HN Theater @HNTheaterMonth

Matt from DIYPerks has recently built a f0.4 lens on an estimated total cost of $190: https://www.youtube.com/watch?v=9cT0jXI7l4E

⬐ nicoburns

Impressive as that project is, for the most part they bought that lens rather than building it.

⬐ rglullis

So is this one here, no? Both projects seem to assume that the glass itself is a given.

⬐ hwsmythe

But here the aperture and focus is also 3d printed

⬐ rglullis

Matt also did the part about focus (between the projector lens and the fresnel lenses) but ok, I guess it is an important distinction that you made.

⬐ lesuorac

Not my area of expertise but you might be able to CNC the lens.

(Part 2: Goes into math) https://www.youtube.com/watch?v=ADtw6cxEK28

(Part 1: Shows CNCing / usage) https://www.youtube.com/watch?v=ZW2lj0KjyT8

⬐ digdugdirk

Super cool project, and they did a really great job documenting the process.

That said, a hobbyist level CNC will not be able to make a functional lens. Tolerances are way too high. Maybe it'll be good enough for focusing light and burning holes in paper, but it's not going to be remotely close to photography level.

⬐ mikewarot

Man uses old school episcope lens to build a virtual camera box, with amazing Bokeh.

I really enjoyed watching this, and seeing the progression of ideas as he went.

⬐ mikewarot

I saw this in my YouTube feed, and the thumbnail had me avoiding it. Since it showed up here, I've gone and watched it, and WOW!

I agree that it was worth the effort.

⬐ tambourine_man

Yeah, the guy has an excessive happy/friendly attitude that puts me off in some ways, but is one heck of an engineer and the results are remarkable.

I loved this[1] recent video by DIY Perks and think you would enjoy it too. He essentially builds a housing for a lens with a massive aperture.

[1] https://www.youtube.com/watch?v=9cT0jXI7l4E

⬐ tobr

Worth watching to the end (demo starts at 10:53). The result is absolutely outstanding. I can’t wait to see what some really good photographers would be able to do with this camera.

⬐ csours

From the DIY Perks channel. I wonder how hard it would be to generate the channel name to add to the domain in the header.

⬐ mgdlbp

Wow, essentially an extraordinarily large view camera built around a repurposed lens, then converted into a depth-of-field adapter[0] in lieu of a digital back.

There's actually a known technique for taking wide angle photographs with depth of field this shallow using only a typical long lens:[1] stitching together frames to build a wider field of view is all that's needed; long lenses all have shallow DoF by nature.[a] This interestingly can also be used to explain why the episcope lens has such shallow DoF: its focal length of 432 mm would make it a super telephoto lens, yet its large image circle means it has a wide-angle field of view. If it were replaced by a telephoto lens with the same focal length and aperture but a smaller image circle, and that lens were swung around in a spiral to 'paint' the same area as the episcope lens image circle, the two lenses would produce the same result, only the episcope lens can do it all at once instead of needing multiple exposures.

[0] https://en.wikipedia.org/wiki/Depth-of-field_adapter [1] https://en.wikipedia.org/wiki/Brenizer_Method

--

[a] Annoyingly, I still don't know a satisfying explanation of why depth of field depends on subject/background distances, aperture, focal length, etc. The formulas exist, but every attempt at intuitive explanation I've seen has been incomplete or incorrect. Here's some videos to show those who say that longer lenses have shallower DoF solely because reframing by standing farther away from the subject causes the background and its blur to become relatively larger: https://www.youtube.com/watch?v=7xHMOzZM2ts&t=38s https://www.youtube.com/watch?v=RkTaMyatsTo&t=116s

(One's a $1000 Nikon bridge superzoom with a 4.3-539 mm (125x) f/2.8-8 and 1/2.3" sensor (5.6x = 24-3000 mm). The other's a $200000 Fuji box lens, 8.4-900 mm (107x) f/1.7-4.5, for 2/3" sensors (3.9x = 33-3540 mm). They fight crime!)

Huh, found a DoF simulator that seems physically accurate at least: https://dofsimulator.net/?x=FDgBkATiAAAAJU4kcF3TgAA

--

Other cool unconventional imaging projects:

- forum thread for DIY DoF adapters going back to 2003 https://www.dvinfo.net/forum/alternative-imaging-methods/171...

- very similar project to this one, using a reflecting surface rather than a screen https://www.youtube.com/watch?v=0ZixDTrQdzo

- flatbed scanners as large-format camera backs, focusing on resolution instead of bokeh https://news.ycombinator.com/item?id=649150

- telecentric/hypercentric lens https://www.youtube.com/watch?v=iJ4yL6kaV1A, photolithography via microphotography by view camera https://www.youtube.com/watch?v=YAPt_DcWAvw

⬐ schroeding

Absolutely incredible, he just DIYs a nicely working optical system like it's nothing. IMO the most impressive thing he has build until now.

Watch all episcope lenses disappear or skyrocket in price on eBay in 3, 2, 1... :D