[mde1970]

I've just hit the button and purchased a Auto Takumar lens. I assumed it functioned the same as my super takumar 55mm but just noticed it's listed as having a semi - auto diaphragm. I'm now uncertain if the operation of this will be different to my super takumar lens?? (I'll be using this on mirrorless so any advice much apprechiated)???

Mark

[Just1MoreDave]

It depends. Some Auto-Takumar lenses are functionally the same as Super-Takumars, with an Auto-Man switch on the base of the lens. I have a couple of 55/1.8s like that. Other Auto-Takumars have a cocking lever on the base. If I remember this correctly, it was supposed to work like this: set an aperture using the aperture ring on the lens. The blades move to that position so the camera can meter. Then cock the lever and the blades are held wide open for focusing. When the shutter fired, the camera pushed in the chrome pin on the back of the lens, releasing the aperture blades to their chosen position. You should be able to move the blades with the aperture ring with either type. With the Auto-Man switch, you can quickly go from wide open to the aperture ring setting,so the lever is less useful.

[dsmithhfx]

I've just hit the button and purchased a Auto Takumar lens. I assumed it functioned the same as my super takumar 55mm but just noticed it's listed as having a semi - auto diaphragm. I'm now uncertain if the operation of this will be different to my super takumar lens?? (I'll be using this on mirrorless so any advice much apprechiated)???

Mark

According to this Early Pentax Takumar Lenses

1958 Asahi Optical launched their new top model Pentax K - here the rare black version. Basically the same cameras as the Original Pentax but the first Pentax (and one of the first SLRs ever) with Semi-Automatic diaphragm mechanism which can be used with special, marked "Auto-Takumar" lenses.
Lenses can be cocked with a lever without looking at it, in this manner open to full aperture before focussing (if the photograph decides to do so).When the trigger is pushed halfway by the photograph, a lever inside the lens mounting closes the diaphragm to the preselect value through a small pin. The photograph then can do a last depth-of-field check. Fully pushing the trigger actuates both mirror and shutter. After firing, lens remains closed at preselect aperture until it's cocked again. Despite the name Auto- this is what we now call semi-automatic diaphragm

You didn't say which lens you just bought (but presumably not another 55), if it was an 85/1.8, you may be in luck:

At least two lenses had despite of its name fully automatic diaphragm mechanisms: the Auto-Takumar 55mm f/1.8 in black (1960-1962) and the the 85mm f/1.8 (1960-1962 and black as well).

[mde1970]

Thanks Dave. So it sounds like there will be no real downside to having an auto as oppose to super takumar?

[Just1MoreDave]

The 55/1.8 without the lever, 135/3.5 with the lever on the left:

[mde1970]

Yes the 85mm Auto Takumar 1.8

According to this Early Pentax Takumar Lenses

You didn't say which lens you just bought (but presumably not another 55), if it was an 85/1.8, you may be in luck:

[stevebrot]

Yes the 85mm Auto Takumar 1.8

Ka...CHING!!!


Steve

[sergysergy]

The 55/1.8 without the lever, 135/3.5 with the lever on the left:

I might be wrong and this might be irrelevant but I think the Auto Takumar in the 1st picture does have a lever (being an early super takumar with the name of its antecessor)

[mde1970]

so reading the link above it sounds like the 85mm has a fully automatic diaphragm. However from the pictures of the lens its unclear to me. There is a Button at the base so I assume this is either the button to cock the semi automatic diaphragm or possibly the Auto/Manual switch (as I have a similar switch on my Super Takumar 55mm).

Picture attached just in case anyone has the Auto Version and can clear this up for me :-)

[noblepa]

In general, the Auto-Takumars did not reopen the aperture after the exposure. That is what the cocking lever was for. You had to cock the lens, as well as the shutter, before each shot. Some of the last lenses to be labelled Auto-Takumar did, in fact, have the auto-reopening apertures.

You can easily tell which yours is by simply selecting the smallest aperture and pushing the stop-down pin. When you let go of the pin, does the aperture reopen?

The other difference between an Auto-Takumar and a Super-Takumar is the lens coatings. Lens coatings got progressively better over the years. Again, there are exceptions, but, in general, the coatings on a Super Tak are better than on the Auto Tak. Likewise, the later Super-Multi-Coated Takumars are better still.