Magnifying lens

Magnifying lens Canon MP-E 2.8 / 65 mm

A loupe lens is a lens that is optimized for image ratios of approx. 1: 1 to 20: 1. Macro lenses are usually used for smaller imaging scales, microscopes are used for even larger scales .

General

As a rule, magnifying lenses do not have their own option for setting the distance . If the extension is selected (and the image scale is set), the focus is adjusted by adjusting the distance between the object and the camera, for which purpose an adjustment slide is helpful. In contrast to macro lenses, magnifying lenses cannot be focused at infinity, but can only be used at close range.

An iris diaphragm is usually present. However, magnifying lenses should not be stopped down too much, as this is associated with a loss of resolution due to diffraction , especially at high image scales . A comprehensive focus range can be achieved with the technique of focus stacking .

Earlier models

Today only relatively few magnifying glass lenses are manufactured; most of the designs date from the 1950s to 1970s. Well-known series were, for example, the Luminare from Carl Zeiss, which were manufactured up to the 1990s, or the Photare from Leica with image scales of approx. 0.4 to 40 times each across the entire range. Other manufacturers of special lenses of this type were Nikon , Novoflex and Olympus (Zuiko) .

Many of these objectives have an RMS thread (W 0.8 "× 1/36"), i.e. the usual connection for microscope objectives . These can be connected to commercially available lens mounts using an appropriate microscope adapter . The required extract is z. B. using a bellows device .

In the 1960s and 1970s, Carl Zeiss built the Tessovar, a zoom magnifying lens that is attached to a tripod bracket like a stereo microscope . It does not have an eyepiece , but is operated with a camera housing. The image scale spans 1.6 to 6.4 times and can be expanded to 0.4 to 12.8 times with accessory lenses. The working distance is 3.6 to 32 cm, depending on the magnification.

Magnifying lenses with bayonet connection

The Canon MP-E 65 mm lens when fully extended

These lenses are connected directly to a camera housing . No additional extract is required. This is part of the lens.

Canon has been building the MP-E 2.8 / 65 mm, a 65 mm full-frame magnifying lens with an adjusting screw , since 1999 . It can be connected directly to the Canon EF camera bayonet and is suitable for image ratios from 1: 1 to 5: 1. The working distance at maximum magnification is approx. 4 cm.

Zhongyi Optics has been building a manual full-frame magnifying lens since 2016, the Mitakon Creator 20 mm f / 2.0, with an adjusting screw and a variable reproduction ratio from 4.0: 1 to 4.5: 1. It is available for various lens bayonets , also with adapters permanently mounted by the manufacturer for various APS-C format bayonet connections and for MFT . The lens is extremely compact. The working distance is approx. 2 cm. Since 2019, Zhongyi Optics has been selling a manual 85 mm full-frame magnifying lens with a variable reproduction ratio of 1: 1-5: 1, the Mitakon Creator 85 mm f / 2.8 1-5 × Super Macro, which is available for various lens bayonets. It is characterized by a large working distance.

Venus Optics has been building a manual full-frame magnifying lens, the Laowa 25 mm f / 2.8, with an adjusting screw and a variable image ratio from 2.5: 1 to 5: 1 since 2018. It is also available for various bayonets. With accessory adapters, the lens can also be used on APS-C or MFT format cameras. The working distance at maximum magnification is approx. 4 cm.

See also

• Macro photography
• Macro lens
• Microphotography

Web links

• Details and experiences with the MP-E magnifying glass lens from Canon at arstechnica.de
• Macro and close-up photography by Enrico Savazzi
• Magnifying glass lenses in macro photography at www.makrofotografie-anleitung.de

Individual evidence

1. ↑ Enrico Savazzi: Digital Photography for Science. Lulu-Verlag, 2011, ISBN 978-0-557-92537-7 , p. 349ff.
2. ↑ Enrico Savazzi: Digital Photography for Science. Lulu-Verlag, 2011, ISBN 978-0-557-92537-7 , p. 361.
3. ↑ Enrico Savazzi: Zeiss Tessovar , accessed on November 3, 2019.
4. ↑ Canon Camera Museum ( Memento from December 15, 2012 in the Internet Archive )
5. ↑ Damien Demolder: New 20mm f2 4.5x macro lens released by Mitakon. DPReview, December 19, 2016, web link, accessed September 1, 2019
6. ↑ Gannon Burgett: ZY Optics announces its Mitakon Creator 85mm F2.8 1-5X 'Super Macro' lens. DPReview, December 3, 2019, web link, accessed January 11, 2020 .
7. ↑ Lars Theiss: Extreme "Macro Zoom": Laowa 2.8 / 25 mm 2.5-5x , fotoMAGAZIN, March 8, 2018 ( web link, accessed September 1, 2019 )