Hi there

Please could someone tell me how T stops of Cine lenses works compared to F Stop?

If I have a T2.3 what does it equal to in F Stops?

Thanks
Rory

Hi there

Please could someone tell me how T stops of Cine lenses works compared to F Stop?

If I have a T2.3 what does it equal to in F Stops?

Thanks
Rory

A T stop is the f stop with the lens transmission losses factored in. You can lose up to a stop with some of the older zoom lenses from the 1960s. More modern zoom lenses tend to lose around a 1/3 stop or even less because of the improvements in lens coatings.

What T 2.3 will be as an f stop will depend on much light a particular lens will lose due to internal reflection etc. A zoom lens will lose more than a prime lens.

You use the f stop for working out your depth of field and the T stop for exposure. Professional cine lenses are marked in T stops.

F stop is a mathmatical equation and does NOT measure the amount of light coming out teh back end of the lens that hits the film plane ... T stop is the measurement of the light that hits the film plane ...

Hi guys

Thanks for the response.

So I still don't really understand the T stop reading.

I understand F Stops and am used to working with them so can easily distinguish between say F1.2 and F2.4 but I can figure out much slower a T2.3 lens be compared to T1.3.

I can see it would be T1 difference, but what is that like 1 F stop?

Thanks
Rory

A stop difference is the same in both. Both run in the same progression (1, 1.4, 2, 2.8 etc)

http://en.wikipedia.org/wiki/F-stop

Because you're changing lenses on film cameras you have to know that if you set an exposure of a certain stop on a fixed focal length lens, it'll not change when you put on a zoom which has a lot more elements (with the increased light loss).

You want exactly the same exposure on the film. With the Transmission or T stop you don't have to work out how much extra exposure you need to give when using zoom compared to the prime lens to achieve the accurate exposure on the film.

T stop = f stop + (transmission loss in lens measured in stops)

Hey Brian

thanks for the info.

So a T2.3 will be alot slower than a T1.3.

I'm looking at purchasing a set of lenses and of course want T1.3 but the cost is alot higher than T2.3 lenses.

I'm trying to figure out how much of a difference this will make and if the T2.3 will still do the job for me or should I hold out and save for T1.3's.

Many thanks
Rory

80% of the time i rented ziess 2.1's over the hi speed 1.3's ..when using 35mm i usually light sets for T 2.8-4 ... for 16mm i try to get at least a T2-2.5

Hi Don

Why would you have 2.1 over 1.3's? Is it that you shoot mainly daylight or brighly light subjects and the 2.1 would have a better sweet spot?

I'm thinking I really want a set of 1.3's as I mainly enjoy night scenes and really trying to shoot with available light. But hey this trend could change.

Would you recommend going for cheaper 2.1 or 2.3 over a set of 1.3's?

Kind regards
Rory

i have only ever shot one shot at 1.3 and that was 16mm using a 25mm lens dolly in on tight med shot to C/U = that was 1st shot production , 1st time working with new AC and he did pull focus excellent - after that shot he asked for more F stop so i gave him T2 on all interiors on that film..

i shoot wide night street scenes at T2 ( wide open with 2.1) when using 1.3's .. i try to lay in 3ft candles general fill and a few key area's if there are none but i find if stores have lights on and there are street lights T2 will do it ...
i always use a little filtering on 1.3's = could be 1/8-1/2 =ultra con ,double fog, low con ..with 2.1's i'll shoot with no filter = so i find for my taste i prefer a little less contrast/dirtering on the 1.3's ... once i hit T 2.5 then i go with 1/2 to 1 filters

either set i try to keep 5.6 as max f stop ( use ND filters to keep it there)

also i get 6 to 7 2.1 primes vs. 5 to 6 1.3 primes for less $$ ...

i rent the lens ... so depending on the project i can go with either set and/or both sets and/or mix the sets but most of time 2.1 full set ( to 135mm)...

i do have RED 103 reserved .. when it comes time to BUY ??
well i have few months to think about it ...
i'll be starting off with a S16 zoom lens .. and i'll be using 35mm nikon/canon still lens with PL adaptor to F or canon mt ( older manual lens not EFs ) ..
at some point i may add used zeiss lens ?? 2.1 or 1.3 's ??
depends on price and the set ...

you might test out both sets to see if the $$$$ difference is worth it ?

Rory,

There's nothing wrong with asking questions to fill in knowledge gaps, but it is rather surprising that you work for MINE in London and don't know an f-stop from a T-stop. That's about as fundamental as it gets. It's frankly hard to believe that you're a working pro. In any event, I suggest that you do some serious reading on the subject of cinematography. There are many excellent books available.

Greg

i know many persons shooting and getting paid 1000-1500 day ( including betaSP camera) that would find F/T stops difficult to explain ..i find that most persons that have a video background have not had to deal with t stop vs f stop .. infact i find most just turn on lights ,move the f stop ring till they have the zebra settings the way they want ( looks good on monitor) and don't know what the current f stop is actually set to .. where as in general film background persons i find tend to light for a F stop ( use a light meter) and prefer to shoot at a favorite f stop ... either way will work ...

Thanks Brian & Don

Understanding T stop vs F stop is clear now.

"It's frankly hard to believe that you're a working pro." -
Greg, I sometimse wake up and think the same thing, yet go on and create amazing images for my clients who all seem to think we are pro's, so I must be doing something right :-)

Knowledge is power.
Sharing knowlege is just nice :-)

Donatello is correct in saying that those with television and video backgrounds haven't had to deal with the difference between F stops and T stops. I think it's important to remember, in a convergent media world, where lenses and techniques of cinematography, and electronics of videography are converging, not to be cine-centric in our approach to the concept of acquiring images. Are videographers less "professional" than cinematographers just because they haven't had to deal with T stops and other requirements of the cinema world? (Tape measures, hand held light meters, mechanical shutters, etc.) Definitely not.

I shoot both styles, so in a way I'm a poster child for convergence. Am I any less of a professional when I shoot TV/video/ENG-style than when I shoot cine-style? Absolutely not! I just have to use different techniques and equipment to get images that satisfy the needs of the project. For those of you that are entirely film and cine-centric in you backgrounds, here's a short primer on how TV/video shooters in an ENG-style production environment deal with light and focus.

Because of continuous multiple focal length needs, 1/2" and 2/3" lenses are generally zooms. They have switches top and bottom to enable quick changes from manual to auto operation for servos and iris. You have to know when to switch from manual to auto lens modes to be effective. Focus is always manual on 1/2" and 2/3" lenses, but aperture can be switched between auto and manual. In some run 'n gun environments, with 1/3" chip camcorders, all lens operation is auto. Depending on the camera make, it can still be quite effective. Other times it is partial auto/partial manual. Other times it is all manual - focus, aperture, white balance. We're talking a real fast moving environment, where you either capture the story or you don't - no focus pullers, tape measures, lighting tweaks, etc. You rack focus and judge DOF quickly. And then move on to the next shot. Good principles of shot composition: framing, lighting, focus, DOF, action follow, etc., still apply, as in cine-style shooting, but you're usually on your own to get the images very quickly. After shooting that way, you may then need to go full manual with the lens, and shoot cine-style b-roll and creative shots with shallow DOF, soft light etc. The best ENG-style shooters also have cine-style skills. It's unbelievably challenging at times.

So, back to ENG-style light (and color) management. Most often you're using available light that changes rapidly - but your footage still needs to be exposed correctly. Professional ENG-style cameras usually have three channels of white balance (plus black balance): Preset, A, and B. If you don't have time to do a custom white balance you need to use Preset, which is very accurate in most modern ENG cameras. If you're constantly going indoors and outdoors, you'll probably do a custom white balance on A & B, and simply switch between them when you change from interior to exterior lighting. Modern ENG-style lens/camera combinations are quite accurate on auto iris modes. Most shooters also use zebra pattern to quickly judge the light level of the brightest objects in the frame. In manual iris mode the zebra is your lifeline for getting correct exposure. When there is time to do so, many ENG-style shooters will put the lens on auto iris, frame up the shot to see what F stop the camera/lens want for exposure, switch over to manual iris on the lens, check the zebra level, back down the iris about ½ stop, and shoot the shot. Same thing on the next setup, and on and on. HD is especially critical not to overexpose. I routinely shoot precisely exposed HD and SD footage using the above procedures - footage that wins Emmy Awards and scores of other national awards.

My experience shooting ENG-style really helps me when I shoot cine-style, and conversely, my experience shooting cine-style really helps me when I shoot ENG-style. I’m already used to quite often working alone, but I merely have to switch to my cine-style knowledge base. Quite often my cine-style shooting is actually a melding of cine-style and ENG-style.

I’m quit comfortable with someone on this board not knowing what a T stop is. After all, this is DV Info (as in Digital Video). With media convergence, a lot of guys are going to arrive here with TV/video backgrounds. Conversely, many will arrive with cinema/film backgrounds. They’re both equally valid mediums of expression. Though cinematography is the older art, I don’t feel that makes videographers less professional. I’m a true convergence shooter who respects the nuances, knowledge, challenges, and professionalism of each discipline.

Respect leads to collaboration - which fosters progress in art.

Well said Mr. Gibby.

I personally find the term "pro" or "professional" bandied around far too much as a dividing line in the sand. All that means, by definition, is that one is paid for whatever occupation the term is being applied to. (we all like a roll in the hay, but consider which of us are called "pros" in that particular arena...!)

I have met TV news cameraman who may have garnered awards and been on the job for years who wouldn't know a T-stop from an F-stop; I also know folks who I work with in the film industry who know FAR less or even nothing about the barely arcane terminology of the video world; there's quite a few 17 year olds on this board that could school these Hollywood veterans on the intricacies of compression, file formats and the like. (Whether they like it or not, most of them are having to learn as HD is pushing film out slowly but inexorably).

I think that certain basics of optics and image making are universal, format-agnostic and should be learned as a core knowledge base. I can well see that someone who has only dealt with video zooms would not have necessarily come across a T-stop marking, but such things are becoming more relevant in the video world when "film-style" techniques are observed. For instance, if one is shooting at a T4.3 and wants to apply a "skinny shutter", perhaps a 1/120th of a second, they would need to know how much to compensate the aperture to match the footage shot at 1/48th.

Convergence really is the name of the game these days!

You may all think it's fine, but I wouldn't hire a shooter whose fundamental knowledge of photography was so thin, and I none of the people I know would either. But that's just me and my circle I guess. There are too many other truly qualified, talented and dedicated people available. If somebody comes here and asks the difference between and f-stop and a T-stop it means they haven't taken even a few minutes to research the subject themselves. In my book, they're lazy. And that's strike two. Just my opinion.

Well-said Charles. Image acquisition may be ENG-style, cine-style, or a combination of the two - which may be termed as convergent acquisition. There are people who spend a whole career shooting ENG-style, and conversely ones who spend an entire working life shooting cine-style. I think we're seeing less and less of those mono-dimensional shooters in the marketplace. As the lenses and techniques of the traditional film world have converged with the electronics of the traditional television/video world, the labor force demand for shooters who understand both has increased exponentially - and will continue to do so.

Greg, I've hired and worked with thousands of top-quality television and video shooters who probably couldn't tell you what a T stop was - and yet they maximize the equipment of their trade and constantly bring back perfectly exposed and focused footage. As a producer/director I’m not concerned with hiring theorists who can quote me a broad-spectrum of tech specs, but rather people who can get me great footage with the equipment we’re using for that particular project. If the project at hand I’m hiring them for is ENG-style, its genre won’t require my shooters to use cinematic techniques, and I know they’ll nail the footage the way I want, they’ll get hired. As a producer/director I'll continue to hire those same people for projects where the equipment used and the genre of production simply don't require them to shoot to know what a T stop is. When I produce/direct a project that will require the use of cinematic equipment and techniques, obviously the shooters I hire will be people with cinematic backgrounds. If it’s a production where we use both cine-style and ENG-style gear and techniques, I’ll hire people whose skills span both disciplines. These are the true media convergence shooters – and they’ll be in highest demand in the years to come.

There’s a huge spectrum of project types in the overall motion media imaging industry that don’t require shooters to know film style equipment or techniques. I don’t agree with writing them all off as being lazy, ignorant proletariat who haven’t done their homework, anymore than I buy TV/video people looking at traditional film people as all being a bunch of plodding, slow –working, electro-phobic elitists. The fiscal realities of the media marketplace dictate that the shooters with the broadest skill sets get hired for the widest range of motion media projects. If someone wants to shoot themselves in the foot by being mono-dimensional in an increasingly multi-dimensional image acquisition industry I guess they’ll have to lie in the techno-challenged grave they dug for themselves.

Nobody is born knowing anything. We all start learning from birth. If someone’s career path has not required them to use cine-style equipment or techniques, they now want to learn, and they don’t know what a T stop is, I’ll reel them out some slack and welcome their desire to learn.

Patience and tolerance from both persuasions are the glue that can unify the disparate halves of a convergent motion media industry.

To suggest that someone who knows the difference between an f-stop and T-stop is a "theorist" is absurb. If someone working professionally in the industry doesn't know the basics, one cannot communicate properly with that person and therefore one cannot hope to achieve optimum results. I'm happy for you if your experience is otherwise. This appears to be an exercise in having the last word. I defer that to you as I've expressed my point of view.

I think you missed the point of my theorist comment. I was illustrating that it is one thing to memorize and quote tech specs, but If they're not also a practical applicationist (translation: actual good camera person) all the tech memorization in the world won't get them by on location. There's a gigantic array of ENG-style TV and video production projects going on continually around the world where nobody on the crew needs to know what a T stop is - and yet they do top-level work in their particular niche of the motion media industry. Do we write them all of as being a lower class of production people because of that? I don't think so...

You see, having a background in both cine-style and ENG-style production, I've earned a healthy respect for both persuasions. That said, I've enjoyed learning both disciplines. It's been rewarding professionally and financially.

Post script: We've had a few ping pong matches before, but I think you know that I respect your knowledge and opinions. Everyone has to have strong opinions to survive in the media industry. We've both been around for awhile, so we must be doing something right...

Me, I don't judge people on this forum based on their lack of experience or knowledge--that's what this board is for, to pass information around. I do however pay attention to how they ask questions, and how they "play" with others, and I think Rory did well even when defending himself (although it probably would be a good idea to do a search on similar subjects before creating a thread, I know we've discussed this topic before)

I probably wouldn't hire someone to shoot for me who didn't know the difference between f-stops and t-stops either, but that's neither here nor there. I think it's pretty clear that Rory was asking a simple question, not soliciting us for employment.

It's too hot to go jousting, lads, let's get back on subject.

(every now and then the Wrangler in me pops out--just a leeeetle bit)

Good points...and as a Wrangler for this forum my entry into this thread was to keep everyone playing nicely.

Every now and then the Wrangler in me pops out a leeeeeeetle bit too!

Interesting convo. I have a confession to make: I don't know jack about anything, at least not yet-I'm still not quite sure I know the difference between f-stops and T-stops; in fact, I don't know most of the stuff I read about here, but I'm learning. As long as the people at RED don't require me to know anything about anything in order for me to qualify as a buyer, I plan on purchasing me a pair of RED Cameras. If you sell it, doggone it, I will buy it! Any objections?

As a moderator for this forum, I can tell you that this forum is a learning center. The only stupid question is one that isn't asked. We're here to help you learn...

LOL...I'm sure RED won't mind if you buy a couple of their cameras! You have about five months or so to gather knowledge, but some things just take time. I'd suggest you bring in some experienced shooters to shoot your RED cameras for you and that you pick their brains and watch them closely until you're real proficient with them.

You may all think it's fine, but I wouldn't hire a shooter whose fundamental knowledge of photography was so thin, and I none of the people I know would either. But that's just me and my circle I guess. There are too many other truly qualified, talented and dedicated people available. If somebody comes here and asks the difference between and f-stop and a T-stop it means they haven't taken even a few minutes to research the subject themselves. In my book, they're lazy. And that's strike two. Just my opinion.


So Greg, now that I know the difference between an F stop & T stop would you hire me :-)

If you had done a little research yourself you would have found out that I'm a 31 year old director and colourist with a post production background.

http://www.whatismine.com/html/who.htm

I'm not a cameraman.

We hire cameramen for our projects and recently I have been getting involved in a bit of DOP'ing myself as I really enjoy creating imaginary.

I am very familiar with F stops as sometimes put on my photographer shoes...

http://www.whatismine.com/html/photography.htm

Having done a little research and talking to other directors about T Stops I wasn't satisfied so thought I would ask the knowledge base of the DVinfo forum.

Mine plans to shoot a feature film with RED early next year and in preparation I'm looking around at used Arri lenses as I don't want to go down the hire route. Before I make a $21,000 purchase I'd like to learn all I can about the subject so I know I'm buying the right tools for the job and that the tools will deliver what I want artistically.

I've been playing with my DVX and M2 35m Lens adaptor which is proving to be an amazing learning exercise in storytelling with Depth of Field. I recently purchased a SteadiCam like stabiliser and having a skateboarding background I'm really enjoying it.

The term Motion Media Convergent, to me tells the same story of the Print world years ago. When DTP changed the old ways of doing things. A lot of old school Print pro's where very scared of computers, and failed to realise that it was still all about the end product.

"Media Convergent" - you can no longer just do one job to survive financially.

At Mine we produce Music commercials, Music Video's, Short and Feature films. We also create DVD's, our latest being for the band Muse and the BBC's Ray Mears.

We offer HD Finishing including Colour Correction and Visual Effects and handle all the necessary broadcast paperwork. We've done event photography and produced countless Radio commercials as well as doing graphic design and web site development.

Our rates remain competitive and our attitude flexible to accommodate the wide variety of clients.

Don Donatello & Brian Drysdale explanation that T Stop is the measurement taken of the amount of light out the back of the lens was perfect for me to get clear in my head.

Understanding that you can safely change lenses and set the same T Stop would provide the same results was priceless share information. Using a zoom to a prime would give you the same exposure when using T stops.

Cool, I feel I have expanded my knowledge. Yet I have so much more to learn.

My thurst for knowledge is relentless.

I can't wait to see some RED footage at IBC

To suggest that someone who knows the difference between an f-stop and T-stop is a "theorist" is absurb. If someone working professionally in the industry doesn't know the basics, one cannot communicate properly with that person and therefore one cannot hope to achieve optimum results. I'm happy for you if your experience is otherwise. This appears to be an exercise in having the last word. I defer that to you as I've expressed my point of view.

Now why a TV/news cameraman has the need to know what a T-stop is to do a "professional" job scapes me the sense of reason.

Okay, I will formulate the hype: these Greg Lowry's posts scape us the sense of any reason viewing from the strictly sense of common streetwise. It's just ordinary corporate professionalism and not real one. This is shown in the field not posting from here. Just my opinion.

Mathieu, completely off topic, but still: are you interested in the RED camera?
I read in your posts you're very interested in the Silicon camera, but I was curious of RED was in your interest too?
sorry to go off topic

I have a small prediction:

In the future, professionals will look at shooting on film much in the same way that editors look at cutting on flatbeds.

However, no matter what you're doing, shooting is about light, and F-stops (and t-stops) is a useful way of talking light because it takes into consideration light's logarithmic attributes. One of the reasons I like the DVX-100 is that it tells me what f-stop I am at. Now, the depth of field I'm getting is different (I.E: since you are stopping down the sensor as opposed to the actual apeture of the lens, I imagine you DOF stays constant), But it's useful, in using filters gels lightmeters and flags.

If you're not using lightmeters, flags, gels, multiple light set ups, then there's no need. On the flipside the video guy knows that what he sees is what he gets (which is the video world), and simply adjusts things accordingly.

In a world where you *don't* know what your getting until it comes back from the lab, all this mucking about with f-stops and light meters is *crucial*. Much like, knowing that 40 frames of 16mm = 1 ft.

I see an advantage of the red camera will allow us to control the traditional F-Stop as well as the gain (acting as our ISO/ASA). So you can control your DOF without touching a single light or changing the angle of view of the lens. Just theorizing...

Oh, and I know this isn't the place for this but... Shout out to Mathieu (J'suis un ex-pat a newyork, J'ai beacoup aimer La Haine. Tu savais qu'il y'a des jeunes qui s'ont passez leurs adolescense dans les cité de harlem et brooklyn l'ons vu conte le film comme une experience transformative?)

As a person just getting in to more 'professional' areas of movie making, thanks to every one who answers these questions and doesn't cast judgement on the questioner. I didn't know the difference between t and f either. Using 'video' cameras' and using f stop for everything, even when trying to make it look like film. At least when I buy my Letus35, I'll have some knowledge to start with.

Thanks to all.