I think the lenses feed back focus zone info rather than precise extension or focus distance... but it might be possible to achieve something useful just through focus motor run time.
I think that this would be worth perusing, as DOF is, perhaps, the main problem with MF.
This is an interesting idea ... if I am understanding it correctly.
Feed back in what way?
Some data is fed back to the camera from the lens, the zoom setting, F stop and the shutter speed, as this info is required for exposure calculation, and it is also recorded with the picture, and this was possible when the controls for setting the aperture and shutter speed were on the lens.
It would be possible to feed back the focus distance or extension... it is difficult to work out how true focus can work without this info, as the camera has to re-calculate the extension to correct the focus distance to maintain focus on the subject component on which you originally focused.
I seem to recall some camera I once had that showed you exactly where the critical point of focus actually was in an image after taking it ... but I can't recall if it was on the LCD or in the software when processing.
Also, a number of cameras I've used had a feature where you focused on two different points in a scene and the camera set the proper f stop to keep it all in "reasonable" focus. Question is wether "reasonable" is enough with MFD as these sensors get bigger and DOF gets thinner?
Please help me understand how focus bracketing would work, and how you would apply it in practice.
Thanks,
-Marc
The Sinar P2 & P3 systems have a mechanical system with which you focused on one point in a scene, and you can read off the proper f stop to keep it all in "reasonable" focus from a scale as you re-focus to the other end of the extension range.
With the Hasselblad you would focus on one end of your desired DOF range, press a button to record the setting and then do the same for the other end...
The electronics would then tell you what aperture you would need to get it all in focus, or how many exposures you would need to DOF stack to get it all in focus. If you have to use DOF stacking you would probably want to use the aperture for optimal sharpness (e.g. f8) but the software could give you the option to use any specified aperture, and would calculate the number of shots required accordingly, depending on the disc of confusion for the lens in use at the specified aperture.
Then you would press the button and let the camera get on with it, dividing the extension range by the number of shots required and setting the extension for each shot.
The true focus technology would allow you to point the rangefinder spot at subject components and re-calculate the focus distances for you.
I am a retired "has been" real-time computer programmer, electronic engineer, mechanical engineer, technical author, part-time professional photographer... an I am now trying to come out of retirement as a "solutions provider" photographer, specializing in work that the average Professional Photographer cannot cost-effectively undertake with standard pro kit.