Focusing in 4k
- Thread starter dapoopta
- Start date
Realdvxuser
Well-known member
Don't shoot wide open 
Good tools to monitor are quite crucial I think. A possibility to zoom in on the monitor really helps.
Good tools to monitor are quite crucial I think. A possibility to zoom in on the monitor really helps.
timmytimetravel
Well-known member
I was waiting for this thread. The early reports from those who shot 4k with sony recorder all said the same thing (able cine I think was one of them). They either always had big 21/24 inch monitors on set or they gave in and shot at medium fsstops.
i would further expect to hear things like many of the stock or less sharp lenses I use for HD being no good for 4k.
its not like it's the first camera to shoot 4k though. So I'm expecting some trickle down info from those shooting on red in regards to monitors, glass etc. Though probably many of those using red would be shooting on higher end pl mount glass and possibly more often have nice large pricey monitors on set. I've been thinking about a cheap 4k seiki monitor not for color but for on set 4k focus.
looking forward to doing more 1:1 punch in tests with my glass and putting 4k suitable coloured dots on them
i would further expect to hear things like many of the stock or less sharp lenses I use for HD being no good for 4k.
its not like it's the first camera to shoot 4k though. So I'm expecting some trickle down info from those shooting on red in regards to monitors, glass etc. Though probably many of those using red would be shooting on higher end pl mount glass and possibly more often have nice large pricey monitors on set. I've been thinking about a cheap 4k seiki monitor not for color but for on set 4k focus.
looking forward to doing more 1:1 punch in tests with my glass and putting 4k suitable coloured dots on them
4K is only 8 megapixels. Still cameras have exceeded that for a long time. I'm a still photog just getting into video but why should video be much different in this regard? Use a very fast lens - say f1.2 or f/1.8 - and do all your focussing wide open so you have paper-thin depth of field for focussing. Then stop it down to your desired aperture for shooting. Stopping it down will give you some slop incase your focussing effort wasn't perfect.
If you're starting with an f2.8 lens focus at that aperture and shoot a stop or two slower. Most lenses give their best performance a stop or two more closed than wide open anyway.
Mitch Gross
Veteran
I think the point is that it can be hard to judge focus on a lower resolution monitor, especially in motion where the focus needs to change during the shot.
I suggest you explore the different modes of the Odyssey7Q Focus Assist tool. There are different viewing modes and the sensitivity can be adjusted in them very precisely. For each Focus Assist mode there are High Medium & Low quick tabs and each of these can be fine tuned to the sensitivity you desire. The Focus Assist mode can also remain active while using other monitoring tools, including the Pixel Zoom. Once you find your comfort point you should be able to find your focus with good certainty and less stress. BTW, the Focus Assist display will not effect the readings of the exposure tools such as the waveform or histogram. They are on searate processing paths, unlike some other monitors!
alaskacameradude
Veteran
One reason video is much different in this regard, is that you are 'tracking' a moving subject as
opposed to getting one frame in focus. Even in interviews, subjects rock back and forth which
means you are pulling focus if you are shooting WFO. Of course you can stop down as you say,
and probably should do that, but it is a little harder shooting motion and keeping focus than
stills in my experience. Also, most stills cameras have pretty good autofocus mechanisms on
them as they are shooting 8-10fps maybe? That's why focus throw on stills lenses is so short, so
the autofocus can quickly get where it needs to be. Cinema lenses are different and don't
have nearly as good autofocus or it comes with some caveats. Sony's PDAF on it's LA EA2
for example will only work if the lens is at F3.5 or stopped down further. But yeah, 4k
is going to be harder to get correct focus.....just like it was harder in HD than it was in SD.
morgan_moore
Major Contributor
I think 4k focus is a huge issue. Coming from stills I realised a point where my mf skills were just not keeping up with the res. af was it from then on for stills. I mean focusing a 6ft print on a bit of glass the size of a stamp - just not going to happen.
af will become huge - intelligent af that nuges you from 2foot11 to 3foot, pending those developments good monitoring tools are the best we can muddle along with.
af will become huge - intelligent af that nuges you from 2foot11 to 3foot, pending those developments good monitoring tools are the best we can muddle along with.
alaskacameradude
Veteran
As you say.....I wonder if some of the lens makers are starting to understand this. Sony has
PDAF for the FS100/700 on Alpha lenses through the use of an adapter. And Canon now has
PDAF on certain lenses for the C100 and C300 I believe. I wonder how the Sony FS700 with
LAEA2 adapter and a good Sony/Zeiss lens works while in autofocus and recording to the Odyssey
7Q in 4K? It'd be interesting to see a test.....
paulcurtis
Veteran
Out of all the monitors i've tried the sharpness of the O7Q combined with the focus assist makes the job a little easier. Sometimes i find it better without focus assist, depending on the scene.
With low light, low contrast scenes it can be quiet difficult and one day when we get different LUTS we can have ones especially to aid with focusing (higher contrast for example)
As Sam says though, for real scenes with real people i try to aim for an f4 to give a fighting chance of tracking focus. My personal days of, oh look f1.4 makes the background look so creamy are long over, once i realised i was the only person admiring the bokeh
If your deliverable is HD though then you do get some latitude in post to sharpen areas before scaling. That can be a bit of a crutch if needed!
cheers
Paul
With low light, low contrast scenes it can be quiet difficult and one day when we get different LUTS we can have ones especially to aid with focusing (higher contrast for example)
As Sam says though, for real scenes with real people i try to aim for an f4 to give a fighting chance of tracking focus. My personal days of, oh look f1.4 makes the background look so creamy are long over, once i realised i was the only person admiring the bokeh
If your deliverable is HD though then you do get some latitude in post to sharpen areas before scaling. That can be a bit of a crutch if needed!
cheers
Paul
Realdvxuser
Well-known member
We shoot Red One, with original monitor. I find that monitor with the edge focus assist to work well. The monitor has a button ontop assigned to quikly punch in for critical focus. That is all I need really.
It does pay off to get good lenses, still or cine - new or older, and to know what these lenses do. You'll find out eventually anyway, but some good testing to get to know your lenses behavior will help to know what to aim for and what to avoid.
It does pay off to get good lenses, still or cine - new or older, and to know what these lenses do. You'll find out eventually anyway, but some good testing to get to know your lenses behavior will help to know what to aim for and what to avoid.
Colinelves
Well-known member
I wouldn't worry about it so much. Most regular audience members can't tell when stuff us out of focus anyway and decent editors realise this (of course young or arrogant editors don't and will happily berate you because yo're not there to defend yourself). Most films I watch in the cinema have a few soft shots in them.
I'd also advocate shooting at 4/5.6 rather than wide open. The lenses perform better at those apertures (sharper, better contrast, more consistency edge to edge) plus shooting wide open makes everything look like it was shot on a 5D - it's rather outdated IMO.
also, use the focus assist. I generally have it set to low and that works for me as it means, if I can't see it, it's probable soft (doesn't always work mind, if the subject contrast is low).
I'd also advocate shooting at 4/5.6 rather than wide open. The lenses perform better at those apertures (sharper, better contrast, more consistency edge to edge) plus shooting wide open makes everything look like it was shot on a 5D - it's rather outdated IMO.
also, use the focus assist. I generally have it set to low and that works for me as it means, if I can't see it, it's probable soft (doesn't always work mind, if the subject contrast is low).
morgan_moore
Major Contributor
IMO the bigger picture is the manufacturers need pressure to produce usable tools. We should not make excuses for tools that are not fit for purpose.
The centre only focus check on the F5, for example, is one thing that convinced me that it was not a tool developed hand in hand with people working the cams.
Ive 'requested' to Mitch that CD develop a lanc style controller for the 7q with focus pop (and of course a roll button) - a simple button with a 15mm mount?
Let us make calls like that louder.
S
The centre only focus check on the F5, for example, is one thing that convinced me that it was not a tool developed hand in hand with people working the cams.
Ive 'requested' to Mitch that CD develop a lanc style controller for the 7q with focus pop (and of course a roll button) - a simple button with a 15mm mount?
Let us make calls like that louder.
S
paulcurtis
Veteran
That's a fair point too.
A +1 for a remote that can be added to a grip that allows me to :
- turn focus assist on/off
- can do a 1:1 zoom
- can turn waveform on/off
- start and stop (although that's a camera driven function)
The O7Q has the remote port so perhaps it's just a case of publishing the specs?
cheers
Paul
morgan_moore
Major Contributor
Yep it should be possible, and hopefully not a plastic bit of junk on a 50cent wire.
Start/stop - I dont know the details but if you are recording to SSD then it doesnt have to be camera lead.
(might be safest to just leave the cam recording to onboard and use SSD start stop)
S