Data sheet: ENNA München Tele-Ennalyt 240 mm f/4.5 (M42)

Versions and variations

If you think 240 mm is an odd focal length for a tele lens, ENNA München’s clearly did not see it that way. In fact ENNA had a 240 mm tele lens in their product lineup from the late fifties all the way until the company quit the lensmaking business. During that time, the only thing that stayed the same were the lens’ mainline specifications: a focal length of 240 mm and a maximum aperture of f/4.5.

There have been (at least) three fundamentally different optical recipes: A 3 elements in 2 groups design that was able to cover medium format and a 5 elements in 3 groups designas well as a later 5 elements in 4 groups design that was used on 35 mm film cameras. The lenses have used (almost) every conceivable form of aperture, from manual to preset, to semi-automatic to automatic aperture. While M42 and Exakta clearly were the most frequently offered mounts, I have seen Enna 240/4.5 lenses offered in Leica thread mount, Praktina, Hasselblad 1000/1600 mount, QBM and T-mount. See more under ‘versions and variations’

While I have not been able to pin any timestamps on many of these, it is nevertheless possible for me to trace the general development of the various 240/4.5 designs as follows:

Version 1: Fluted body form (narrowest at mount, broadest at filter thread), broad zebra pattern, 52⁷ mm filter ring, name on outside of lens (ca 1958)

This is chronologically the first version of the Enna 240/4.5 lens.
It uses a 5 elements in 3 groups design⁸, and was offered in M42, Exakta and Enna Sockel (v1) as well as (more rarely) in Praktina and LTM mounts. Conflicting reports on aperture mechanism⁹.

Version 2: Tube body form with protruding rings (barrel stays roughly same diameter, but control rings extend out from the tube as if they were bracelets on a wrist), broad zebra pattern, 67 mm filter ring, name on name ring (ca 1959)

This is chronologically the second version of the Enna 240/4.5 lens.
It uses a 3 elements in 2 groups design (a doublet at the front and a single lens at the back), making it a simplified classic tele lens (a positive group followed by a negative single lens). It is also a considerably larger lens than the first version.

Seemingly it was designed to cover the medium format frame, and it was sold with interchangeable mounts (samples with a Hasselblad 1000/1600 mount are regularly visible on eBay). Even though the idea was for it to be used on medium format, it seems most lenses were supplied with mounts for the usual 35 mm suspects (M42 and Exakta).
Based on serial numbers, all the manufactured samples originate from a single batch, so it’s safe to say that this was deemed a less than entirey successful foray.

Version 3: Fluted body form (narrowest at mount, broadest at filter thread), narrow zebra pattern, 52 mm filter ring, name on outside of lens (ca 1960-1964)

The third version of the Enna 240/4.5 lens.
It uses a 5 elements in 3 groups design¹⁰, and was offered in M42, Exakta and Enna Sockel (v2) mounts. In terms of shape this clearly the successor of version 1 (shape and dimensions are very similar).

Most lenses supplied for Exakta and M42 mounts are preset lenses, but unlike with version 1, some samples were produced featuring all the arrangements necessary to facilitate fully-automatic aperture on compatible bodies.

Version 3b: Fluted body form (narrowest at mount, broadest at filter thread), ribbed control rings, 52 mm filter ring, name on outside of lens (ca 1964)

The fourth (largely undocumented) version of the Enna 240 mm lens. The body form, ergonomics and barrel design seems identical to version 3, but the focus ring and aperture ring’s zebra patterns have been exchanged for a tight lengthwise ribbing. Was offered in at least M42 and Exakta mount as preset lenses, but based on very few samples more details cannot ve offered.

This is the last ersion of the 240/4.5 to proudly display its serial number.

Version 4: Tubular, svelte body form, ribbed control rings, 52 mm filter thread, name on outside of lens, body largely made of plastic (1964->)

The first modern body construction of the 240/4.5 Enna. All-black featuring the use of plastics for both aperture and focus rings (as well as other parts of the outer barrel.

Besides the extensive use of plastics, this lens differed from the previous versions in another important way: First, it ditched the 5 elements in 3 groups design for an even more compact 5 elements in 4 groups design.

Based on the samples I’ve seen I can state another few things:
– I have not seen a version with the Exakta mount. Given that I’ve only seen ca 20 samples this is no guarantee that it was never made in the Exakta mount, but is is a strong indicator of that the Exakta system’s star was waning. On the other hand, there seems to have been a custom batch manufactured sporting a T-mount.
– In contrast to all previous versions, the relative share of auto aperture equipped lenses rises to be the majority approach for the first time.
– All the samples I’ve seen have optics in a dismal state. It seems as if the coating used by Enna during this era was especially soft and liable to get ‘cleaning marks’ or then they were all used to photograph sandblasting world championships.

Version 5: Tubular, svelte body form, control rings with very fine pyramid texture, 52 mm filter thread, name on outside of lens, body largely made of plastic (likely 1970s ->) (pictured lens)

All characteristics (except for the control ring pattern) as above.

Version 6: A black swan. Tubular, svelte body form, rubberised control rings with coarse rectangular pattern, 52 mm filter thread, multicoated, name on outside of lens, body largely made of plastic (late 1970s)

This is an odd duck in three respects. First I have only ever encountered one sample¹¹, and it looks quite different from any other Enna lens. Second, unlike all the other 240/4.5 lenses, this lens is multicoated. Third, it features a Rollei QBM mount. Anyone who wants to shed more light on this lens should feel welcomed to do so.

History of ENNA München

ENNA München (also: Enna Werk München) is one of the 1950s and 60s most prominent and innovative German optics companies. ENNA is especially well-known for being the West-German pioneer in developing retrofocus wide-angle lenses (such as the Lithagon here).

You can read more details in the ENNA München company profile.

Adapting the ENNA München Tele-Ennalyt 240 mm f/4.5

Obviously, a crucial question is which mount your copy of the Tele-Ennalyt has. Once you have determined that, see below:

Adapting Enna Sockel Lenses

The Enna Sockel is not strictly speaking a lens mount, but is instead an intermediate mount. This means that if you have managed to procure an Enna Sockel mount lens without the Enna Sockel adapter, your best bet is to head to your preferred online classified’s or marketplace and procure an Enna Sockel to whatever lens mount you already have an adapter for (Personally I think the Sockel-to-M42 adapter is most tempting, but it also usually the most expensive).

Adapting Exakta mount lenses

Exakta mount lenses cannot be used natively on any current SLR or dSLRs. To use it in its native environment, you will need an Exakta-mount film body. Exakta bodies were manufactured in large numbers, but many of them are no longer in a good shape. That said, procuring a workable sample should not be impossible or especially expensive.

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

Using Exakta 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 Exakta lenses perfectly using a simple adapter ring.
• Nikon F, Pentax K and Minolta / Sony A dSLRs need an adapter that uses corrective optics for Exakta lenses (the difference in flange focal distances is not enough to enable reaching infinity focus without corrective optics).

Adapting LTM mount lenses

This chapter will discuss adapting the Leica Thread mount version of the ENNA 135/3.5.

To use this lens natively, you will need a Leica thread mount film body. This means either a Leica body from before the 1954 introduction of the Leica M-mount, a Soviet Leica (Zorki or FED) or one of the more modern Japanese LTM rangefinders. You can also use this lens on any Leica M mount body using the LTM-Leica M adapter ring.

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, LTM lenses are so uncomplicated that a simple ‘dumb adapter’ will do the job perfectly. However, due to LTM mount’s relatively short flange focal distance, special adapters (helicoid adapters, tilt/shift adapters, speed boosters) are not an option.

Due to the short flange focal distance used by LTM cameras, there is no meaningful way to adapt this lens to any SLR or dSLR.

Adapting M42 mount lenses

If you want to natively mount an M42 lens you need to find a functioning M42 mount film camera. Luckily that should be relatively easy as M42 bodies were produced in their millions and most of them lack features that are especially likely to have deteriorated to the point of making the entire camera inoperable. If your sample of the ENNA München Lithagon offers a switch to choose between auto- and manual aperture, I recommend using the lens on a body that is capable of stopping down the lens automatically and offers stop-down metering.

Adapting this lens to a mirrorless, full-frame digital camera is a breeze thanks to the lens having full manual controls (aperture ring, focus ring). You simply need a dumb adapter from M42 to your mirrorless system.

Due to the medium flange focal distance used by the M42 mount (45,46 mm), whether you can adapt this lens to dSLR/SLR mounts depends on which dSLR mount: Canon EF, Four Thirds, Minolta/Sony A and Pentax K can mount m42 lenses using a simple adapter ring. Nikon F on the other hand is not as problem-free, and – to retain anything near infinity focus – the adapter will necessitate corrective optics. In all cases, your camera will work only in stop-down metering.

Footnotes