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plaubel
9-Sep-2016, 02:06
Dear specialists,

are there different constructions/lens groups , or is it approximatively able to change the Heliar into an Universal Heliar out of the original and fixed lensgroups?

Thanks,
Ritchie

Steven Tribe
9-Sep-2016, 03:14
In theory, yes. In practice, quite difficult.
First you have to have a genuine Heliar. The so-called "Heliar" was replaced by the Dynar lens design pre-ww2, whilst the Universal Heliar continued with the original optical design always.

The front cell of the Heliar and the central cell are joined together in a unit. It is frequently mentioned that the exact positioning of the central cell is vital to the performance of the Cooke triplet design. I know this first-hand as I attempted to modify a late projection triplet to work a la Universal, but I lost the positioning of the middle lens - which was a source of frustration!

I have some photos of the Universal double cell unit, which I needed to service some years ago. The brass is full of marks made by Voigtlander to ensure the mechanism worked without sticking!

The system means that there is an extra brass tibe thickness - meaning that the total diameter of the lens is greater than the normal Heliar of similar length.

Of course, it is possible to cut the ordinary double cell mounting close to the middle lens and remove most of the internal barrel of the cell mount up to the mounting thread. Then you would have to make a stop mount so the loose central lens doesn't go further down the barrel than the standard Heliar position. Then you would have to make a bearing to take up the slack between the inside of the barrel and the outer diameter of the mount of the central cell. Perhaps velvet would be OK? Finally, you would have to mount a brass slider (or perhaps two, one on either side!) which would run in two slots cut into the barrel's length. You could even engrave numbers which would correspond to the usual Universal graduations! The slot(s) would need to be covered with a dark cloth during exposure.

Steven Tribe
9-Sep-2016, 04:59
I need to modify my last comments a little!

I show the front section on a 36cm Heliar when screwed apart. As can be seen, the section where the central lens is mounted, the barrel is considerably reduced in diameter. This means that the barrel of the Universal could well be the same as an ordinary Heliar. It is also obvious that an extra ring is necessary to make a sliding fixture out of this section with the central lens!

plaubel
9-Sep-2016, 08:59
Steven, thanks to your suggestions !

So, at first, I would have to check the design of my 360mm Heliar.
Next, I have to understand what exactly happens while moving the Universal Heliar - the back lens and the middle lens stay in a precisely defined distance, and the front lens moves?
Maybe you could help out with a technical drawing of the Universal Heliar design?

And the lenses of both types are identically?
I am not only interested in a possible movement of the lens, I love the idea to have prints with an Universal Heliar look :-)

The rest sounds doable to me, my greatest "fear" has been a different lens design/lens types of my Heliar compared with the Universal .

Instead of internal brass sliders supporting and leading the movements, I am thinking of a normal thread with wide steps ( don't know the right word for this steps and their distances, which per example may have 10 steps per inch, or 3 Gänge pro cm).

In this case, no darkcloth would be necessary.

Ritchie

cowanw
9-Sep-2016, 10:33
It is the central lens that moves.
Have you seen this
http://www.antiquecameras.net/heliarlenses.html

Steven Tribe
9-Sep-2016, 10:38
Exactly the same lenses and the middle lens moves forward. The nearer it gets to the back of the front lens, the softer is the image.

Moving the middle lens forward needs quite a lot of precision engineering if you don't cut channels in the barrel.

plaubel
9-Sep-2016, 11:21
Moving the middle lens forward needs quite a lot of precision engineering if you don't cut channels in the barrel.

Now it is clear to me, thanks both.
I understand it requires deep thoughts about the engeneering, yes.
I am not interested in breaking the original body, if possible, but I remember that the middle lens did not come out alone...

Let me have a look at my Heliar, next.
Can I somehow find out the date of birth via serial number?

Steven Tribe
9-Sep-2016, 12:17
The CCHarrison "Heliar" web page shows the serial number/year table.

The photos I posted are from a 36cm serial number 99910.

I wish I had never read this thread and contributed as I think it is genuinely do-able! Perhaps someone at Grimes, or similar, would be interested?

plaubel
9-Sep-2016, 13:53
Steve, don't panic, I really love my lenses - thanks for reading, answering and contributing :-)

This idea lurks since years into my brain, and now I am interested in knowing more.
I think, I will give it a try, if my serial number is ok.


Ritchie

Steven Tribe
9-Sep-2016, 14:34
I am more afraid for myself and my 36cm Heliar.

The Universal I showed dismantled is just a 30cm version.

Tim Meisburger
9-Sep-2016, 16:34
How about a Meopar? That is supposed to be a Heliar design, and would be cheaper to experiment on than a real Heliar.

By th eway, I have a 30cm Universal Heliar, and it is my favourite lens. My dream would be a smaller version in shutter I could use on 4x5.

tonyowen
10-Sep-2016, 01:23
I am thinking of a normal thread with wide steps ( don't know the right word for this steps and their distances, which per example may have 10 steps per inch, or 3 Gänge pro cm).Ritchie
For information only, the words are pitch and threads per inch (tpi)
With 'imperial threads the identification is the thread diameter in inches and the tpi ( 3/8" x 20)
With metric threads the identification is the thread diameter in mm and the pitch in mm ( M6x1)
regards
Tony

plaubel
10-Sep-2016, 01:58
Tony, thanks for the missing words.
Identification and identifying threads was clear to me, but I cannot see the difference between "pitch" and "threads" - oh, yes, now I've git it, threads means "Gänge", and pitch is "Steigung". Different things, but at least the same result.
All threads have a pitch..
This differences sometimes make it hard to find out the correct thread or thread type; the other things are the angles, here 55 degrees, there 60 degrees...

Tim, a Meopar seems to be a good idea, but I own a cheap Heliar and would have to buy a Meopar, so trying my Heliar is the cheapest way to me.

With my mill, my lathe and some circumspection/attention it could be able.

Ritchie

tonyowen
10-Sep-2016, 02:37
, but I cannot see the difference between "pitch" and "threads" - oh, yes, now I've git it, threads means "Gänge", and pitch is "Steigung". Different things, but at least the same result. Ritchie
Hi Ritchie
My German is minimal, but tpi (threads per inch) is identical to pitches per inch where the pitch is the distance between two adjacent crests (peaks) of the screw. Think of the projected image of a screw thread being a series of adjacent pyramids where the distance from the peak of one pyramid to the next peak is the pitch.
As you state it is a language thing where a word can have many different meanings.
regards
Tony

tonyowen
10-Sep-2016, 02:44
This differences sometimes make it hard to find out the correct thread or thread type; the other things are the angles, here 55 degrees, there 60 degrees...Ritchie
Ritchie, I've just noticed this comment, If you have specific queries about threads let me know - I can give you a specific answer or at least indicate what might be the answer. The main confusion comes with things like instrument threads which are unique to themselves and often to the manufacturer of the particular instrument. They tend to be (relatively) large diameters and very fine threads
regards
Tony

plaubel
10-Sep-2016, 05:31
Thanks, Tony, I will remember your offer some day.
Especially old threads may be difficile in finding out; some of them have never been used the last 100 years, and i don't know their name..

In german language, "Gänge" and "Steigung " means nearly the same, too, if you have a look at the result. One depends on the other.

Best,
Ritchie

Steven Tribe
11-Sep-2016, 01:45
How about a Meopar? That is supposed to be a Heliar design, and would be cheaper to experiment on than a real Heliar.

By th eway, I have a 30cm Universal Heliar, and it is my favourite lens. My dream would be a smaller version in shutter I could use on 4x5.

I too have 30cm Universal. I got hold of an earlier 36cm ordinary (?) Heliar at a very reasonable price. I have looked at the construction quite a lot during the past few days and think it would be possible to make a quite simple and clean looking adaption.

A few notes:

- the problem of an open slot (approximately 3.5mm wide) can solved by mounting a slider which covers the gap and which is long enough to cover at the extremes 0 and 5.

- the best way to retain the normal position is to mount an internal stop ring in front of the iris mount. The Cooke triplet is very sensitive to exact positioning.

- unfortunately, the central lens is mounted so that the glass would touch this stop ring. However, the middle ring between the lens mount ring and the lens barrel could be mounted to ensure that this engages the stop ring.

- I had previously mentioned using velvet as a bearing, but with respect to Voigtlander I think that that a brass/brass fit will provide more reliable tolerances.

- obviously, it has to be a design which allows cleaning and a grub screw system of locking the central unit in the normal position.

I'll start posting drawings/measurements as a DIY thread in a few days.

The 36cm is a good size to work with. I imagine it would be more difficult to work on smaller Heliars?

plaubel
11-Sep-2016, 10:43
Measurements and drawings will be fine !
Why not continueing this thread?

""I imagine it would be more difficult to work on smaller Heliars? ""

My tools are big enough to take this or that, but the bigger the lens, the bigger - and way more expensive - the needed brass material.
I don't know about such big brass tubes as a buyable standard, so maybe I have to start with a 2 Kg brass block, and copper as a part of brass is very expensive thisadays, even at the metal recycle men...

Maybe a prototype of aluminium would be a good idea.

Ritchie

Steven Tribe
11-Sep-2016, 15:08
I have suggested to the mods long ago that this thread be moved to the DIY. I received a very friendly reply (as always) saying it was OK here at present but perhaps when "adventures with a hacksaw begin" it would happen.

plaubel
12-Sep-2016, 02:32
Yes, here is more the theoretical stuff, but I'm sure, sawaction will follow, anywhere.

Ritchie

Steven Tribe
12-Sep-2016, 03:03
OK, I'll continue here for the time being!

I was thinking more of using available brass/bronze tubing, rather than lathe working using blocks.
I measured up the barrel and innards a little this morning. There is just enough space between the flange of the internal iris and the normal position of the central lens to mount a ring spacer that would act as a stop. This would ensure that the regular position is not lost. There would also be enough room for intermediate (new) ring to stick out a little to ensure the glass lens doesn't knock against this spacer. The diameter of the main barrel is 93.80mm and the external diameter of the barrel holding the central lens is 85.90mm. So wall thickness is just under 4mm - probably too thick for something just off the shelf. I do have a barrel length that is exactly between these measurements which could be of use. But perhaps aluminium would be more appropriate, although the Universal mechanism is made of brass.

I need to check movements and where the mount needs to installed in relation to the lens position in order to avoid getting the slot and the slider adjustment too close to the iris and the top barrel/lens cell thread. I think it may be impossible to get the full 0 - 5 movement with a covered slot system, perhaps just 0 - 4. Drawing later to-day will make it clearer, I hope

plaubel
12-Sep-2016, 05:35
Without respecting the flange base and threads, my main barrel has nearly 98mm, so it seems to be more thick, a bit.
My lens is made of aluminium instead of brass, serial number is 119105; this looks like a built between 1912/1913.
If I'm right, it is not the original design from 1902, but on the other hand a solid base for tuning up into an Universal Heliar ?

Meanwhile, I have found a seller of big brass tubes, so no reason to start from a big brass blog for creating new parts.

For lighttight covering of the leading slots, which will stabilize the movements of the central lens, I can imagine another tube with a function as the moving grip, which covers a big part of the main barrel and in this way the slots, too.

My memory has been wrong: my central lens comes out easily ,no problems there.
But up to this moment, I have no idea how to loosen / bringing out the front lens; I can't see any screws or threads, nor do I understand the construction of this connection..
Any suggestions, please?

It could be a good idea to mark the direction of the central lens; it may be symmetric by itself, but it may be not.
My lens got a little arrow now.

Ritchie

Pere Casals
12-Sep-2016, 05:45
I think that next shot explains very well how Universal's difussion works, by zooming in we can see the out of focus distant lights, here difussion is set at 2.5

The shape of the out of focus bright points (coma) inicates how the light from a source point is distributed, radially to the center for points farther than the focus plane, (I don't know for nearer points). I guess mainly because spherical aberration...

https://c2.staticflickr.com/6/5715/24080971035_d2b9904710_o.jpg


What I suggest (to experiment) is to use far and near small bright points to see how the light from a single point is difussed in certain shapes, this explains the diffussion chararcterization of every soft-focus glass.

This also explains to the non belivers of the "Universal's religion" :) that it works not the same like Imagon and Fuji SF range.


Universal's have not that price by chance: they have a unique footprint and they are not manufactured. Another think is that one can like it or not... really today there are not much people around that may consider such a refinement, such an exquisiteness... but less glasses are available.

Steven Tribe
13-Sep-2016, 01:05
Pere,

I have only used my Heliars for Landscapes! Yours is very well chosen!

I have problems with my printer at the moment so drawings are restricted. I have a half "Slice" drawing of an early Heliar from a 1910 catalogue. Unlike most catalogue drawings, this is a very good representation of what my Heliar looks like. The only slight error I can find is the rear of the mount for the central lens is shown just proud of the lens. In reality, the lens is just proud of the mount!

APart from perhaps a few at the start, when the diaphragm was positioned in front of the middle lens, all Heliars are aluminium These stand up to corrosion quite well, but the hoods are very brittle and crack rather than bend.

Pere Casals
13-Sep-2016, 04:04
Pere,

I have only used my Heliars for Landscapes! Yours is very well chosen!

I have problems with my printer at the moment so drawings are restricted. I have a half "Slice" drawing of an early Heliar from a 1910 catalogue. Unlike most catalogue drawings, this is a very good representation of what my Heliar looks like. The only slight error I can find is the rear of the mount for the central lens is shown just proud of the lens. In reality, the lens is just proud of the mount!

APart from perhaps a few at the start, when the diaphragm was positioned in front of the middle lens, all Heliars are aluminium These stand up to corrosion quite well, but the hoods are very brittle and crack rather than bend.


"the 1926 f/4.5 "Universal-Heliar is identical to the 1902 f/4.5 version Heliar, however it features the ability of the central lens element to be adjusted by the user, thereby introducing varying amount of spherical aberrations."


I found that here : http://www.antiquecameras.net/heliarlenses.html, mentioned in post #5


So it is clear that it is possible to emulate the "universal's" soft focus feature from the 1902+ elements by ajusting the inner element position.

I guess that it can be done with other triplets of similar design... But, again... to evaluate how "difussion" works in a SF lens (the way I consider...) is to look how bright spots are projected in the GG: center and corners, near and far, in focus and out of focus, wide open or stopped, at one difussion setting or another...

So... a lot of fun ! :)