Why extreme deep focus is useful and extreme shallow focus is useless

[Karim D. Ghantous]

A rule of thumb is to avoid extremes. In some cases it actually works for you, such as exposing to the right as much as you technically can - unless of course there are reasons to expose to the left. But when it comes to deep focus vs shallow focus, the former is actually useful whereas the latter is completely useless.

I can prove it. If you want shallow focus, your goal is to get the background as soft as possible. You still want the subject - like a person's head - more or less sharp. But if you want deep focus, you will take all that you can get. And if that means everything from the surface of the front element to infinity, you will happily take that.

Conclusion: some extremes are useful but others are ruinous.

 

[Alex Zeder]

That's a bit too broad a statement for my taste. Just shot an intro f0.95 fully open last week and the goal was to get the foreground as soft as possible. Looks great! But according to your statement, it shouldn't look good

It might be true for many scenes, just not for all and everything, although I agree that shallow focus has great potential for ruining it.

 

[DJ Meyer]

Apples are useless to those that hate apples and prefer oranges.

 

[Phil Holland]

Won't dive too deep into this, but I'll describe an interesting choice that I have made numerous times during my career for very deliberate reasons.

Imagine a full head closeup, perhaps with a slight turn of the head, but nearly straight on, but you can see on ear revealed. And for the sake of argument we'll lock focus on her closest eye to lens.

Professional image makers, cinematographers and photographers have a choice to be made regarding depth of field.

1. Aim to have the head and nearly no separating between that and the background, i.e. a deep stop
2. Likely a balance between 1 and 3
3. Aim to have the entire head in focus back to the edge of face and ear, a fairly common thing to do
4. Focus more on the facial plain with likely both eyes in focus
5. Focus mainly on the closest eye and let it all blur away

This is merely one example of a common frame that everybody will have to shoot whether it be narrative, reality, commercial, or corporate work.

Outside of technical merits, optimal stop selection (avoiding diffraction/avoiding vignette, cleaning up the lens, etc), and even specific working distances for a given focal length the choices above will be informed by the story, style, and what you want the audience to feel. And hopefully you're not in a situation where "you didn't have enough light" to force you into something you didn't want to do, which is more common now. But I will certainly say much like low contrast the shallow depth of field look certainly is rampant. But certainly not everywhere.

Respectfully the title of this thread is about 15,000 miles off the mark from where your head should be regarding this topic. You use the lens in the way you want the shot to look. No more complicated than that. I spend a fair bit of time in prep designing our light and lens strategies. All deliberate choices even when shooting out in the wild. If others have opinions about your depth of field being too shallow or too deep, whelp, that's their opinion. And they may even be right or wrong if looking back in hindsight.

 

[Phil Holland]

I'll add one additional note as this is relevant between many stills versus motion concepts and exposure mindset.

Though you do see still photographers using ND filters for long drags to blur out water and what not, ask yourself how often you see somebody rocking NDs and shooting stills. They are out there, but they clearly hide in the shade comparatively to most you see pressing a shutter button.

Point I'm making there is many rely on an exposure triangle. Others know that the triangle is a lie when you have other tools to control the light entering frame.

 

[Bill Ravens]

hmmm...a rather drastic oversimplification

 

[Karim D. Ghantous]

That's a bit too broad a statement for my taste. Just shot an intro f0.95 fully open last week and the goal was to get the foreground as soft as possible. Looks great! But according to your statement, it shouldn't look good

It might be true for many scenes, just not for all and everything, although I agree that shallow focus has great potential for ruining it.

Ah, yes, my friend, but there is a distinction between extreme shallow focus and a very wide aperture. Not the same thing! In your shot, the background would have been mostly in focus. Or enough that it would not have been an extreme. I'm not really talking about the stop, I'm talking about the result. You could photograph the moon with an 800mm f/2 and all of it would be in clear, perfect focus.

You use the lens in the way you want the shot to look.

A shot where there is only 0.5mm of DOF might be interesting but it has no utility. Your focus puller will hate it and if your lens mount is off by just a hair, your shot is ruined.

I saw a question on Quora about someone seeking a possible refund for his wedding photos. The photographer shot everything with super shallow focus, and the client hated it because he couldn't see anything. Quite frankly it's the client's fault for not giving the photographer a reference. But, this is what happens when people get caught up in affectations.

The deep focus extreme is 0.00' to infinity. Nobody would say no to that if they wanted deep focus. The shallow focus extreme is 1/64" with hard rolloff. No sensible person wants that. It doesn't matter what the stop is.

P.S. If/when light field becomes mainstream, you will be able to track any moving subject in post, no matter how shallow the focus is. It might be an undesirable thing to do, but you could still do it.

P.P.S. If a movie had zero music, you wouldn't notice. But if a movie is saturated with music, it would grate. One extreme is perfectly fine, the other isn't.

 

[Marc Wielage]

I think it's a creative choice like anything else. I don't find a shallow depth-of-field or a deep depth-of-field objectionable, as long as it compliments the story and works for the visuals. The only time I can recall the audience objecting to shallow depth-of-field was with Christopher Nolan's Inception, and the people I saw it with in the theater asked me later, "why was the background often out of focus?" So they were confused and annoyed with it.

 

[M Harvey]

A shot where there is only 0.5mm of DOF might be interesting but it has no utility. Your focus puller will hate it and if your lens mount is off by just a hair, your shot is.

I don’t know why I’m weighing in, as I take this topic to mostly be trolling. But what you are describing here is not a lack of utility, it is merely difficulty.

And some focus pullers I know take pride in succeeding under difficult circumstances.

 

[Karim D. Ghantous]

This isn't advocacy for deep focus, and it isn't rejection of shallow focus. It's an observation that if you take each to their extremes, one actually becomes maximally useful while the other becomes totally useless.

 

[Marc Wielage]

This isn't advocacy for deep focus, and it isn't rejection of shallow focus. It's an observation that if you take each to their extremes, one actually becomes maximally useful while the other becomes totally useless.

BTW, I can note (without naming examples) that we routinely will go in during the final color process and reduce depth of field to slightly defocus the background in lots of situations, particularly interviews. This is done under supervision, so the filmmakers are well aware of what we're doing. Stuff like this does help take the "edginess" off some kinds of footage, and it also helps draw attention to the person in front of the camera. It depends on the situation.

 

[Phil Holland]

BTW, I can note (without naming examples) that we routinely will go in during the final color process and reduce depth of field to slightly defocus the background in lots of situations, particularly interviews. This is done under supervision, so the filmmakers are well aware of what we're doing. Stuff like this does help take the "edginess" off some kinds of footage, and it also helps draw attention to the person in front of the camera. It depends on the situation.

Blasphemy! Kidding. Lots of blur and cleanup to some of that bokeh has been going down as of late.

Was going to dive into topics surrounding lenses with various starting T and f/stops, shooting at specific stops, DOFs, hiding/revealing elements, etc. But yeah. Overall this is a much deeper subject than enforcing this particular opinion.

I will say though, throughout the 2000s I ran into many, many cinematographers who lived on certain T-stops. Perhaps the most famous of the era was the 2.8/4 split when using speeds or slightly slower glass. Works great on S35 for so many situations and gets you in a nice working spot on most glass of the time through now.

I think another notable point is working wide open was not very common due to the optics themselves until fairly recently. Around the era of Ultra Primes is when people really danced there. Though some very thoughtful DPs and Directors deployed it pretty early on. Don't need to bring up Barry Lyndon again, but yeah.

 

[Karim D. Ghantous]

BTW, I can note (without naming examples) that we routinely will go in during the final color process and reduce depth of field to slightly defocus the background in lots of situations, particularly interviews. This is done under supervision, so the filmmakers are well aware of what we're doing. Stuff like this does help take the "edginess" off some kinds of footage, and it also helps draw attention to the person in front of the camera. It depends on the situation.

I can see the logic here. Take what's already soft and make it a bit softer. Personally I find this kind of thing indulgent. But if people want to spend the time and money, sure, go for it.

I think another notable point is working wide open was not very common due to the optics themselves until fairly recently. Around the era of Ultra Primes is when people really danced there. Though some very thoughtful DPs and Directors deployed it pretty early on. Don't need to bring up Barry Lyndon again, but yeah.

Back in the day of Barry Lyndon and the older generation of Noctilux lenses, all those lenses were not very sharp wide open. That actually gave the impression of more DOF than there actually was. Add to that the grainier, faster films that were used with these lenses and you have even more apparent DOF. Even there, though, lens mount calibration had to be perfect.

Leica did a spectacular job with the new 75/1.25 and the 90/1.5 lenses. Still, I find them almost useless, despite their amazing performance wide-open. Now, if they were as cheap as the slower lenses, well, I still might not have them. But hey, that's nothing but a hypothetical.

 

[Björn Benckert]

I can see the logic here. Take what's already soft and make it a bit softer. Personally I find this kind of thing indulgent. But if people want to spend the time and money, sure, go for it.



Back in the day of Barry Lyndon and the older generation of Noctilux lenses, all those lenses were not very sharp wide open. That actually gave the impression of more DOF than there actually was. Add to that the grainier, faster films that were used with these lenses and you have even more apparent DOF. Even there, though, lens mount calibration had to be perfect.

Leica did a spectacular job with the new 75/1.25 and the 90/1.5 lenses. Still, I find them almost useless, despite their amazing performance wide-open. Now, if they were as cheap as the slower lenses, well, I still might not have them. But hey, that's nothing but a hypothetical.

Are you trolling?

There are more ways to pull focus these days than going by the focus marks on the lens. 10 years back or so, Exprienced AC´s most often said that only those that does not know how to do it look at a monitor when pulling focus... Quite a few of those guys stand with they heads under black cloth infront of a good screen doing their stuff these days. Then you got Pdaf focus and quite a few tools to pull focus by image / zoom in functions etc. Not to mention all lidar, stereoscopic and IR focusing tools that exist today. So no, you dont need perfect back focus or lens marks to pull good super thin focus these days.

Then the rest is taste, style or whatever you want to name it. Sure, an image with something that looks like it has infinite DOF is always an image but controlling focus falloff has kind of been as much as an artform in filmmaking as lighting.

So no, Extreme shallow focus is not useless. Quite often one does not want to give everything in the image the same amount of attention. A shallow dof let you point things out in an image and hide other stuff. Sure every shot, film or scene might not benefit from it but that very much also goes for a super deep focus.

So what you state in your headline I think most filmmakers find simply to be quite far from the truth.


Then there is trends, more or less focus falloff. People that shot video on small 3 chip sensors very much wanted more focus falloff. When the 5D came a lot of those people jumped on it and yes a lot of stuff was shot wide open on that sensor and more than a few would probably looked better if they stopped down a bit. Everything needs to be balanced and shooting wide open quite easily becomes to much when the sensors get bigger.

 

[Nick Morrison]

I think any creative maxims are perilous. Your trash is someone else's treasure.

 

[Karim D. Ghantous]

There are more ways to pull focus these days than going by the focus marks on the lens.

Björn, you're talking about the present. I am talking about the future, where you can pull focus in post. That is, if light field tech comes to the mass market. In any case, if you can't look at the monitor to pull focus, maybe your lenses and mounts should be calibrated.

And when I say extreme shallow focus is useless, I am right. Shallow focus per se isn't useless, but the extreme of it certainly is. And the proof is that if it is taken even near the extreme, people realise that they have to back off, just like you said. You are not disagreeing with me.

 

[Phil Holland]

And when I say extreme shallow focus is useless, I am right. Shallow focus per se isn't useless, but the extreme of it certainly is. And the proof is that if it is taken even near the extreme, people realise that they have to back off, just like you said. You are not disagreeing with me.

You are right for "you". While I have no problem saying that some people who just automatically aim for wide open filming or stills, putting such a brash and somewhat limited opinion on the concept of working shallow for various creating or even technical reasons, it's fairly clear you're overlooking a lot of image makers desired intent. It's even more glaring as we have a bevy of optics that have opened up that opportunity in the last 3 decades. Separation of subject, elements in a frame, light gathering, and so many more reasons.

Most filmmakers would likely say they don't shoot wide open, certainly not all the time, but there's literally revered and award winning material that certainly has. In which case, that's far from useless if it made the picture.

 

[M Harvey]

This is just trolling. A discussion of depth of field is interesting at the moment, given the trend of emphasizing shallow depth of field with large format sensors and glass that’s sharp wide open. However, the move here is to go to discussion of an extreme that isn’t much seen in the wild, e.g. DOF of .5 mm. (Per one online DOF calculator, the depth of field on a 135mm f2 lens wide open at 3’ is approximately 3mm—so 1/6 of that!) The only people who are interested in that kind of depth of field are working on macro projects.

 

[Karim D. Ghantous]

This is just trolling.

It's mostly a hypothetical, which I found interesting. As for macro, almost every macro photographer prefers their subject in focus to some degree. Thanks to modern cameras like Olympus, with features like focus stacking and bracketing, class leading lenses, and a smaller sensor, macro is better than it ever was in the film days. Not that it was terrible, but cameras like Olympus took it up a notch. If macro photographers had an option for infinite DOF, they would absolutely use it some of the time.

Eventually you'll see focus bracketing on Red cameras, too.

 

[Björn Benckert]

It's mostly a hypothetical, which I found interesting. As for macro, almost every macro photographer prefers their subject in focus to some degree. Thanks to modern cameras like Olympus, with features like focus stacking and bracketing, class leading lenses, and a smaller sensor, macro is better than it ever was in the film days. Not that it was terrible, but cameras like Olympus took it up a notch. If macro photographers had an option for infinite DOF, they would absolutely use it some of the time.

Eventually you'll see focus bracketing on Red cameras, too.

You can easily do focus bracketing images with any camera and especially red cameras pull focus while holding camera still and filming. Then use a braketing app of choice and off you go. Red shoot raw, no need to do the bracketing comp in camera.