Kuribayashi 35mm f3.5 Lens

[colinbm]

Is there a diagram of the optical design of the Kuribayashi 35mm f3.5 Lens Please ?

Cheers

Col

[Cadmium]

Colin, I drew this once, but I am sure there is something better out there.

I think the second element is actually two elements together...?...not sure. I think there are 5 elements in total.

[colinbm]

Thanks Steve

This is a start, as I haven't found anything......

I'll hope for better....:-)

Cheers

Col

[Cadmium]

Alex would probably know, send him a PM.

[Andrea B.]

I was just going to suggest that very thing!

 

I'm also curious as to whether there is some kind of universal design which produces f/3.5 speed lenses?

[Cadmium]

The Kuri/Kyoei is 5 elements in 4 groups. None are glued. A good copy will permit you to take the entire lens apart and get to each element pretty easy, but I have a couple copies that are stuck, and I have not tried too hard to take those apart. I don't think any tools are needed to take the elements out, they just screw apart with your hands, except for the rear element, you need a pair of sizzlers or a caliper to remove that rear retention ring.

 

[colinbm]

Thanks Steve

It is the rear elements that I am most concerned about at present.

I have used your photo & added some comment....

The rear elements 1 go into rear element holder 2 that screws into rear of lens 3.

The question is....how many rear elements are there ?

& what is the order of their arrangement in the rear element holder Please ?

Cheers

Col

[Cadmium]

No, your diagram in post #7 immediately above is not correct.

There are two rear elements (with three retaining rings), my photo doesn't illustrate that well at all.

The deeper element is slightly concave on one side, and more concave on the other side (shallower concave oriented toward front, deeper toward rear, the depth of each side is very hard to differentiate between)).

The second rear element mounted on the outside rear, is domed on one side, and fairly flat on the other side (dome is orientated toward the rear).

Hold on.

[Cadmium]

Why? Is it not working right, or what?

I will update the diagram in a minute.

[colinbm]

No I have another, I think Solinger, I pulled apart ages ago, that I thought about polishing off the coatings, that I want to get it back to working to see what it does.

[Cadmium]

I updated the Kyoei/Kuribayashi 35mm diagram (above), but I can't say that is is the same for the Soligor.

[colinbm]

Thanks Steve

There is a thin metal ring in there somewhere too...?

Col

[bvf]

Well, if it's a Soligor branded one, you may want to look at http://www.savazzi.net/photography/35soligor.html .

 

But a word of caution. I think there are at least 2 variants of these lenses (and the other rebranded ones that are/may be based on the Kuri. The versions with the smaller front element (23mm diameter), smaller rear element (11mm diameter), and probably 46mm filter fount are the ones which seem good for UV. The versions with 31mm front element, 14mm rear element and probably 49mm or 52mm flter mounts are probably mediocre at best.

 

It's not clear which version is covered by the Savazzi diagram.

[colinbm]

Thanks Bernard, I'll have a look at it.

[JCDowdy]

The Kuri/Kyoei is 5 elements in 4 groups. None are glued.

 

If none are glued or in contact is that not 5e/5g?

 

I always thought they were 5e/5g but cannot locate an authoritative reference for that.

[Cadmium]

John, I don't any are glued in the Kyoei/Kuri 35mm. I am not a lens person. What do e and g mean?

[JCDowdy]

What do e and g mean?

 

e = element

g = group

where group = cemented elements

 

I am not really a lens person either, that is why I asked......

[Cadmium]

Hmm, so 'group' (g) always means cemented?

I don't think any of the glass in these are cemented.

3 in the front of the aperture, and 2 in the rear behind the aperture and accessible from the back of the lens.

[JCDowdy]

Hmm, so 'group' (g) always means cemented?

 

Not exactly, a single element alone is also a group. Groups must always be less than or equal to elements, so if all groups are single lens elements then g=e as in 5e/5g. So as I understand it g is always less than or equal to e. I have seen optical blocks or assemblies sometimes also referred to a "groups" but do not know if that is correct nomenclature.

 

As far as I know group usually means cemented, but I guess plastic molded onto glass is technically not cemented and I suppose a liquid such as oil would work optically but I never heard of that in a camera lens. I have seen an oil filled lens assembly in a rear projection TV. Same reason a filter guy like you would glue filters or air space but never stack in direct contact - avoiding Newton's rings yes?

[dabateman]

 

 

Not exactly, a single element alone is also a group. Groups must always be less than or equal to elements, so if all groups are single lens elements then g=e as in 5e/5g. So as I understand it g is always less than or equal to e. I have seen optical blocks or assemblies sometimes also referred to a "groups" but do not know if that is correct nomenclature.

 

As far as I know group usually means cemented, but I guess plastic molded onto glass is technically not cemented and I suppose a liquid such as oil would work optically but I never heard of that in a camera lens. I have seen an oil filled lens assembly in a rear projection TV. Same reason a filter guy like you would glue filters or air space but never stack in direct contact - avoiding Newton's rings yes?

 

Yes that is correct. Groups have air between them (air seperating the groups), a group is composed of one or more elements.

[Cadmium]

How is a group ever less than an element? I mean a group is a group of elements, right?

Wouldn't it be the other way around like this: "Groups must always be more than or equal to an element" ?

See what I am saying?

 

Right, you don't want glass to touch, unless glued of course, and then the glass is not technically touching.

Newton rings are easy to see when filter glass touches. I don't know what the exact results are when shooting through Newton rings, but it is not suppose to be good.

Sounds like another good test example...

 

Here are examples of Newton Rings, when glass touches without cement or separation.

 

[dabateman]

How is a group ever less than an element? I mean a group is a group of elements, right?

Wouldn't it be the other way around like this: "Groups must always be more than or equal to an element" ?

See what I am saying?

 

Right, you don't want glass to touch, unless glued of course, and then the glass is not technically touching.

Newton rings are easy to see when filter glass touches. I don't know what the exact results are when shooting through Newton rings, but it is not suppose to be good.

Sounds like another good test example...

 

Here are examples of Newton Rings, when glass touches without cement or separation.

 

 

No, the group number will be equal to or less than the total element number for a lens. What it indicates is the number of air interfaces.

So a lens with 6 elements in 4 groups maybe written as 6E/4G and may have the first two elements cemented and middle cemented.

As in 1 cemented to two, so only 2 air interfaces, not four, then element 3, then element 4 cemented to element 5 and then finally element 6. That would be 4 groups and 8 air interfaces, with 6 elements.

Does that make sense?

The cement should have the same refractive index as the lenses cemented. Unless you are going for an odd effect.

[ulf]

The cement should have the same refractive index as the lenses cemented. Unless you are going for an odd effect.

 

The very same effect is used for microscopy between object-glass and cover-glass.

Usually water is used, but for som situations a special immersion oil with well-controlled refractive index is used.

[dabateman]

 

 

The very same effect is used for microscopy between object-glass and cover-glass.

Usually water is used, but for som situations a special immersion oil with well-controlled refractive index is used.

 

Yes typically the oil immersion objective will be corrected to 1.5, like the oil used and coverslips. The water corrected objectives will be 1.33, as this is roughly the refractive index in aqueous solutions and an optical plastic coverslip should be used with 1.35 refractive index to avoid issues. But many people just use standard coverslips and loose some resolution.

 

 

[Cadmium]

Colin, the main question I have about the Kyoei/Kuri 35mm elements, pertains to the second element from the front, the element that is domed on both sides.

The element looks like it has identical domes, like you could reverse its direction and it would work the same either way, but will it or not? Is that element the same if it is installed in reverse?

Because unless you are extremely careful, you will loose track of which way it was installed if you take it out. Even with close examination, I see no difference in the front and back of that element.

Something to remember or investigate if you take the lens apart...