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Which is the fastest lens?


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Quick pop-quiz on lens choice for low-light filming (i.e., which is the fastest in your opinion?)

 

1: 16mm T2 prime;

2: 5.7mm - 57mm T2.4 zoom;

3: 12mm - 120mm T2.8 zoom: or,

4: 50mm T1.4 prime ?

 

I'm personally thinking the 16mm T2 but would like to hear what others think.

 

Cheers,

Steve

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Quick pop-quiz on lens choice for low-light filming (i.e., which is the fastest in your opinion?)

 

1: 16mm T2 prime;

2: 5.7mm - 57mm T2.4 zoom;

3: 12mm - 120mm T2.8 zoom: or,

4: 50mm T1.4 prime ?

 

I'm personally thinking the 16mm T2 but would like to hear what others think.

 

Cheers,

Steve

 

Hmmmm,

 

At a guess, I'd say out of that lot the 50mm T1.4 is the fastest

 

yup, lock it in

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This is what we've come too? A self proclaimed cinematographer who doesn't know what a T-Stop is? Please tell me this is tongue in cheek, please...

 

Woah, David - you're kidding me right? Of course I know what a T stop is so what's with the personal attack? The question I'm asking is not about the T-stop alone. Let's ignore the red-herrings of 2 and 3 for a second and ask the real question of which prime in the list is the fastest? That is, will the shorter focal length of the 16mm T2 result in a lens that is better in low-light situations than the 50mm T1.4? It's a simple question that I'd like people's opinion based on personal experience, so I don't understand why you gave a bitchy reply like that; have I done something to piss you off or are you being tongue in cheek 'cause mate, if you've got nothing to say then don't say it. Otherwise, in your opinion, which lens do you think would be better in a low-light situation and, in the meantime, forgive me for not knowing everything and asking a question of those who may know more than me. Self-proclaimed cinematographer indeed...

 

Steve

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The focal length is irrelevant, the speed of a lens is determined by how much light is transmitted through it. The T-stop is a measure of how much light gets transmitted through a lens. So the smaller the T stop, the faster the lens. Cinematography 101.

 

If you're asking how well a particular lens handles at its widest aperture, that's a different question.

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I understand that you get frustraded Steve, Davids comment was kind of childish. But i have to agree that i dont really understand your question. If you just want the fastest lens then the t/1.4 is ofcourse the way to go, if you rather have a shorter lens then the 16mm might be better but its still slower

Edit:Dom Jaeger has a point, are you wondering how well they proform at a specific t-stop that isnt wide open?

Edited by linus rosenqvist
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Seems like a trick question because obviously the faster lens is the T/1.4 instead of the T/2, the focal length is a different issue altogether. It's like asking "which is longer: 12" or 24"?

 

Thanks David. I haven't shot in a low-light situation for over ten years; the question came up and I had a nagging suspicion that, over a range of apertures, the 16mm lens would perform better than the 50mm. I think in wanting to scratch an itch my mistake was asking which is the fastest when, obviously, I should have asked which is the best.

Kind regards,

Steve

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If this is for Super-16 work, then a 16mm lens is going to be more generally practical than a 50mm lens. 16mm is a medium focal length and 50mm is a long lens in Super-16. But the T/1.4 lens is still a stop faster than the T/2 lens.

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Woah, David - you're kidding me right? Of course I know what a T stop is so what's with the personal attack? The question I'm asking is not about the T-stop alone. Let's ignore the red-herrings of 2 and 3 for a second and ask the real question of which prime in the list is the fastest? That is, will the shorter focal length of the 16mm T2 result in a lens that is better in low-light situations than the 50mm T1.4? It's a simple question that I'd like people's opinion based on personal experience, so I don't understand why you gave a bitchy reply like that; have I done something to piss you off or are you being tongue in cheek 'cause mate, if you've got nothing to say then don't say it. Otherwise, in your opinion, which lens do you think would be better in a low-light situation and, in the meantime, forgive me for not knowing everything and asking a question of those who may know more than me. Self-proclaimed cinematographer indeed...

 

Steve

 

Steve, you couldn't possibly understand what a T-Stop is, or you would not have asked this question. I wouldn't classify my response as an attack, I was just dumbfounded by such a 2+2=? cinematography question by a working cinematographer, and simply could not work out if you were serious.

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A wider lens will give you more DOF per given focal length which works in the favour of the 16mm, but FOV/perspective is a complete factor in itself, sometimes but certainly not strictly a result of exposure considerations...

 

But hmmm, yup, the way you phrase your question could/should have rung alarm bells

 

"hang on, this is the internet - I'm pretty much asking to be dumped on"

 

yes/no ? huh.gif

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If this is for Super-16 work, then a 16mm lens is going to be more generally practical than a 50mm lens. 16mm is a medium focal length and 50mm is a long lens in Super-16. But the T/1.4 lens is still a stop faster than the T/2 lens.

 

Thanks David, that's the sensible answer I was after.

 

Steve, you couldn't possibly understand what a T-Stop is, or you would not have asked this question. I wouldn't classify my response as an attack, I was just dumbfounded by such a 2+2=? cinematography question by a working cinematographer, and simply could not work out if you were serious.

David Williams, I accept what you say but I too was dumbfounded by your attitude (arrogance?) in your first comment:

 

This is what we've come too? A self proclaimed cinematographer who doesn't know what a T-Stop is?

 

I'm sure you're aware (as the secretary for the Vic branch of ACS) that the ACS defines a cinematographer thus: "A cinematographer is a person with technical expertise who manipulates light to transfer visual information by the use of a camera into aesthetic moving images on motion picture film or electronic recording systems."

 

Over the last ten years I've filmed on three continents using a variety of cameras utilizing multiple formats with a large number of lenses including fixed prime and zoom. I have a certificate in cinematography from a UK film school in which Jack Cardiff OBE, BSC (RIP) was the patron and which, at night times, I complimented my practical studies with a university course in Contemporary European Cinema which preceded a full scholarship for a degree (BA) in which I majored in Film Theory. I've worked on feature films from 2nd A.C. through to camera operator and 2nd unit cinematographer. One of my short films was nominated for an award at a film festival (I didn't win but the nomination was nice) for its cinematography. I've filmed from several hundred feet up while hanging out of a helicopter (as well as sweeping shots that were called Herzogian); and I've filmed from a moving RIB (Rigid Inflatable Boat) travelling at over thirty-five knots an hour on the North Sea. I've shot documentaries, news, current affairs, OB, studio, live international OB, over fifty commercials, reality TV, observational factual and even an underwater dance film. My work is in the public domain, has been broadcast nationally and internationally as well as screened theatrically and also formed part of a national UK tour of the projected portion of a dance company's performance. You can even buy my work on DVD. I'm accredited as a professional SCUBA diver (from the Fort William Dive Centre, Scotland) which allows me to be paid to film underwater. I also hold professional accreditation with the AFI (Australian Film Institute) and, like yourself, I'm a full member (two years standing) of the ACS. Cinematography is my primary source of income (over 95%) and it's what my accountant writes on my documents to the ATO. Although I consider myself as early career (I do not advertise myself as a Director of Photography as I believe I have a lot more to learn before I'm capable of that position (and the accreditation that follows)) you can bet your ass that I've earned the right to call myself a cinematographer. So, forgive me for asking a bog-standard question in a dumb way but that doesn't detract from my integrity or capabilities as many will attest to. I said "fastest" and meant "best", but that doesn't explain your hostility as I took your response to be.

Steve

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I couldn't understand, given what looked like your experience. why you were asking the question in such a way.

 

I suppose even "best" would depend on what you want to use the lens for and the format you're using, but 16mm would be a useful lens on a number of formats, especially Super 16. I know one feature film that was shot mostly with that focal length on Super 16.

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Over the last ten years I've filmed on three continents using a variety of cameras utilizing multiple formats with a large number of lenses including fixed prime and zoom. I have a certificate in cinematography....I said "fastest" and meant "best", but that doesn't explain your hostility as I took your response to be.

Steve

 

That's all well and good but you shouldn't be surprised why you got that reaction. Somebody who purports to be a professional, working cinematographer should know a simple technical question like "which lens is fastest: X, Y, or Z?" Hell, to not know that would imply that you might fall for the old "go get a bag of f-stops" trick.;) If you meant "which lens- X, Y or Z- would be the best all around choice for_______________?", you should have stated the question thus. If you really didn't know the answer, you can admit it. We're all here to learn something, whether we're just starting out, a long-time professional, or (me) somewhere in the middle ground.

 

For the record, I would have probably preferred the 5.7-57 T2. I've rarely wanted to shoot wider-open than T2 and that's a great range of expressive focal lengths for 16mm or Super 16.

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For the record, I would have probably preferred the 5.7-57 T2. I've rarely wanted to shoot wider-open than T2 and that's a great range of expressive focal lengths for 16mm or Super 16.

 

The only lens that I've quickly come across with that zoom range is a 1/3" Computar 5.7-57mm f1.2. I believe they may be used on surveillance cameras.

 

There may be confusion with the Angenieux 9.5-57mm T1.9

Edited by Brian Drysdale
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That's all well and good but you shouldn't be surprised why you got that reaction.

 

Ah Chris, in a way you're right and I feel humbled by the experience. Someone mentioned to me that, between the two lenses, the 16mm would be better in low-light situations and I just wanted to check the professional opinion based on my own gut feelings that maybe they were right. Ok, I asked the question in the wrong way but that shouldn't mean it leaves me open to attack in a forum of like-minded people. Personally, I'd rather ask a dumb question to get the right answer rather than keep my mouth shut and get it wrong when it matters the most - there is a lot of poorly exposed work out there already (quite a lot by people who claim superiority I might add) and I would hate to screw up my work by not asking the questions. It should be that when we enter a forum with a question, the person asking it should feel safe in the knowledge that the question will be answered rather than the integrity of the person suffer attack. If all we do is attack then it just means that less people will ask questions through fear of appearing stupid in an apparently professional auditorium which, ultimately, can lead to poor standards such as under-exposure being cheaply sold off as "atmospheric" or lights being placed in ridiculously unjustifiable positions. I don't mind if someone says "ha ha, you're an idiot - you should know that; in my opinion the lens you need is X" - then I'll take it on the chin. But if I get an answer that includes "self-proclaimed cinematographer" (i.e. I'm just calling myself a cinematographer without actually being one, like if I called myself a Director of Photography and I worked as a theater technician for example) then I see that as hostile and an attack on my professional integrity. Most of the time I wouldn't dignify that attitude with a response, but even your president has to show his birth certificate on occasion ;).

 

Kind regards,

 

Steve

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my mistake was asking which is the fastest when, obviously, I should have asked which is the best.

 

Asking which one is 'best' doesn't really make much sense either. From a point of view of which is 'best' in low light, the answer is still which ever one is fastest. I don't really understand what bearing the focal length has on low light shooting.

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Asking which one is 'best' doesn't really make much sense either. From a point of view of which is 'best' in low light, the answer is still which ever one is fastest. I don't really understand what bearing the focal length has on low light shooting.

 

Focal length does have a bearing - to quote myself:

 

A wider lens will give you more DOF per given format (correction) which works in the favour of the 16mm, but FOV/perspective is a complete factor in itself, sometimes but certainly not strictly a result of exposure considerations...

 

 

 

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Focal length does have a bearing - to quote myself:

 

sorry Chris, but Focal length has no bearing whatsoever on low light shooting. You don't suddenly switch to wider lenses because it's getting dark, you switch to faster lenses.

 

A wider lens will give you more DOF per given focal length which works in the favour of the 16mm, but FOV/perspective is a complete factor in itself, sometimes but certainly not strictly a result of exposure considerations...

 

 

A wider lens only gives you more DOF if the FOV changes. If you compensate for the altered FOV by moving the camera, the DOF is the same for both lenses.

 

I don't understand why we are talking about DOF, when the question asked was which of these lenses is 'best' for low light shooting. In this respect, forgetting any other considerations, the answer is the fastest lens is best.

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Stuart, I'm not saying my answer is a solid rule, it's just discussion regarding the considerations. Remember we don't all have access to every lens set ever developed... You've kind if forced my hand in that I just need to ask: So if low light was causing you to shoot wide open for exposure and the resultant DOF was too low because of that your solution is to go to a faster lens so you can open it up more??? Maybe a wider lens and/or a FOV change could work yes?

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Maybe a wider lens and/or a FOV change could work yes?

 

As Stewart already said, a FOV change by moving backwards which has the same effect as changing the lens.

It's really a question for the "Students and First Time Filmmakers" forum

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Maybe a wider lens and/or a FOV change could work yes?

 

Ok, it's the last shot of the day. You're shooting an MCU on a 50mm at 10ft from your actor, wide open because the light is dropping. The director says, 'oh the background is too soft'. So you change to a 25mm, but you still need to be shooting the MCU, so you move the camera in to 5ft from the actor, but the director complains 'the background is still too soft'. Guess what - the DOF is exactly the same. The wider lens achieves nothing.

 

Of course, if having the background sharp is important narratively, then you could leave the camera where it was, at 10ft, and have the extra DOF, but you're no longer getting the shot you wanted. I don't know any directors who would sacrifice a CU on an actor for the sake of DOF.

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