D7100 wont focus for video, set for back button focus.

[dannylightning]

cant find anything in the manual or on google. i figured out how to set a button for auto focus but i would also like to have a button so i can make it focus when i want it too. auto focus was not so great for filming the great blue heron today, kept going in and out of focus if i did not have the center point right on the bird.

 

[dannylightning]

actually its not auto focusing i guess i had it wrong,

i just played with it a bit to see what i could figure out.. when i press the back button which is set for auto focus on, but that is not what its doing. when i press the button on the back it will focus once and will not focus again till i press the button again instead of auto-focusing like it should.

maybe i am wrong but i though auto focus for video mode would focus on it own when your subject moved around and went out of focus.. i took a video once with my other DSLR and that is how i remember it working but i may be mistaken. after reading and watching some videos i am thinking maybe that is not how it works.

i guess i need to get the manual back out again and read over it another time

 

[STiZzle2010]

This may help...
How to Set the AF-Area Mode on Your Nikon D7100 - For Dummies

 

[runnah]

Very few DSLR have "active" AF for video. I know canon has 2 models that currently do this but I don't think Nikon had any models that can do that.

 

[dannylightning]

This may help...
How to Set the AF-Area Mode on Your Nikon D7100 - For Dummies

for dummys, are you calling me a dummy ???? thanks, ill check that out.

 

[dannylightning]

Very few DSLR have "active" AF for video. I know canon has 2 models that currently do this but I don't think Nikon had any models that can do that.

you may be right, i am gonna pull my manual out in a few min here and see what i can figure out and ill check out that link that was posted and figure out exactly what she can do. when they say auto it makes it sound like it will automatically focus. should be called manual focus if it does not do it automatically.

 

[wfooshee]

Back-button focus is supposed to work as you describe. It's only active while the button is held down; it does not start an AF mode "on."

It does auto-focus, but only while the button is pressed.

That makes it easy to switch between AF-S and AF-C modes when shooting stills. Hit it and let go, or hold it down. You don't have to make a menu or settings change.

The camera's behavior of ignoring focus until you press the button is not manually focusing; that's triggering the auto-focus at a specific time. Manual focus is turning the thing on the lens and judging for yourself through the viewfinder.

All of that said, I don't see the point of back-button focus for video. I'm not sure the manual even describes the button's behavior in Live View or video.

Consider also that the AF operation is through a completely different system for video than for stills. the super-duper ultra-hot-shot 51-point AF system is locked out of view when the mirror is up for Live View, and unable to contribute to video in any way. The AF system during video is contrast sensitive to what it sees on the sensor, a much slower system, and more prone to "guessing" which way to move the focus, which results in focus hunting, none of which you'll see in still photography.

 

[dannylightning]

when i have the camera set up for back button focus the shutter button does not focus when shooting video so i guess it needs to be on back button focus. it does seem to hunt a bit when you let it auto focus which is annoying. when i was filming i had the big lens on there and did not have my monopod with me so trying to manual focus and hold up 8lbs would not be a easy task.. or i would have just went that rout.

thanks for that info..

 

[wfooshee]

Yep. AF on video is still painful on most Nikons. Slow, hunting, sometimes unable to focus at all. No aperture control during video shooting, either; whatever the aperture was when you started recording is the aperture for the duration. I'm still of the mind that if you want a video camera, you should get a video camera.....

 

[KmH]

See page 153 of your D7100 User's Manual.
Your D7100 can only AF using contrast-detection AF when using Live View for stills or for video, and not the way faster phase-detection AF used to make still shots when not using Live View.
See the Live View Auto Focus specifications on page 339.

If you want to use AF-On in Movie mode it looks like you have to set that to the FN button on the front of the camera, not on the the AE-L/AF-L button on the back of the camera - see page 259 - g: Movie.

You should get your keyboard Shift key fixed. All lower case is harder to read than making sure yo can make the appropriate capital letters.

 

[dannylightning]

See page 153 of your D7100 User's Manual.
Your D7100 can only AF using contrast-detection AF when using Live View for stills or for video, and not the way faster phase-detection AF used to make still shots when not using Live View.
See the Live View Auto Focus specifications on page 339.

If you want to use AF-On in Movie mode it looks like you have to set that to the FN button on the front of the camera, not on the the AE-L/AF-L button on the back of the camera - see page 259 - g: Movie.

You should get your keyboard Shift key fixed. All lower case is harder to read than making sure yo can make the appropriate capital letters.

the AE-L/AF-L button on the back of the camera works. i did assign one of the buttons on the front of the camera to do that, seems to do the exact same thing as the the AE-L/AF-L button when focusing for video.


the shift key works fine. my fingers only know where the letter keys and the space bar is.

i have never had a hard time reading all lower case letters when people type.. people on some of the forums i am on often type much worse than i do. i am not sure how a capital letter at the beginning of each sentence would make something easier to read. as far as capitalizing anything other than if you are supposed to do that other than the first letter of a sentence i have no idea what is supposed to be capitalized for the most part.

my spelling is bad, my punctuation is probably bad, i am dyslexic I was never able to pay attention in school. even now if i try and set down and read a book or do some paper work, after about 10 or 15 min i cant stand it any more and start freaking out, loose concentration and have to get up to do something else. when i write on paper half the letters are capital and half are lower case. i cant really read or write in cursive well.

my brain does not work well for allot of things, writing, reading, spelling and math are things i have never been any good at.