MACRO photography accessories - focusing rail and bellows using 2020 v-slot profile

prusaprinters

Introduction:Photographic bellows is a very efficient tool that allows to achieve high magnification ratios with pretty much every lens. Below you can see a gif composed of three images taken using Cosina COSINON AUTO MC f/2.8 135 which by itself has magnification ratio of just 0.1. Adding the bellows from this design in its folded state (62 mm of extension) raises the M to ~0.8. In its fully extended state (200 mm) it allows for magnification ratios much exceeding 1:1 (and please note that bellows are more effective with lenses of shorter focal length).Description:Encouraged by my previous design which used 2020 v-slot profile as a sturdy camera holder I've designed macro photography bellows and focusing rail, that uses the profile as a guide rail. As I'm a Canon guy the bellows are designed to work with EF-mount camera, however in my design I've decided to not attach any 3d printed part directly to the camera, so I've used EF bayonet scavenged from a broken lens. Therefore It would be easy to 3d print or use different mount-style bayonet without big changes in the design. On the lens side I've decided to go with M42 mount which is easy to 3dprint and used by many cheap and optically good vintage lenses. With high magnification ratios proper focusing of the image becomes a problem. Especially when non-macro dedicated lenses are used focusing has to be achieved by simply moving the camera in relation to the object. For such precise movements a focusing rail is commonly used. In the second part of the design I present a focusing rail that uses the 2020 v-slot profile as a key component. It's not ideal, because it uses rack and pinon mechanism instead of leadscrew that good quality commercial rails use, but it does it's job!Parts list:Bellows:3d printed:bellowsbellows_camera mountbellows_m42 lens holder2x bellows_holderbellows_gearbellows_knobbellows_rail166mmhardware:200mm 2020 v-slot railM3x50mm bolt2x M3 nutM3 locknut4x M3x6 DIN912 bolt5x M3x10 DIN912 bolt2xM2.5 DIN912 bolt2xM2.5 nut2x Φ3xΦ4x4.5 bushing (optional)Canon EF bayonet - I used one scavenged from a broken lens, It's possible to 3d print a substitute or adapters for different style mountFocusing rail:3d printed:focusing_railfocusing_rail_knobfocusing_rail_gearfocusing_rail100mmhardware:200mm 2020 v-slot railM3x30mm boltM3 nutM3 locknut2xM2.5 DIN912 bolt2xM2.5 nut3/8-UNC to ¼-UNC thread reduction insert2x Φ3xΦ4x4.5 bushing (optional)Printing guidlines:For 3d printing bellows black flexible filament has to be used (I've used Print-me TPU 40 ShD).  It's printed in vase mode with 0.2 mm layer height using 0.6 mm nozzle to avoid clogging and to increase the strength and impermeability to light.PETG parts are designed to be printed without supports - in some of the models there are tabs to brake off directly after printing. Dark coloured filament is recommended for bellows to avoid light contamination of your photographs.Assembly instructions:Bellows:press two bushings into the holes in bellows_m42 lens holderinsert a M3x50 bolt through the bushing and press it into bellows_gear using a drop of CA glue to keep it from spinningscrew on a M3 locknut (warning: don't overtighten, otherwise knob will be hard rotate)put on the bellows_knob and tighten firmly using a regular M3 nutinsert bellows_holder into both ends of the bellow (note that it is slightly tapered and the wider side has to face inside of the bellow)insert bellows with bellows_holder into bellows_m42 lens holder and secure it with 4x M3x6 boltsinsert M2.5 nuts into bellows_rail166mm and slide it partially into the profile.slide bellows_m42 lens holder onto 2020 v-slot rail, make sure that the gear engaged properly with the rack.slide bellows_rail166mm into final position and secure with 2x M2.5x4 boltsslide the bellows_camera mount to the other end of the railinsert the other end of the bellow into bellows_camera mount and secure it with 4x M3x10 boltinstall the bayonet using dedicated screws.Focusing rail:Repeat steps 1-4, 7-9 from bellows assembly instructions, then install 3/8-UNC to ¼-UNC reduction into focusing_rail.