After the close of World War II both German and Japanese lens manufacturers began using a single MgFl (Magnesium Fluoride) coating on lens surfaces. This coating greatly increased light transmission through the glass elements resulting in lowered reflections within the lenses. One major benefit was reduced flair due to bright lights either within or outside the frame. But even with coated lenses, flair could spoil a picture, if the light source was bright enough. There was no solution (at that time) for in in-frame flair, but blocking non-imaging sources of light could add contrast under certain lighting conditions. For this reason (blocking stray light from outside the imaging area) most lens manufacturers provided lens hoods for all the lenses they sold.

Topcon was no exception; almost every Topcor lens they offered either had a built-in hood or a separate one that could mount to the front of the lens. Of course the angle of coverage necessary varied with the focal length of the lens, so, for maximum benefit the hoods were designed to match a particular lens. The wrong hood--or one of the generic type sold by third parties-- could  result in either a vignetted image or susceptibility to flair. For this reason Topcon provided a unique hood for each lens. All of the Topcon hoods were well made, all from machined metal (the GN lens hood excepted), and all had the inside of the cylinder threaded with a fine pitch and painted in flat black to eliminate specular reflections inside the hood.

The following images show the complete family of the Topcon hoods offered with lens sold for use with the RE Super/Super D camera.

The two 300 mm focal length lenses of this series (the F/5.6 and the F/2.8) incorporated telescoping hoods. The image above shows the hoods supplied for the others.

Left to Right

9 cm F/3.5 and         The same hood was provided for attachment to either of these lenses. The means for attachment
13.5 cm F/3.5           of this hood was unique, and quite different from the screw-in or bayonet mounts of other hoods. For this lens, two thin tangs, inside the rear-end of the hood, engaged a thin groove machined into the outside of the lens barrel near front end. Pressing two chrome buttons at the base of the hood caused the tangs to be retracted for mounting, or un-mounting, the hood. This is not a satisfactory method since the tangs are on opposite sides of the base and the hood tends to droop. Also, the attachment is not secure.

13.5 cm F/2              A large hood for an already large lens. It is mounted by screwing it into the 77 mm lens filter ring. The stepped construction is probably not necessary from a purely flair-reduction point of view. However, the step does allow the hood to be reversed and mounted to the lens for storage.

20 cm F/4                This hood screws into the lens 62 mm filter ring and is typical of lens hoods of the era in which it was designed.

All the RE Auto Topcors with focal lengths of 135 mm or longer had built-in, telescoping lens hoods. Separate, individual hoods were provided for the eight lenses between 20 mm and 100 mm. With the exception of the two widest angle lenses (20 mm and 25 mm) they were all similar: cylindrical with black barrels and a bright chrome base. These six hoods were attached to the lens with a three-tang bayonet mount and could be reversed for storage when not in use. The filter ring for the lenses 28 mm through 100 mm had three machined tangs facing out where the mount on the hood could  engage them. The hoods for the two super wide angle lenses clamped onto the outside of the forward end of the lens barrel and required the rectangular opening at the front to be aligned with the camera body.

The eight hoods for the RE Auto Topcor lenses are shown above. The following list identifies, and describes each:

Front Row (left to right)
20 mm F/4         Almost identical with the one for the 25 mm lens. However the front rectangular opening is larger and has squarer corners. A green dot on the hood faces up when the alignment is correct. This hood is also a holder for a series IX filter. The lens itself accepts 62 mm screw-in filters. (I have never tried mounting both a filter and hood.)
25 mm F/3.5     No alignment aid on this hood. Also no filter threads on the lens for a screw-in filter. For filters other than the 10 rear-mount type, a series IX filter must be used.
28 mm F/2.8     Basically the same hood as the one for the 58 mm F/1.8 lens, just shorter.
35 mm F/2.8     The only conical hood in this group.

Back Row (left to right)
58 mm F/1.8
58 mm F/1.4
85 mm F/1.8    Near identical with the one for the 58 mm F/1.4 lens except the barrel is longer.
100 mm F/2.8  Near identical with the one for the 58 mm F/1.8 lens, except the barrel is longer.

The early RE Auto hoods were a carryover from the previous series of Topcors, the F Autos. For these, the base of the hood is a single machined piece with the retaining springs fabricated by sawing (with a jeweler's saw, I assume) first vertically, then around the circumference, leaving a flat piece of metal attached to the base at one end. The free end was bent for contact with the bayonet tang on the lens. Three such saw cuts were made, one for each bayonet tang. The upper image at the left shows this type of base.

The later configuration for the hood bases were assembled from several parts with a flat phosphor-bronze spring attached between the two base parts. Spacers were added to allow room for the lens tang. This later configuration is shown in the lower image.

I suspect this change in manufacturing was made to reduce fabrication time, since the sawing operation must have been labor intensive.

From the images it is a little difficult to see the exact detail of the difference. Suffice to say that if a hood shows a cut on each of the inward-facing bayonet attachment segments, then it is of the older type.

Hoods for the GN Lenses

Since both the F/1.4 and F.1.8 GN lenses were of the same diameter, only a single hood was offered and could be attached to either lens. This barrel of this hood is the same as that for the RE Auto Topcor 58 mm F/1.4 lens, but the base is of a new design. Instead of a base made of metal, with a shinny chrome surface, the one for the GN lenses is made of a single-piece, black, molded plastic. The plastic material seems to be the same as that used for the lens caps. While this plastic base seems to work as well as those made of metal, they certainly loose the elegance of the earlier ones.

A Hood for the Short-mount Macro Topcor, 135 mm F/4 Lens

In some material supplied by Tokyo Optical, a hood for the 135 mm short-mount macro lens is shown. I have reason to believe that a hood, specific for this lens, was never made. Rather, it seems, the hood for the RE Auto 100 mm lens was to be used for this purpose. Shown at the left is the combination of this lens and hood.