Canon Accessories

By Arseny Voroshilov

Review contents:
Accessories for television lenses Optical accessories and converters from Okno-TV Company Canon Accessories Optical accessories from Cavision Products from Chrosziel Film & Video Optical accessories from Cinema Technologies Optical accessories from Fujinon: a glance in the other dimension Expanded possibilities of DSR-PD170

The Canon company is produced the wide assortment of the accessories, such as the filters, converters, extensions, extenders and etc.

Filters

This Canon accessory category is the most various and includes ultraviolet, blue-sky, ND-, polarizing, color-conversion, softly-focusing and beam filters.

The ultraviolet filter is practically colorless. It filters the rays of the short-wave ultraviolet portion of spectrum, which is invisible for unaided eye. It is necessary to note that the zoom contains the large number of the lenses so practically all ultraviolet radiation is absorbed. However, the ultraviolet filter using is extremely advisable for protection of the external lens surface.

An image obtained with ultra violet filter (right) and without it

An image obtained with sky filter (right) and without it

The filter of the blue-sky light is mildly purple. It use for shooting with clear sunny weather. This filter also cuts off the ultraviolet rays and also prevents the appearance of the blue-green tone on a picture.

Neutral (ND) filters simply reduce a whole beam of light, which falls into lens. The filter of this type is used when brightness of the shooting object is so high that the provision of its qualitative shooting by diaphragm reduction only is impossible. The other variant of using such filter is a shooting of the object (to example, person or flower) with big aperture. This allows obtaining the small depth to sharpness, under which a clear object is situated on blurred background, and intensifying the impression of three-dimensional space.

The action of ND-filter can be expressed by density D, transparency T or exposure factor. These parameters are jointed as follows:

D = lg T, Exposure factor = 1 / T,

where T is expressed by decimal fraction (that is to say 100%=1)

ND-filter type	Transparency (T)	Density (D)
ND2	50%	0,3
ND4	25%	0,6
ND6	12,5%	0,9

Usually as the parameter for filters, applicable with lenses for cinema, exposure factor is chosen.

ND-filters with high density is more efficient in short-wave portion of spectrum so the adjustment of the white balance can be needed.

Polarizing filter for interception of the light, reflected from surface of water or glass. Since light, passing through atmosphere, is partly polarized, filter of this type is efficient also at shooting of the objects on blue sky background. The filter mildly suppresses brightness of sky, making the objects, for instance mountains, more clear.

Polarizing filter twisted in cartridge and then turns round until reflected light will not be filtered. In this position the filter is fixed.

	Polarizing filter (left) and the effect of its use at shooting thru the glass window (bottom right)

When use of this filter it is necessary to remember that it approximately on quarter reduces the light flow and changes the color balance so after its installation it is necessary anew to adjust the white balance.

The light consists of ensemble of the waves, which fluctuations occur in determined planes. Under natural light these planes are situated in casual manner so to define it polarization is impossible. When the reflection of the light from some plane is occurred and reflected light interacts with direct light, in some planes the fluctuations are got more intensive than in all remaining so reflected light becomes polarized.

The polarized component, which fluctuations occur in planes, located under angle to surfaces of the reflection, is identified as P-polarized light. The polarized component, fluctuating perpendicular to the slopping planes, is identified as S-polarized light.

a — light polarization principle; b — polarizing filter influence; c — polarization of reflected light

The reflected light contains powerful S-component, and polarizing filter is transmitted only one linear polarized component.

The action of CC (Color Conversion) filters is understandable from their names already. The color temperature reflects the color balance of the light source, coming from color, radiated absolutely black body under it heating. The lower color temperature, the more red component in the light. Alongside with color temperature increasing the color becomes yellow and then blue.

The yellow filter reduces the color temperature, but blue filter increase it. The TV cameras is designed under standard conditions of the illumination, created in television studio, under which the color temperature is fallen in the range 3000…3200K so yellow filter follows to use at shooting outside of studio.

Color transforming filter influence (right)

Soft focus filter effect

The unit of the color-conversion abilities of the filter is mired, which presents the relationship of 1 000 000 to color temperature in K, or decamired (10 mireds).

The manual cameras are usually equipped by two built-in CC-filters: 16 decamired for transformation of the sunshine color temperature (5600K) in 3000K and 10 decamired, which will convert the light from florescent lamps (4300K) in 3000K.

Softly-focused filters have a dull surface so shot with their using the picture has soft mysterious view. These filters are often used at shooting of the different pictures of the lyrical nature.

The beam filters allow creating the star effect at shooting of the light source. Moreover the more bright and point the light source, the stronger the effect, created by filter. These filters are often used under night shooting (for instance, night streets with illumination) and at shooting of show.

Soft focus filter and beam filter and the effects form different beam filters

Converters

Long-focused converter (tele side), fixed on zoom, displaces the range of the change of its focal length to increasing, transforming lens in more long-focused with increased range. For instance, the T15II-85II converter enlarges the maximum focal length of the lens J14ax8.5 (the focal length 8.5…119 mm) in 1,5 times that is to say to 179 mm.

Long-focused converter does not bring to any falling of the parameter F that exists during the internal extender using. This parameter remains as beside lens without converter.

But nevertheless long-focused converter is provided for using under greater focal lengths of zoom only. To function this converter under minimum focal lengths (wide angle) of the lens, it diameter must be such big that camera will be very bulky. That is why in name of the converter the word side is appeared: it works only on the one side of the focal length range.

Long distance converter and the effect of its use

Lens + converter	Minimum distance to the object, m
J15x9.5 + T15II-85II	2,14
J18x8.5 + T15II-90II	2,03

When the T15II-85II converter is in the use the shading of the frame edge is already existed at focal length equal to 80 mm and hereinafter with angle increasing that does this part of the range the dead zone.

The minimum distance to shooting object is changed proportional to square of lens multiplicity. As example, for the system, consisting of J14ax8.5 lens and T15II-85II converter, this distance is increased from 0.8 to 1.8 m. Another two examples are demonstrated in table.

Also the Canon Company produces the wide-angle converter of several models. These are W80-IIIB and W80Y-85 converters (both with multiplicity 0.8x), which can be used in conjunction with many lens, and W83-86 converter with multiplicity 0.83x, which is intended specially for J9ax5.2B lens.

Accessories (extensions)

The wide-angle extension is used for the same purpose, as wide-angle converter, but is provided by simpler design. Under its using aiming on sharpness is produced by macro focusing mechanism so extension works under minimum focal length only. Under its increase the sharpness get lost. But if lens is not equipped by macro focusing mechanism, and sharpness is done by the focusing ring then after taking down of the extension it is necessary to execute the focusing again.

Wide-angle extension and the effect of its use

The extension of the fish eye type is used for reception of the picture effect, got on spherical surface. Either as wide-angle, this extension works on minimum focal length of the lens only, and focusing is provided by macro mechanism also. When use of such extension with J14ax8.5 lens the focal length becomes equal to 5 mm, and angle of the field of vision is 127.7°. This angle is less than 180°, but wholly it is enough to vastly increase the possibility of the lens.

Fish eye extension and the effect of its use

In Canon assortment these products are presented by models WA-75II (wide-angle, 0.75x) and FEA-IIIB (fish eye, 0.6x).

Lens for near shooting is used for macro plan shooting of small objects. This can be an insect, flower etc.

An image shot with macro shooting lens (top) and the scheme illustrating the principle lens with macro shooting extension

If on lens J14ax8.5 the lens 82CL-UP1300H is fixed and focusing ring is installed in infinity position, actually lens is focused at distance 1.3 m. But if focusing ring is installed to minimum value 0.8 m, the real focal length is 0.5 m. Under such distance the object with size 34×25 mm fills the whole frame area. The sharpness inducing in this case it is enough difficult since the sharpness depth is minimum. So the distance to object must be as more as possible.

For near shooting the Canon company produces the lenses of the following models: 82CL-UP800H and 82CL-UP1300H (the thread diameter is 82 mm, focal length 800 and 1300 mm accordingly), 105CL-UP800HD and 105CL-UP900H (the thread diameter is 105 mm, focal length 800 and 900 mm accordingly).

Extenders

Shooting with extender (right) and without it and the scheme of extender mounting

The extender is a device, allowing with great distance to shoot different objects close-up, for instance players’ face during translation of the sport events. The extender is fixed between camera and lens. It enlarges the lens focal length, transforming it in more long-focusing. The double extender not only doubles minimum and maximum focal length, but also double the value of F parameter. However velocity of the change the zoom focal length herewith falls down on 75% (as in the case when aperture is decreased in two times). The reason in that the focal length turned out to be duplicated without change of the lens diameter.

For 2/3 lens with B3 or B4 fastening the Canon company is produced the H2.0-B3 and X2.0-B4 extenders.

Adapters

The accessories and converters of the Canon Company can be used with many models of the lens. They are fixed on front ring of the lens. Since the ring diameter of different lens is differed, for installing of majority of extensions the special connecting rings — adapters — are used. The Canon company is manufactured the adapters of the following models: 80II, 85II, 90II, 98II for external rings with diameter 80, 85, 90 and 98 mm. Wide-angle converters W80Y-85 are fixed without adapter (for ring by 85 mm diameter) and W83-86 for J9ax5.2B lens.

Since extenders are used very often, they are built-in in many lenses. The great studio lenses can be provided by two or three built-in extenders that vastly increase the possibilities of the operator. The built-in extender can be considered as adapted afocal converter.

Till now the main problem of the extenders use was the accuracy of its fabrication. But at the last years the production technology improvement has allowed to obtain very high quality of these devices.

Material is provided by Okno-TV Company and
Representation of Canon Company in Russia and C.I.S countries.