making full use of interchangeable lenses

8/13/2019 Making Full Use of Interchangeable Lenses

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Motonari Sasaki, Video Technology Analyst, Up Side

Making full use of interchangeable lensesStill Lenses and Cinema Lenses

Photo 1: The Panasonic AG-AF100 series allows a vast range of lenses to be used via the mount adapter.

To enable a photographer to create exactly the video

they have in mind, the photographer has to consider

a wide variety of elements, including the camera’s

performance. The imaging power of the lenses is one of

the crucial elements.

The previous generation of small camera

recorders suffered from small sensor sizes and non-

interchangeable lenses, so images naturally had a deep

depth of field. Photographers overcame this problem

by attaching still lenses or PL mount lenses with DOF

adapters to the small camera recorder lenses. Examples

of these solutions included the Letus35 from Letus and

the Mini35 PL from P+S Technik. These arrangements

enabled photographers to achieve unique video results

and shallow depth of field that fixed lenses could not

provide.

Later, between 2005 and 2009, camera recorders

such as the Canon XL H1S (1/3type) and the Sony

PMW-EX3 (1/2 type) made their debut. Though the

sensors were still small, these camera recorders offered

interchangeable lenses, as well as adapters for easy

changing of lens mounts. By choosing the right lens for

each shoot, photographers were able to significantly

expand the expressive range of their small camera

recorders.

Today, with the rich array of digital SLRs now on offer,

large image sensors are routinely installed in compact

bodies, making it easy to achieve a shallow depth of

field. The major lens manufacturers are busily producing

lenses that support digital SLR mounts; for example, Carl

Zeiss makes set lenses for the Canon EF and Nikon F

mounts.

Panasonic introduced the AG-AF100 series. Launched

in December 2010, the AG-AF100 series is the industry’s

first camera recorder to incorporate the Micro Four Thirds

system, which was designed for mirror-less digital SLRs.

The sensor size is 3/4 type, and lenses for the Micro Four

Thirds mount are now offered by all major companies,

including Panasonic (the lineup of lenses is fuller

than that for the E Mount, which is based on a similar

concept). Furthermore, a key feature of the Micro Four

Thirds system is the use of a short flange back, which

enables a huge variety of lenses to be applied through a

mount adapter (Photo 1).



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Photo 2: A wide range of mount adapters

are sold for the Micro Four Thirds mount,

including the PL, B4, Leica Screw, M42,

Nikon G and Canon EF.

Photo 3: Triad PL: The Micro Four Thirds mount adapteris fitted with a flange-back adjustment mechanism.

Photo 4: The Jupiter-12 35 mm F2.8 lens with Leica screw mount

has a protruding rear element that interferes with the sensor, so it

cannot be mounted on the AG-AF100 series.

Mount Adapters

The conversion adapters for the Micro Four Thirds mount

are available, including the PL, B4, Leica Screw, M42,

Nikon G and Canon EF. With the right combination of these

adapters, virtually any lens can be mounted on the AG-AF100

series (Photo 2).

The PL l ineup o f mount adapters i s par t i cu lar ly

comprehensive. The range in types of adapters is stunning,

including ange-back adjustable types designed for factor-freeuse and xed mount adapters mounted with 15 mm diameter

rods to serve double duty as lens supports (Photo 3).

The lens adapters for the Canon EF series incorporate a

built-in iris mechanism, enabling them to restrict the aperture

just before the light reaches the camera through the lens.

However, if the selection of mount adapters is varied, the

lenses available is far more so. Be aware that some lenses

have long rear elements that prevent them from being used

with mount adapters (Photo 4).

Notes on Combining with Still Lenses

The AG-AF100 series can be mounted with a wide varietyof still lenses, giving video photographers a whole new

dimension in exibility.

■Zoom lenses

In video photography, complete flange-back adjustment

capability is a highly desirable feature for zoom lenses.

However, still camera lenses are not built with zooming for

video effects in mind, but instead to focus on and capture a

single image. As a result, still zoom lenses often cause out-

of-focus problems in video shooting, depending on the focal

distance of the still zoom lens.

Moreover, the zoom rings of still lenses do not deliver the

smooth, steady movement demanded in the zoom rings of

video and cinema lenses, as this feature is less critical in

still photography. In some cases, the direction of rotation is

opposite to that which video photographers expect.

For example, the zoom ring on the Canon EF zoom lens is

the same as that on zoom lenses for camera recorders with

the B4 mount. When holding the camera (pointing it toward

the subject), this ring is turned clockwise to move to the wide-

angle end. In contrast, the zoom rings on the Lumix G Vario

series and Sony E mount lens go to the telephoto end when

rotated clockwise. Shooters accustomed to using video lensesare bound to be confused.



Advantages of Still Camera Lenses

Still camera lenses are compact and lightweight, yet they

deliver excellent imaging performance. Adding these lenses

to your tool box will allow you to move around nimbly if the

job requires.

The weaknesses of classic lenses are exposed at the

open end of the iris, but image quality can be improved

dramatically by adjusting the iris one step. A weakness in

the eyes of one photographer may be an appealing quirk to

another. Some effects are out of reach for video lenses andcinema lenses with a PL mount, such as scenes that are

extremely blurred or darkened on the periphery only. These

images shoot on purpose can be interesting for your toolkit.

Naturally, still camera lenses suffer many more problems

than camera recorder lenses do when used in video

photography. But many are inexpensive, offer great imaging

performance, and are easy to use. By combining these

lenses with the AG-AF100 series, you can adjust your

settings menu to overcome the weaknesses of still lens and

capture better quality images.

Cinema Lenses and Accessories

Like video lenses, cinema lenses are lenses designed for

video recording, so the movement of the zoom and focus

rings won’t pose any problems. You can handle them with

none of the confusion that can arise when using still camera

lenses. Of course, the iris ring rotates smoothly instead of

clicking through stages.

Cinema lenses offer crisp, sharp images for a gentle look,

with shallow depth of eld that lends depth and richness to

images. Cinema-lens users nd that these lenses effectively

translate their photographic intentions into the results they

were looking for.

On the other hand, PL mount zoom lenses are bulky

and heavy, so they are normally used with a lens support.

For this reason, a rod-mounting support system has to be

fitted on the bottom of the AG-AF100 series. As a result,

the camera becomes heavier, and the center of gravity is

heavily skewed to the front of the camera (Photo 6).

The rotation of the focus on PL mount zoom lenses is

over 180°, so follow focus is more or less essential, and

attachment of a matte box for filter work is necessary.

With so many attachments, it’s difcult to keep the camera

balanced with a tripod head alone, so shooters have tocompensate by using a slide base, attaching a battery to the

back for balance, and so forth.

When a cinema lens is used, even if the AG-AF100 series

itself is light, the system as a whole becomes heavy, making

handheld video capture difcult. Consider adding a grip or

other items to compensate.

Support systems for the AG-AF100 seires are available

from a wide variety of manufacturers, and equipment rental

companies carry original products as well. Be sure to fit

these systems correctly to prevent damage to the camera

mount and avoid shifting the optical axis.

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Photo 6: Combination of the AG-AF100 series with the Cooke Cine Varotal 25–250 mm T4 PL mount zoom lens. The weight is severely

skewed forward; even with the slide base to improve the balance, the system hardly seems stable.

making full use of interchangeable lenses

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