Pentax Close-up Accessories
Similar to a filter, a close-up lens is screwed into the filter thread of a lens. Without light loss, it reduces the minimum focus distance of the lens and increases the magnification ratio.
The names of the Pentax close-up lenses are made up as follows:
- S – to be used with standard lenses
- T – to be used with telephoto lenses
- n – focal length of the optical element (in cm). It gives the distance from film to subject when the lens to which the close-up lens is attached to is focused at infinity. It can be converted to diopters d as follows: d = 100 / n.
The Pentax close-up lenses are listed in the Table 1. The ones with the larger diameters are the older versions, designed to fit the filter threads of the K-series lenses.
|Close-Up Lens||Diameter (mm)||Use With Lenses with f (mm)||If Used With||Subject Distance (cm)||Magnification|
|S25||49, 52||50||50/1.7||32.6 ~ 22||1/4.8 ~ 1/2.7|
|S40||49, 52||50||50/1.7||48 ~ 27||1/7.6 ~ 1/3.5|
|T80||49, 52||85 ~ 150||85/2||91.6 ~ 50.5||1/9.4 ~ 1/4.2|
|T95||52, 58||135 ~ 200||200/4||111.7 ~ 80.3||1/4.96 ~ 1/2.61|
|T160||49, 52||100 ~ 150||135/3.5||174.2 ~ 79.1||1/12.3 ~ 1/4.31|
|T183||52, 58||135 ~ 200||200/4||200 ~ 108||1/9.5 ~ 1/3.77|
This set is meant to be used in combination with a ring flash and a Dental Macro lens (see the diagram). It consists of two close-up lenses (DS9 and DS25) and a magnet holder. DS9 has a yellow painted ring around it, and DS25 has a red one. Both names follow the close-up lens naming convention explained above, with the addition of "D" for "dental."
There are two Dental macro lenses, the SMC-M Dental Macro 100 mm f/4 and the SMC-A Dental Macro 100 mm f/4. The only difference between these two lenses and the respective non-dental ones are the additional yellow and red magnification ratio markings that correspond to the use of the two close-up lenses.
Extension tubes are mounted between the camera and the lens. They increase the distance between the two, thus allowing closer focusing and therefore a higher magnification ratio. The longer the extension, the closer the distance to the object.
The following extension tubes are available:
|Auto Extension Tube K||50 mm|
|Auto Extension Tube K||100 mm|
|Helicoid Extension Tube K||26 ~ 46 mm|
|Manual Extension Tube Set K||9.5, 19, 28.5 mm|
|Auto Extension Tube Set K||12, 19, 26 mm|
Pentax does not offer AF-capable extension tubes, although some of the 3rd party manufacturers do.
- The auto bellows (identical with auto bellows M and auto bellows A) can be extended 38 mm ~ 170 mm. It has a lens reversing system, automatic diaphragm, double cable-release, an extension measuring scale, and a moving tripod mount. (The image shows the auto bellows A together with the slide copier A.)
- The bellows unit III has an extension range 32 mm ~ 137 mm and a moving tripod mount.
- The slide copier A/M attaches to the auto bellows, and can be used for copying slides at magnifications from 1:1 to 1.5:1. (The image shows the auto bellows A together with the slide copier A.)
- The slide holder 1X K holds a slide so it can be duplicated.
- The slide holder K holds a slide so it can be copied at magnifications between 1:1 and 1.15:1.
- The macro focus rail III has a tripod receptacle and allows fine focusing by moving the entire camera-extension tube-lens assembly back and forth. This allows keeping a pre-determined magnification ratio constant.
Reverse Adaptor K
Reverse adaptors are used for mounting a lens backwards. One side of the adapter screws into the lens’ filter thread and the other mounts onto a camera body or an extension tube. Using such an adaptor is advised when shooting at magnifications higher than 1:1. Two reverse adaptors are available: for 49 mm and 52 mm filter threads.
Reverse Ring Light Holder K
Stands and Tables
- The macrophoto stand is very convenient for macrophoto photography. In the picture it is shown with a macro focus rail III and a bellows attached. The stand includes a reversible gray/black plate (the grey side has 18% reflectivity).
- The lighting table is designed as an accessory to the macrophoto stand and is ideal for shooting transparent and semi-transparent objects.
- The copypod is a compact, portable copy-stand which attaches to the filter thread of a lens or a closeup lens. It is available in two sizes (49 mm and 52 mm), and comes with a soft case.
- The copy stand III is used for copying work. It is equipped with a fine adjustment device and an 18%-gray reflector.
- The copy stand III p is portable, the carrying case serving as a base when the unit is assembled.
- The table clamp is useful for fixing the copy stand III to a table-top less than 6 cm thick.