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Re: LG PF50

Posted: 22 Jan 2020, 21:17
by Mr_Lafuente
mading wrote: 22 Jan 2020, 21:03 I would like to compare it to the PF1500.
A trial from Amazon could be a good option.
For now I'm happy for using the PF50 for netflix!
The PF1500 is discontinued and the used ones i found (here in brazil) are insane expensive for it's age, like 1000 USD. I can get a brand new PF50 for half of this price in Paraguay.
I think i will replicate you rig, mading.
Thanks again!

Re: LG PF50

Posted: 22 Jan 2020, 22:06
by mading
Micr0 wrote: 22 Jan 2020, 16:04 ..can you try scanning that piece with fewer individual scans? The topology of the violin is fairly simple so you should be able to reduce the number of individual scans you need. that may also help with the surface quality. Please keep us posted a on tweaking things I look forward to hearing about your results.
Thanks Micro, seeing improvements it's a good thing.
This part is already glued to the rest of the instrument! :lol:
I hope I can do a one-shot on the body with (or without) the neck.

Re: LG PF50

Posted: 22 Jan 2020, 23:04
by OBNRacerMan
mading wrote: 22 Jan 2020, 21:00 minimum distance 41 cm ca.

minimum screen size 18x32 ca.
Thanks. It seems that scanning small objects (such as coins or magnets on a refrigerator) with such a projection size will be extremely difficult ...
But, if you look from the other side - at such a great distance there should be a very good depth of field (for me, at short distances for macro scanning) it should be no more than 20-40 mm - this also creates certain problems.

Re: LG PF50

Posted: 06 Feb 2021, 14:32
by mading
I resume this old post.

I opened the protector.
The optics can be removed without harm (I hope).
A tape was glued in the upper part.

Unfastening the three screws let you move the optics outward.

You can focus a really small area.
Of course it's really close to the projector, since the throw ratio is not increased.

I attached a picture. Everything is out of focus since I just unscrewd and moved the optics. Suitable spacer is needed. Also to avoid dust inside the optics.

Re: LG PF50

Posted: 06 Feb 2021, 14:47
by mading
More pics.
The tape was glued in the area signed in Orange.

Re: LG PF50

Posted: 06 Feb 2021, 15:11
by Micr0
mading wrote: 06 Feb 2021, 14:47 More pics.
The tape was glued in the area signed in Orange.
That's encouraging. Please keep us posted.

The throw of that projector is listed in the spec's as being 1.44 which is about the same as the PF1500 and longer than my new AAXA at 1.2. With the ease at getting at the lens mount, it looks like it would be vary easy to mount different lenses.

I'm starting to think that my previous bad experience bricking two other projectors may have just been choosing the wrong projectors to experiment on. I have and old 720p Benq that was given to me that I plan on dissecting. Hopefully that will work better.

Re: LG PF50

Posted: 06 Feb 2021, 16:20
by mading
Definitely need help for the lens choice.
I read Avogra's experiences in one of the first posts of this forum. I think it's not impossible but not easy at all.
Best would be a 3d printed c-mount kind of adaptee to switch camera lenses. If their aperture is big enough.

Re: LG PF50

Posted: 07 Feb 2021, 09:00
by Tzk
When you choose a lens, you have a certain flange focal distance. This usually is the distance between the mounting surface of the lens (when mounted flush onto the camera) and the ccd sensor. Of course your projector doesn't have a ccd sensor like a camera... But let's talk about the focal distance first:

-> https://en.wikipedia.org/wiki/Flange_focal_distance
-> https://en.wikipedia.org/wiki/C_mount

C-Mount has about ~17.526mm and sensor sizes between 1/3" and 4/3"
Canon EF-M and Sony E 18mm (APS-C)
Canon EF/EF-S 44mm (APS-C, APSH)
Sony A 44.5mm (APS-C)
Nikon F 46.5mm (APS-C)

The other variable is the picture size of the projector. If the projector has a huge picture size (let's say it's ~24x36mm), then using C-mount lenses will be quite a challenge, as these lenses are usually made for smaller sensor sizes. However in this example 24x36mm is APS-C size which could allow for the usage of a lot of different Sony, Canon or Nikon lenses.

I'm not entirely sure what happens if you use a bigger sensor and place it further away from the lens, effectively increasing the flange focal distance. It might be that your focus is somewhat out of range afterwards.

--

At least i can tell you what happens when you use spacers on a given camera/lens setup. I got a 16mm and 10mm spacer for my Sony e-mount camera. If i put them between the camera body and the lens, it'll convert my standard 18-50mm lens to a macro setup, but also change the focus range (with adapter i have to be as close as 40mm to the object). Not the exact problem we're facing here, but i thought it might give some background info...

---

and here's a review and disassembly of the PF1500 (in german):
http://www.cine4home.de/tests/projektor ... 1500_2.htm

Re: LG PF50

Posted: 07 Feb 2021, 14:18
by mading
Thanks for the info.
Especially for the 1500 dissection!

At least we need the dlp size and flange focal distance to start with.
Optics size can be an issue, since the projector case cannot host something bigger than a camera lens, unless we can move lenses out of the case.

Re: LG PF50

Posted: 07 Feb 2021, 17:50
by mading
Looks like it's really hard to get access to the optics of LG PF1500.
What look like the screws that fasten the optics are accessible only after removing everything else:
Immagine 2021-02-07 184842.jpg