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Author Topic: Using AF on Nikon D4 / D800 with HDMI output  (Read 3283 times)
Roskav
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« on: August 01, 2013, 07:23:52 AM »
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Hello I am setting up a pair of Atomos Ninjas on a D4 and D800 and have come across a problem.  Normally when you activate AF in Live view the display momentarily gets brighter or darker to take account of the focusing.  This is not a problem when you are recording a movie to the card in camera as there seems to be a overriding fix for this phenomenon.  When the HDMI is outputting to the Ninja however, the pulses of light/dark become a feature of every focus acquisition.  This makes it impossible to use the AF when recording from the HDMI.  This is how it seems anyway to me.  Any thoughts?
Ros
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RFPhotography
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« Reply #1 on: September 02, 2013, 10:48:36 AM »
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Focus manually. Grin  AF in DSLRs just isn't ready for prime time when video is concerned.
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Roskav
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« Reply #2 on: September 06, 2013, 04:43:10 PM »
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Hi Bob thank you for your wisdom!  Yes I know it pays to keep it simple but to be fair I have found both of the nikons to be pretty good at getting focus in video mode using af.  If you are trained on a subject who gets up and walks to another spot during your recording and you want to keep rolling, a little dab on the af snaps the focus in quickly and nicely  - honest!  I have been using focus peaking on the ninjas though for most of my recent work ... which is fine ... but has drawbacks if you have to make a quick focus change while recording.  You have to get used to the vagaries of how the peaking behaves, as you will get some readings when close to the right focus which make you assume that it may be ok ... but rotate the ring a gnats cock further and you realise you weren't really there as your target becomes saturated with the red honeycomb lines.
I let Nikon know about this pulsing issue and they seemed to take it in, I wonder will they address it. I haven't grappled fully with everything yet but I am frustrated with how the auto iso works in any automatic metering mode... it ramps right up to 11 with no option for you to set the max allowed.  (At least this is as much as I can figure out at the moment)  I know .. you are going to give out to me for using any auto exposure... why have all these great capabilities and not use them though? 

R
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RFPhotography
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« Reply #3 on: September 06, 2013, 05:36:28 PM »
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At this point, auto-anything with a DSLR capturing video is, I believe, an accident waiting to happen.  I know it's not what you want to hear but, while SLRs can capture some pretty terrific footage in terms of quality, using them in other than full manual is leaving yourself open to problems.  AF may work in some instances, like the one you note, but then may go walkabout the next minute.  I don't have a Ninja but have been playing with peaking in a a few other ways recently (love the 'gnat's cock size reference btw, haven't seen that one before) and have found it quite good, but that could he a function of the application.
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lowep
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« Reply #4 on: September 20, 2013, 07:04:49 PM »
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If as you suggest DSLR autofocus is an accident waiting to happen what entry level camcorder would you point to as an autofocus champ that also has a good image stabilizing system, performs well in low light and doesn't cost two arms as well as a leg?


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bcooter
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« Reply #5 on: September 20, 2013, 08:53:43 PM »
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If as you suggest DSLR autofocus is an accident waiting to happen what entry level camcorder would you point to as an autofocus champ that also has a good image stabilizing system, performs well in low light and doesn't cost two arms as well as a leg?




Opinions are going to fly on this, especially when anyone talks about autofocusing motion content.

Most people think it's heresy, but really most of that comes down to how bad most autofocus is on cameras that have anything larger than 1/3" chip.

We just finished a series of projects we had to shoot fast to slow.  Kind of documentary style for advertising, some dialog, some mos wild, some real scenes, some crafted.  Yea I know, that's a mouthful.

Anyway, I looked at every camera imaginable to compliment our main cameras which are RED 1's and Scarlets.  I bought and/or tried Nikons, Canon's then settled on the GH3 Panasonic.

Now, I'm not going to say that the autofocus is perfect . . . it's not, but I shot 90% of all the GH3 footage at 2.8 or more open (depending on lens) and if you use care and thought the autofocus is really good.

The key is setting the camera up after blocking the shot.  The GH3's have various ways to autofocus, continuous or single, face detect, single point, size moveable focus size and different forms of tracking.

The few times we hunted or missed focus was just pure operator error, or not the right setting,  never from the actual camera function, but once again, there is no one size fits all setting.

If your handholding, or tracking with a dolly, or in our case I use a wheelchair when possible and you have a subject going one way, your going the other, which I think is one of the hardest scenes to hit focus on, even for experienced focus techs, if I set the camera right, it would hit focus time after time.

The only glitch is on slow moving subjects, like a kind of moving side to side walk/talk, but those are easy scenes to manually focus.

Sorry to go on about this, but I've tested and used about every motion camera I could afford and went with the RED's because at the time they produced the most robust file of any digital motion camera under $50,000, but honestly the gh3's shoot way about their weight.

I'm not saying the GH3's produce a 13 stop range or go much past 1000 iso without some noise in the shadows, but quality wise in 2k they very much get close to the REDs.  Almost crazy when you think the bodies sell for $1,200.

Now the GH3's do have a dslr form factor which doesn't make for the easiest motion camera and they only have on sound channel for input, (which is fine for scratch, or for single interviews quite good if coming from a good sound tech and mixer) and they're small and for most motion subjects I would disregards the lens stabilization because sometimes you get a strange skewing of the image.

Also they will jello cam on horisontal whip pans, but other than that, s__t, they're damn good.

One key is to plan your look and coloration. You can't insert logs (as far as I know) but with some tuning in the menu, careful selection of white balance you get a file that grades very, very well and the sharpness is very good.

The new Pana 2.8 zooms could be faster, but they don't breath near like Canon still lenses and they have a very pretty and soft roll off from highlights to midtones, midtones to shadow while holding great sharpness.


IMO

BC

p.s.  Just a note, but we had one shot with the gh3 that I did on a whim, a subject getting out of a car and walking towards camera.  I never thought I'd use it in the edit and didn't add any fill light.  The subject, actually the whole image was at least 2 1/2 stops under.  It was one of those overcast days where the light source was behind the subject and the sky had very little detail even underexposed.

Anyway, turns out I needed it to fit the voiceover so I threw it in the edit, knowing it would never grade, but tonight in secondary grading, I twisted the curves, opened it up the color was good the detail good, even the backlit sky held some detail.  I was floored and even ran it full screen to make sure I wasn't fibbing to myself.   These are very good little cameras.
« Last Edit: September 20, 2013, 09:34:48 PM by bcooter » Logged

lowep
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« Reply #6 on: September 21, 2013, 10:50:22 AM »
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...how bad most autofocus is on cameras that have anything larger than 1/3" chip

Good to hear not everybody brushes this question off with a jaded sniff as if a lapdog had just pooped on their gucci loafers ie "real pros use manual focus so anybody who asks about a video cameras autofocus system is a jackass blah blah blah!"

Is this the same issue that dogged DSLRs like the Canon 5D Mark II?

Does the same principal apply to the relationship of the camcorder's sensor size and the effectiveness of the stabilizing systems as it does to still cameras. Or if hand holding camcorders gets more difficult as the sensor size gets bigger in camcorders as for example it does with full frame compared to apsc dslrs. And if larger sensors can be expected to perform better in low light and provide better DR than small ones... in which case it is difficult to understand why a camera with a relatively small sensor like the GH3 gets so much praise compared to other combocams with larger sensors?

Maybe there is more hocus pocus going on in the background of modern camcorders and combocams like the GH3 than in legacy models. 
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bcooter
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« Reply #7 on: September 21, 2013, 07:45:11 PM »
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...how bad most autofocus is on cameras that have anything larger than 1/3" chip

Good to hear not everybody brushes this question off with a jaded sniff as if a lapdog had just pooped on their gucci loafers ie "real pros use manual focus so anybody who asks about a video cameras autofocus system is a jackass blah blah blah!"

Is this the same issue that dogged DSLRs like the Canon 5D Mark II?

Does the same principal apply to the relationship of the camcorder's sensor size and the effectiveness of the stabilizing systems as it does to still cameras. Or if hand holding camcorders gets more difficult as the sensor size gets bigger in camcorders as for example it does with full frame compared to apsc dslrs. And if larger sensors can be expected to perform better in low light and provide better DR than small ones... in which case it is difficult to understand why a camera with a relatively small sensor like the GH3 gets so much praise compared to other combocams with larger sensors?

Maybe there is more hocus pocus going on in the background of modern camcorders and combocams like the GH3 than in legacy models. 


There is a new paradigm in the world of professional images, especially in motion imagery.   It's kind of like moving stills and no I don't mean animated Gifs, but motion imagery shot, framed and cut with the dynamics of motion and the framing and lighting of a dramatic still image.

More Anthony Dod Mantle, less Roger Deakins, or in other words, more drama, faster cuts, less time with each image spent on the screen, unless it's a virtual slow motion.

These little cameras are perfect for that style of work, but once again the system has to be learned and used, (or not used) when it's appropriate.

What kills autofocus is hunting.  Now that one is worse than just a bad miss, but if you watch any theatrical or episodic release and don't see a lot of slightly missed focus then your not looking.

Motion allows for missed focus in some instances, as long as it's slight or the subject is in the range long enough to give the impression of focus.

Actually some out of focus imagery can be wonderful and add to the human element, but there has to be a reason.

Really great human focus pullers that do it manually are like Zen, I mean they're amazing that they can look across a street and say 24 ft. 4" and be right, but even with that I think the day will come where you will see a larger separate lcd like on the GH3, where a focus puller just tapes the subject or the area and it racks in, taps back on cue.

I think you'd see it today on large productions, because obviously it's possible to have manually assisted autofocus, except all the good, beautiful, very expensive prime movie lenses in the world are all manual mounts.

Though no, I don't think it's the size of the GH3's format that allows good autofocus, I just think it's a well thought out system for some uses.  Actually it's a very well thought out camera, but what is good and acceptable to some, other's find the opposite, which doesn't matter if the end result is there.

I believe the reason people have a hard time taking the gh3 seriously is the price and the form factor.  If it was shaped more like a specialty camera, had a metal exterior casing and cost $15,000 then I think the reviewer world would wet themselves over it.  But it looks like a small prosumer camera and even with that if it had the issues that RED, or Black Magic had and someways still has with their cameras, (and both these brands have a huge fan base), then the reviewers would have dragged panasonic out into a field, set them on fire and tossed them over the cliff.

Once again, the only thing that matters is the final result, not what any segment of the industry considers good or proper.

IMO

BC



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Hywel
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« Reply #8 on: September 23, 2013, 05:44:02 AM »
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As usual, Cooter has nailed it.

If you are shooting in the frenetic modern style, you can live with slightly missed focus. But you need to be able to get the focus on the fly, possibly with only loosely rehearsed and blocked action. Few actors can nail marks every time when running the whole length of a stage, and if you are doing semi-improv in the great outdoors, forget it.

For those purposes, I believe that the "movies must have manual focus" people are wrong. I think decent autofocus lets you get shots with one or two crew in 15 minutes that would take a whole day and a large crew to nail "properly". I'm finding that a GoPro is even fine for this stuff, shooting HD 50 fps and intercutting with a Scarlet shooting 4K 25 fps. You just can't leave the shots on screen for too long. You don't want to use the GoPro for a smooth lingering opening shot or a long conversation, but for running through a building or a fight scene, it's acceptable. 

Rumors just starting of Panasonic's replacement for GH3... I'll wait a few months and either grab the replacement if its AF is better, or pick up a second hand GH3 once the gotta-have-latest guys start eBaying their GH3's.

  Cheers, Hywel.

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lowep
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« Reply #9 on: September 23, 2013, 05:04:30 PM »
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Sounds like different strokes for different folks. For shooting documentary-style footage with no rehearsal, no actors, no blocked action, no focus puller and no script I find autofocus is very helpful. Interested to see what Panasonic has up their sleeve.  
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bcooter
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« Reply #10 on: September 23, 2013, 06:51:34 PM »
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Sounds like different strokes for different folks. For shooting documentary-style footage with no rehearsal, no actors, no blocked action, no focus puller and no script I find autofocus is very helpful. Interested to see what Panasonic has up their sleeve.  

I'd love to see them go to a 444, 10 or 12 bit file and add two sound channels way before they do 4k, but I'll bet it's the opposite.  Numbers sell and Panasonic is more than cameras, they gotta sell TV's and TV sales are not good, so they probably think 4k will help.

I keep saying most of this stuff like 4k is just a catch phrase and we all get way too caught up in the numbers less caught up in what goes into the camera, but I don't make this stuff, I just buy it and use it.

I still stand by the fact the GH3's are the most usable cameras I've ever owned, price regardless.  They turn on, work professionally and take the learning curve of a flip phone.

I'd also like to see them go nuts and make some killer F1.2 primes and F2 zooms.  I know they'd be big but man what that camera could do with one more stop.

I hope Panasonic doesn't screw it up.

IMO

BC
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