Why are Anamorphic Bokeh Oval? (it's not the aperture)

It may not be the reason you think it is! Wrapping your head around anamorphic lenses can be tough - here I lay down the REAL reason why anamorphic lenses have that characteristic oval bokeh.
Consider supporting this channel on Patreon: / filmmakeriq
If you want to play with the ray tracer here's the address:
ricktu288.github.io/ray-optics/
Here is a public folder of the set ups I have created to load into the simulator:
drive.google.com/drive/folder...
#Bokeh #AnamorphicBokeh #AnamorphicLenses

[@RothmanHarv]

This is exactly the kind of video I love to see from this channel. I always wondered about the "why" myself; super informative. Really interesting that it applies to sphericals too, with the bokeh's size being squared. As was the putting the aperture behind the anamorphic element. When I was a teen I was trying to make my own anamorphic element using a few surplus spectacle lenses from the optician. Of course focus was impossible, but it did indeed squeeze the image, and while the image quality was useless for any actual filming, it was an educational experience. Lovely to see a video on this subject! Thanks, Mr. Hess!

[@TheChachalacaRMX]

Honestly, every time I looked at that oval bokeh I wondered this very thing. Thank you very much for explaining it!!!

[@thestyx6233]

Absolutely fascinating! Not gonna pretend I understood first time around but few more passes and I’m gonna know the answer to a question that I didn’t know existed 30 mins ago!

[@henrycaspian4297]

instaBlaster.

[@Pants4096]

I LOVE discussions of optics from the safety of never having to be responsible for truly understanding it. Thanks for the wonderful tutorial!

[@MuscarV2]

This isn't a tutorial at all... A child would understand that.

[@matthewneiman]

I went into this video like 'pft, obviously it's just because the anamorphic element squeezes on a single axis', but about two minutes in I was like 'oh, I'm actually one of the stupid ones' As always, fascinating video and demonstrations!

[@KendrickHarrisKenfinity]

Here IT is! It's so awesome and important to find out how these oval shaped bokeh lights work, and can be altered. Keep doing what you're doing and stay safe!

[@IanZainea1990]

Way more complicated than I expected. Great analysis! Worth the deep dive

[@paulsmith554]

I'd always wondered why anamorphic lenses have that weird stretch effect. This video makes everything a lot clearer, the only question I had left was why anyone would go to the trouble of using one of these lenses but you've already answered that in the comments. The bit about small sensor cameras cleared up another thing that's been confusing me for a while too. Thanks for the great video!

[@RivuSouravBanerjeeVideoEditor]

*Filmmaker iQ is one of my filmmaking classes .. thanks for sharing the info about the anamorphic lens,*

[@MaximilianonMars]

Thank you my guy, I couldn't puzzle it out and figured it was some funky physics thing to do with the lenses, and you've answered the question beautifully!

[@DGaryGrady]

Really informative and clear, and glad to see I'm not the only one interested in these things!

[@Metaldetectiontubeworldwide]

Oh yeah this i love ! I was missing my Jedi of Cinematics ☆ But this worth waiting for ! Always was curious in the optical explenation of what happens physicaly , as always your the first who takes the time and effort to dive deep , well done *Master* I too noticed something curious in the 'video continium' lol : -Sometimes i see banding in my and others video's on yt , but seeying it on a television screen banding and artifacts are gone ? I guess it has todo with the interlacing , all hail 'interlacing' .. Grtzz johny geerts

[@fredstratford5104]

I may never be a filmmaker, but I always enjoy your videos no matter the topic. This one: applied physics for everyone. Good job.

[@leopard8152]

Excellent high quality work well done! Thanks for all the research and investing in visual examples!

[@TheHandOfFear]

A great video as usual, John!

[@DanielCaiMedia]

Brilliant and succinct video, explanations, and visualisations!

[@vladbobe26]

Awesome as always! Now I just need to watch 3 more times, like the rest of your videos, to get it :)

[@David2222]

Thank you! So well researched and explained. AWESOME resource....YOU, John. Tak fur yelpin

[@VariTimo]

The legendary Ultra Panavision 70 lenses from the 50s utilize the prism system.

[@exooptik]

This was an excellent, excellent explanation. There's not a video to link to when someone asks why. Come join our group on facebook, it's called Anamorphic Shooters, we'll help you with your DIY setup.

[@dennis1954]

Thank you for the in-depth explanation. Liked, Subbed with notification bell and commented.

[@sevfx]

Wow, that is complicated. But you did an awesome job explaining it!

[@joekestrada9476]

too much science! it is amazing ! I really enjoyed listening your explanation

[@22freedom33]

I never thought about the squeezing of the bokeh

[@JohnDlugosz]

Now _that_ sounds like the name of a _Doctor Who_ episode!

[@pyalot]

Awesome! Now explain swirly bokeh as evidenced by old timey projector lenses and sovjet vintage glass like Helios. 😜

[@FilmmakerIQ]

I think it's just barrel distortion. You see that abberation in old photo lenses like the Petzval lens.

[@theMorgia]

Great video ! Can’t wait for the next one already 👍🏻👍🏻👍🏻

[@Murphistic]

One comment just for the Algorithm :)

[@FilmmakerIQ]

The algorithm is life. The algorithm is love.

[@patrickfreeman8257]

@@FilmmakerIQ Algorithm: Anything Al Gore ith famouth for thaying or doing

[@SteinGauslaaStrindhaug]

<a href="#" class="seekto" data-time="339">5:39</a> No no, I don't have a vision problem. I have Anamorphic eyes! Yeah! ;)

[@ksspang]

thanks for the video! It's very much not intuitive so the thorough explanation is much appreciated

[@VFXforfilm]

Sir, you are a master professor.

[@nucspartan321]

Great video

[@AbhinavanandSingh]

Gem of content!!

[@chengong388]

When I first saw the title of this video I thought, oh, I knew that all along, it’s the stretching afterwards. But then 5 seconds later I was like wait no that would make it horizontal not vertical, what sorcery is this? Btw I have played with some high powered laser pointers, the laser diodes are essentially real world point sources of light, the actual emitter is extremely small, but very high powered models have wider emission angles on one axis compared to another. So if you only use spherical lenses you can never focus the beam back parallel, what you get is a horizontal rectangle beam profile, which then shifts into a vertical rectangle profile and there’s a lot of dispersion associated with this. So I always thought I’d need some cylindrical elements in there to make a perfect beam, turns out all of this are very much related to astigmatism ,cylindrical optics and anamorphic lenses...

[@makestuffmike]

So good

[@ndolaboy]

Great explanation, thank you.

[@saikatchattopadhyay8263]

If Filmmaker IQ and Gerald Undone make a video together on a tech topic, the Earth will explode that day. I swear!! Keeping it aside, I need to watch it 10 times to understand ;/

[@leestripp7387]

Nice!

[@swerdnagk611]

thank you so much for the TLDW explanation.

[@jordel2010]

You did it again 👏👍

[@bennmurhaaya8518]

That was amazing video! I loved those demonstrations, it all makes sense now! Thank you!

[@olivermengershausen2686]

Thanks for that well explained video. I‘m not sure if anamorphic shooting in times of digital filmmaking makes any sense except giving a special „cinematic look“ (bokeh, softness e.g.) to movies. What do you think?

[@FilmmakerIQ]

This video actually demonstrates why Anamorphic shooting still has a place, it's because you can create a unique look where your vertical depth of field is half that of your horizontal. This sort of wraps depth of field around your subjects. It's a unique look that can't be replicated in any way digitally. Also popular are the characteristic flares. Although I suppose there are some hacks to get that in spherical lenses. But in terms of technical advantage in resolution, you're right. But Artistically they still have a real place.

[@DethronerX]

Thanks!

[@MDMart]

Thank y ou for explaining this, it made a lot of sense whilst also being interestingly technical :) I was wondering, digressing a bit here, merchwise why not make a not-so-obviously-filmmaker's shirt that says "Go make something great", it's a nice catch phrase and an awesome message, and subtle hints to filmmaking could be hidden within somehow :D

[@FilmmakerIQ]

Good idea!!

[@horaciogarg]

Thanks about this video 🤗🤗🤗

[@financialliteracy_hr]

Question, do you get more views if I download the video onto my KZbin library? I need to watch this video at least 3 more times and i usually download them but I really want to help you with the view count! Thank you so much for unloading so much fascinating information on your channel! It's well appreciated!

[@FilmmakerIQ]

No idea

[@sclogse1]

Makes me wonder what Geoffrey Unsworth meant when he said on the set of 2001 after 25 years in the biz, "If anyone had told me six months ago that I had anything to learn about my profession at this stage of the game, I would have told them they were mad. In fact, I have learned more about my profession from that boy in the last six months than I have in the last twenty five years. He is an absolute genius. He knows more about the mechanics of optics and the chemistry of photography than anyone who's ever lived."

[@seanodonnell429]

I have a new question. When you did the spherical lens demo, why did the bokeh size change by a different factor than everything in focus? Shouldn’t everything just follow the inverse square law? What is the reason for that difference?

[@FilmmakerIQ]

Same reason why anamophic bokeh is oval - the focal length affects the depth of field by the factor squared (Inverse square law is not applicable here)

[@bruinflight1]

Most anamorphic zooms (including the Angenieux) incorporate aft-deployed 'squeezing' elements (which are modular and removable) so yes, the aperture is in front of it, which is also why most anamorphic zooms are pretty well pointless in the digital age.

[@FilmmakerIQ]

I was thinking that. The only advantage I can see is you're getting more resolution than just cropping to get the scope look...

[@bruinflight1]

Yes perhaps resolution, probably depending on the sensor size more than anything to be honest; but you are also losing at least a stop and likely introducing other aberrations. The aft adapters do the opposite of squeezing: they actually stretch the image vertically and throw away a lot of photons in the process. You can actually see the element clearly as a horizontal cylinder at the back of zooms sporting this feature.

[@renatolobo4959]

Wow.

[@lidarman2]

good think we are not dealing with diffraction or things would really get weird real quick.

[@starc0w]

OK! Thx!

[@eyeln9ne696]

I like you. Smart man.

[@frxprince]

Wow now I know why anamorphic projector lens requires some minimum throw distance or it won't be able to make a good focus image.

[@JohnDlugosz]

You're the only one I've ever heard pronounce _bokeh_ like "bouquet". When I learned about it, it was explained that it's from the Japanese word (transliterated "boke") and the early popularizer of the term (Mike Johnston) soon added the "-h" to better signal to English speakers that it should sound like a "long" O but does not become a silent 'e', but is "-eh". The spelling was chosen in English to reflect the pronunciation. Mike didn't choose "bokay", but "bokeh". "it is properly pronounced with bo as in bone and ke as in Kenneth, with equal stress on either syllable" If you look up the Japanese word's pronunciation, it ends with the 'e' sound as in "bet". In fact, the language does not have a "long E" sound. Also note that Mike notes "equal stress on both syllables"; you are very much stressing the second. P.S. I studied photography in the mid to late '80's. "Bokeh" is a _new_ term for me, being popularized in the 1997 magazine article. I never heard an instructor mention it; all my interaction at this time was online (textual) or magazines, and I saw the re-repeating of Johnston's original editorial on why he spelled it that way.

[@FilmmakerIQ]

You haven't watched many videos on the subject if I'm the first person you heard pronouncing this way. I'm not saying I say it the Japanese way, but my pronunciation is very common. And common is good enough in my book

[@FilmmakerIQ]

Exhibit A: even the Japanese don't agree on how to pronounce it kzbin.info/www/bejne/j2Glo5looZ2MqcU

[@twothreebravo]

"Circle of Confusion" Thanks, that's my band name now.

[@joshuamartinstudios]

Mind blown

[@popsfreshenmeyer7607]

A great show as always. I love such explanations! You never know when you might need that knowledge.

[@denismurin]

I tried to like this video twice. Do speedboosters and optic’s resolution for high res cameras next, please! I am still intrigued why Blackmagic 12K doesn’t resolve full 12K resolution

[@FilmmakerIQ]

I was thinking about the 12K camera video but I didn't want to step out on a limb of I didn't have the facts and it's very technically complicated. My thought was it's actually an 8K camera but the departure from the Bayer pattern FORCES it to be 12K

[@denismurin]

@@FilmmakerIQ Yeah, I gathered that it’s very good at 8K and 4K finish. Didn’t have a chance to shoot with it yet but the unique tech behind the camera is fascinating!

[@Veptis]

instead of T stop you should have used F stop there. T stop will change from lens to lens due to coating and will not be a perfect indication of dof and bokeh. never wondered about this much but I love to learn. There is another mystery tho: why are anamorphic lenses so damn expensive?

[@FilmmakerIQ]

The lens I'm using is measured in t-stops, I don't know what the precise f-stop so that's why I didn't use it. But it doesn't matter what the value is on a different lens - I'm only comparing this lens to itself.

[@jcf20010]

An easy way to demonstrate the oval aperture isn't the cause all you need to do is rotate the oval aperture independent of optics. If the aperture is the cause the the oval bokehs should rotate with it.

[@FilmmakerIQ]

That won't work because the aperture is in reality a circle, it's the optics that make it look like an oval. If you spin the aperture without rotating the optics the oval shape will just stay consistently straight up and down.

[@booga2007]

2 focal lengths, means different DOF horizontal from vertical? You can have only one DOF right?

[@FilmmakerIQ]

Not in the weird world of anamorphic. Things fall out of focus FASTER in the vertical than the horizontal, hence why oval bokeh

[@booga2007]

@@FilmmakerIQ Hmm but which angle decides what the DOF at a certain point or pixel is? In an extreme case of 4x anamorph the difference in DOF horizontal from vertical can be quite extreme. Is the blurriness of a pixel decided by horizontal or vertical DOF?

[@FilmmakerIQ]

>Is the blurriness of a pixel decided by the horizontal or vertical DOF? It's both - the horizontal DOF determines the blurriness along the horizontal axis. The vertical DOF determines the blurriness along the vertical axis. I think it would behoove you to stop thinking in terms of pixels - pixels are never blurry - they just represent a single sampling point in an image.

[@calinguga]

i don't get it either. "depth" of field is neither horizontal nor vertical, it's along the optical axis, "through" the scene. objects have to move closer or farther to fall out of focus, not up or down. if you're thinking about say vertical and horizontal slopes away from the camera, i can easily think of a situation where i can juxtapose such two slopes and end up with a discontinuity. i'd really like to get to the bottom of this, it interests me a lot.

[@FilmmakerIQ]

@@calinguga late to respond but you you need to look at anamorphics as two different focal lengths along two different axis... Rewatch the video, fully explained there.

[@frankcastle8130]

Impressive! Now, I know why real anamorphic lenses are the same price as a house on beachfront property!

[@sriharsha5036]

Let's goo

[@beaudanner]

Anybody smart enough to understand this by watching it once likely didn't need to watch it in the first place. 🤓Definitely going onto my "study" list. Great stuff! Next viewing I'm bringing my notebook. And a pencil... With a lot of lead.

[@syrophenikan]

FANTASTIC!!! (as always)

[@mr88cet]

Excellent topic and explanation! Thanks.

[@prakul697]

Thank you 👍🏼

[@ryantmarx]

My brain is mush.

[@oracleofvalerius]

Thank you sooo much!!! this helps a lot.

[@northrouter]

Where could I buy this tshirt?

[@FilmmakerIQ]

Merch store should be on our shelf. If you can't see it I think there's a link on our site: filmmakeriq.com

[@JohnDlugosz]

@@FilmmakerIQ You need a "T-stop" shirt!

[@michaeltrende6251]

finally!. thank you.

[@casadelosperrosstudio200]

Ooohhhhhh I get it now..... Anamorphic lenses created "anamorphic mumps," leading to "the camera adds 10 pounds", leading to actresses, then their fans, wanting to be thinner... then marketing spread that image... and anamorphics led straight to anorexia.

[@KOTAKVISUAL]

Ovalicious 😎🤘

[@IsmaelDerruci]

Great video! Thanx!!!

[@caernavon]

"Because direct (i.e. not reflected) light gets squeezed more than indirect (i.e. reflected) light; therefore direct light doesn't get un-squeezed enough when the resulting image is projected." I think that about covers it, without the brain-melting optics and math.

[@FilmmakerIQ]

Lenses cannot distinguish direct and indirect light. It's all the same thing. Your deduction is more brain melting than the actual thing that's happening :) If you want the basic answer stick with the tldw explaination in the video

[@caernavon]

@@FilmmakerIQ Too late; Brain Melt Syndrome is permanent, and there is no cure.

[@JohnDlugosz]

@@FilmmakerIQ He's referring to the ray-tracing diagrams you present. If he changes "direct" from not-reflected to "off axis" it's OK. Your emitting sources in the ray diagrams are diverging as opposed to the image rays which are parallel. I think a better distinction is light that comes from beyond the depth of field. Normally these are emitters not reflections from the subject's light, but that is not necessary for the effect.

[@FilmmakerIQ]

That doesn't clarify anything. My ray tracing diagrams were not dependent on being on or off axis

[@wmka]

Thank you and have a great day.

[@MirekFe]

*#2020* 🤣😂😭

[@M3n747]

Thank you for explaining how my glasses work, it almost makes me want to forgive you for saying 'bokay'. ;)

[@FilmmakerIQ]

Potahto, tomahto

[@denismurin]

As far as I know common US pronunciation “bokah” is also incorrect, if that’s what you are implying ;)

[@8lec_R]

@@denismurin comes from the Japanese word Bokeh-turi. It's pronounced Boe-keh (the H is not silent)

[@FilmmakerIQ]

Oh yeah... That cleared it up /s

[@hDesk]

niubi

[@schitlipz]

Can I set up my account to auto-thumb-up these vids? There's never a crappy one!

[@Crlarl]

Let's hear it for math!