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Author Topic: focus by wire far superior to direct manual focus? and other stuff  (Read 1480 times)
simonstucki
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« on: January 28, 2013, 06:45:55 AM »
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in the DP3m thread someone mentioned that the DP3m has a non linear focus (by wire) it slows down when you get closer. that of course makes a lot of sense and is much easier with focus by wire.

that got me thinking what other cool stuff would be very easy to achieve with focus by wire (I'm no expert in focus by wire, so maybe some of these things already exist, then please let me know):
0. it needs to be configurable in the camera menu, you should be able to turn things of, make it faster, slower or whatever
1. accelerated focus. if you turn the focus ring faster the lens focuses faster (just like with a computer mouse)
2. aided manual focus with eye control: I don't know if that would work (it definitely won't be easy to perfect) or even make sense but maybe it is interesting to think about. one of the biggest problems with manual focus is that the accuracy is not very high without a magnified image, but the magnified image for me often defeats the purpose of manual focus (manual focus for me has the advantage that I can focus on any area of the image in a very intuitive way, I don't have to fiddle with badly placed buttons and stuff). so my Idea would be that the camera measures where you look and as soon as you focus manually and get close to perfect focus in the area where you look at the camera focuses there. I think to work really well that would have to calibrated to a specific user (not just the eye control but also the dynamics) and it would work better the more precise the eye control is (if the eye control is not fine enough you won't be able to make very small focus changes).
you might ask why not just eye controlled af? of course that would also be possible, but the advantage of the manual version is of course, that the camera does not focus if you don't turn the focus ring (for it to work properly I think the camera should still fine tune the focus for a short period of time after you turned the focus ring) so if you stop turning the focus ring the camera won't do any thing and you can look at some other part of the image (for whatever reasons) without changing the focus. true you could also achieve that with a focus lock button, but I personally hate those buttons it is just not intuitive for me.
3. ?


Current problems with focus by wire: lag, if you turn of the camera the focus changes (olympus has a very nice solution here on their 12mm and 17mm lenses) but as far as I'm concerned I think these problems can be solved (one actually already is). any other problems?


and a note on af: why is there no camera with a something like a joystick on the front of the camera (on the shutter button side of the lens) for focus area selection? I think that would be far easier to use while shooting than anything on the backside of the camera. don't you hate the focus area selection interface on every camera? I know I do very much!


what do you think?
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Hulyss
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« Reply #1 on: January 28, 2013, 07:14:11 AM »
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I might add that the DP2 Merrill (as well as the DP1 Merrill) have the same focus mechanism : It slow down when you come closer to the limit.

Just to say it is not "new" and, as a DP user, I would say that it is effective but the " focus feeling" is gruesome. When you come close to the focus limit, the lens make some little noise like "takatakatak..." and some very light vibrations you can feel in your fingers at each little noise. The reasons are simple : The focus ring do the job but the piezoelectric progressive wave motor is absolutely not smooth; look like he work by impulsions instead of linear continuous signal.
« Last Edit: January 28, 2013, 07:16:50 AM by Hulyss » Logged

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uvl
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« Reply #2 on: January 28, 2013, 11:36:56 AM »
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Most lenses I know have logarithmic rather than linear focus scales. This is what the Sigma DP Merrill developers simulate (with steps of slightly overlapping DOF at open aperture ->taktaktak).

Uwe 8-)
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