Building a DIY Lens

[David Mitchell]

Ok, I have taken delivery of a few older cameras from something I won on ebay - I was just bidding as there was a Purma special and I wanted a spare one lol there were 2 127 box brownies with 2 different simple shutters, plus my cheap point and shoot plastic camera.

On closer inspection they all basically have a spring loaded blade that is flicked and the spring then returns the blade to its rest position, the older Kodak had a much slower shutter with a few more moving parts which covered the opening whilst the blade retracted back.

Here are my comments on the way some of these simple shutters worked:

Plastic camera - shutter blade is pivoted and attached to a spring, on firing the shutter a spring loaded finger is released and flicks the shutter blade open and is then closed via the spring, fairly fast shutter speed
Newer 127 camera - shutter is pivoted and attached to a spring, lots of other spring loaded parts are also attached to stop double exposures etc but it basically releases a spring loaded finger much like the plastic camera
Older 127 camera - 2 distinct movements, on firing the shutter opens and closes, on release of the button it all returns back - on pressing the shutter one blade moves forward which is connected to a second blade, both are pivoted, once the first blade moves and spring has enough force it pulls the second the second blade trips and shoots forwards. On release of the button the first blade covers the opening until both blades are back at rest.

Here are some photos of the shutters I have:

Plastic - not much to see but the front blade is sprung:



Newer 127 camera:

At rest:



Cocked - copper coloured trianular piece flicks the end of the shutter blade



Shutter is spring loaded, quite a fast shutter



Older 127 camera:

Shutter blade on top moves down on the press of the button putting tension on the spring connecting the 2



Spring pulls the second shutter down once the spring tension increases between the 2



On release of the shutter the first blade is curved and covers the opening until everything is back to the rest position.

What I have learnt about the simpler shutters is that it seems that all that is needed is a pivoted shutter blade which is spring loaded, the other end of the shutter arm is then flicked and then released which then lets the shutter spring back to rest - the power of the spring gives the shutter speed.

I am going to mock up a possible design on how I could create a larger version of this, due to these cameras having all sorts of fail safes and other features (like putting a flag in the view finder informing of a shot being taken) it might be quite simple to make something.

I will have a think and work something out that is simple, cheap and effective

 

[David Mitchell]

A 4" lens barrel and board arrived today - anyone guess what it actually is?



Also some 110mm lenses arrived, they are 4 dioptre and are over 4" wide - I will be getting a wider barrel and board made up to fit them, they are 4 dioptre lenses (although they are double convex so not ideal) but I will try and see what they are like stopped down.

Someone on another forum also very kindly sent me some bellows, the front of a larger set has a 4" hole which I will perhaps look at building a front standard for as well.

Things seem to be progressing quite well so far, I will see how much progress I can make on Saturday, hopefully the macro slider rail will arrive soon so I can attach the standards etc.

 

[Pete Askew]

An exciting day it seems. That lens barrel looks suspiciously like a flange for ducting!

 

[David Mitchell]

No Pete...how could you say such a thing lol it is indeed a ducting wall flange, 4" was the smallest, metal construction (there was plastic as well) it also has internal notches which I will use to seat the elements. I need to get some smaller 4" elements for that lens though.

Just had a quick test with the lenses, due to the MASSIVE lens circle these things seem to generate the 5x4 area only really gets the centre of it meaning that its actually quite sharp and clear which is what I was aiming for - if they were smaller and of this design then the 5x4 area would have been nearer the edges which would have meant a lot of imperfections, will be interesting to stop the lens down.

250mm f2.2



125mm (ish) f1.1 - its a tad out of focus due to having to hold 2 lenses together and shoot using a manual lens lol but you get the idea, still quite a good image, slight bit of distortion.

 

[Pete Askew]

That first one certainly looks promising.

 

[David Mitchell]

That first one certainly looks promising.

The second one is about as sharp, the single lens is 250mm (4 dioptre) lens, its a 2x magnification lens, I could also look at getting the 5x magnification lens, however it would have a much more curved surface and therefore increase the amount of imperfections etc. Which is why I am going to go with 2 weaker lenses rather than 1 stronger lens.

I do still have the 85mm positive meniscus lenses coming (close up filters) so it will be interesting to see what those are like in comparison.

 

[David Mitchell]

I have the basic parts for the larger lens, just went out to buy the barrel:



Rubber gasket - unfortunatly the lenses don't hold in at the moment as the barrel is 110mm and so are the lenses, the seals are slightly larger but can probably sort out by packing out the sealing surface



There is a lip in the centre (there were some without) but I will use this to hold the waterhouse stops in the centre



Needs a clean but this is just a test lol



150mm f1.3 - it looks amazing on the ground glass, it looks almost 3D



I really need to use my other camera lens but this is it stopped down using some cardboard - guessing around f15



This lens will be called the Q1, in honour of the Carl Zeiss super-Q 40mm f0.33 lens, the Q stood for "Quatsch" translation 'Nonsense' lol

Carl Zeiss Super-Q-Gigantar 40mm f/0.33: The Fastest Lens Ever Made? | The Dream Within Pictures

 

[David Mitchell]

Image circle example



I then free lensed it with the NEX-3, this is ISO 200, 1/160, 150mm f1.3 - this is on a crop sensor so its somwhat enlarged - bicycle across the way

 

[Pete Askew]

Looking more and more interesting David. Drain pipe. Classy! Mind, I'm a bit disappointed you didn't use a ceramic one!

 

[David Mitchell]

Looking more and more interesting David. Drain pipe. Classy! Mind, I'm a bit disappointed you didn't use a ceramic one!

Need to cut a slot for the waterhouse stops so went with plastic - its the Mitchell Q1 lens, what else did you think I would make it up of

 

[Hamish Gill]

cool! You're certainly not achieving the light gathering power of the average f/1.3 lens eh
still, "nonsense" is a bit strong ... it looks a most enjoyable project!

 

[David Mitchell]

cool! You're certainly not achieving the light gathering power of the average f/1.3 lens eh
still, "nonsense" is a bit strong ... it looks a most enjoyable project!

Yeah, its a bit slow, will be making a 71mm f0.85 soon, should be sharper than this lens. I just checked my other 150mm LF lens, the Zeiss London one for its image circle which is actually tiny in comparison lol

I would be needing the faster lenses due to the slow speed of the paper negatives I will be using - although that has caused an additional issue of now needing faster shutter speeds lol

 

[Pete Askew]

Based on my latest estimate, you'd need an exposure of 1/8 - 1/4s at f/1.

 

[David Mitchell]

Thank you for doing that test Pete, I was going with ISO 6 ish for paper negatives, I would probably also stop the lens down a bit as well to perhaps get a 1 second exposure initially - although would be shooting a faster speed if doing portraits although I am tempted to use the Luc shutter on the other camera for that.

 

[Hamish Gill]

you will need to test the actual transmission on the lens surely ... ?

 

[David Mitchell]

Thats true, I will shoot some test strips once I get the rest of the camera together, although I think initially I will be using the 'Q2' lens which will be the lens made up from the macro rings in the speed graphic.

 

[David Mitchell]

My 82mm close up lenses have arrived, you can see the 52mm lenses on the left, the 82mm lenses in the middle and the 110mm lens on the right.



Here is the crazyness that is the +8 lens, means its a 125mm lens so an f1.6 lens, image circle is good and the image is brighter compared to the 52mm lens version (which is why I got this size to give some extra stops of light).



There is also a +3 filter which is a 330mm lens at around f4, I just focused it on the wall, the image circle is around a foot, maybe larger lol

What I am tempted to do is to use the 4" (100mm) wall duct and sleve a filter(s) inside it giving me manual focus and use the bellows on the larger 110mm lens. I might just look at fitting these 82mm lenses with some waterhouse stops and add a lens board so I can use the speed graphic focal plane shutter.

 

[Pete Askew]

That sounds like a good idea.

Looking interesting.

 

[David Mitchell]

I found that the 82mm filter size lenses are the limit before they start getting expensive lol

It does also seem that I can somehow attach these lenses to a board for the speed graphic, I feel that I am going to have an issue with a shutter on these

I am actually looking at using the speed graphic focal plane shutter even for the Q1 lens, its too big to mount on a lensboard (well correction the speed graphic is too small lol), So I might look at attaching that Q1 lens onto the runners and use some material between the lens barrel and the speed graphic body.

 

[Dan Cattermole]

Come on David, really looking forward to the final product.

You are going to complete it aren't you?!