Data sheet: Pentacon 29 mm f/2.8 auto & electric

Pekka Buttler, 11/2022 (Updated 08/2025)

Specifications

The table below summarises the lens’ key specifications (measurements based on 4th generation sample):

Brand:	Pentacon	Lens name	auto 2.8/29 multi coating
Focal length 1	29 mm	Angle-of-view 2	73 °
Maximum Aperture	f/2.8	In Production	1970-1990 (all versions together)
Lens mount (this lens)	m42 (auto & electric)	Other lens mounts	Exakta
Length 3	45,0 mm	Diameter 4	64,3 mm
Filter ring diameter	55 mm	Weight	202 grams
Lens element count	7	Lens group count	7
Aperture blades (S/R/C) 5	6 S	Focus throw	150 °
Minimum focusing distance	25 cms	Maximum magnification	1:6,5
Has manual aperture ring	YES	Has Manual focus ring	YES
Aperture mechanism type	Automatic	Aperture click stops 6	2.8•4•5.6•8•11•16•22

Further notes:
• No, there’s no typo. The focal lens of this wide-angle is indeed 29 mm. If that is not idiosyncratic enough for you, consider that Pentacon was simultaneously also selling a 30 mm focal length lens (!).
• The Pentacon 29/2.8 is the successor of the Meyer-Optik Görlitz Orestegon 29/2.8 [data sheet] (Basically it’s the same lens, just rebranded).
• This lens was never manufactured for the Praktica B mount. On Praktica B mount there was the Pentacon Prakticar 28/2.8 [data sheet] – an altogether more modern lens.

Versions

I’ll admit this is a bit complicated…

Firstly, Pentacon/Praktica cameras used two variants of the m42 mount,
• one was the classic m42 auto mount (pin at the bottom of the lens for stopping down). These lenses were generally indicated by the phrase ‘auto’ on the lens’ name ring.
• the other was Pentacon’s proprietary m42 variant which used electric contacts to communicate set aperture values to the camera, but still used the same m42 auto pin for stopping down. These lenses were generally indicated by the phrase ‘electric’ on the lens’ name ring.

• Moreover, for some time (until Pentacon gave up on the Exakta), the Pentacon 29 was also manufactured in a variant of the Exakta-mount.

Having been manufactured for ≈20 years, there are several ergonomically and outwardly different models of the Pentacon 29/2.8. Furthermore, Pentacon (as well as MOG before them) often tended to – when possible – use up parts stocks, meaning that one can also encounter hybrids.
• Early, 1st generation models lacked multi-coating (indicated by the lack of either ‘MC’ or ‘multi coating’ on the lens’ name ring. These models would also typically have some zebra-like cosmetically elements, aperture values would be in black against a metallic background and distance values in feet were in red. The focus ring would be a milled metal ring. These lenses would not have an auto/manual switch but instead offered a button for DOF preview.
• 2nd generation models would be all-black, still have the feet indications in red, still have the DOF preview button, still not offer multi-coating, but the shape of the metal focusing ring would have changed from being lengthwise ribbed to a checkered pattern.
• 3rd generation models would outwards look like 2nd generation models, but would instead sport an auto/manual switch and offer multi-coating.
• 4th generation models would be very similar to 3rd generation models, but the color of the feet-indication would switch to green, and the typography of the name ring would change [the lens pictured above is a representative of this generation]
• just before the winding down of operations, a 5th generation would be introduced, most easily distinguishable by that the checkered pattern of the focus ring would stop being quadratic, and would instead become elongated along the optical axis. This version seems to be relatively rare.

That final, 5th variant was also sold in some markets under the name “Carl Zeiss Jena P 1:2.8 f=29 mm MC”. See more on the phenomenon of selling Pentacon lenses as ‘Carl Zeiss Jena’ lenses in this JAPB article.

Except the last, 5th generation variant, I’ve seen exemplars of all variants having been available in both m42 auto and m42 electric variants.

Adapting

[The following applies to the Pentacon 29/2.8 in m42 mount. If you have an Exakta mount sample, see adapting guidelines in JAPB’s article on the Exakta mount]

This lens cannot be used natively on any current SLR or dSLRs. To use it in its native environment, you will need an m42-mount film body. Luckily there are a lot of those available and in working order.

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, m42 lenses are so uncomplicated that a simple ‘dumb adapter’ will do the job perfectly. Further, due to the popularity of the m42 mount, special adapters (helicoid adapters, tilt/shift adapters) are readily available. Alternatively, one can choose to daisy-chain adapters (e.g. m42->Canon EF; Canon EF –> mirrorless) which also opens up a wide range of speed boosters .

Using m42 lenses on dSLRs can also be an easy option, depending on which dSLR.
• Canon EF has the shortest flange focal distance among full-frame dSLR’s and Canon’s wide range of dSLRs are able to mount m42 lenses perfectly, using a simple adapter ring.
• Minolta / Sony A dSLRs and Pentax dSLRs are likewise able to mount m42 lenses using a simple adapter ring.
• Nikon F dSLRs have a long flange focal distance, meaning that mounting either M42 or Exakta lenses needs an adapter that uses corrective optics to allow anything close to infinity focus.

Footnotes

1. 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’. ↩︎
2. 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 ↩︎
3. Length is given from the mount flange to the front of lens at infinity. ↩︎
4. Diameter excludes protrusions such as rabbit ears or stop-down levers. ↩︎
5. S=straight; R=rounded; C=(almost)circular at all apertures. ↩︎
6. Numbers equal aperture values on aperture ring; • intermediate click; – no intermediate click. ↩︎