Focus Problems on the AF100

Jon Furtado

Jon Furtado

Well-known member
So,

I just heard back from a short film I shot on the AF100 in March and the director said almost half the footage was out of focus! My heart sank. I'm sorta bummed that it ended up this way. I used a set of Zeiss standard speeds, (16,24,32,50,85mm) a Tokina zoom 28-70mm and the hot rod PL adaptor. I didn't have a monitor and focused via the focus assist on the camera EVF and the side monitor.

Am I doing something wrong?! What could be wrong? Do I need to have my entire system bench tested in LA?! Help!
 
I just shot a ten minute proof of concept with my AF100 and while using longer lenses I found I could hit focus pretty consistently just using the LCD's focus assist. But on short lenses with anything wider than a close-up, I was almost always off (and had a 720p monitor on set to set my focus marks with).
 
How out of focus? Can you post screengrabs?
Did you turn your sharpening all the way down? While many others have recommended this setting in their scene files, I've found it to look a bit too soft myself unless planning to apply sharpening in post.
 
It is unlikely to be the camera at fault.

Do some tests in a controlled situation (preferably with an HD monitor) and some focus charts and your box of lenses.

FWIW. We find the red focus assist to be amazingly accurate and extremely helpful. I actually prefer to operate with it on now that I am used to it being there.
 
Ughhh. I feel your pain Jon. I got burned once as well. I settled on the Zacuto Z-Finder EVF as a solution and haven't looked back.
 
I find it very difficult to hit perfect focus on the AF's LCD and VF on anything wider than telephoto. I use a Cineroid EVF to set and check focus.
 
Jon Furtado said:
So,

I just heard back from a short film I shot on the AF100 in March and the director said almost half the footage was out of focus! My heart sank. I'm sorta bummed that it ended up this way. I used a set of Zeiss standard speeds, (16,24,32,50,85mm) a Tokina zoom 28-70mm and the hot rod PL adaptor. I didn't have a monitor and focused via the focus assist on the camera EVF and the side monitor.

Am I doing something wrong?! What could be wrong? Do I need to have my entire system bench tested in LA?! Help!
Click to expand...

A little rant..

Firstly - unless you are focussing using the witness marks on the lens there is no reason for your camera to need setting up on a bench

Secondly..

This is large sensor (narrow DOF) high resolution image aquisition

Something that has not really been avaialble to the 'general public' (sub hollywood crews) before 2009

'Hollywood' has been dealing with Narrow DOF, HD for years, using tape mesures, expensive calibrated lenses and extremely talented focus pullers, even talented actors who can hit marks

Often they use $10K sonic distometers too

Also 'hollywood' often use a lot of light and actually shoot quite deep DOF compared to smaller crews - often on large sets where the subject gains isolation through set design/lighting - not open apertures

Fast forward to 2011

You are trying to shoot a narrow focus camera by yourself !

You are shooting 1080 while looking at a 480 monitor - 1/4 of the final resolution

You just cant tell focus off a monitor however talented you are because you can only see at 1/4 of the recorded resolution

(same goes for a evf)

The peaking of an EVF is only working at that 480px resolution too

So that wont work either - it will help but wont actually work

That you or your director even thought you could sustain focus was the error

Unless you are on set with a 1080 monitor neither of you can tell either - you just cant with a device that shows 1/4 of the final resolution

Equipment makers are bringing us the resolution but not the technology to actually use it

So dont beat yourself up for any error apart from trying the impossible

A way forward?

Well a 1200px monitor is a start, but only a start, zoom it in to 1:1 and you are getting there, but cannot see all of your frame!

I think you need to need to be aware that tiny monitors and peaking cannot be relied upon and look at your approach

you can move towards the tape mesure or shoot in a different new way

For example a shot walking towards the camera - very hard to focus - Id just do a second take from the side (easier to focus) if you drop focus on the walk in shot - cut to the side on view

Maybe not what the director wants - but he/she is the one who did not hire a full crew and technology package and has to live with the compromises - and cutting to a side or a wide may be a good compromise

Also consider new techonolgy - be a heretic - use the kit lens for walk in shots - if it works it works

I think 'new' filmmaking is an art of learning a new set of workarounds and technologies and one of those truths is that AF, steadishot and other 'amateur toys' can be very useful

BTW Im not a traditional cinamatographer - i come from a background of shooting 5k stills on a hasselblad having started my career shooting manual focus soccer stills in the early nineties - and all I can say is

If you think you have got problems try shooting 5k with only a tiny ground glass to evaluate your image : ) - its near impossible to get one frame sharp let alone 24 every second

S
 
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Sam makes a lot of good points.

When using the AF100, never ever use EVF DTL and Focus In Red simultaneously. It is too generous and it will make you think that things are in focus when they are actually borderline.

Don't use your lenses wide open. Lenses are always softest when they're at their widest-open, and they have the flattest contrast (which makes things look softer) when they're at their widest-open. This is general advice for any camera, and has nothing to do with the AF100, but I'm just pointing it out -- if you want the sharpest, crispest, best footage you can get, avoid shooting wide-open. All lenses perform better when stopped down at least 1 stop to 2 stops from wide open.

Turn the viewfinder to black and white, and use the focus-in-red religiously. That's the way to assure sharp focus on an AF100. Don't try to focus off the LCD.

Get a 1080p monitor. That's the ultimate judge of how sharply focused your image is.
 
You should also be familiar with the mechanics of dof...what it means and how it works.

Ex...You should know that if you are shooting with an 85mm lens at 2.8 that at 10' you might have only 5" of dof. (I use pcam fir this) And that focus is a plane the rest just "appears" in focus roughly a third in front and two thirds behind. Big difference if you are focusing on the ear instead of the eye.

Knowing how it works helps in the execution.
 
So basically the EFF detail will screw you. Got it. I've had that on. I'm turning that off from here on out. As for what kind of lenses I used on that short, it was Zeiss Standard speed primes, 16,24,32,50,85mm. We used the 12,24 and 50 almost for the whole shoot.

Here are my settings I almost always use:

1080/24P
Detail Level -4
V Detail Level -4
Detail Coring +2
Chroma Level -3
Chroma Phase 0
Color Temp Ach 0
Master Ped -2
DRS off
Gamma Cine-like
Matrix Cine Like
Skin Tone DTL Off

Any suggestions?
 
"4/3 System". Brings up the same results as GH1. (use the lens' true focal length... don't 2X it for MFT)
 
Zak Forsman said:
I just shot a ten minute proof of concept with my AF100 and while using longer lenses I found I could hit focus pretty consistently just using the LCD's focus assist. But on short lenses with anything wider than a close-up, I was almost always off (and had a 720p monitor on set to set my focus marks with).
Click to expand...

I was shooting with a lot of shorter focal length lenses in a small room. 16, 24, 32mm. It's very difficult to judge focus at this range it seems.
 
I would also second the "film style" focusing aids mentioned above. If you are having a hard time judging the focus in red, why not pull out the depth of field calculator and a tape measure, check your focal plane and mark the floor? With so many different calculator apps available for a smart phone, I use this technique all the time, in conjunction with the focus in red, and always measure shallow DOF shots and have yet to miss focus. EVF's and monitors with 1:1 help, but they still don't give you the guarantee/ease of mind of knowing your focal plane.
 
That requires your adapter and lenses to be properly collimated though. Only workable with actual cine lenses, Nikons and Canons (or other still lenses) are nowhere near calibrated with their focus scale accurately for that to work. And even if they are, that doesn't mean that the lens mount is perfectly collimated for that type of lens.

For cine work with cine lenses on a top-grade PL adapter like the Vocas or Hot Rod, it's a totally viable workflow. For stills lenses, or using a cheap adapter like the Ciecio7, it just won't work.
 
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