Manual Focusing
Jun 26, 2015 23:37:21 #
tradio wrote:
Another advantage of BBF.
How so? Please understand that I'm not trying to be sarcastic or argumentative with my question. I am truly interested in how BBF can mitigate this problem. Thank you.
Jun 27, 2015 06:03:28 #
John_F wrote:
This is a general question and I realize there will be variations amongst different cameras. Here it is. If I have the camera set to any one of the various auto-ficus options, would I damage the lense mechanism by rotating the lens barrel in the event I am dissatisfied with the auto-focus result. Should the camera software reassert its focus.
What would be the point?
Unless you turn off A/F or use back button focus, the lens will focus back to where it was when you press the shutter.
Jun 27, 2015 06:11:04 #
John_F wrote:
This is a general question and I realize there will be variations amongst different cameras. Here it is. If I have the camera set to any one of the various auto-ficus options, would I damage the lense mechanism by rotating the lens barrel in the event I am dissatisfied with the auto-focus result. Should the camera software reassert its focus.
It depends on the lens/camera. What gear are you asking about?
Jun 27, 2015 06:18:41 #
tradio wrote:
Another advantage of BBF.
This has nothing to do with back button focus. For example, if you have an old Nikon 80-200 F2.8 AF-D, there is an AF/MF switch on the lens barrel. If it is set to AF, the focus ring is locked and non-functional. You can not manually focus - regardless of which button activates focus acquisition on the camera. A Tamron 180 F3.5 Macro is similar - the focus ring itself is a switch. To let the camera focus you move the ring forward, which disengages the ring from the lens' mechanical focus. Shift the ring to the rear, the lens can be focused manually. Again, independent of shutter or back button focus.
Jun 27, 2015 06:48:48 #
Jun 27, 2015 07:07:33 #
Jun 27, 2015 07:16:05 #
SharpShooter wrote:
Tradio, I don't see how BBF has anything to do with it?! ;-)
SS
SS
That's because you shoot Canon. :D
Jun 27, 2015 07:18:26 #
jerryc41 wrote:
That's because you shoot Canon. :D
And we all know what C.A.N.O.N. Stands for - Can't Afford Nikon Oh No. :XD:
Jun 27, 2015 07:40:46 #
tradio wrote:
Another advantage of BBF.
The question is valid in BBF also. Some lens allow it and others don't.
Jun 27, 2015 07:44:59 #
tradio wrote:
With BBF, the auto focus only activates when the back button is depressed. If you want to manual focus, just don't press the back button.
You have auto focus at the touch of a thumb or if you want manual, let off the button and focus away.
You have auto focus at the touch of a thumb or if you want manual, let off the button and focus away.
Yres. With BBF the AF mechanism is essentially off until the button is pressed
Jun 27, 2015 08:00:35 #
Gene51 wrote:
How so?
Gene
My understand is that when using the shutter button to activate AF you are fighting the the focus motor when you have the button half pressed and try to manually focus (possibly damaging the motor). If you release the shutter button, you can manually focus but when you press the shutter button again the camera will refocus.
When using BBF you can manually focus and release the shutter without having the camera refocus. (as long as you don't press the button you are using for AF)
If I'm wrong....it wouldn't be the first time.
Jun 27, 2015 08:33:52 #
wingclui44
Loc: CT USA
tradio wrote:
With BBF, the auto focus only activates when the back button is depressed. If you want to manual focus, just don't press the back button.
You have auto focus at the touch of a thumb or if you want manual, let off the button and focus away.
You have auto focus at the touch of a thumb or if you want manual, let off the button and focus away.
This is only work when using AF-s lens with built in motor, it doesn't work on any screw type lens. If you have the camera set on AF, using BBF for auto focusing with a screw focus type lens, you have to switch the AF/MF switch on the camera to MF for using the focus ring to MF. Otherwise, you may damage the driving linkage in both of the lens and the camera. It's like you are towing your car with out shifting the gear to neutral. That will damage the transmission of your car.
Jun 27, 2015 09:09:46 #
Psergel wrote:
Gene br My understand is that when using the shutt... (show quote)
Paul, at least in the case of Nikon AF-S lenses, when you use the focus ring to manually focus, even if the camera is attempting to autofocus by either BBF or shutter half press, the moment you move the focus ring the AF motor will disengage. The reason it works this way is precisely the reason you state - Nikon does not want people putting stress on the AF motor by trying to focus when the cameras AF is engaged.
Now Sigma is different. If you grab the focus ring on an HSM lens while AF is engaged, it will fight you for focus, so your observation is correct for Sigma lenses, and the BBF is a good workaround for that.
Personally I like the Nikon approach. It's a little more flexible. And you are correct for Sigma (and possibly other) lenses.
Jun 27, 2015 09:15:41 #
Gene51 wrote:
Paul, at least in the case of Nikon AF-S lenses, w... (show quote)
Many of the canon lenses have what they call "full time manual focus"
and then there are the new STM lenses which won't focus at all unless the camera is "awake"
Jun 27, 2015 09:37:42 #
wingclui44 wrote:
This is only work when using AF-s lens with built in motor, it doesn't work on any screw type lens. If you have the camera set on AF, using BBF for auto focusing with a screw focus type lens, you have to switch the AF/MF switch on the camera to MF for using the focus ring to MF. Otherwise, you may damage the driving linkage in both of the lens and the camera. It's like you are towing your car with out shifting the gear to neutral. That will damage the transmission of your car.
I have Tamron and Nikon AF lenses that use the camera's focus motor. You can switch the lenses to manual focus and leave the camera in autofocus mode. In fact, switching the camera alone to manual focus will not allow you to manually focus these lenses. You still need to switch the lenses to manual focus. Switching the lens to manual focus will not allow the camera to try to autofocus. The camera will "see" a manual focus lens and won't try to focus with either BBF or shutter half press.
As far as cars are concerned, what you say is true if you have a manual transmission. If you have an auto transmission, you need to tow with the drive wheels off the ground, even if you are in neutral. The transmission lube pump in most automatic transmission cars is driven by the motor. The only safe way to tow a car with the drive wheels still on the ground is to disengage the drive shaft from the transmission. If you have an all wheel or four wheel drive, you need to use a flatbed or tow dollies. If you have manual lockout hubs and manual transfer case lockout, then you can tow with all wheels on the ground.
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