Telephoto Lens Without The Fiscal Pain

August 24, 2022 by Jenny List 20 Comments

If you’re in the market for a telephoto lens, the available range of optics for your camera is limited only by the size of your bank account. So when [Pixels and Prisms] promises a telephoto for $13 USD it has to be worth a second look, right? Where’s the catch.

The lens has a 3D printed shell containing the optics, with associated focusing and aperture, and has a mount designed for Canon cameras to give a result with 163 mm focal length and f/2.5 . When a Canon lens costs many times more it’s evident that there is some compromise involved, and it comes in the lens system being very simple and comprised of off-the-shelf surplus lenses without the great effort put in by the manufacturer to correct distortion. The result is nonetheless a very creditable lens even if not the first choice for a paparazzo in pursuit of an errant politician.

The real interest for us in this open source project comes in it being something of an experimenter’s test bed for lenses. There’s no need to use the combination shown and the design can be readily adapted for other lenses, so spinning one’s own lens system becomes a real possibility. Plus it’s achieved the all-too-easy task of engaging a Hackaday writer’s time browsing the stock of the Surplus Shed.

We’ve featured a lot of lens projects over the years, but they more often take an existing camera lens as a starting point.

Ultimate Bokeh With A Projector Lens

August 2, 2022 by Danie Conradie 22 Comments

Bokeh is a photography term that’s a bit difficult to define but is basically soft, aesthetically pleasing background blur, often used to make a subject stand out. Also called “background separation” or “subject isolation”, achieving it optically requires a fast lens with an aperture below 2.8 or preferably lower. These lenses can get very expensive, but in the video after the break [Matt] from [DIY Perks] blows all the commercially available options out of the water. Using an old episcope projector, he built a photography rig with background separation equivalent to that of a non-existent 35mm f0.4 lens.

Unlike most conventional projectors used to project a prerecorded image, episcopes were used to project an image of physical objects, like books. To use this lens directly in a camera is impossible, due to the size of the imaging circle projected out the back of the lens. At a diameter of 500mm, there is simply no imaging sensor available to capture it. Instead, [Matt] built a projection screen for the image and photographed it from the opposite side with a normal camera.

The projection screen was made by sandwiching a sheet of diffuser film between two sheets of clear acrylic held in a frame of aluminum extrusions. To block out all other light, [Matt] added aluminum shrouds on either side of the screen, which also serves to mount the lens and a camera. The shroud on the lens’ side is mounted on a separate aluminum frame, enabling the image to be focused by adjusting the distance between the screen and lens. Linear rods and bearings on 3D printed mounts allow smooth motion, while a motor-driven lead screw connected to a wired remote does the actual adjustment. The gap between the two halves was covered with bellows made from black paper. Continue reading “Ultimate Bokeh With A Projector Lens” →

Re-Creating The Unique Look Of Unobtainable Aerochrome Film

August 1, 2022 by Donald Papp 23 Comments

Ever heard of Aerochrome? It’s a unique type of color infrared film, originally created for the US military and designed for surveillance planes. Photos taken with Aerochrome film show trees and other vegetation in vivid reds and pinks, creating images that aren’t quite like anything else.

A modified method of trichrome photography is the key behind re-creating that unique Aerochrome look. Click to enlarge.

Sadly, Aerochrome hasn’t been made for over a decade. What’s an enterprising hacker with a fascination for this unobtainable film to do? [Joshua] resolved to recreate it as best he could, and the results look great!

Aerochrome isn’t quite the same as normal film. It is sensitive to infrared, and photos taken with it yield a kind of false color image that presents infrared as red, visible reds as greens, and greens are shown as blue. The result is a vaguely dreamy looking photo like the one you see in the header image, above. Healthy vegetation is vividly highlighted, and everything else? Well, it actually comes out pretty normal-looking, all things considered.

Why does this happen? It’s because healthy, leafy green plants strongly absorb visible light for photosynthesis, while also strongly reflecting near-infrared. This is the same principle behind the normalized difference vegetation index (NDVI), a method used since the 70s to measure live green vegetation, often from satellite imagery.

Aerochrome may be out of production, but black and white infrared film is still available. [Joshua] found that he could re-create the effect of Aerochrome with an adaptation of trichrome photography: the process of taking three identical black and white photos, each using a different color filter. When combined, the three photos (acting as three separate color channels) produce a color image.

To reproduce Aerochrome, [Joshua] takes three monochromatic photos with his infrared film, each with a different color filter chosen to match the spectral sensitivities of the original product. The result is a pretty striking reproduction of Aerochrome!

But this method does have some shortcomings. [Joshua] found it annoying to fiddle with filters between trying to take three identical photos, and the film and filters aren’t really an exact match for the spectral sensitivities of original Aerochrome. He also found it difficult to nail the right exposure; since most light meters are measuring visible light and not infrared, the exposure settings were way off. But the results look pretty authentic, so he’s counting it as a success.

We loved [Joshua]’s DIY wigglecam, and we’re delighted to see the work he put into re-creating an authentic Aerochrome. Fantastic work.

Upgraded Film Scanner Handles Bigger Formats At No Cost

July 30, 2022 by Donald Papp 2 Comments

Film scanners are a useful tool for digitizing slides and negatives, and the Plustek 8100 that [Christian Chapman] had was capable, but limited to small format film only. Rather than pay for a much more expensive medium format scanner that could handle 120 film, he modified his 8100 to accomplish the same thing with a combination of good old software and hardware tampering.

On the software side, [Christian] modified a driver for the Plustek 8100 so that it sweeps the scan head further than usual. At the application level, to scan medium format frames, it does a total of four scans: one for each quadrant. The results get stitched together in software with a thoughtfully-designed shell script that provides previews and handles failures and restarts gracefully.

Hardware-wise, the scanning carriage needs modification to ensure nothing interferes with the scan head as it moves further than originally designed. Some CAD and 3D printing made short work of this. Incidentally, this hardware mod is an excellent demonstration of one of the core strengths of 3D printing: the ability to make geometrically-straightforward objects that would nevertheless be troublesome or impractical to construct in any other way.

Trying Out A 3D Printed Microscope Lens Adapter

July 7, 2022 by Al Williams 11 Comments

If you want to take pictures of tiny things close up, you need a macro lens. Or a microscope. [Nicholas Sherlock] thought “Why not both?” He designed a 3D-printed microscope lens adapter that you can find on Thingiverse. Recently, [Micael Widell] tried it out with a microscope lens and you can see the results in the video below.

A $20 microscope lens allows for some amazing shots. There are two designs that fit different cropped-image and full-frame cameras. As you might expect, the depth of field is razor-thin, probably sub-millimeter. Additionally, with a 4X lens on a 35 mm sensor, the field of view is about 9 mm so you have to have a steady hand just to keep everything in frame.

Continue reading “Trying Out A 3D Printed Microscope Lens Adapter” →

AI Image Generation Sharpens Your Bad Photos And Kills Photography?

July 3, 2022 by Al Williams 66 Comments

We don’t fully understand the appeal of asking an AI for a picture of a gorilla eating a waffle while wearing headphones. However, [Micael Widell] shows something in a recent video that might be the best use we’ve seen yet of DALL-E 2. Instead of concocting new photos, you can apparently use the same technology for cleaning up your own rotten pictures. You can see his video, below. The part about DALL-E 2 editing is at about the 4:45 mark.

[Nicholas Sherlock] fed the AI a picture of a fuzzy ladybug and asked it to focus the subject. It did. He also fed in some other pictures and asked it to make subtle variations of them. It did a pretty good job of that, too.

Continue reading “AI Image Generation Sharpens Your Bad Photos And Kills Photography?” →

Laser Brings Autofocus To Tricked-Out Large Format Film Camera

June 17, 2022 by Dan Maloney 6 Comments

You can’t argue with the results of large-format film cameras — picture the boxy bellows held by a cigar-chomping big-city press photographer of the 1940s — but they don’t really hold a candle to the usability and portability of even the earliest generations of 35mm cameras. And add in the ease-of-use features of later film and digital cameras, and something like a 4×5 Graflex seems like a real dinosaur.

Or maybe not. [Aleksi Koski] has built a large-format camera with autofocus, the “Conflict 45.” The problem with a lot of the large-format film cameras, which tend to be of a non-reflex optical design, is that it’s difficult or even impossible to see what you’re shooting through the lens. This makes focusing a bit of a guessing game, a problem that [Aleksi] addresses with his design. Sadly, the linked Petapixel article is basically devoid of technical details, but from what we can glean from it and the video below, the Conflict 45 is a 4″x5″ sheet-film camera that has a motorized lens board and a laser rangefinder. A short video has a through-viewfinder view showing an LCD overlay, which means there’s some kind of microcontroller on board as well, which is probably used for the calculations needed to compensate for parallax errors during close focusing, as well as other uses.

The camera is built from 3D printed parts; [Aleksi] says that this is just a prototype and that the finished camera will have a carbon-fiber body. We’d love to see more build details, but for now, we just love the idea of an easy-to-use large-format camera. Just maybe not that big.

Continue reading “Laser Brings Autofocus To Tricked-Out Large Format Film Camera” →