looks like you are getting some good results.
Time to expose some film with the lens pointing at real subjects!
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.
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
Sponsored Ad. (Subscribers to APUG have the option to remove this ad.)
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.
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.
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.
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
Or, forget the springs and add solenoids and electronic control :P That's what I am going to do.