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8mm-ish lens from DLP projector on Lumix GF3
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PostPosted: Fri Jul 07, 2017 6:25 pm    Post subject: 8mm-ish lens from DLP projector on Lumix GF3 Reply with quote

I fancied one of those cheap 8mm fisheye lenses for shooting video on M4/3, but then I came up with a cheaper DIY solution. The lens is from a broken Viewsonic projector, temporarily mounted in extension tubes with tape, no markings on it so I have to guess the specs, I think it's around f2 and 8mm. It's sharp enough and no distortion until the very outer edges, will be very useful for video and architectural stills.






PostPosted: Sat Jul 08, 2017 12:02 am    Post subject: Reply with quote

Wow..... Like 1 small

Pic's of the lens?


PostPosted: Sat Jul 08, 2017 12:24 am    Post subject: Reply with quote

I'll take a pic of it tomorrow.

This is the projector it came from:



PostPosted: Sat Jul 08, 2017 8:23 pm    Post subject: Reply with quote

Thats worth a look Ian!

Better coverage for that format than most things I've seen that are "free".


PostPosted: Sun Jul 09, 2017 11:54 am    Post subject: Reply with quote

Here's some samples in better light on my Lumix G3 which has a much better sensor than the GF3.

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PostPosted: Sun Jul 09, 2017 2:22 pm    Post subject: Reply with quote

This works very well indeed!
How does the rig look?


PostPosted: Sun Jul 09, 2017 5:25 pm    Post subject: Reply with quote

amazing what you can salvage from defunct equipment!

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PostPosted: Sun Jul 09, 2017 11:15 pm    Post subject: Reply with quote

Here's some pics of the lens mounted on my G3:




PostPosted: Mon Jul 10, 2017 11:19 am    Post subject: Reply with quote

Like 1
Pretty cool.


PostPosted: Mon Jul 10, 2017 2:42 pm    Post subject: Reply with quote

Like 1 Like 1


PostPosted: Mon Jul 10, 2017 7:31 pm    Post subject: Reply with quote

What lens did you stick that on Ian?
It seems to work as a fisheye adapter.
Unless you are using a junk lens as just a focusing mount.


PostPosted: Mon Jul 10, 2017 7:37 pm    Post subject: Reply with quote

I'm using the body of a Teleplus focusing macro teleconverter as a helicoid, the optics are all from the projector, it's in one block and I just taped it to the helicoid for testing.

These ultra short throw projectors are very easy to find for very little money, they were used in huge numbers in schools, colleges and offices and have no resale value.

An example is the Epson Powerlite 410W, which has an f1.8 6.84mm lens.


PostPosted: Wed Jul 19, 2017 6:57 pm    Post subject: Reply with quote

I had a dig in my parts box and found the right bits to mount this thing properly. I used a tube from the back of a crappy 135mm t mount lens that had long ago been pulled apart for bits, it still had the T-M42 mount on it. I had to remove some plastic from the back of the lens to make the tube fit over it, then securely epoxied it in place. Then all I had to do was screw it into an M42-M4/3 helicoid and the job was done.


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PostPosted: Wed Jul 19, 2017 7:03 pm    Post subject: Reply with quote

In this helicoid, it will focus anywhere from infinity to actually touching the front glass, which is how I took this photo of a bottle - the front element was pressed up against the bottle:



100% crop:


However, I will probably only ever shoot this lens at infinity, where the distortion in negligible and any smeariness is limited to the very corners and is only moderate so I'm very happy with how it performs, especially as it's an extremely fast lens for so wide a FOV, it is somewhere in the f1.7-f2 range.



PostPosted: Thu Jul 20, 2017 1:00 am    Post subject: Reply with quote

HDR series, I like this lens for architectural shots.


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PostPosted: Thu Jul 20, 2017 1:01 pm    Post subject: Reply with quote

Not bad at all for a moulded plastic piece!!


PostPosted: Thu Jul 20, 2017 2:10 pm    Post subject: Reply with quote

The price of Old projectors will now skyrocket on Ebay!! Smile


PostPosted: Thu Jul 20, 2017 2:16 pm    Post subject: Reply with quote

Some brilliant stuff there Ian!

Britain looks a lot better in the sunshine.


PostPosted: Thu Jul 20, 2017 3:42 pm    Post subject: Reply with quote

Cheers folks. There's a plentiful supply of projectors on ebay, they are basically worthless secondhand. There are a lot of models of ultra short throw projector out there, by many manufacturers, they cost 20-50ukp on ebay, I can list come models if people want to look for them.

Here's a few more HDR, I chose to shoot HDR with this lens because I discovered that the G3 was unable to accurately expose many scenes shot with this lens as so much of the frame is sky, so it tends to expose for the sky and leave you with the buildings and ground 2-3 stops underexposed. The G3 has very good bracketing however, I used 5 shots in 1 EV steps, althoguh 3 shots would probably suffice.


#1 Stitched from 7 shots


#2 Another stitch, but sadly slightly out of focus


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PostPosted: Thu Jul 20, 2017 3:47 pm    Post subject: Reply with quote

My original intention for this lens was to use it to shoot video, it works quite well for that, albeit with some stretching at the edges of the frame:

https://www.youtube.com/watch?v=v2P4Dlq-grY


PostPosted: Thu Jul 20, 2017 8:43 pm    Post subject: Reply with quote

I like the rendering of this lens - pic's 16 and 17 show it nicely, the contrast on the stone building and the railway steps is wonderful, it captures the textures. The look at the pastel sky, there's a glow - but it's a nice glow. It's a distinctive lens for sure, and rather good as well. Like 1 small


PostPosted: Thu Jul 20, 2017 10:33 pm    Post subject: Reply with quote

Cheers Dave. This lens has a slight diffuse glow, largely only apparent on oof areas, which I expect is due to a tad of uncorrected spherical aberration. One of the things I like best about using unusual optics that were not intended for use taking pictures on a camera is that often they were designed with totally different criteria therefore the corrections of aberrations are often quite different to most camera lenses which means you get an unusual aesthetic 'look' to the images. This is not always a good thing, it can mean awful colour fringing on oof areas due to LoCA (a common issue with projection lenses) but in the case of this lens, it works out nicely, CA is very minimal and mostly only visible on the edges, one click in ACR when loading the RAW images into PS CS6 removes it so it's a non-issue.