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Epson f1.85 16.6mm projector lens of Olympus OM-D E-M5
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PostPosted: Mon May 30, 2022 5:04 pm    Post subject: Epson f1.85 16.6mm projector lens of Olympus OM-D E-M5 Reply with quote

I removed this lens from an Epson DLP projector, and to be honest, the results are rather poor. It's sharp in the centre but has smeary edges and the whole frame is veiled by a strong diffuse glow. This makes the images produced somewhat characterful but also poor in technical quality.

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PostPosted: Mon May 30, 2022 7:46 pm    Post subject: Reply with quote

The barrel could be unscrewed into two halves, so I fitted a crude cardboard aperture disc, roughly f4 I think, to see if it improved the IQ by much.

It did, the diffuse glow is gone, it's now a decent lens.


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PostPosted: Mon May 30, 2022 8:40 pm    Post subject: Reply with quote

I bought a box of ten identical digital projection lenses with a practically identical focal length, but abit faster (f1.6) - but turned out to be almost distortionless, and completely consistent across APS-C frame and barely any vignetting to boot. Sharpness is good when focus is nailed but undercorrected spherical aberration appears if you miss it.

I hadn't posted about it yet because I hadn't perfectly centered the mount (mask on front lens causes vignetting), but for proving the point that you can get good luck, I'll post anyway:



100% corner crop shows sharpness:



The bokeh on this lens is buttery smooth, way better than the 35mm SLR ultrawides I've tested. The low optical vignetting makes for nice, clean rendering.



Here is a background crop, first off Tokina AT-X 17mm f3.5 wide open



Now this projection lens





The mask:



It's long, all metal and glass which means it weighs 1kg(!) - I haven't taken it out since testing it once adapted. I should probably get some more samples...


PostPosted: Mon May 30, 2022 8:54 pm    Post subject: Reply with quote

Taht cardboard did really improve a lot, I've always wanted to do that to the colorplan ,just had no time yet , and still ,can't recall seeing anyone do it before


PostPosted: Mon May 30, 2022 9:07 pm    Post subject: Reply with quote

The cardboard disk trick usually works.

Nice work on that ultrawide, I've got an 8mm and a 9mm I removed from data projectors and they work as you say - distortionless, plenty of sharpness, no vignetting, the only issue is a bit of uncorrect SA and some CA on the highest contrast edges, but a bit of PP ccan fix both issues.

Here's a couple of shots taken this weekend with the 9mm on my OM-D E-M5.


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PostPosted: Tue May 31, 2022 9:27 am    Post subject: Reply with quote

I really like the rendition of the lens. It should be perfect for scenic portraits - also in focal length.
And it seems to clean up nicely in post:
[url=http://forum.mflenses.com/userpix/20225/big_12143_4077_P1010146_1_1.jpg][img]http://forum.mflenses.com/userpix/20225/12143_4077_P1010146_1_1.jpg[/img][/url]


PostPosted: Tue May 31, 2022 1:18 pm    Post subject: Reply with quote

Surprised they work as well as they do; projector lenses are usually designed in conjunction with the condensor of the illumination system which (generally speaking) projects an image of the light source in or near the optical centre of the projector lens hence no adjustable aperture (it wouldn't do much really). The illumination when used as a photograpic lens is quite different to what they were designed for and therefore the addition of an aperture quite beneficial...


PostPosted: Tue May 31, 2022 3:29 pm    Post subject: Reply with quote

Indeed, the use as a taking lens is rather different to their original application, luckily used projectors cost next to nothing so it's not much of an investment to play around with these lenses.

BTW I made a small error, the lens is actual f1.44, not f1.85.


PostPosted: Thu Jun 02, 2022 9:43 am    Post subject: Reply with quote

Here's how I fitted the aperture disk, dead easy because the lens barrel is in two halves and can just be unscrewed. I used thick black plastic and then sanded it to remove the glossy surface and reduce reflections.


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