What does shorter tube lens do to focus step size?

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Beatsy
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What does shorter tube lens do to focus step size?

Post by Beatsy »

Just to keep the math simple, if I have an objective on a 200mm tube lens that requires 1µm steps for optimum focus stacking, what is the optimum step size if I put it on a 100mm tube lens instead?

I ask because from practical experience I suspect it could be more than 2µm, but that doesn't seem right. What aren't I getting here?

Pau
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Post by Pau »

If the sensor wasn't limiting resolution you'd need the same step size because the NA is the same and so the DOF, but because the sensor likely will be outresolved you'll be well served with longer steps...others could be able to do the calculation
Pau

ChrisR
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Post by ChrisR »

Beats - absorb... http://photomacrography.net/forum/viewt ... 606#126606 !

I think I had to read it 3 times to get the point. :roll: But it's very useful as a guide. My version of Rik's sheet has grown.
Chris R

rjlittlefield
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Post by rjlittlefield »

ChrisR wrote:I think I had to read it 3 times to get the point. :roll:
Reading it only 3 times sounds pretty efficient. I had to write it more like 10 times before it made sense to me. :lol:

--Rik

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