40mm f/2.8 vs 50mm f/1.8 for video

[leeys]

 

There is also the focus mechanisms.  the nifty fifty for example has a really nasty manual focus mech.  as I imagine the 40mm does?  Focus pulls look very non cinematic from most af lenses when used in manual mode

​Nope, the 40mm is different. As a STM lens it's actually focus-by-wire.

[richg101]

​Nope, the 40mm is different. As a STM lens it's actually focus-by-wire.

​

even worse than a mechanical focus mech then!  - for cinematic purposes at least

[TheRenaissanceMan]

• ​

  even worse than a mechanical focus mech then!  - for cinematic purposes at least

  ​Indeed! Weirdly, you're best off getting the 50mm f/1.8--metal mount and a nice wide focusing ring. The 50/1.8 II focus ring is not only tiny and plastic, but has several degrees of play before the helicoid actually engages. AVOID.

 

 

 

[Jonesy Jones]

​No, they're not. The only people talking about focal length equivalents are DSLR/mirrorles stills camera users. In cinema 50mm is 50mm is 50mm, no matter 65-mm, 35-mm or 16-mm film/sensor is used. Also in cinema world "full frame" is called VistaVision.

​How sure are you about that? Here's how it's been explained to me... 25mm cinema lens on s35 camera is equal FOV to 25mm dslr lens on full frame camera. 

[Guest Ebrahim Saadawi]

​How sure are you about that? Here's how it's been explained to me... 25mm cinema lens on s35 camera is equal FOV to 40mm dslr lens on full frame camera. 

​s35 is APS-C, Full frame is bigger. 

50mm on S35 is equivalent to 85mm on FF. 

50mm on s35 is equivalent to 50mm on APS-C

I think what he was trying to say: If you work with 35mm film cameras in Hollywood, you know the s35 standard, so you don't think about how it equates in FF terms. So if you're that guy, a 50mm is a 50mm, it gives the FOV you expect (which is equal to 85mm on FF, but you don't think about that, you just don't think in FF terms) But if you work with FF formats, you think in that formats' terms, so a 50mm is an 85mm.

The significance of this is to keep in mind how FOV changes with sensor sizes, when you're shooting on a 5D and Scorsese tells you to put a 50mm lens, you put an 85mm one, because he means 50mm on s35. And if your shooting on a 550D, and a fullframe stills shooter tells you to put a 50mm lens, you put a 35mm one, it will give him what he expects from a 50mm on FF. Just keep that difference in mind... You can think in s35 of FF terms, there's no shame in doing either, use what you're used to. 

[Jonesy Jones]

​s35 is APS-C, Full frame is bigger. 
50mm on S35 is equivalent to 85mm on FF. 

50mm on s35 is equivalent to 50mm on APS-C

​I understand all that, perfectly. What I think you are missing is that cinema lenses do not have the same FOV as their DSLR equivalents. I learned this at Alex Buono's workshop. He was using a 25mm Canon cinema lens on a Canon with APS-C sensor, but it was yielding a FOV of (roughly) 25mm on a Full Frame. When I asked him about this he told me the cinema lens is designed and marked that way. In other words, our Full Frame focal lengths are equal to the same cinema lens focal lengths on s35. I cannot confirm this with absolute certainty because I don't own any cinema lenses, but this is how I have been lead to understand it.

[Chrad]

​I understand all that, perfectly. What I think you are missing is that cinema lenses do not have the same FOV as their DSLR equivalents. I learned this at Alex Buono's workshop. He was using a 25mm Canon cinema lens on a Canon with APS-C sensor, but it was yielding a FOV of (roughly) 25mm on a Full Frame. When I asked him about this he told me the cinema lens is designed and marked that way. In other words, our Full Frame focal lengths are equal to the same cinema lens focal lengths on s35. I cannot confirm this with absolute certainty because I don't own any cinema lenses, but this is how I have been lead to understand it.

Cinema lenses and full frame photographic lenses exist in their own separate worlds. There's no reason for cinema lens makers to manufacture their lenses so as to keep equivalent field of view with the 35mm DSLR standard that they don't even consider. 

So if you're that guy, a 50mm is a 50mm, it gives the FOV you expect (which is equal to 85mm on FF, but you don't think about that, you just don't think in FF terms) But if you work with FF formats, you think in that formats' terms, so a 50mm is an 85mm.

The significance of this is to keep in mind how FOV changes with sensor sizes, when you're shooting on a 5D and Scorsese tells you to put a 50mm lens, you put an 85mm one, because he means 50mm on s35. ​

​Technically a 50mm on S35 is a 75mm on S35.

Pedantic maybe, but this is a thread about a 10mm difference. 

[MattH]

​ And if your shooting on a 550D, and a fullframe stills shooter tells you to put a 50mm lens, you put a 35mm one, it will give him what he expects from a 50mm on FF.  

 

​​

Unless that person knows you have a 550D and knows exactly what a 50mm will get him. Which is a lot more probable with a stills shooter. But other than that you're right.

[MattH]

​I understand all that, perfectly. What I think you are missing is that cinema lenses do not have the same FOV as their DSLR equivalents. I learned this at Alex Buono's workshop. He was using a 25mm Canon cinema lens on a Canon with APS-C sensor, but it was yielding a FOV of (roughly) 25mm on a Full Frame. When I asked him about this he told me the cinema lens is designed and marked that way. In other words, our Full Frame focal lengths are equal to the same cinema lens focal lengths on s35. I cannot confirm this with absolute certainty because I don't own any cinema lenses, but this is how I have been lead to understand it.

​​So that would mean that a canon cinema 14.5 - 60mm zoom actually delivers the full frame equivalent of 14.5 - 60mm. So is actually a 9.6 - 40mm t2.6 lens? Because fuck me that is some lens! (it might even justify the price).

But na, it sounds like a load of bulshit to me, sorry mate.

50mm is 50mm. Which is to say: The stated focal length is as near as makes a difference the actual effective focal length.

[Guest Ebrahim Saadawi]

 

 

 
He gave you incorrect information. A 50mm Zeiss Cine Ultraprime gives you the same field of view as a Canon 50mm 1.8 (both on same sensor of course)

[fuzzynormal]

Not sure what the confusion is.  mm's is mm's.  What camera you put a 24mm on matters for FOV, but mm is a measurement.  millimeter.  People that use s35 sensors/filmstock don't have a different metric system than someone shooting with a full frame, 4x5" film, or a m43 sensor.

Forget the cameras anyway.  That's actually irrelevant.  You're talking about a lens.  On your glass it's the distance from the point where light rays converge to the point where they form a sharp image onto the focal plane. 50mm is 1 millimeters plus 49 other millimeters.  

If you're arguing otherwise you've been misinformed.  The idea that film shooters have special math that is unique for them is ... well, not right.

This issue really gets convoluted because folks new to all this stuff (and even some pro's apparently) tend to overthink it and conflate various camera terminology.  But if you just consider the lens, ultimately it's pretty simple.

Which is why, if I was shooting a low budget action film with an ASP-C sensor, I'd tend towards the 40mm lens, as it would be a nice "standard" FOV.  Not too wide, not too tight.  But nothing wrong with a lens with a bit longer FOV either, you just adapt to what you got and go.  

I wouldn't burn time worrying about 10mm.  

I'd worry more about other aspects of film making.  Actor and camera blocking, sets, design, stunts, lighting, acting, EDITING.  Holy crap, that's the stuff that matters more.  Try not to get wrapped up in gear-centric-fetishism on the low end of film making.  If all that other stuff is half-assed I don't care what FOV you have, whatever film you're trying to make is going to suck.  Make the most of what you have and be creative around your limitations. 

[Guest Ebrahim Saadawi]

If we want to get down to the cause of this confusuon,  it's the DSLR revolution that converted a sizeable number of photographers (where fullframe 35mm is the standard) to videographers (where 35mm APS-C is the standard) 

 

In photographic film cameras a 35mm film was exposed horizontally while the same film was used in motion cameras but had to be run vertically, so while they use 35mm film, for photography cameras a larger area ofthe stock was used (full frame sized) while on motion cameras a smaller "aps-c-sized" portion was exposed.

 

so when digital took over, companies offered photographers the same size they were used to (full frame), and offered the for videographers the smaller one they're used to (aps-c)

 

Canon cleverly termed that large sensor that's equivalent to photographic 35mm film, as Full Frame, so every professional shooter back then suddenly felt he's missing something, that he's not full... and they all bought Canon 1Ds and 5D, then later Nikon followed with the D3 and D700, while motion cinema cameras wanted to stick with their smaller standard (aps-c)