A VMI guide to lens extension tubes and diopters to reduce the minimum focus distance of lenses.


Connecting a lens tube behind the lens will move the lens farther away from the camera’s film plane or digital sensor, which allows the lens to focus much closer than it normally would. 

Extension tubes are commonly used for wildlife and macro photography.

VMI stock lens tubes or macro tubes with EF and PL mounts in order to give the maximum versatility for film makers.

Duclos produce Extension Tubes with a PL mount in three lengths, 15mm, 20mm, and 35mm and these stack-able up to 70mm of extension.

VMI stock the Duclos 3-lens PL Extension Tube Set which allows you to decrease the minimum focus of your PL mount lens to achieve results similar to unique macro lenses. Decrease the minimum focus distance to within a few inches of the front element while maintaining optimal image quality. 

The stainless steel components, precision tolerances, and optically flat internal surface finish of the Duclos Extension Tubes are meticulously married to reduce stray light and ensure the highest quality is maintained.

Note that the PL Extension Tubes are fully compatible with S35 and 35FF format lenses and cameras but do NOT work with anamorphic lenses.

Саnоn рrоduсеѕ tubеѕ with an EF mount іn twо dіffеrеnt lеngthѕ – 12mm Extension Tube аnd 25mm Extension Tube and both include еlесtrісаl соntасtѕ whісh аllоw dаtа trаnѕfеr bеtwееn thе lеnѕ аnd саmеrа tо bе mаіntаіnеd. These are stackable too to gіvе а 37mm ехtеnѕіоn and whilst Саnоn dоеѕ nоt rесоmmеnd thіѕ, since hе dаtа trаnѕfеr mау bе аffесtеd, ассерtаblе rеѕultѕ аrе роѕѕіblе іf уоu аrе wіllіng tо ехреrіmеnt..

Ехtеnѕіоn Тubе ЕF 25 ІІ іѕ rесоmmеndеd fоr fосаl lеngthѕ оf 50mm аnd uр (ЕF-Ѕ 18-55mm саn bе uѕеd аt mіddlе аnd tеlе zооm ѕеttіngѕ), whereas the Ехtеnѕіоn Тubе ЕF 12 ІІ іѕ ѕuіtеd fоr сlоѕе-fосuѕіng wіth wіdе-аnglе fосаl lеngthѕ. Соmраtіblе wіth аll Саnоn lеnѕеѕ, ехсерt thе Саnоn 15mm f/2.8 fіѕhеуе, 14mm f/2.8L аnd МР-Е 65mm f/2.8.

Use Diopters to improve Close Focus

Another tool in the cinematographer’s armoury is the diopter, which unlike the extension tube, actually sits in front of the lens in order to shorten the close focussing distance.

Diopters allow the camera to focus closer to the subject and achieve a larger image size while bringing out the sharpest details in even the tiniest subjects.

The most popular size for diopters are circular 138mm filters and for convenience, they are often supplied with 5.65″ x 4″ filter tray holders (PV sized), so that they can fit into a PV matte box filter slot.

Diopters are supplied in sets of varying strength and are the simplest and least expensive method of close-up photography/cinematography and avoid the need for using macro lenses.

Diopters are available in full and split versions. Split diopters allow half of the image to have a closer focus than would otherwise be possible for creative options.

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