Attachment lenses allow to reduce the minimum focus distance of a given lens, thus enabling you to do close-up and macro shots with bigger magnification ratios. For use, the attachment lens is screwed on the front of the lens just like a filter. With the attachment lens in place, the lens cannot be focused to infinity any more.
The use of an attachment lens is very easy and comfortable, you still get the full functionality with fully automatic AE exposure. Different from the use of extension rings, you do not have much loss of light. An attachment lens is light and compact and can be taken with you anywhere. In addition, attachment lenses are a cheap entry in the world of close-up photography.
Draw-back is mostly the limitation in achievable magnification ratios. Much larger ratios are possible with extension rings or bellows and reverse adapters. Magnifications bigger than 1:1 cannot be achieved with close-up lenses without dramatic loss of image quality.
At first, Konica offered two attachment lenses in different strengths, both for 55 mm filter thread diameter.
The figures about possible distances below are based on the use of a lens with a focal length of 50 mm and a minimum focusing distance of 0.45 m (1 ft 53/4"), like i. e. the Hexanon AR 50 mm / F1.4 or the older variation of the Hexanon AR 50 mm / F1.7:
- No. 1
0.32 m – 0.65 m (1 ft 5/8" – 2 ft 15/8")
- No. 2
0.26 m – 0.37 m (101/4" – 1 ft 21/2")
Both attachment lenses can be combined to achieve still closer distances::
- No. 1 and No. 2
0.24 m – 0.29 m (91/2" – 113/8")
Later, from the introduction of the FS-1 onwards, only one attachment lens was offered unter the name »Close-up Lens AR«. The strength of this attachment lens is somewhere in between the older attachment lenses No. 1 and No. 2. This attachment lens is also for 55 mm filter thread diameter:
- Close-up Lens AR
0.284 m – 0.468 m (113/16" – 1 ft 67/16")
The earlier Konica attachment lenses where achromatic lenses made of two elements. The later variations were single-element lenses. Therefore, the earlier variations have a better image quality than the later ones.
The earlier variations were delivered in a plastic box inside a fake leather case, the later ones only in the plastic box.
You can download a user's manual for the Close-up Lens AR in English, French, German, Japanese, and Spanish language if you follow the link.
Use of attachment lenses
Close-up lenses inevitably reduce image quality. To limit the losses and to get satisfying results, some things should be kept in mind:
- Always stop down as far as possible, to aperture 8 or smaller. The bigger the aperture is, the more quality loss you will get with the attachment lens.
- The stronger an attachment lens is, the more image quality degradation you get. Always use the weakest attachment lens that is sufficient to achieve the magnification ratio you need.
- If the desired magnification can be achieved with a single attachment lens, avoid combination of attachment lenses. If you cannot avoid the combination, put the stronger attachment lens on the front of the lens and the weaker on top of the stronger attachment lens.
- Do not combine more than two attachment lenses, their losses add to each other.
- The shorter the focal length of the lens, the bigger the change in minimum distance caused by the attachment lens. On the other hand, the longer the focal length, the stronger the effect on magnification ratios when using an attachment lens. In most cases, one attachment lens on a telephoto lens gives better results than two attachment lenses on a standard lens. At the same time, the shot becomes easier to make, because the distance to your subject is longer and small animals like insects are not so easily disturbed.
- To use attachment lenses on long telephotos with focal lengths above 135 mm is mostly not sensible, as these lenses have a long minimum distance.
- At the small distances used with attachment lenses, the depth of field is already becoming very narrow. When not shooting from a tripod, precise focusing might be difficult as camera shake has a potential to put your subject out of the in-focus plane. If possible, the use of a tripod and a cable release is recommended.
Attachment lens or extension rings?
Large magnification ratios cannot be achieved with attachment lenses. In a certain range, the desired magnification ratios can be achieved with extension rings as well as with attachment lenses. Which gives the better results?
A widespread misconception is, that extension rings do not harm image quality because there are no optical elements inside. But the change of the lens-film distance which causes in fact a projection of the image is also a big change in the optical system. With some lenses, the use of extension rings can cause a dramatic fall-off in sharpness towards the corners and edges. If this is the case, is depending on the lens' optical construction and must be tested with the specific lens.
Mostly well-suited for use with extension rings are prime lenses with a moderate speed for their focal length, like i. e. a Hexanon AR 50 mm / F1.7. Such lenses usually give better results with extension rings than with attachment lenses.
Mostly not very well-suited for use with extension rings are zoom lenses or lenses with internal focusing. Extremely fast lenses also can be critical. With such lenses, attachment lenses frequently give better results than extension rings.