0-35mm variable extension tube for wideangle macro (Canon EF/EF-S lens, Sony F/FE camera)

prusaprinters

<p>This variable-length extension tube allows you to mount a Canon EF/EF-S lens to a Sony F/FE mount camera. When you twist the middle section of the tube, it expands to vary between 0mm and 35mm of effective extension. When used with a 35mm lens this allows you to focus from infinity up to 1x macro magnification.</p><p>Since this tube allows you to go all the way down to 0mm of extension, it allows even ultrawide lenses to be used for macro (e.g. the tube allows you to use just 7mm of extension to suit a 15mm lens). Although your subjects will be just millimetres away from the end of the lens! Shooting macro with wide lenses allows you to include more of your subject's surroundings in the image, as there will be detail in the background instead of it being a featureless blur.</p><p>I'm shooting with Canon 35mm and Samyang 14mm lenses, but other SLR lenses can be adapted with a cheap metal adapter ring to Canon too, including Pentax K and Nikon F.</p><p>Filament should be black PETG or similar (PLA likes to deform under pressure, which can loosen pieces over time). Please note that your PETG should be nice and dry to minimise stringing, since some of these strings would end up gumming up inaccessible threads.</p><p>TPU filament is required to print the spring for the Canon lens locking mechanism. I'm using Flexfill 98A.</p><p>Extra parts required:</p><ul><li>M2x10mm cap head screw x1</li><li>M2 hex nut x1</li><li>M2x6mm screw, black finish, x3</li><li>M3 hex half-nut/jam-nut, brass x1</li><li>M2x20mm countersunk screw x1</li><li><a href="https://www.amazon.co.jp/gp/product/B00MIA7EHC?tag=thingiverse09-20">M1.7x6mm plastic self-tapping screws x2</a></li><li>Silicone grease</li></ul><p><strong>Please note that the grease used in this tube is super not good if it comes into contact with optical elements like your lens or camera sensor. At the very least this will require a wet cleaning of your camera sensor, and in the worst case this will render your camera into scrap.</strong> Take care.</p><h3>Shooting with the tube</h3><p>To mount a lens to the tube, align the Canon lens' alignment mark with one of the two circles on the top of the printed mount (one for EF lenses, the other for EF-S lenses), and push the lens downwards slightly to push the lens locking plunger out of the way, then twist the lens onto the mount as normal. You may need to press upwards on the bottom of the 10mm lens locking bolt to return the locking plunger to the locked position (which prevents the lens from unscrewing).</p><p>To mount the tube to the camera, align the hex nut on the mount face of the tube to about the bottom of your camera mount, and twist it on until the camera's lens locking pin engages.</p><p>You can twist the centre section of the tube to collapse or extend it. The collapsed position corresponds to 0mm of extension for Canon lenses, so you will be able to focus to infinity. Max extension is 34mm, so you'll get 1x magnification when shooting with a 35mm lens. Shorter lenses give stronger magnification and longer lenses give weaker magnification.</p><p>To disengage the tube from the camera, note that the extension tube overhangs your camera's release button enough that it's impossible to get a finger in there to press the release button (I've included a photo in the gallery above). I pressed it with a toothpick instead.</p><p>To remove the lens from the tube, looking from the bottom of the tube, use pliers to pull downwards on the head of the 10mm locking screw, which will retract the lens locking plunger, then untwist the lens.</p><h3>Looking to go longer?</h3><p>I also have a version of this tube which extends from 50-150mm, for shooting at 1-3x magnification with 50mm lenses: <a href="https://www.thingiverse.com/thing:4941924">https://www.thingiverse.com/thing:4941924</a> (it can no longer focus to infinity, though)</p><h3>More macro accessories</h3><p>Pictured in the photos above are my <a href="https://www.thingiverse.com/thing:4652788">Twin Loc-Line Arm Mount for Camera Tripod Sockets</a>, <a href="https://www.thingiverse.com/thing:3844481">Diffusers for Canon MT-24EX Macro Flash</a>, and <a href="https://www.thingiverse.com/thing:3785376">MT-24EX mount system for Loc-Line arms</a>.</p><h3>Print Settings</h3><p><strong>Printer Brand:</strong></p><p>Prusa</p><p><strong>Printer:</strong></p><p>I3 MK3S</p><p><strong>Rafts:</strong></p><p>No</p><p><strong>Supports:</strong></p><p>No</p><p><strong>Resolution:</strong></p><p>0.1mm</p><p><strong>Infill:</strong></p><p>10%</p><p><strong>Filament:</strong> Kiwi3D PETG Black&nbsp;</p><h3>Post-Printing</h3><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/8a4aa4d5-43b9-4b72-a77d-2a9a0b5f317f/wa-large-parts.jpeg#%7B%22uuid%22%3A%222fb7cb3d-c365-4f81-a560-4118a593683a%22%2C%22w%22%3A1920%2C%22h%22%3A1450%7D"></figure><p>The STLs are arranged into three 3MF project files for PrusaSlicer: large parts, small parts, and the spring. I'll explain how the settings in these projects were customised so you can apply those to other slicers too.</p><p><strong>Large parts</strong></p><p>These Large Parts need to be printed one-by-one, not all 4 at once. You can right-click the eye icon next to the remaining parts on the plate to disable them for printing.</p><p>In general, layer height is 0.1mm, filament is black PETG, supports for enforcers only, 2 perimeters, seam position random, infill 10% rectilinear.</p><p>On the "slip ring", a layer range from 0 to infinity has been added to override the layer height for this entire part to 0.2mm</p><p>The Body STL has the "body finger zone" added to it as a modifier region, with 100% infill set (this makes the region of the body with the screwhole in it fully solid).</p><p>The little angled shelf in the body finger gets painted for support enforcement.</p><p>A layer range from 21.80mm to 27.20mm on the Body overrides the layer height for this region to 0.2mm. This encompasses the entire solid top of the mount, and in particular ensures that the blue bridging (shown below) that closes the top of the tube is printed at 0.2mm instead of 0.1mm (the 0.2mm bridges are more robust and fail less often):</p><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/5f8bbcf3-56d6-4a74-ba3a-15e5e060e3ee/wa-bridging.jpeg#%7B%22uuid%22%3A%2293187689-5083-419c-b2b3-7accf8fdbe5c%22%2C%22w%22%3A1275%2C%22h%22%3A1080%7D"></figure><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/5623ef11-0a3c-495f-895f-7d829ac5ed14/screen_shot_2021-08-31_at_60706_pm.png#%7B%22uuid%22%3A%229ad69181-0c26-49c5-a7f5-149550369751%22%2C%22w%22%3A1212%2C%22h%22%3A910%7D"></figure><p><strong>Small Parts</strong></p><p>The two Small Parts shown above should be printed at 0.1mm layer height in PETG. Perimeters is 2, infill is 100%.</p><p>A colour change has been added at 3.1mm, where you should unload the filament and install an M2 hex nut in the Plunger on the left. Verify that the top of the nut sits below the level of the surrounding plastic before reloading the filament to continue, otherwise the extruder could crash into it.</p><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/76bfd69c-558f-4504-bb8b-14e49965a0bd/screen_shot_2021-08-31_at_60852_pm.png#%7B%22uuid%22%3A%22fce793be-6a4b-441e-8f99-1d108726ba92%22%2C%22w%22%3A1168%2C%22h%22%3A1118%7D"></figure><p><strong>Spring</strong></p><p>This spring needs to be printed in flexible filament such as 98A Flexfill. Lots of custom settings are required here.</p><p>Starting with the 0.1mm DETAIL preset, Spiral Vase mode was turned on in the print settings. Top and bottom layers are set to 0. The stiffness of the spring can be tuned by changing the extrusion width, I set all of the extrusion widths up to 0.5mm from the default of 0.45mm.</p><p>I started with a filament profile of "generic FLEX", but big changes need to be made to the filament settings get enough cooling to be applied to each layer. Because each layer is so tiny and prints so quickly, if they are printed using the default settings the whole thing just melts and warps and there are severe gaps in the structure.</p><p>Set Keep Fan Always On, set the min fan speed to 100%, change "disable fan for the first" to "1 layers". On the advanced page, set max volumetric speed to 0.5mm^3/s (down from the default of 1.2mm^3/s) so that there is enough time for the layers to cool as they are laid down.</p><h3>Assembly</h3><p>Clean up any stringing or blobs on the large parts. I do this by very briefly waving a pocket butane torch near the print (a fraction of a second) which causes all the strings to shrivel up into little balls. These are then easily rubbed off the surface with a finger. Don't actually touch the flame to the print, or it'll melt and warp almost instantly.</p><p>On the Body piece, superglue the M3 brass hex half-nut into the slot pointed to by the red arrow below, and ensure it sits below the plastic surface (to avoid scratching your camera's mount). Pierce the bridge that is blocking the camera mount (shown below in blue) and clean up the resulting edge with a deburring tool or blade. I used superglue to stick down any bridge lines that were dislodged inside the body.</p><p>Apply silicone lube to the threads in the Body and screw that into the Middle and unscrew it a couple of times to distribute lube between these two pieces. Leave them disconnected when you're done. Mop up any squeeze-out with a paper towel.</p><p>Apply silicone lube to the threads in the outer perimeter of the Lens print (I used a toothpick to help me get it down into this slot). Note,<i>don't</i> apply any lube to the ribs in the inside ring of the Lens, this is not a thread, it is a light scattering baffle.</p><p>Thread the Lens part into the Middle to distribute lube like you did with the Body and Middle, and leave them separated when you're done.</p><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/8e1d832e-f5ad-46f4-ad91-93950afbb39f/bridge-removal.jpeg#%7B%22uuid%22%3A%22edd8bed4-d3bf-4b11-b7e1-081360c4d36c%22%2C%22w%22%3A1920%2C%22h%22%3A909%7D"></figure><p>At the tip of the Body finger, trim off the 0.2mm brim as shown below:</p><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/e946bdc7-db7a-4c30-afa1-f40711fca717/trim-finger-brim.jpeg#%7B%22uuid%22%3A%22ae38fd00-c7fd-441d-a576-5fdb6aa02178%22%2C%22w%22%3A1920%2C%22h%22%3A931%7D"></figure><p>Now flip the Body upside down and put it onto a nice flat surface, then install the M2x20mm countersunk screw into the corresponding screwhole in the body finger as shown below. The tension added by this screw adds some shear strength to the finger.</p><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/9eed2f5c-2e24-4089-be6c-3ef98ad1c102/body-finger.jpeg#%7B%22uuid%22%3A%22b4a67ed7-841c-4604-af1d-af5f9e17cdfc%22%2C%22w%22%3A1080%2C%22h%22%3A600%7D"></figure><p>The Slip Ring is going to be installed into the Middle part using a hammer, and once this is installed it won't really be removable again, so let's get those mating surfaces ready now.</p><p>On the Slip Ring, ensure that on the outside of the part there are no blobs sticking to the surface (you can scrape it clean with a blade). On the Middle part check the same except on the inside. While you're here, make sure there are no debris stuck in the vertical channels in the inside of the Slip Ring.</p><p>Apply silicone lube to outside of the Slip Ring and inside of the Middle with a finger.</p><p>The image below shows how these two parts need to end up once the Slip Ring is installed. To install the Slip Ring, first ensure that each piece is oriented the correct way up. For the Slip Ring the blocked tops of the skinny slots needs to be uppermost (circled in red below). For the Middle piece the small vertical gap shown by the arrow at the top right of the image must be uppermost, or else the Middle will shatter during assembly.</p><p>Prepare a flat work surface and put the Middle piece onto it in the correct orientation (the base of the Middle must be fully supported to avoid it shattering). Place the Slip Ring on top of the Middle in the correct orientation, place something flat on top of it like a board, and tap this board with a hammer to slowly work the Slip Ring into the Middle piece, ensuring you do this evenly so it doesn't tilt too far over. Once fully installed you should be able to freely rotate the slip ring around inside the middle piece with your fingers. (Also double check that you didn't shatter the walls of the Middle piece during installation).</p><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/a1e0eafc-4b34-4311-8f31-91dc9a2a6c39/slip-ring-install.jpeg#%7B%22uuid%22%3A%22818ab5f3-3ade-41ae-9968-5853f07fb03c%22%2C%22w%22%3A1920%2C%22h%22%3A942%7D"></figure><p>For the Lens print, we'll prepare the Canon lens locking mechanism now.</p><p>Looking at the bottom of the Lens print, there are two 1.7mm screwholes that are covered by a sacrificial bridge, and need to be uncovered by poking them with a sharp object like a toothpick, tweezers or a blade (red arrows below):</p><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/9772846b-953e-4eb3-b239-d76fd8c8d79d/m17-screwholes.jpg#%7B%22uuid%22%3A%220c0a0e30-8579-4e5c-a280-4f64d6a62e10%22%2C%22w%22%3A1164%2C%22h%22%3A1080%7D"></figure><p>Looking at the top of the Lens piece, there will be some remnants of a bridge over the locking plunger slot (the triangles highlighted in blue below) which need to be torn out:</p><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/0fa33881-82b1-4c61-becb-9a533b46d6b9/lens-bridging.jpeg#%7B%22uuid%22%3A%229fe5b23c-7381-4646-9e8e-35d3ac4242c6%22%2C%22w%22%3A1145%2C%22h%22%3A1080%7D"></figure><p>Now we'll assemble the locking plunger assembly as shown below.</p><p>Thread the 10mm screw through the bottom of the door print. Onto the protruding threads add the spring. Screw the locking plunger (with its embedded M2 nut) onto the end of the thread, compressing the spring somewhat in the process. Only tighten the screw until it reaches the top of the nut.</p><p>Apply a little lube to the sides of the plunger, then push the whole locking assembly into its home in the Lens print. If the plunger refuses to pop out of the top of the Lens part, don't try to force it, this will cause the top of the Lens part to blow out and break (ask me how I know, lol). Instead clear any debris left in the gap in the Lens using a hobby knife or sharp tweezers until it can push through cleanly.</p><p>Secure the Door to the Lens using two M1.7 screws. You should now be able to grab the head of the 10mm screw with pliers to retract or deploy the locking plunger, work it backwards and forwards a few times to work out the kinks.</p><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/fc902059-9a02-4548-bcf1-a422c8dbf0c3/827c2096.jpeg#%7B%22uuid%22%3A%22955f0964-7b37-45f3-b67d-66c5cc00cf14%22%2C%22w%22%3A2880%2C%22h%22%3A2160%7D"></figure><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/e6fcd4b9-014a-4575-9f2b-edf067b414dd/locking-lever-assembly.jpeg#%7B%22uuid%22%3A%2285b9601f-fb8f-4d94-ad9c-e0d747bdbd73%22%2C%22w%22%3A1080%2C%22h%22%3A447%7D"></figure><p>Now we'll perform the final aligned assembly of the Body, Lens and Middle. First we'll join the Body to the Middle. Begin threading the Body into the Middle, but it can only thread in a fraction of a millimetre before the Body Finger crashes against the Slip Ring. Looking from the bottom, you need to spin the Slip Ring so that the Body Locking Finger (highlighted blue below) can drop into the corresponding slot in the ring:</p><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/603c71a6-fd65-449b-b2b8-56527c270eda/body-finger-drops-in.jpeg#%7B%22uuid%22%3A%22e1a450a4-cb8f-4dc7-bc6d-b9f4c76b3814%22%2C%22w%22%3A1147%2C%22h%22%3A1080%7D"></figure><p>Now continue screwing the Body into the Middle until the top of the Body Finger passes the bottom of the Slip Ring by about 1.5mm:</p><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/688b09fe-f5eb-4678-b30e-187e7d1a7941/body-finger-overlap.jpeg#%7B%22uuid%22%3A%225c7cf975-e186-4359-abcf-d3b63350994c%22%2C%22w%22%3A1681%2C%22h%22%3A1080%7D"></figure><p>Now the Lens can be joined to the Middle. Thread it in so that the Lens Finger (red arrow below) drops into the corresponding slot in the Slip Ring (there'll be a little bit of resistance before it manages to drop in):</p><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/116bd03f-d928-4f2c-9ffe-e9a6b80838f1/lens-tab.jpeg#%7B%22uuid%22%3A%2241711baa-d463-4344-826a-e5930db191f4%22%2C%22w%22%3A1190%2C%22h%22%3A1080%7D"></figure><p>Now the Body and Lens cannot rotate relative to each other. Hold the Body piece and twist the Middle so that the Body and Lens are both drawn in and fully engage:</p><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/63d9c19c-9346-44d1-9e44-bfacacaf21f8/full-engage.jpeg#%7B%22uuid%22%3A%221bf05ff6-2caa-45a5-ac10-69ff156ef5eb%22%2C%22w%22%3A1080%2C%22h%22%3A492%7D"></figure><p>Finally, we need to add three M2x6mm screws to the Lens piece so that it doesn't just fall out when you extend the tube to its maximum length. Add one screw to each of the three screwholes in the inner walls of the lens tube. These screws fit into corresponding slots in the Slip Ring:</p><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/3aec6015-97b7-4adc-9def-15430cc17e53/stop-screws.jpeg#%7B%22uuid%22%3A%22a223f092-aa9c-4676-b3c2-da9107db9c92%22%2C%22w%22%3A1080%2C%22h%22%3A533%7D"></figure><p>Looking from the bottom side of the mount, you can confirm that the screw tails made it all the way out of the Lens piece and into their slots:</p><figure class="image"><img src="https://media.prusaprinters.org/media/prints/143759/rich_content/d58fe045-b0e8-46fa-8910-0e1ebfb5d973/screw-tails.jpeg#%7B%22uuid%22%3A%227e25c4f2-13a6-4fea-a010-9c0ed896610b%22%2C%22w%22%3A1153%2C%22h%22%3A1080%7D"></figure><p>Assembly is now done, but as silicone lube might migrate out of the tube over time, I would leave it for a day and mop up any excess that appears. Avoid storing the tube when it is connected to lenses or cameras for this reason too.</p><p>You can paint the inner ribs of the Lens piece with matte black paint to reduce internal reflections in the tube, this will increase image contrast.</p>