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Adapting a popular lens..
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PostPosted: Mon Apr 15, 2019 9:27 am    Post subject: Adapting a popular lens.. Reply with quote

So far, the most crazy DIY project I have ever heard of...
https://www.instructables.com/id/How-to-Adapt-a-Door-Viewer-quotFish-eye-Lensquo/

Have a great week
N.


PostPosted: Mon Apr 15, 2019 11:19 am    Post subject: Reply with quote

Ha! That's excellent.


Best I've seen lately isn't adapting a lens, but adapting ice -

https://www.youtube.com/watch?v=jWvwt3mCu68


PostPosted: Mon Apr 15, 2019 2:57 pm    Post subject: Reply with quote

I remember fitting a door viewer into a cap back in the '70's and using it on my Zenit. Once the necessary exposure had been established it was a bit of a novelty, but the image quality hardly justified the effort!

Last edited by kypfer on Tue Apr 16, 2019 7:31 am; edited 1 time in total


PostPosted: Mon Apr 15, 2019 8:31 pm    Post subject: Reply with quote

Not so crazy.....I did it back in 2012 and it worked. I 'fixed' a door viewer threaded into a flexible plastic lens cap and stuck on the front of a lens. For the snowdrop picture I used a 28mm lens, on my Pentax K10. It's not a mega-buck fisheye, it's a bit of fun. Wink







PostPosted: Wed Apr 17, 2019 2:44 pm    Post subject: Reply with quote

I did something similar to this with an old 8mm format Wollensack 1/2" lens (about 6mm). I drilled a hole in a 49mm lens cap, and glued it in place, but I reverse mounted it, so that it would increase the magnification. Mounted the cap to my Tamron 90mm macro. Unlike the door lens, it doesn't do a fisheye -- in fact, it delivers a full-frame image, at tremendous magnification. Sharpness is quite good.


PostPosted: Wed Apr 17, 2019 6:08 pm    Post subject: Reply with quote

cooltouch wrote:
I did something similar to this with an old 8mm format Wollensack 1/2" lens (about 6mm). I drilled a hole in a 49mm lens cap, and glued it in place, but I reverse mounted it, so that it would increase the magnification. Mounted the cap to my Tamron 90mm macro. Unlike the door lens, it doesn't do a fisheye -- in fact, it delivers a full-frame image, at tremendous magnification. Sharpness is quite good.


Sounds fascinating indeed! Can you be kind enough to share some stuff done with it? Best, jt


PostPosted: Thu Apr 18, 2019 1:45 am    Post subject: Reply with quote

This door viewer would be nicer attached to a new gen 48mp cellphone sensor Smile like Xiaomi note 7


PostPosted: Thu Apr 18, 2019 9:39 pm    Post subject: Reply with quote

I really don't need another fish-eye, but this appeals to the point I just couldn't resist spending £1 on a door viewer from e-bay.
If things run true to form by the time it arrives I'll probably have forgotten why I got it... Thank You Dog


PostPosted: Fri Apr 19, 2019 1:39 am    Post subject: Reply with quote

Lloydy, a very good quality of sample shot that one does not expect from a humble spy hole!


PostPosted: Sat Apr 20, 2019 7:28 am    Post subject: Reply with quote

Focusthrow wrote:
cooltouch wrote:
I did something similar to this with an old 8mm format Wollensack 1/2" lens (about 6mm). I drilled a hole in a 49mm lens cap, and glued it in place, but I reverse mounted it, so that it would increase the magnification. Mounted the cap to my Tamron 90mm macro. Unlike the door lens, it doesn't do a fisheye -- in fact, it delivers a full-frame image, at tremendous magnification. Sharpness is quite good.


Sounds fascinating indeed! Can you be kind enough to share some stuff done with it? Best, jt


Sure. Here's a shot of the lens glued to the lens cap. Kinda crude looking, I know, but it works:



Here's a shot of the subject at a "regular" focal length. It's the side of an old Lexmark printer box. Note the lens sitting on top of the box:



And a close up of the area that I was zeroing in on. The "XP" in Windows XP was my final point of focus:



And finally, the high magnification image. Resolution's not bad, eh?



I was kinda surprised I got a full frame image with no vignetting from that tiny 1/2" lens, but coverage was decent. As you can see, the image is getting soft toward the edges, but center sharpness is good.

A great thing about using 8mm format, aka "D" size lens mount lenses, is those old lenses are dirt cheap. Some of them, like the Swiss Kern Palliards built for the old Bolex 8s are optically excellent, but somewhat pricey. But as you can see, even that lowly old Wollensak did a decent job. I don't think I paid more than about $5 for that old Wollensak.

Another important thing to remember whenever reverse-mounting a lens is, the wider angle the lens, the greater the magnification.