8mm Forum: Sankyo lens conversion upgrade

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Posted by Lee Mannering (Member # 728) on March 16, 2019, 04:57 AM:

And another brain wave.

Been looking around for a better lens for a Sankyo sound projector with a bit of a struggle unless I wanted to break the bank and so opted to convert a standard Sankyo lens with a good Bauer lens I had laying around.

Hope this helps someone else.

I stripped out the old Sankyo lens. Unscrew the silver front and with some grippers unscrew the metal back lens retainer. One empty barrel.

Next job is to file down the Bauer lens removing the pin and file off the strip down the side.

Biggest part now. File out the Sankyo lens barrel with a half circle file until the lens fits neat in it. Not sure what type of plastic Sankyo had but my goodness it took me way over an hour to file it out and with a brand new file.

Slip the lens inside it and result, one upgraded lens.

Next day a very painful arm no doubt due to the filing.

I did a light meter test on the old lens VS the new higher spec type and I am getting 11% more light on screen and a crisper picture.

Posted by Leon Norris (Member # 3151) on March 16, 2019, 02:40 PM:

It sure looks good Lee! A better lens makes a difference!

Posted by Dominique De Bast (Member # 3798) on March 16, 2019, 02:59 PM:

What kind of tool do you use to measure the light on the screen, Lee ?

Posted by Lee Mannering (Member # 728) on March 18, 2019, 07:13 AM:

Hi Dom. Traditionally a light or Lux meter held centre of a measured screen. It's worth remembering that lamps take a short time to get up to full power as they heat up as well so best to run the projector for a few minutes. One lumen is one lux per square mtr so I've always used a white card 1mtr. All this takes me back to our old film clubs over here where we used to carry out tests on practical nights and a memorable battle of the projectors for light onto screen. I just take the highest reading then the lowest to create a rough percentage, but to see the increase in screen illumination and crispness is enough for me really. Its interesting but I'm not OTT about it.
[Cool]

Posted by Dominique De Bast (Member # 3798) on March 18, 2019, 10:02 AM:

Thanks, Lee. I will investigate about that device.

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