Sensor size and focus stacking -- LOTS ABOUT FOCUS STACKING

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Ever since I got my 850 I thought Nikon had the parametrization the user is obliged to input is based on at least one unknown quantity = the "delta" of advance the focus motor can move. What does an increment of "one" mean: 1 unit of advance the focus motor is capable of, 1/10 of millimeter, 1 millimeter, 1 what? Only Nikon knows the the focus motor can do... That complicates the next parameter, how many images to take in the "set" How can you know, again because the delta is unknown. Similarly for the increment.

The sane way, involving NO UNKNOWNS is: Start focus "HERE" (user focuses lens at desired starting position, press the a button to remember this stepper motor position (or count) from minimum focus), finish focus is "THERE" (user focuses lens at desired stopping position press a button again (remember this stepper motor position or count), tell user how many focus advances will be needed to go from HERE to THERE. The camera and lens in combination are smart and know, or can compute, all the increments and counts that the user will need for the eventual stack. Do you want to use every stepper motor advance - enter number into the menu, 1 to use every stepper motor increment; 2 to use every second stepper motor increment, 3 or 4 , et cetera ? Press "START" in the menu. Then the camera moves the lens to HERE focus position, take as many images as focus advances until the THERE point. Photographer sees TTL the starting point he/she wants and sees TTL the ending point he/she wants and has no need to know "secret" Nikon information (but the camera & lens do to yield the set of images that will yield focus stacked image).

Doing it this way will give the user FULL CONTROL of the image gathering process, no wasted images because too many were taken, no incomplete focus stack because insufficient were taken.

I said "stepper motor" assuming increments could be counted, but I'm sure Nikon can "know" the exact position of the lens based on the electronics of the focus drive motor at any point of the lens travel from minimum focus to infinity.

Nikon is famous for their stepper motors which drive their electronics lithography division, which leads me to think they use circular stepper motors in their lenses.
 
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Doing it this way will give the user FULL CONTROL of the image gathering process, no wasted images because too many were taken, no incomplete focus stack because insufficient were taken.
The CamRanger Mini (and presumably the CamRanger) work essentially the way you want except that it doesn't tell the user how many photos will be taken until it begins taking them. (I actually don't have a need to know how many will be taken when inputting the nearest and farthest focal distance.) Some detailed information is provided that can be changed by the user and might be related. However, I've used the device only for one week and haven't taken the time to understand those details, especially because the user manual makes no attempt to explain them.

However, the method you (and I) want doesn't always work on the CamRanger Mini, which makes me wonder if Nikon also hasn't been able to figure out how to make it work all the time. I've only tried making several focus-stacked images using the CamRanger Mini, but half the time I've tried, either the nearest or the farthest focus distance is not actually photographed in focus. That's despite that both were displayed very sharp when viewed at 200% on my phone. The CamRanger Mini also has its legacy method of inputting the information, which seems to be the same as the Nikon system, and using that method is my only solution so far when the other system I prefer doesn't work properly.
 
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Given Nikon's history of "Not invented here (at Nikon)" I'm sure my idea(s) will be continuously ignored ...

I ran into the the same concept multiple times over 44 years when I worked as a programmer for a French geophysical exploration company.

I'm still kickin' and scratchin' but the geophysical company went belly up and has now been absorbed by an investment firm, most likely for the debt to offset their earnings, but not management"s bonus plan. (Yes, I am a cynic ( :))>
 
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The sane way, involving NO UNKNOWNS is: Start focus "HERE" (user focuses lens at desired starting position, press the a button to remember this stepper motor position (or count) from minimum focus), finish focus is "THERE" (user focuses lens at desired stopping position press a button again (remember this stepper motor position or count), tell user how many focus advances will be needed to go from HERE to THERE. The camera and lens in combination are smart and know, or can compute, all the increments and counts that the user will need for the eventual stack. Do you want to use every stepper motor advance - enter number into the menu, 1 to use every stepper motor increment; 2 to use every second stepper motor increment, 3 or 4 , et cetera ? Press "START" in the menu. Then the camera moves the lens to HERE focus position, take as many images as focus advances until the THERE point. Photographer sees TTL the starting point he/she wants and sees TTL the ending point he/she wants and has no need to know "secret" Nikon information (but the camera & lens do to yield the set of images that will yield focus stacked image).

Doing it this way will give the user FULL CONTROL of the image gathering process, no wasted images because too many were taken, no incomplete focus stack because insufficient were taken.
Fuji have implemented this feature in the X-Pro3. I am hoping they also include it in the upcoming X-T4. I’m not sure if it uses some form of intelligence for landscape focus stacks where it adjusts the steps based on the camera to subject distance. I generally only do closeup/macro photography which as far as I know the steps sizes are the same throughout the capture.
 
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WRT Step Width, i do not think that there can be a precise measurement in mm etc because, for a given Step Width and Aperture the "distance travelled" will vary.

Step width at f2.8 means something different than Step width at f32.

DG
 
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Like I alluded to earlier, users have no access to the “secrets” Nikon engineers know Intimitely, yet they expect the user to make an uninformed guesses to guide an undocumented algorithm. An attitude of “if it ain’t what you want, just reshoot it.” CRAP! We live in a dynamic world where conditions rarely if ever repeat.
 
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