Confused about the data on the Focus screen

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kwgagel
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Joined: 17.05.2015 06:44

Confused about the data on the Focus screen

Post by kwgagel » 17.05.2015 07:03

I'm a little confused about what I'm looking at on the Focus screen. Between the A & B, to the right of the Shots & Interval and at the bottom of the image window are the numbers I'm wondering about.

If I'm thinking right, the values between A & B are how many steps it will take to capture the image based on the to two focus points.

The shots multiplied by the interval should then compute to the max between A & B - right?

In the attached screen shot from my tablet I see 25/25 between A & B and Shots at 10 and Interval 3 which equals 30 - not 25.

What am I looking at - or is this a bug?
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mike_mccue
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Re: Confused about the data on the Focus screen

Post by mike_mccue » 17.05.2015 13:52

The stack, as you have set it, will cover 25 steps

8 of the ten shots are obvious; 3 steps x 8 shots = 24 steps.

Consider that the first shot is at step "0" not "1", and that the last shot is at step 25, so the app adds a shot at each end for a total of 1+8+1=10 shots.



edited grammar to increase clarity
Last edited by mike_mccue on 18.05.2015 14:09, edited 1 time in total.

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Stas Yatsenko
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Re: Confused about the data on the Focus screen

Post by Stas Yatsenko » 18.05.2015 12:34

Mike is correct. The interval between shots (simply speaking, the depth of field) has been calculated at 3 steps. That means you need at least 10 shots to cover 25 steps, and the last shot will be made at 3 * (10 shots - 1 at position zero) = 3 * 9 = 27 steps. The app doesn't have to hit the point B (position 25) precisely. Instead, it makes sure that B is covered by the DOF and that the intervals between all shots are even, which is important for focus stacking.

kwgagel
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Joined: 17.05.2015 06:44

Re: Confused about the data on the Focus screen

Post by kwgagel » 23.05.2015 23:00

If I'm understanding correctly...

Steps = Intervals which are calculated based on the lens/camera combination in use at the time and each step represents each programmable movement the lens is capable of.

The total steps is based on the beginning and ending points of the best focal plane available for the depth of field involved based on the start/end points chosen which may or may not involve the best focus point for each particular position.

The depth of field determines the total amount of image captures based on the steps but may or may not require an additional image capture to complete the chosen overall depth.

Might I suggest that the various points:
  • Number of images
    Number of steps
    Total steps
    Running steps/steps completion display
Be amalgamated into a more user friendly version. Just show how many images will be required for the capture and then when running the image number its on.

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Stas Yatsenko
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Re: Confused about the data on the Focus screen

Post by Stas Yatsenko » 25.05.2015 15:51

That sounds more or less correct.
I don't see how removing information from the screen would make it more user friendly. You'll need that information from time to time to understand what's going on or how to best setup your stack. The only thing missing is the shooting progress in terms of images (as opposed to percentage), it's on our to-do list.

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