How was this look achieved? Shallow DOF techniques

[BRANDON JAMESON]

Additional blurring around the edges could have been done in post.

I sure see that too.

 

[Nick Gardner]

I'm easy ;-) I said my piece and I'm out.

Nick

 

[David Kuhn]

I didn't think there was any debate about this. The trifecta is:

Focal length (& distance to subject)
aperture
Frame size

Is there something else?

I guess I'd add a couple:
objective but not typically relevant for the type of imaging you guys do:
illumination wavelength(s) (DOF is wavelength dependent)

possibly subjective:
desired resolution - DOF is ultimately subjective unless you apply a specific metric such as "depth range where edge quality measured in LPPMM at 30% contrast is >90% of peak measurement at optimum focus & averaged across the entire ROI"... but you can also think of it as the more subjective "depth range where the image looks sufficiently sharp enough that it can be considered 'in focus'"... which is pretty darn subjective.

On the 'desired resolution' question I also think of it this way... If I put the exact same lens with the same settings (call it a 50mm F1.2 wide open at 8') on an 9MP camera and then on a 36MP camera with with the same imager size, the apparent DOF will be deeper on the 9MP camera... because the 9MP camera can't see the razor shallow peak resolution of the lens wide open (not even close).

 

[David Kuhn]

Flickr does the handy thumbnail thing if you'd like to see a visual example of the subjective nature of DOF, if you look at a 320 thumbnail of an image and take a stab at what you think the DOF is for the image:



I might estimate from the ear tip to the nose tip (maybe 2 inches).

Then you pull the full resolution image (embedded a 1600, click to get 36MP)

and it's a different story (I'd say from the front of the right ear to the eye... maybe 0.5 inch). It also shows off the downside of too much sharpness... her coat goes from silky chocolate black to silky chocolate black with tons of little chunks of stuff in it (maybe she was rolling in the dirt).

Cools stuff, imagers and optics (D800 w/Nikkor 50mm F1.2 wide open).

 

[Will Keir]

If you look at her face there the sharpness from eye is crisp and sharp. My trouble shooting the Super speeds is their DOF is so shallow I can't get the same look.

So I'm thinking there is a sweet spot. As Scott mentioned, 6-8 inches to keep your character's face completely focused. Now I'm going to need to test and figure out exactly what my
setup is going to be.

I'll start to take some screenshots of my work to share.

Thanks guys.

Looks like they shot anamorphic 35mm. BTS: http://youtu.be/xDJLsPd6NdY?t=34s

 

[Will Keir]

Nick. So with 6k Dragon, even shallower DOF is to be expected?

Utilizing 5k on the epic will yield shallower dof as well.

Nick

 

[Will Keir]

Yeah, they keep knocking at my door. Are there anamorphic zooms?

What's a good single anamorphic prime to get me started? Suggestions?

Will, dip your toe in anamorphic... if you want this look/feel, you'll get there quickly

 

[Scott Crawley]

Nick. So with 6k Dragon, even shallower DOF is to be expected?

Yes, the larger the imaging area, the more pronounced the effect. It is one of the reasons for the popularity of the 5D during the shallow DOF craze.

David's point seems to suggest that the added resolution could offset, or lessen the perceived effect to a degree.

@10' or so 85-105mm on MX 4k will give you about 8" @ f5.6-f8 by my calculator, @5k just walk it in a foot

pCam... Lot of good tools ;-)

 

[David Mullen ASC]

Most anamorphic zooms are just spherical zooms with rear anamorphic attachments, so they don't exhibit most of the optical effects associated with anamorphic such as stretched bokeh or horizontal flares. The focal lengths are longer just as with the anamorphic primes to achieve the same field of view as shorter spherical lenses, but most of the anamorphic zooms are T/4.5 at the widest so you don't get as shallow a focus as with a T/2.8 anamorphic prime.

There are a few rare Panavision and Hawk anamorphic zooms with front anamorphic elements like the primes.

That close-up of the face was made with a longer lens so it probably wasn't shot wide-open but it allowed the distant background to look more out of focus, being enlarged by the compression of the focal length.

But assuming a 4-perf 35mm anamorphic target area, a 2X anamorphic lens roughly has 2-stops less depth of field than a spherical lens on the same target area being cropped to 2.40 and matched in field of view by using a lens that is twice as short. In other words, assuming the same width of the sensor is used to create 2.40, you'd get the same depth of field of a 40mm anamorphic at f/2.8 as a 20mm spherical at f/1.4, both matching subject distance and shot size.

If f/1.4 is too shallow in focus, then stop down. Otherwise you can match the shallow focus of 2X anamorphic with spherical by opening up 2-stops... what you can't match is the stretched bokeh and other distortions.

Now in the real world, the anamorphic area used on the 5K sensor of the Epic is not quite as large as 4-perf 35mm anamorphic uses, so the matching spherical lens won't be twice as short and the difference in depth of field won't be by 2-stops because you are going to have to use slightly shorter focal lengths with anamorphics on the Epic compared to on a 4-perf 35mm camera to get the same field of view, so I would guess that comparing anamorphic on the Epic versus cropped spherical is more like a 1.6-stop difference in depth of field characteristics once you match field of view and distance to subject.

 

[Neil Cronin]

A little brain fry on this matter....This is something I asked many experienced DOP's and the replies really differ.

What is the factor or factors that change DOF?

The math is figured out: https://en.wikipedia.org/wiki/Depth_of_field

Nick is correct -- DOF doesn't have to do with focal length in a strict sense. You can do the algebra to prove this.

Paul is right -- perceptual DOF does have to do with focal length, because the sensor/film has a different perspective because the camera is in a different physical place.

A 100mm lens 10 feet away will have a certain size ratio of the subject and background that a 25mm won't have at 2.5 feet away. They are different compositions, so the bokeh "reads" differently to normal people.

Sensor/film size can be mathematically factored out too, in a similar way. 8mm film (or an iPhone) doesn't have a deeper or shallower DOF than a 35mm FF sensor in a 5d, but the lenses you would typically use on it have a big impact on the perceptual separation between the subject and background.

So on one hand, focal length and sensor size have zero mathematical impact on DOF, but on the other hand, watch The Shining with its 20mm-something lenses on 35mm film and compare it to The Dark Knight with its 200mm-something lenses on IMAX, and compare for yourself. Long lenses on huge sensors typically evoke shallower DOF, even if it doesn't make any sense from a physics/math point of view.

-n

 

[Liam Hall]

I didn't think there was any debate about this. The trifecta is:

Focal length (& distance to subject)
aperture
Frame size

Is there something else?

Circle of confusion.

@Will, try a 18Omm.

 

[Will Keir]

They even nailed it with the BTS camera. 1:55.

Looks like they shot anamorphic 35mm. BTS: http://youtu.be/xDJLsPd6NdY?t=34s

 

[Andy White]

Yeah, they keep knocking at my door. Are there anamorphic zooms?

What's a good single anamorphic prime to get me started? Suggestions?

Will - was about to reply then saw David's answer - so no need for anything more from me really

I'd suggest a 35mm or 50mm Squarefront as a starter prime. 35 being 17.5 in Hfov or 50mm being 25mm in Hfov. 50mm will probably be a cheaper pickup as 35mm Squarefronts are pricey ATM.

 

[Nick Morrison]

Nick. So with 6k Dragon, even shallower DOF is to be expected?

Yup!

 

[Will Keir]

Thanks Andy for being part of this discussion and for your suggestions.

Will - was about to reply then saw David's answer - so no need for anything more from me really

I'd suggest a 35mm or 50mm Squarefront as a starter prime. 35 being 17.5 in Hfov or 50mm being 25mm in Hfov. 50mm will probably be a cheaper pickup as 35mm Squarefronts are pricey ATM.

 

[Will Keir]

I've used a 300mm. Not a lens you can put on the shoulder rig without a crazy amount of shake.

Circle of confusion.

@Will, try a 18Omm.

 

[Matthew Scott]

I've used a 300mm. Not a lens you can put on the shoulder rig without a crazy amount of shake.

Unless it's the 300mm f2.8 nikkor with VR

 

[Scott Crawley]

I get all the separation I need <200mm at normal shooting distances... Big, creamy bokeh. Why would you need to go longer for DOF characteristics? I had a big honking Pinocchio once that made me wish for 300mm compression, but never DOF. ;-)

 

[Will Keir]

This is an IS lens and can be used on a shoulder cam? Even slight movements at 300mm track quite a bit, more than I'm comfortable.

Unless it's the 300mm f2.8 nikkor with VR

 

[Will Keir]

Yeah that smooth silky background is nice. Great for compression without the artifacts too.

I hear a diopter is a good tool for achieving this same effect. Are prime diopter expensive? They probably vary just like lenses? So you match a diopter to fit your lens choice?

I get all the separation I need <200mm at normal shooting distances... Big, creamy bokeh. Why would you need to go longer for DOF characteristics? I had a big honking Pinocchio once that made me wish for 300mm compression, but never DOF. ;-)