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  1. #31
    Steve Smith's Avatar
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    looks like you are getting some good results.

    Time to expose some film with the lens pointing at real subjects!


    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  2. #32

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    Quote Originally Posted by Steve Smith View Post
    looks like you are getting some good results.

    Time to expose some film with the lens pointing at real subjects!


    Steve.
    I still have a camera to build for it lol I could use the speed graphic though to test but my plan is to have a DIY lens with a DIY camera, developing the paper negative myself, the only thing that would be bought would be the paper negative

    I am going to be getting some larger 88mm close up filters (same dioptre values just bigger) and see how those stop down, my guess is with the larger diameter optic (85mm vs 50mm) and with the lack of edge sharpness a stopped down 85mm diameter lens should yield a better result than a 50mm diameter optic fully open (eg same size diameter of lens focusing the light).

    I thought I would try out these close focus lenses and having found out on here that those are the diopter values I could actually make a lens up from shop bought filter rings - I could even use a revese macro adaptor to reverse the lens groups and still retain the screw mounting threads.

    I will perhaps post up another thread for the camera build and leave this thread as the lens build

  3. #33

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    I'm not sure about shipping cost to your location but we have a member here, Reinhold Schable, who sells single element "Wollaston" lenses for 4X5 already mounted with aperture cards. They come in several focal lengths and the ones for 4X5 are $65 and that could save messing around with plus diopter lenses. His buseness is a sponser of APUG and he posts here sometimes.

  4. #34

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    Quote Originally Posted by pen s View Post
    I'm not sure about shipping cost to your location but we have a member here, Reinhold Schable, who sells single element "Wollaston" lenses for 4X5 already mounted with aperture cards. They come in several focal lengths and the ones for 4X5 are $65 and that could save messing around with plus diopter lenses. His buseness is a sponser of APUG and he posts here sometimes.
    Thanks for that, I will check it out, I seem to remember the name from when I was reseaching a while back for large format lenses, it seems that the lenses I can easily get (the close up filter lenses) seem to actually do a good job when stopped down.

    I am still going to look into creating an RR lens or maybe a single Gauss lens, I just had a look around my local hardware store - looked at some plumbing parts and found that there are 50mm compression fitting joints - I could use one of those to add a lens at each end symetrically and then cut a slot in the centre to put in some waterhouse stops

    I also noticed that they did 110mm connectors...bit big but would be awesome for a massive aero lens lol there are 110mm lenses that are cheaply available which might be an interesting idea if I do larger format eg 8x10.

  5. #35

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    Just ordered some larger close up filters which should give me 2 lens combos:

    166mm f2 = 55mm equivilent for a 5x4 camera
    71mm f0.85 = 23mm equivilent for a 5x4 camera

    I also have most of the parts in place for:

    150mm f1.4 = 50mm equivilent for a 5x4 camera

    This could also possibly make the below lens (or event wider) however I probably won't make this as I want a longer lens for portraits:

    100mm f0.9 = 33mm equivilent for a 5x4 camera

  6. #36

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    I now have a lens barrel on order and it should arrive in the next few days hopefully, I have also been thinking about shutters, even stopped on paper negatives these will be quite fast it seems so I might need to look into building a shutter for them as well.

    I am thinking something like a drop/gravity shutter with different sized slots cut in the plate for different shutter speeds, I could also perhaps look at creating a simple leaf shutter or indeed something more experimental, will have a look into it.

  7. #37

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    I might also have to make my own shutter as well looking at the shutter speeds I will probably need for these lenses, I might however look at adding ND filters on the front to stop down the lens but not change the aperture.


    I could do try 2 options:


    Variable shutter speeds + no ND filters
    Fixed shutter speed + ND filters


    I am thinking about creating either a leaf, packard, rotary or guillotine shutter (will probably spring load the guillotine if I use that).


    I could try something simple such as a fixed shutter speed shutter by simply having a spring loaded/rubber band powered shutter:


    Lens cap on (or dark slide)
    Pull a board in a runner with a set sized slot across against a spring/band
    Lens cap off
    Let go of the board with the slit in it to go past the now open lens
    Lens cap on (or dark slide)


    Basically firing a board with a slot cut in it across the lens so that its tight tight, slot passes past and then light tight again.

    I could have a set of slotted boards with different shutter speeds depending on the slot gap, or I could used a fixed board and simply put an ND filter on the lens.

  8. #38

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    Hmm just thought of a shutter design, its simple and i've never seen it done before so it might be a first lol


    I am going to look into building a double iris shutter using springs and 2 sets of iris one in front of the other, the first is sprung so that the iris is held closed, the other the iris is held open. To use it you would simple put tension on each in the opposite way to put them under spring tension, remove the lens cap and let go. If the spring tension is different on the front and rear then one would close sooner than the other with one of them being closed in the 'rest' position.


    I will try and draw a diagram of the idea later.

  9. #39

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    Ok, so here is my initial idea with regards to the shutter, I might just go with a powered guillotine or a rotary but here is the idea I have:

    There would be 2 states the shutter will be in, at rest and tensioned, the first 2 image are the front and rear irises at rest and the last 2 are under tension (as can be see by my badly drawn springs/bands).



    Basically the delay between the closures of them will give the exposure much like the slots in the curtain shutters etc.

    One iris is closed at rest and the other open at rest, I guess what I could do is have the shutter release like a pin I could pull out at different speeds. The gap between the shutters going back to rest will depend on when they are released so I could have some sort of pin which I can pull out, pull out half way one fires, pull out all the way the other fires.

    If I pull the pin out quickly then both fire close to each other, pull the pin out slowly then the gap is longer - pulling the pin quickly would allow me to have a much faster shutter speed than if I tried to do it manually due to the spring tension.

    Here is a badly made gif showing the 2 states open and closed


  10. #40

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    Or, forget the springs and add solenoids and electronic control :P That's what I am going to do.

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