly the effect of light leakage and probably ???? alignment precision from my hand-held tryout. The field of view seems all-out bizzarely wide in all directions and I did not perceive vignetting.
I looked at flange focal distances and adapters, and the flange focal distance of a "D" cine lens is 12.29mm, whereas, for CS, its 12.526mm. So a CS lens on a D adapter face will end up focusing a bit past infinity and lose a bit of its close-focus end of adjustment, unless you shim it, but I am not sure that 0.266mm will be of vast consequence (although maybe it will, given that we are in the land of tiny-everything) eBay is swarmed with very low cost "D-PQ" adapters and I have picked up a few. The diameter of the D lens threads is much smaller than C, but it's easier to make a hole larger than smaller....
Someday when the "roundtuit" aligns, I want to put one of my "D" adapters in my lathe and spin the hole wider to match a CS lens flange. If I am feeling methodical, I may cut the hole small at first and see if I can use a 10-32 tap, with the lathe leadscrew set to 32tpi feed, to 'kiss' the 32 tpi thread that both the C and CS use into the edge of the opening (1"-32tpi taps to directly match the C/CS thread seem ridiculously expensive.). If I am in a less methodical mode, I may just use the lathe to hog out the center to a snug fit on the CS threads, and, if no major shimming is needed, get out the adhesive du jour.
If/ when the 'roundtuit' aligns on my D to CS experiment, I will try to post the results here- but I wanted to mention that hacking a cheap D-PQ adapter looks like the fast lane to a low cost CS adapter
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