[TwoUptons]

I just picked up a Super-Takumar 55mm f2.0... it is version 1 of the Super-Tak described here, with the fine ribs and backwards aperture ring:
SMC/Super-/Auto-Takumar 55mm F2 Reviews - M42 Screwmount Normal Primes - Pentax Lens Reviews & Lens Database

The weird thing is that it has an extra click past f2.0... and the aperture actually moves when I do that, so the aperture is actually wide open at this unlabeled click past f2
The lens is labeled as a F2, and it sure looks like a f2... which also apparently looks just like a f1.8 apart from the labeling...

I want to say I've heard that the f2 is just the f1.8 with a baffle in the optical path, but that doesn't seem to be the case here, since I can see the aperture blades close down.
And I can't see a catalog number anywhere on it like I've seen on some lenses (I think that came later).

Is this just a case of Pentax being lazy?
"Well, you can buy this S1a with a 1/500 shutter speed and the 50mm f2.0 lens, but really it will still shoot at 1/1000 and f1.8, we just didn't want to change the hardware..."

-Eric

[Argos]

I just picked up a Super-Takumar 55mm f2.0... it is version 1 of the Super-Tak described here, with the fine ribs and backwards aperture ring:
SMC/Super-/Auto-Takumar 55mm F2 Reviews - M42 Screwmount Normal Primes - Pentax Lens Reviews & Lens Database

The weird thing is that it has an extra click past f2.0... and the aperture actually moves when I do that, so the aperture is actually wide open at this unlabeled click past f2
The lens is labeled as a F2, and it sure looks like a f2... which also apparently looks just like a f1.8 apart from the labeling...

I want to say I've heard that the f2 is just the f1.8 with a baffle in the optical path, but that doesn't seem to be the case here, since I can see the aperture blades close down.
And I can't see a catalog number anywhere on it like I've seen on some lenses (I think that came later).

Is this just a case of Pentax being lazy?
"Well, you can buy this S1a with a 1/500 shutter speed and the 50mm f2.0 lens, but really it will still shoot at 1/1000 and f1.8, we just didn't want to change the hardware..."

-Eric

Your lens basically is a 1.8/55 with a built-in limiter ring.

[MarkJerling]

Now, that's interesting Eric! I think I have one of those, much check mine! (Unless, of course, mine's a later one.)

[TwoUptons]

So here's a really bad iPhone shot of the lens set at f2. You can see the aperture blades just inside the ring.



I did notice it is a vastly earlier serial number than the one Argos posted...

I guess I need to see what the photos look like... though it's not the cleanest lens I've ever seen, it is close to 60 years old...

-Eric

[Argos]

So here's a really bad iPhone shot of the lens set at f2. You can see the aperture blades just inside the ring.



I did notice it is a vastly earlier serial number than the one Argos posted...

I guess I need to see what the photos look like... though it's not the cleanest lens I've ever seen, it is close to 60 years old...

-Eric

The Super-Takumar 1:2/55 mm [Model I] was produced between 1962 - 1965, but only the first series had the counter clock-wise rotating aperture ring. I think your lens shows traces of wear and/or play in the aperture mechanism. The aperture blades should not be visible at f/2. Later series have a clock-wise rotating aperture ring that does not move beyond f/2. The aperture ring has ribbings in both cases. I have written a book that deals with things like this.

[TwoUptons]

The Super-Takumar 1:2/55 mm [Model I] was produced between 1962 - 1965, but only the first series had the counter clock-wise rotating aperture ring. I think your lens shows traces of wear and/or play in the aperture mechanism. The aperture blades should not be visible at f/2. Later series have a clock-wise rotating aperture ring that does not move beyond f/2. The aperture ring has ribbings in both cases. I have written a book that deals with things like this.

Maybe that's all it is... more play over the intervening 60 years...

But the fact it clicks into place below f2 is the part that made me think it's weird... is it the same mechanism as the f1.8 just without the label (and with the limiter)?

And that's obviously something that changed over the intervening years, so maybe this is just one of those weird early-series things that was fixed later...

-Eric

[Argos]

Maybe that's all it is... more play over the intervening 60 years...

But the fact it clicks into place below f2 is the part that made me think it's weird... is it the same mechanism as the f1.8 just without the label (and with the limiter)?

And that's obviously something that changed over the intervening years, so maybe this is just one of those weird early-series things that was fixed later...

-Eric

Yes, the f/1.8 and the f/2 are virtually identical. The only difference is the limiter ring. This must have been a commercial decision to sell the f/1.8 at a higher price, although the f/2 may have been more expensive tot produce.

[TwoUptons]

Yes, the f/1.8 and the f/2 are virtually identical. The only difference is the limiter ring. This must have been a commercial decision to sell the f/1.8 at a higher price, although the f/2 may have been more expensive tot produce.

So it really is the perfect lens for the H1a

-Eric

[wkraus]

I have written a book that deals with things like this.

I wanted to ask for a reference but looking at your other posts made it clear that this is the famous Gerjan speaking… The book is highly recommended!

[Argos]

I wanted to ask for a reference but looking at your other posts made it clear that this is the famous Gerjan speaking… The book is highly recommended!

Correct, it's me, Gerjan van Oosten, as you can see in my profile.

[TwoUptons]

Well, whatever aperture it is, it seems to work just fine



Though this obviously is not a test wide open...

-Eric

[Argos]

Well, whatever aperture it is, it seems to work just fine



Though this obviously is not a test wide open...

-Eric

Looking good!

[wkraus]

Well, whatever aperture it is, it seems to work just fine

Though this obviously is not a test wide open...

-Eric

It is definitely not cheepnis inside. I tested my two copies of the Super-Takumar 1:1.8/55 (S/N 1211… and 3486…) and the 1:2/55 (S/N 4885…) and the latter was the best performing.