Which Pentax M42 200mm F4 this one based on my description...?

[maiku]

Hi,

 

Today, while shopping at a recyle shop I came across a Pentax M42 Takumar 200mm f4 lens. The unusal thing is that

the apreture rings are not based near the screw mount, but at the opposite end at the front element lens. There

are 2 apreture rings. Both function properly. I assume one apreture ring is for manual operation and the other

for auto metering.

 

I am curious about the lens. It does not look or feel like any other Pentax M42 lens I have come across before.

It is quite heavy. The front element is double size of any M42 lens (i.e. 28mm, 50mm, 55mm or 135mm) I have come

before. I think is might be a bargain at 50$ USD, but I do not know as I have not been able to garther info

searching the net.

 

Any and all help will be greatly appreicated.

 

Mike

[les_lammers]

There was an off brand spelled Takamur or some thing similar. Make sure what you are looking at really is a Pentax lens.

[johan_van_t_leven1]

Takumar is (was) the name of all Pentax lenses (not an off brand!). When you're talking about 2 aperture rings this means that you're dealing with a manual stop down aperture. It was used to set the aperture manually and quick. There's one ring with click stops and one without.

You can meter the light with the lens stopped down and focus wide open. For taking a picture you have to turn one ring to the other to stop down to the used aperture.

So it's an old lens, but very usable when you have the time (and it's not Multi Coated).

[miserere_mei]

I never knew Pentax manufactured these type of lenses, with the manual aperture rings... Any chance it's a Russian lens?

[davidimage]

This seems to be the only one close? the super-takumar and the super-multi-coated takumar both had aperture rings at the back. But it's a 3.5? Maybe the front face plate has been sneakily replaced...

 

http://whitemetal.com/pentax/t_200_35/index.htm

[maiku]

David,

 

Thank you for the link. The photo of the lens is in fact the one I came across. I guess I did not read the apretrue ring correctly. The f-stop number must be 3.5. Why? Because the lens body in every other respect is the same. No wonder I could find any info on the net.

 

Why did I miss the f-stop? I guess I was excitied about looking at all the other M42 mounts (55mm/50mm/135mm) and K-mounts they had. I guess someone cleaned out there closet and sold them off.

 

Thanks. Now I can read some reviews.

[maiku]

Sorry, for the poor spelling everyone. Ugh! Proofread, proofread, proofread. Not there, but their... and not `No wonder I could find any info on the net,`, but `No wonder I could NOT find any info on the net.` UGH!

 

It is a good thing I teach English mostly to Japanese elementary school kids.

 

Mike

[will_daniel1]

Michael,

 

The reason the lens is so large is because it was designed by humans instead of a computer. In the 1970s, Asahi turned a computer loose on optical formulas (formulae?) and the result was compact lenses of equal or superior quality.

 

Will

[will_daniel1]

And another thing... I bet if you measure that lens, it is almost exactly 200 mm from the front element to the rear element. That is how lenses got their designation in the "old days." The actual length was the focal length. I am no scientist or physicist, but here is how the modern, compact design was explained to me: Before computer design, it was known that refracting rays of light must intersect at various points in the optical formula. When computers took over the design, an amazing discovery came about -- those intersect points do not have to be INSIDE the lens. The computer was able to construct a formula in which light rays intersected at points OUTSIDE the lens, and hence the compact design that we see today. Repeating -- I don't have firsthand knowledge of this; it's the way it was explained to me 30-some years ago by Pentax tech reps when I worked for the company.

 

Will