This is the second half of a two-part episode. In this half, we talk about the aperture.
Nick and Graham start off talking about the purpose of an aperture on a camera and the collimation of light that is required for a sharp image. Graham floats the crackpot concept of using variously-sized holes in lens caps as aperture controls (10:22). Nick then talks about the optical test-bench he wants to create (14:18).
Returning to the real world from their flights of fancy, they discuss the issues with apertures that get too small and the issues with the wave portion of the particle-wave behavior of light (15:48).
The effects of various numbers of blades in a given aperture are discussed in relation to the holiday movies that make their appearance on The Hallmark Channel (17:47).
Nick describes a lens that uses rotating shutters, rotating apertures, and rotating neutral density filters in a single barrel (29:00).
They discuss what type of aperture each would work with on a quick and simple build (34:32).
Nick talks about a camera he is in the process of designing that uses a dead Fujifilm GX680 body (36:42).
Nick talks about his experience with the Sixty3 plastic panoramic camera that Graham designed and built (49:50) though it takes Nick a bit of time to realize what Graham is hinting at. Graham also discusses another build, the Sixty7 pinhole camera (53:50) made with a Graflok 6X7 back.
Nick laments the lack of email interaction with our listeners (1:02:45) but talks about the cameras Dora Goodman has built (https://www.instagram.com/doragoodman/?hl=en, https://www.doragoodman.com/) and made available for 3D printing.
E04a The Shutter Notes
This episode was originally planned to cover both the shutter and the aperture but as the recording topped two hours, we decided to separate the two concepts. In two weeks we will continue as we focus on the aperture.
Right off the bat, Graham can’t remember the name of the camera repair guide he read. It’s Camera Maintenance & Repair by Thomas Thomosy.
Contributor to the forums on the Homemade Camera Podcast Flickr group, Flaver-D’s projection-TV-lensed experiment is discussed (12:10) and how having an adjustable aperture is not always very important. Nick brings up the concept that along with shutter speed and aperture, you can use neutral density filters to control exposure as well (12:35).
They discuss the Garbage Cam Build of listener jojonas on Flickr that uses a magnifying glass and black and white printing paper to get some very interesting effect (22:55). They also talk about how the movement of shutters can cause distortions in the image such as the famous forward-leaning race cars from the 1930s (38:25).
The boys try to tackle the concept of slit-scan photography such as that produced by James Guerin, maker of the Reality So Subtle pinhole cameras (41:15).
The Phochron XA shutter tester is mentioned at (58:00) and how it can help with determining the accuracy of settings of older shutters.
Nick reminds us that in the early days of photography the Guillotine was a handy way of creating a consistent shutter opening (1:13:00). Almost immediately afterward they talk about Flickr group member Jonas and his schematic for a shutter that employs magnets from headphones to actuate.
Thomas Thomosy’s book on camera repair: https://smile.amazon.com/Camera-Maintenance-Repair-Book-Comprehensive/dp/0936262869/ref=sr_1_1?ie=UTF8&qid=1528131057&sr=8-1&keywords=camera+repair+book
Flaver-D’s Flickr stream: https://www.flickr.com/photos/17202358@N00/
Oval-wheel race car image: https://en.wikipedia.org/wiki/Focal-plane_shutter#/media/File:Bundesarchiv_Bild_183-1991-1209-503,_Autorennen_im_Grunewald,_Berlin.jpg
James Guerin’s slit-scan photography: https://aupremierplan.fr/page/5/
Phochron XA shutter tester: http://www.phochronxa.com/