Pekka Buttler, 03/2026
Specifications
The table below summarizes the lens’ key specifications (Measurements based on pictured sample):
| Brand: | Expert | Lens name | 1:2.8 f=28mm |
| Focal length(s) 1 | 28 mm | Angle-of-view 2 | 75 ° |
| Maximum Aperture | f/2.8 | In Production | turn of 80s |
| Lens mount (this lens) | Konica AR | Other lens mounts | uncertain3 |
| Length 4 | 53,9 mm | Diameter 5 | 66,3 mm |
| Filter ring diameter | 52 mm | Weight | 295 grams |
| Lens element count6 | 7 | Lens group count | 7 |
| Aperture blades (S/R/C) 7 | 5 S | Focus throw | 150 ° |
| Minimum focusing distance (measured) | 27 m | Maximum magnification (measured) | 1:6,8 |
| Has manual aperture ring | YES | Has Manual focus ring | YES |
| Aperture mechanism type | Auto | Aperture click stops | 2.8•4•5.6•8•11–16 |
Further notes:
• First off: ‘Expert’ is not a lens manufacturer, but a rebrander (see more below).
• This Expert 28 mm f/2.8 is with a high likelihood a Tamron lens, probably a repackaging of the late 1970s Tamron adaptall 28 mm f/2.8, but rehoused in a way common to a batch of lenses Tamron made for rebranders in the late 70s.
• This lens is unusually large and heavy for what is a decidedly modest-spec lens
History of Expert
Expert was not a lens manufacturer but a rebrander. Expert is/was a giant, European electronics retail chain that for some time also sold lenses under their own house brand. You can read more in the JAPB company profile on expert.
Versions
It is more than likely that this lens existed also in other mounts than Konica AR, and in that case the measurements of those lenses may differ slightly.
Expert also offered altogether three 28 mm f/2.8 lenses, namely:
• Expert 28mm f/2.8
• Expert 28mm f/2.8 Multic.
• Expert MC Auto 28mm f/2.8
While the first two designs are rebrand of a Tamron lens (in both multicoated and non-multicoated guises) the third design seems to be a rebrand of an Osawa lens.
Adapting
We’re going to be discussing adapting Konica AR mount lenses. If your copy of the Expert 28/2.8 sports another mount, please study the JAPB article on the requisite lens mount for adapting tips.
This lens cannot be used natively on any current SLR or dSLRs. To use it in its native environment, you will need a Konica AR-mount film body.
Thanks to being a fully manual lens (manual aperture, manual focus), the lens can be adapted to all mirrorless cameras using a suitable adapter. Moreover, Konica AR lenses are so uncomplicated that a simple ‘dumb adapter’ will do the job perfectly. However, due to Konica AR lenses not being among the most numerously manufactured, special adapters (helicoid adapters, tilt/shift adapters) are not easy to come by and speed boosters are currently unavailable.
Using Konica AR lenses on dSLRs is possible, but difficult. Due to the exceptionally short flange focal distance of the Konica AR mount (at 40,5 mm, a lot shorter than that of any full-frame dSLR mount), any adapter will necessitate some optics to achieve anything near infinity focus.
Footnotes
- Focal length is (unless stated otherwise) given in absolute terms, and not in Full-frame equivalent. For an understanding of whether the lens is wide/tele, see ‘Angle-of-view’. ↩︎
- Picture angle is given in degrees (based on manufacturers’ specs) and concerns the diagonal picture angle. Rule of thumb:
> 90 ° ==> Ultra-wide-angle
70–90 ° ==> Wide-angle
50–70 ° ==> Moderate wide-angle
40–50 ° ==> ‘Standard’ or ‘normal’ lens
20–40 ° ==> Short tele lens
10-20 ° ==> Tele lens
5-10 ° ==> Long tele lens
< 5 ° ==> Ultra-tele lens ↩︎ - Expert-lenses were usually available in the typical lens mounts of the era (M42, Canon FD, Konica AR, Minolta SR, Nikon F, Olympus OM, Pentax K), but it is not certain that each lens was offered in everyone of these mounts. ↩︎
- Length is given from the mount flange to the front of lens at infinity. ↩︎
- Diameter excludes protrusions such as rabbit ears or stop-down levers. ↩︎
- Data on lens elements and groups is based on a single source. Alternatively, it might also be a 4 elements in 3 groups design. ↩︎
- S=straight; R=rounded; C=(almost)circular at all apertures. ↩︎