I don't know to answer this right now, it needs research.

But if I start to pursue the helicoid focus now, the project will fail. I would need to find another machining service or offer more money for my current partner. I would need to buy many pieces of metal, and metal is much more expensive than plastic, I would need to build some different systems to compare. Also metal would need another service after machining to turn it into black color and I do not know if this would change the behavior of the helicoid. So it would be "start from zero" again.

I think it is much more important now I try to deal with the optical lab to improve the lens grinding to get the best approach in same thickness. Also do my best to get the plastic body working the best as I can do. And also find the best coating.

If I can get a little more accurate thickness in lenses and the plastic body with a good alignment, this adapter will be a winner. It will work good at a good price range. This is what people call "best price/performance".

Between the "impossible perfect expensive product" and the "possible good enough affordable product" It will be better the possible.

The reason the helicoids have different threads is:

smaller threads you need to do more rotations to move it some distance

bigger threads you need to do less rotations to move it same distance.

The camera lenses needs to be very fine precise focus, so they use small threads

As the anamorphic adapters needs to move font and back much more than camera lens to do the focus, the best option would be the 3mm

The problem for me is not to design it, the problem is to make it happen, to find some service that is willing to build it and do it in high quality. Also at this moment money is a big problem.

But I will consider it for sometime in future. Maybe one year from now, or less if I can raise enough funds.

Now it is impossible for me.

Thank you very much, I got the 25 usd. If I could get just more 9 donations like yours all the money problem would be solved to finish the project.

OK guys, about the helicoid:

I decided to talk to my plastic machining partner one more time. I will beg them all the way I can. First thing I will say is:

"I do not want you to say things are difficult to do, I just want you to say how much you want to do it. I will allow you to destroy some pieces of plastic on your attempts. If you don't want, or if you can't, just point me to someone else."

Lets see what happens.

It is good to see another manufacturer recognizes my efforts and my accomplishments. Thanks.

About the coating, 250 usd will be enough to try the options.

I found the problem in the night shoots.

I used two prototypes, one for day and one for night. I did this to try a slightly difference in the lenses power, using the lenses I have from the first experiments.

The problem was not the difference in the power, I confirmed the problem was the difference in thickness as I said before. Comparing the lenses used in day and night I found the day prototype lenses was good with almost same thickness in both sides of the lenses, but one lens in the night prototype was with a 2,3mm difference in thickness from one side to other, I measured with a caliper rule. This increased the CA and softness in one side. As I said before, when I lifted this lens one side using some shim adhesive tape I got a better balance in sharpness between sides, but the CA could not be corrected.

So I confirmed the need for talk with the optical lab to ask them more precision when grinding the lenses. As I said before, probably I will need to deal with an error margin, but I will request them to do the best they can.

@apefos: Good thinking on the helicoids..!

They have optical/electronic equipment to do measure lenses. I think what they need to do is a better alignment in the tools that hold and friction the lens in the machine which do the grinding. I will talk to them.

Thanks, stay tuned.

I need to say an important thing about the CA:

After the optical lab improve the grinding to get the best balance thickness between the sides of lenses the CA correction will be very better as shown in the day shots (day shoot lenses was good in thickness).

when I said in previous post that the CA could not be corrected when I lifted one side of that lens used in night shoots which shows difference in thickness, it is because it is caused by the angle formed by the inclination generated by the thickness difference. So lifting one side of the lens can help balance the corner sharpness because this aligns the curves between lenses, but it does not change the curves inside the same lens.

As I said I will try to get the best possible grinding from the optical lab to avoid the CA.

I already told that you do not need any of this sites until you want some publicity that they offer (usually only first day and last one).

Just make simple one page site with big paypal button.

About the helicoid:

The plastic service will give it a try, but not in the body, it will be a test in two pieces of plastic, an attempt to make it works, I will use the first donation to pay this test. Price increased a little in the two helicoid parts, the male and the female, other parts keep same service price.

The body will need to be completely redesign because two ring movements need to work together, one for distance focus and one for cylindrical focus. I did some draws yesterday night and found the solutions.

I decided to release the product with the first body because it works pretty good. The helicoid, if it happens, will be a future product, more expensive due to a more complex body with more parts, more plastic and more service. And at this moment I will do just the first test to know if the helicoid works. The body development will be delayed until I make money to work on it, so it is a idea for months in the future from now.

the coating tests and the replication of the finished unit is the main goal now.