The long rail seems to be Kaiser Copy Stand. I can't say the model outright even though I use one too.

As a result of the latest round of discussion, I'm unable to think of a single situation in which Options 2 and 3 would be good choices. What am I missing? (Probably a lot, but hey, I'll never know if I don't ask.) I would use 3 instead of 1. The difference is that after you have learned what kind ...

Testing the microscope objective is easy as it takes just one stack the with recommended Z-step. The Laowa and MP-E are something else. As Rik wrote, you need to find the optimal aperture for each magnification by testing. You could start with whole number magnifications and add values between them ...

Having fun with the numbers it seems that the resolution in that test should then be k*Lambda/NA, where k must be between 0.477 (0.509 if there was 1000 line target, which was not resolved) and 0.536. This naturally assumes perfect target and objectives perfectly according to spec, but it was still ...

I agree, and to my eye the formulas you show look correct. Thanks for checking! I at least checked that the extension part gives same final result when applied at once or in two parts. (Should be "Photons to Photos" -- no second "n") Now that makes MUCH more sense! I guess I misread it once and nev...

P.S. - All of the examples that we have discussed so far have been relatively simple and straightforward. (Hah!) What happens to the step size calculation when the macro rig is complicated by the addition of extenders, extension tubes, diopters, etc.? I seem to recall this exact question was answer...

chris_ma wrote: ↑

Thu Feb 16, 2023 3:13 am

well, as mentioned before, PTGUI does all the lens undistortion automatically but you seem to have made up your made to go the large format lens way.

How does it handle stitching without rotation these days?

3. Clearly the step size calculator in Zerene Stacker is better than any of the ones I have discovered (although the one from PhotoPills looks promising). Would you consider making your calculator available online (for free)? I updated the documentation to include a browser based version of the cal...

3. Clearly the step size calculator in Zerene Stacker is better than any of the ones I have discovered (although the one from PhotoPills looks promising). Would you consider making your calculator available online (for free)? Here's one. Its not quite the same even though it is based on same princi...

By working aperture I mean the object side f-number in the used shooting setup. Effective aperture is same situation, but image side.

I didn't mention the specifics of my Canon 100mm macro lens but you correctly guessed the one I own. Can you explain why the focal length at 1:1 magnification is 74mm? I'm so lost! That's because the lens is designed to lower the focal length as the magnification goes up. It helps to keep the const...

How does defocus affect the exposure calculations ... or does it as long as the illumination covers the image cone at infinity? Whether there is a focused subject should have no effect. A perfect target would be featureless and uniform, as seen all across the lens aperture. I think it's impossible ...

from Gaussian formula, the half angle of entrance cone is solely dependent on magnification and aperture, so basically, for a given magnification, it is the aperture that matters to increase resolving power, ie, reduce diffraction, that also means, for a given magnification and aperture, it does no...

A quick test seemed to indicate that the numbers given at Photons to Photons are not reliable - if so, they likely don't follow what the aperture really does when magnification is changed. I would be interested to hear more about the Photons To Photos issue. I have run only one careful test, for lo...

I think I have one question as well. The formula gives the optimal effective aperture. And in the classic macro lens range (down to 1:1) that value is usually reachable throughout the magnification range. That should mean the required illumination is constant as well, doesn't it? The question is how...