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Mystery Lens - The Canon 50mm 1.4 ltm “Type Ia” (with 8 elements)

The mysterious 8 element 50mm 1.4 ltm tick mark lens...?
Cross Section of the alleged 8 element lens is taken from CANON Eye Vol.1 No.2 by Canon Historical Society *3

The Canon 50mm 1.4 ltm lens has been widely regarded for its excellent image quality.
It is also assumed that two variations of this lens exist: a "type I" and a "type II" lens.

Mr. Kitchingman’s book “Canon M39 Lenses 1939-1971” *1 describes two lens types and one possible "type III" lens (though none of the latter was recorded at the date of printing). The differences between the types appear to be limited to their engraving.

While the Canon Museum Internet Site *2 also describes two types, their images – further below – show some dissimilarities in the technical construction. They also highlight differences in size and price (25000¥ in 1957 / 18500¥ in 1959).

All the information from Mr. Kitchingman’s book and the Canon Museum at one glimpse

On 23.07.2021 Mr. Kitchingman published some very interesting scans from the Canon Eye Vol 1 No 2. on Canon Historical Society *3, where one particular information caught my eye. In the section “The Canon System Of Photography Part II - Lenses for 35mm Still Cameras”, Saburo Kazami describes a small batch of an 8 element lens (1959), adding a cross section of the lens.

On 29.07.2021, again on Canon Historical Society, Mr. Bielecki published a scan from Randol Hooper’s “The other 35 – Canon SM Lenses Part IV: The 50mm Focal Lenght”, describing a "Type I" lens incorporating 8 element lens, in four groups. The attached cross section looks exactly the same of the Canon Eye Publication, while stating it was marketed in 1957, instead of 1959.

Research

10 aperture blades and no screws on the flange

At this point, I was definitely intrigued and therefore gathered and compared all the available info, including my own sample of the lens in question (a very early SN 1004X). It is engraved with: “CANON LENS 50mm f:1.4 Canon Camera Co. Japan No. 1004x”.

Here are the results

A merged image from different sources *2 / *3 My own lens (SN 1004X) looks exactly like the "Type I" lens from the Canon Museum and matches the quite exactely deducted size parameters from the cross section in the CANON Eye Vol.1 No.2 publication *3.

Conclusion and revised typology

So, quite a bit of mismatched info here.

To keep things clear, let’s propose a revised typology and therefore call my own lens (SN 1004X) a “type Ia” one and the lens assumed to be "type I" (e.g. by Mr. Kitchingman *1) with the distance markings engraved in meters OR feet would then be called “type Ib”.
And following the literature, there are the "type II" and "type III" lenses which are marked in meters AND feet. Those Types would remain unchanged in the revised typology.

Opposed to the very slight differences (only engravings) between the "type Ib" and the "type II" lenses, the ones between the “type Ia” and “type Ib” appear to be quite substantial. The machanical construction is completely different and possibly also the optical construction.

Optically there is a fair chance that the "type Ia" lens might incorporate 8 elements, but of course without dissembling it, it can not be said for sure. And if so, the "type Ib" would be the 6 element one.

NEW INFORMATION by 23.08.2021:
In the meanwhile I asked Mr. Cavina *4, if he had any knowledge on patents for Canon 50mm f1.4 ltm with 8 elements, which he denid.

NEW INFORMATION by 03.09.2021:
I am now quite positive about the 8 element hypothesis, because I count 12 internal reflextions, which would fit the number reflexions expected (refer to the lens cross section above). The "type Ib", "type II" and "type III" should show only 10 internal reflextions.

“Type Ia”

There are tick marks on the aperture ring
The lens has 10 - not 9 - aperture blades
The number of lens elements (8 or 6) remains unanswered for now
The lens barrel elongates between the focussing ring and the lens attachment ring
The attachment ring is narrower than on the other types
The ring in front of the focus ring (towards the aperture ring) continues in black - not chrome
The distance scale is in meters OR in feet
The distance scale shows “50 25 … 3.5 ft.” like earlier lenses (e.g. Canon 35mm 1.8 1957 or Canon 50mm 1.2 1956) Afterwards the distance scale showed 60-30 … 3.5ft or 20 10 … 1m. *2
The length from the flange is 39.1mm - not 41.7mm
The length overall is 47mm - not 49mm
On the flange there are no screws and the rangefinder coupling system is RTH (Rotating Threaded Helicoid)
The weight is 215g without caps - not 243/246g

The Canon 50mm 1.4 ltm "type Ia" with recessed barrel (infinity position)

The Canon 50mm 1.4 ltm "type Ia" with elongated barrel BEHIND the focus ring

Rarity

This “type Ia” is definitely a quite rare lens, possibly very rare. Assumingly less than 1000 lenses have been produced since the lowest serial number that I found, corresponding to a “type Ib” lens, is the SN 11043 (1043 lens produced).

The batch might be even smaller...

When was it produced, in 1957 or 1959?

Several information indicates that it was produced before 1959.

First, according to the pictures on Canon Museum site, Canon engraved tick marks on the aperture ring before end of 1958/beginning 1959.
Last standard/wide WITH tick marks: Canon 50mm 2.8 "type III" (February 1959)
First standard/wide lens WHITHOUT tick marks: Canon 50mm 1.8 "type III" (December 1958)

Second, Mr. Kitchingman’s book, referring to a “1968 Canon interchangeable lenses brochure”, reports that a new, non revolving rangefinder coupling system (SDDH) was introduced in February 1959.

Finally, while researching Ebay pictures, I found out that standard/wide lenses - introduced in late 1958 and afterwards - elongate IN FRONT of the focus ring, when focusing. Lenses marketed before, elongate BEHIND instead.

Likewise, the distance markings were changed over time, from 50 25 ... 3.5 ft to 60 30 ... 3.5 ft.
Furthermore the number of aperture blades were gradually reduced in most of Canon lenses.

This data definitely suggests that the “type Ia” lens was put on the market before 1959, and maybe so in 1957.

Rangefinder Coupling System (RTH) in front of a gorgious Canon L1

“Type Ib”

There are no tick marks on the aperture ring
The lens barrel elongates between the focussing ring and the aperture ring
The attachment ring seams to be larger than in the “type Ia” lens
The ring in front of the focussing ring (towards the aperture ring) does not continues in black - but in chrome
The distance scale should be in meters OR in feet, only
The distance scale should show 60 30 … 3.5 ft. OR 20 10 … 1m
The length from flange should be 41.7mm
The length overall should be 49mm
On the flange there are two screws and the rangefinder coupling system is SDDH (Strait Drive Double Helicoid)
It should weight in between of 243 to 246g without caps

The lowest known serial number of “type Ib” lens that I could find evidence of, is SN 11043. According to Mr. Kitchingman the transition to the “type II” lens took place around the SN 30000.

For information on the "type II" and "type III" lenses - please consult the " Canon M39 Lenses 1939-1971" book.

Outlook and open questions

Assessing how many “type Ia” lenses were actually produced, would require owners of Canon 50mm 1.4 lenses with serial numbers from 10000 till 11000 to check if their samples are a “type Ia” or “type Ib”.

Please feel free to send pictures and information to: contact ((at)) lightintuition.com.

To find final evidence if the “type Ia” lens incorporates 6 or 8 elements, it will be necessary to open and dissemble it.

And that was it...

2021.08.08 © l.i.

Sources and remarks

*1: Canon M39 Lenses 1939-1971; Peter Kitchingman; Publisher Peter Kitchingman, 1. Ed. 2008
*2: Canon Museum on S Lenses: https://global.canon/en/c-museum/series_search.html?t=lens&s=s
*3: Canon Historical Society: https://www.facebook.com/groups/443468112473918/
*4: Marco Cavina: www.marcocavina.com / https://www.nocsensei.com/author/marcocavina/

Thanks

A special thanks to Mr. Kitchingman, whose book is such a beautiful and well designed information-mine on this topic and also to Mr. Cavina's kind help and otherwise immense ressources on photographica in general.

Many thanks also to all the above mentioned people, website owners and users for sharing information.