Focus Hold Buttons on Lens

[John C]

A couple of my lenses have focus hold buttons. I understand that these buttons stop the autofocus. They are positioned so you can hold them with the fingers of the left hand. I'm not exactly sure when to use the buttons and was wondering how others might be using them (or not). One is on my 50mm macro. I guess I would use the focus hold button on this lens when handholding the camera and hold the button rather than switching to manual focus. The other lens that has the focus hold button is the 500mm. I suppose this one would have the button used in the same situation but handholding is limted to rather bright conditions.

Anyway, I am wondering how others use these focus hold buttons.

[Colin Southern]

Hi John,

I don't have any focus hold buttons on my lenses, but I can program AF ON/OFF onto a button on the back of the camera - or just switch the lens to MF (which I do a lot when shooting landscape).

So I'm probably not going to be much help in answering your question, but I would guess that it might be handy if for example you were panning the 500mm lens with the AF in SERVO mode, and didn't want it to react to something that pops into the field of view (perhaps a pole). I guess that it's a bit like a "temp" MF switch.

[Dave Humphries]

Hi John,

As Colin says and, for those that actually hold their camera when taking a picture possibly:
To allow you to half depress shutter button on a plane of required focus, freeze that by holding down "focus hold" while releasing shutter button, reframing again and half depressing shutter button, this time on an area to meter from, then holding both focus and metering, do your compositional reframe and complete the press of the shutter button to expose the image.

My lens doesn't have such a button , but there are others on the camera I could progam, as Colin says.

The camera manufacturers seem to provide 2 or 3 methods of doing things like this these days, so people can program the buttons they feel comfortable using. Such user programmed ergonomics builds brand loyalty (for those that can figure out how to do it - now, where did I put my D5000 manual ).

Cheers,

[Faldrax]

Hi John,

On the macro I *think* the idea is that you can AF to get close to the desired shot, then use the focus lock button and control exact point of focus by moving back/forward relative to the subject.

For longer lenses it can be used as Colin suggested - to avoid that sinking feeling you get when panning and suddenly the AF decides some intervening object must be what you want to focus on

BTW: Welcome to a fellow Sony user (I'm an occasional visitor, so miss many of the 'Hello' messages in the Welcome thread).