On discussion forums and online auctions one can regularly see Hexanon lenses being referred to as 'EE version' or 'AE version'. The use of such an expression is a misunderstanding, however, and is entirely unwarranted. In some of Konica's lens brochures of the mid-1970s, the following notice can be found:

'The EE marking on the aperture ring of earlier lenses is being gradually supplanted by the AE indication. However, the performance, functions, and application methods are completely unchanged between EE and AE. EE-indicated items in the pictures and texts of camera and lens operating instructions should be interpreted as synonymous with those referred to as AE, which stands for Fully Automatic Exposure Control.'

In fact, 'EE' and 'AE' are both abbreviations used to describe a setting on the aperture ring of all automatic Hexanon lenses: 'EE' stands for 'Electric Eye' (initially in reference to the Cds cell placed on the speed selector dial of the Auto-Reflex), while 'AE' stands for 'Automatic Exposure'. The automatic exposure operation that is engaged when one turns the aperture ring to this setting is the same irrespective of whether that setting is called 'EE' or 'AE'. Sometime in 1972, Konica felt that 'Electric Eye' sounded a bit passé and changed it to 'Automatic Exposure'. It is something the company seems to have done solely for marketing purposes and it is entirely unrelated to a given lens' technical features, operation or version. Its relation to a given lens' appearance is also purely incidental.

For example, the most common early Hexanon standard lens, the 52/f1.8, exists in three versions – high-gloss finish with aluminum ring (A-type), satin black finish with aluminum ring (B-type), and entirely black with a satin finish (C-type). Yet 'EE' markings are common to all three. Even though 'EE' markings accompanied by a little dot often appear on the first version of this lens, and the very earliest of those have only the dot (see below), one hears little of a 'dot EE' version, and even less of a 'dot' version.

The situation is identical with the 'AE' markings. All automatic Hexanons produced after 1972-74 have 'AE' markings on their aperture ring. For example, the Hexanon 50/f1.4 standard lens exists in a larger version made from 1973 to 1978 and a compact version made from 1978 to 1984. Both have 'AE' markings. Same thing for the Hexanon 24/f2.8, which was in production from 1973 and was replaced in 1980 by a highly compact version with an entirely different optical formula, both of which have the same 'AE' markings. Moreover, there is a number of lenses, all made in the spring and summer of 1973, with either 'EE' or 'AE' markings, such as the first versions of the 24/f2.8, 50/f1.4, 50/f1.7, and a few others.

In some quarters, it is also believed that the 'EE' and 'AE' markings on Hexanon lenses correspond to different coatings – that 'EE' lenses having Konica's earlier amber/straw colored coatings, and 'AE' lenses having Konica's later blue 'Color Dynamic Coating'. As generally Konica's earlier AR lenses are marked 'EE' and its later ones 'AE', this is true, but only incidentally and only for some lenses. Given that the very last 'EE' lenses were made in early 1975 and that Konica seems to have introduced its 'Color Dynamic Coating' technology perhaps as early as 1967, there is a great number of 'EE'-marked lenses in circulation - like the 28/f3.5, 35/f2.8, 52/f1.8, 57/f1.4 - which have Konica's later coatings. There are even Hexanon lenses marked 'EE' that appear with only the later coatings, like the 35/f2 and all the hybrid lenses. The change from 'EE' to 'AE' thus doesn't coincide with any change of optical design, internal mechanism, lens coating or outward appearance. 

The switch didn't take place overnight. My database of ~12,000 lenses shows that the last lenses with the 'EE' markings were made in early 1975, while the first with the 'AE' markings were introduced in early 1972. Over the years, the automatic exposure markings on Hexanon lenses evolved as follows:

1. The automatic exposure marking on the very first batches of the first Hexanon lens version (A-type, high-gloss black finish with aluminum ring – 1965-66) is a little dark orange dot (    •  . ). Lenses with such a dot are quite rare because a few months after production began, the letters 'EE' were added  (   • EE . ). These latter markings would remain unchanged on all A-type lenses and, like all inscriptions on the barrel of lenses of that version, it is written in very thin characters.

2. The automatic exposure markings on lenses of the second Hexanon lens version (B-type, satin finish with an aluminum ring – 1967-70) and the third Hexanon lens version (C-type, entirely black barrel with a satin finish – 1970-74) are indicated by the letters 'EE', without a dot. On the vast majority of B and C-type lenses the "EE" markings are of a noticeably lighter color than the 'EE' letters on A-type lenses ( .  EE  . ), but occasionally one can encounter lenses with darker orange markings (    EE  . ), or even bright yellow ones (    EE  . ), notably on the hybrid lenses (those with both an aluminum ring and a rubber covered focusing ring). The last Hexanon lenses with these markings were made in early 1975.

3. The green 'EE' markings (    EE    ) appear on a small number of lenses of the fourth Hexanon lens version (D-type, lenses with a rubber focusing ring – 1973-88), whose production began a few months before the 'EE' markings began to be phased out altogether. They are the 24/2.8, 28,3.5, 50/1.4, 50/1.7, 57/1.2 and 135/2.5. Four of those lenses didn't exist prior to 1973 and any of them that have the green 'EE' markings were manufactured in the spring and summer of 1973, so they are not very common.

4. The green 'AE' markings ( .  AE  . ) first appeared in early 1972 and were used on all automatic lenses of the fourth Hexanon lens version (D-type, lenses with a rubber focusing ring – 1973-88) with the exception of the Hybrid lenses and those mentioned in point 3. above, and on all lenses of the fifth and last Hexanon lens version (E-type, compact lenses – 1976-88). 

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