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Always the same problem with old Indo with left lens. Before blocking the lens we compensate this with rotating each left lens in opposite direction.

Now is OK. I found my mistake.
One question. This calculation will give a) effective power of tilted lens, and b) power of compensated lense for that tilt.
It is assumed that front vertex of lens...

I have a problem with final axis... It does not match...

I found on OptiCampus calculator for Panto and face form, also found MakeOptic's calculator, but I want to have in my spredsheet that kind of calculator too. So, I need to figure all process of...

To determine the induced prism is not a problem. But, I want to figure is it problem induced unwanted power effect.
For example, person had old eyeglassess OU: +1,00 Dsph, correct PD (59 mm) and ...

Hello,

How can I calculate prizmatic and induced unwanted power effect if we have next situation:
line of sight isn't perpendicular in respect to the back side of lens, it is about 76 deg. and...

12610
Make optic: "It's a math question not an optics question!"
Well, I think that in this case point is on generally understanding. Maybe visual representation will help better. This picture...

I suppose that what you do not know for sure is what I mean with this: [{TABO axis} - {axis of cyl}]. This is the same what you said in previos post: One lens is on 180 degree, and second on 170,...

I got the same results what are in mentioned article with [{TABO axis} - {axis of cyl}]. In one meridian there is small difference, I do not know why, but everything else is ok. Picture 5. seems do...

Hello,
I want to find what power are in every 10 degrees of TABO schema of some lens.
I am using next formula to find powers in meridians: Fsph + Fcyl*sin^2(alpha).
For my purpose there is no need...

Ok, I think I figure. I will tell you what I done. I must refresh my memory about HTML, CSS...

The truth is that atan2 has inside this if statements, so it is easier for user to deal with this function (if we talking about atan2 function in spreadsheet).
https://en.wikipedia.org/wiki/Atan2

How? What language it is? I know something to do only in BASIC in OpenOffice.

Yes your formula works. Nice way to avoid divide-by-zero error.
Wow, now we have a plenty formulas for the same job! But, your last is the shorter. Thanks, I also learn a lot.

Still problem with axis. Try with
L1: 0.00=10.00 ax155
L2: 0.00=-2.00 ax0

If I was correctly applied your formula in previous post (#29), I can't get comparable result about axis. Your formula...

Thanks MakeOptics, I just accidentally droped that part.


I have reserve about your way to find axis, simply it returns results which is not the same with other sources/methods. For example, for...

Just to summarise, and everything to be in one place:
Rules how to solve oblique crossed cylinders:
1. Do transpositions that all cylinders be in "+" form.
For any lens do next...

Can you clarify?

Lensgrinder explained how to get good results in classic way, using formulas from textbooks. MakeOptics, approach what you described (C000 and C045) also get the same results, but not for axis. I...

Thanks for effort and clarifications. I think that I finished my work. MakeOptics, your way is much better for spreadsheet way of thinking, and yes, in yours way it can calculate more lenses then...

The same question: what if C0 is 0?
There is some trick like if cell for C0 is 0 than put value 0.00000000000000000000000001, but this is not perfect solution...

Thanks for clarification. One question. How do you perform claculation when tang2{theta}= {some number}/{0}?

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MakeOptics, if I have
L1: 0,00=-10,00 ax 170 and
L2: 0,00=-1,00 ax55
your new spreadsheet gives
-0.81=-9.39 ax82
but Crossed Cylinders Calculation on OptiCampus gives ax172.

Lensgrinder, you using tanΘ=10*sin(230)/11*cos(230)
About lower part 11*cos(230): are you first sum C1 and C2? Becuse that is different case and result. I found formula in text book as ...