Affordable DIY mod. 50mm 1.2

[petrochemist]

Inspired by a post on MU-43.com I've brought a 50mm f/1.2 projector lens & mounted it in an old helicoid. For the princely sum of $10 (+ postage) & a few hours in the workshop I now have a working f/1.2

frankenlens 1 by Mike Kanssen, on Flickr

The rear of the lens tube had to be removed to get close enough to focus on mirrorless cameras, but the rear elements are well recessed so this wasn't a problem. The lens doesn't fit inside a normal M42 helicoid, but fitted in an old astronomy (T2) helicoid I've had for years (I brought it for £6 before M42 helicoids were readily available on e-bay). To get the lens far enough back in the helicoid I had to enlarge the opening (with a hole saw & finished with a file & sandpaper) & cut of the T2 thread at the base sticking a (£2) c-mount adapter in it's place. If I hadn't had the old helicoid available I'd have used a M52 one readily available on e-bay together with a stepping ring but that would have involed a longer wait...

It's currently to bright to try outdoors, till I arrange some waterhouse stops or ND filters, but here's some quick examples of it's results:
Timmy via frankenlens by Mike Kanssen, on Flickr

Rufus via frankenlens by Mike Kanssen, on Flickr

Cat shots being compulsory on social media!

 

[beagle100]

Inspired by a post on MU-43.com I've brought a 50mm f/1.2 projector lens & mounted it in an old helicoid. For the princely sum of $10 (+ postage) & a few hours in the workshop I now have a working f/1.2

frankenlens 1 by Mike Kanssen, on Flickr

The rear of the lens tube had to be removed to get close enough to focus on mirrorless cameras, but the rear elements are well recessed so this wasn't a problem. The lens doesn't fit inside a normal M42 helicoid, but fitted in an old astronomy (T2) helicoid I've had for years (I brought it for £6 before M42 helicoids were readily available on e-bay). To get the lens far enough back in the helicoid I had to enlarge the opening (with a hole saw & finished with a file & sandpaper) & cut of the T2 thread at the base sticking a (£2) c-mount adapter in it's place. If I hadn't had the old helicoid available I'd have used a M52 one readily available on e-bay together with a stepping ring but that would have involed a longer wait...

It's currently to bright to try outdoors, till I arrange some waterhouse stops or ND filters, but here's some quick examples of it's results:
Timmy via frankenlens by Mike Kanssen, on Flickr

Rufus via frankenlens by Mike Kanssen, on Flickr
Cat shots being compulsory on social media!

Ok, the photos look pretty soft and out of focus but you got a 50 f 1.2 lens for $10 (plus postage)
hooray !
www.flickr.com/photos/mmirrorless

 

[Derrel]

Dreamy. Might be fun to use for floral close-ups; I've seen ultra high-speed copier lenses used for floral close-ups, and the shallow DOF and the 'look' they create is actually quite nifty.

 

[petrochemist]

After posting, the light levels outside dropped enough for me to try it at longer distances. The helicoid I have used changes length far to rapidly, so that it's very difficult to focus on distant objects. The existing set-up should be adequate for close-up where subject distance can be altered to fine tune focus but I'll have to have another go with a better helicoid later on. (I've spent too much on photography recently). In the mean time there's a finer screw thread at the rear of the helicoid that might make it more controllable, as long as I don't unscrew it too far!

As Derrel pointed out subjects like flowers where the exact point of focus is less important would make better subjects for the moment. It should also prove a good lens for playing with Bokeh masks, once I sort some way of holding them in place.