First post here -- Greetings!

[Brian Wells]

Hello everyone,

 

 

My name is Brian Wells and I am a resident of Amarillo, Texas. I am 21 years old and am nearing the end of my one year hiatus from school where I was studying to be an English major.

 

My background related to capturing images has mostly been on various digital mediums (ie - video) and 35mm photography with a Canon SLR. While I have become fairly proficient at tweaking the look of video in the digital world (as nearly everyone else in my generation with a DV cam and a Mac has done) I recognise that I know very about film and I am trying, really, to grow and understand the complexities and palette of tools available to those shooting on film.

 

Here are the things I am unclear on right now. Please tell me where I am wrong or if I am on the right track related to general characteristics on different film stocks on ASA speeds, cooresponding sensitivity and dynamic range, emulsion characteristics, and more. If able to offer some good, old fashioned advice, please read on. . .

 

1. Negative Stock vs. Positive Film

 

My understanding is that negative stock is preferred for the following reasons: It has a preferred aesthetic; better dynamic range (I think also referred as "latitude") from shadows to highlights, and more defined colors over Positive film (I think also referred to as "print stock" or "slide film") and positive film has a different aesthetic (I don't know what that is) reduced latitude (like 5 stops or something) but can be projected immediately without a print, DI, or telecine-then-print.

 

2. Sensitivity has a direct connection to the amount of grain in a film? Yes or No?

 

My understanding is that smaller emulsions create tighter grain at the expense of reduced lower light sensitivity and that stocks with larger emulsions, "soak up more light since they're bigger" at the expense of "bigger emulsions means you see them" hence more grain.

 

3. Shutter angle or shutter speed.

 

My understanding of the effects of various shutter angles comprises contradictory information. One person explained steeper angles produce images with sharp, strobing images and a second person explained that using a shallower angle produced sharper images than the standard angle in a camera. I think the standard is 180 degree for many camera's with an exception being the fixed shutter on the Aaton a-minima which is 172.8 or something.

 

My interest here is the effect of changing that angle to a steeper or shallower (proper terminology?) angle and the effect it has on the image. If you use, say for example, a 45 degree shutter on Super16 at 24fps, is your image sharper at the expense of strobing images if there is high movement? Or is it the opposite... would a 200 degree shutter provide sharper images with potential for strobing? What effect would a person be going after if they used a 90 degree shutter?

 

Does shutter angle have a direct effect on your frames-per-second?

 

Someone told me that a 180 degree shutter on a motion picture camera would be the same as a 1/48 shutter on a 24p camera, at 24 frames per second. Giving that, would going to 1/45 or 1/36 shutter speeds be approximating the look and feel of a shallower angle on film (like a 90 degree shutter would be 1/24, etc) or would it be like a 1/60 or 1/120 on 24p would be like approximating a "shallower" angle on film?

 

Comparing shutter angle to shutter speed on a digital 24p camera is confusing to me. On the 24p camera using, say a 1/15 shutter does not give you a full 24fps. However, at 1/24 or 1/48, et. al. it does provide 24fps. Is there a similar connection to shutter angle and frames-per-second on a motion picture camera?

 

Last on shutter angle/slash/shutter speeds. Does switching from a standard angle such as 180 degrees to a different angle change the way you would expose film? For example, would a change from 180 to 90 give you an extra stop to compensate for, or no? Would going from 180 to 45 mean two stops of exposure difference? Are you losing a stop (darker image at same iris opening) or gaining a stop (brighter image at same isis opening) all other things being the same?

 

4. Iris opening: f-Stop vs. T-stop comparison.

 

I think this is a simple question with probably a simple answer: f-stop is light entering the lens (used on photography and video) and T-stop is.... I think a more exact way of measuring light after it goes through the lens and comes out the other side? Please help me understand the key difference between these two rating systems.

 

5. ASA vs. ISO speeds.

 

A photographer told me recently that no-one uses ASA speeds in photography and it is all ISO speeds. He shoots with a digital SLR and is a student, so I am not necessarily thinking this is all true. What is the difference in these two systems, if any, and is there a particular reason motion picture film is rated by ASA speeds?

 

6. What does a 100, 200, or 500 speed film mean in terms of look and sensitivity to light?

 

For example, why go 7218 vs. 7212 or 7217? Do you expose differently for each one?

 

 

I didn't think I could get it all out. But, here it is; my complete misunderstandings of film. Please advise. Thank you!

 

Brian Wells -- A

Another one of those kids with a camcorder and a mac who is looking to learn a craft not a fad like many other kids his age.

[John Pytlak RIP]

The answers to most of your questions can be found by searching the archives of this user group, as well as others like CML:

 

http://www.cinematography.net/site%20map.htm

 

The Kodak website has many helpful on-line publications that also answer your questions:

 

http://www.kodak.com/US/en/motion/students...0.1.4.9.6&lc=en

 

http://www.kodak.com/US/en/motion/support/h1/

 

http://www.kodak.com/US/en/motion/support/h2/

 

http://www.kodak.com/US/en/motion/support/...0.1.4.9.6&lc=en

 

http://www.kodak.com/US/en/motion/support/...=0.1.4.11&lc=en

[Guest]

Holy smokes some one has a lot of typing ahead of them to answer all of this.

 

Paging Mr. Mullen....Mr. David Mullen...report to this thread please :D

 

Seriously though, a lot of this can be found in back issues of American Cinematographer, or you should be able to check out several books on cinematography from a good library.

 

Myself or any other decent DP here could go through all of your questions, but that is going to take a lot of time.

 

Richard

[Guest]

One thing I will add Brian for your benefit and others in your situation is that the ONLY way to really learn how to shoot film is to shoot film. Period end of story.

 

So....

 

"Brian Wells -- A

Another one of those kids with a camcorder and a mac who is looking to learn a craft not a fad like many other kids his age."

 

A camcorder just won't cut it, sorry. A cine camera and a film camera are different beasts. All the reading in the world is no replacement for experience. Shooting Super 8 will get you further than using a camcorder, at least Super 8 is film.

 

My suggestion is that you buy a K3 16mm camera from a good dealer. Check ebay. Then buy 5-6 100 foot loads of a variety of film stocks. Shoot all of the rolls in the various situations they are designed for, process the neg, and take it to a transfer house.

 

Now you can have first hand experience with the film stocks, lenses, aperatures, etc etc. And you'll get a good look at what colour correction can do.

 

Keep extensive notes of all your settings and slate every roll before you shoot. Then you can go back & review what worked and what did not.

 

Then repeat the entire process again :D

 

Now you're on your way.

 

Richard

[DavidSloan]

A simple google search is going to answer all of your questions! Do you really think someone is going to sit here for 2 hrs answering every single one of your basic questions, when all this info can be easily found onine? :angry: The arrogance of some of these kids blows me away!

[Brian Wells]

David,

 

Please understand my questions are genuine and I recognise a genuine way of finding answers is by asking. I can and have searched online for some of this and will continue to do so.

 

Perhaps my post should not have been as lengthy, but in no way did I intend arrogance nor any sense of expectation or entitlement to someone taking the time to answer them... I promise.

 

I recognise those that are here are experts in this industry and that is why I posed my questions here, rather than say a video-prominent group.

 

I have already received solid resources and support and I truly appreciate it.

 

The Kodak student portion is filling my screen at the moment, and likely by the end of day I will have searched the archives of this and the CML forum and will have found the answers I am looking for.

 

Thanks to those who provided a resource or clues to help out.

 

Best,

 

Brian Wells

[Robert Edge]

Brian,

 

A lot of the available books that address your questions are pretty expensive, but there are two that are fairly cheap and provide solid, reliable information:

 

John Schaefer, "Ansel Adam's Guide to the Basic Techniques of Photography", volume 1;

 

Steven Ascher, "The Filmmaker's Handbook".

 

Many of your questions are about general photography rather than cinematography in particular. I think that the best internet fora on general photography are at www.apug.org and www.largeformatphotography.info. The largest forum is at www.photo.net, which also has some reasonably good articles.

 

If possible, beg or borrow a large format camera that takes 4"x5" sheets of film. Shoot some film and find a darkroom where you can process and print the film yourself. It will teach you an enormous amount. If you post a note on www.largeformatphotography.info saying where you live and that you want to try a large format camera and want to see what processing and printing is about, there is a very good chance that someone will respond favourably. If you can't get your hands on a large format camera, use a medium format or 35mm camera.

 

I can't resist saying something about your question on positive and negative film. Historically, still photographers and cinematographers went down different roads. Professional still photographers tended to prefer postive film (many still do) and cinematographers came to adopt negative film. There are advantages and disadvantages to both, but I think that the divergent paths had to do mostly with the practical differences between the way that still images and film images were printed. Now that all images made for books and magazines are digitized, there are endless debates between still photographers about whether postive or negative film is "better". Much of this debate has to do with arguments about the scanning of transparencies vs. negatives. Cinematographers don't seem to have the same debate. Perhaps that has to do with the fact that Kodak and Fuji don't offer them the range of positive films that is offered to still photographers.

[Robert Edge]

P.S. If some still photographer offers to show you a transparency made from an 8"x10" or 4"x5" sheet of film, beware that you will henceforth be unable to take seriously anyone who tells you that negative film is aesthetically superior :)

[Guest]

Go easy David Sloan, I don't think he's being arrogant.

 

Maybe some one would want to sit down and type answers to all of those questions.

 

It just isn't going to be me, or you, obviously :D

 

Richard

[Brian Wells]

Actually, someone did. Thank you to the individual who sent me a private message during their layover at the airport. Much appreciated.

 

Yes, I think you're right about my inquiry being about basic photographic knowledge or gaps of knowledge, at the least. I have pockets of information and gaps of information and today helped close quite a few of those gaps.

 

For a long, long time (1.5 years) I have been trying to develop an internship with an aquaintance who shoots television advertisements on film and recently he has been more open to having me come along. I am trying to clear up a few misunderstandings (yes, basic knowledge) in the least obtrusive way I know of: a forum on the internet.

 

I am trying to be respectful of everyone's time and figured this would be the least obtrusive way to ask since if it wasn't worth someone's time, then that person simply wouldn't respond and I won't jeopardize my trying to be a good intern for the one person I know that actually shoots with cine' cameras and film.

 

I look forward to being an active, contributing member of this board and also being helpful to the D.P. who is giving me a chance to help out on his shoots. . . In the same way it is awkward to ask something basic on an internet forum, it is to me ten times more humiliating (and likely inappropriate) to ask your mentor during work hours.

 

I am young? Yes. I have a lot to learn? Yes. I have asked stupid questions before that have caused seasoned professionals to ignore my telephone calls? Yes. I have a desire to excel in cinematography? Yes. I value a solid, well-grounded education from a university? Yes. I value learning at one's own pace and asking experts when you simply just don't get it? Yes.

 

That should hopefully explain my post today.

 

Thanks for all the links and personal reply's; your suggestions are valued. Thank you.

 

Brian Wells

[Dominic Case]

I think people on the list have typed extensive anwers to all of those questions in the past - just not all at the same time in one posting!

 

It's a good list and it shows (a) that the sender has worked out quite a lot for himself already, (B) knows that a certain amount of understanding is useful before getting in too deep and © can marshall the facts and knowledge and present it in a fairly articulate way.

 

I'll pick out one or two points:

 

Negative or Positive?

 

There are three basic types of film that you are distinguishing here.

 

Negative film has all the attributes that you describe.

Positive film is a laboratory filmstock, used for making prints from negative: as the basic photographic process results in a negative image, so a copy from that negative results in a "negative of a negative" or a positive. This is what you also describe as "print stock". It actually has much higher contrast (gamma) than negative, (it's designed so that the image itself, coming from negative onto the print ends up with the right contrast for projection). It also has a clear colour, as opposed to the orange masking of negative film. Positive film is developed in a slightly different process from negative, but basically it's the same sort of result on a different image: whereas reversal film goes through a quite different processing sequence.

Slide film - or reversal - is camera-original material, but it goes through a different process, so that you get an immediate positive image. It's also designed to give the correct contrast and colour rendition for projection.

So when you look at a piece of film with apositive, projectable image, it could be a camera original , on reversal stock, or it could be a print (on print stock) made from a camera original negative.

 

Just to round this off, if you load print stock in your camera, expose it and process it, you will get a negative image, but of very high contrast, with a very blue balance, and the film will work at an ASA of around 8, with less than zero latitude. Lots of other problems too - and please don't follow up on this here, anyone, go and search the archives.

 

F/stop or T/stop

 

F/stop is the calculated aperture: an indication of the diameter of the lens in proportion to its focal length. This determines the depth of field ( a wider aperture ie lower f/number has less depth of field). It also is the theoretical factor that determines the brightness of the image, and therefore the exposure. However, lenses with lots of elements may absorb a proportion of the light, so the actual light reaching the film is less than for another lens with the same f/stop. T/stops are the measured, practical equivalent of f/stops.

 

In short, they are similar: but use f/stops to find the depth of field, and t/stops to set exposure.

[David Mullen ASC]

I'll tackle some of this, although most of this is in any basic textbook...

 

>Sensitivity has a direct connection to the amount of grain in a film? Yes or No?

 

Yes. Although a newer emulsion design like Kodak's Vision-2 may be more efficient at light gathering than an older emulsion of the same speed, and therefore use smaller grains to get the same exposure. But within a manufacturer's line-up of the same emulsion design, let's say the Vision-2 line-up, yes, the faster films have bigger grains than the slower films.

 

>My interest here is the effect of changing that angle to a steeper or shallower (proper terminology?) angle and the effect it has on the image. If you use, say for example, a 45 degree shutter on Super16 at 24fps, is your image sharper at the expense of strobing images if there is high movement?

 

Yes, although not "sharper", just with less motion blur. "Crisper" motion. If you were shooting a static subject, there would be no difference in using different shutter angles.

 

>would a 200 degree shutter provide sharper images with potential for strobing?

 

No. I'm mean, a 200 degree shutter is barely different than an 180 degree shutter in terms of effect and exposure.

 

>What effect would a person be going after if they used a 90 degree shutter?

 

Less motion blur than with 180 degrees; slightly more strobiness. Less obvious than using a 45 degree shutter.

 

>Does shutter angle have a direct effect on your frames-per-second?

 

No.

 

>Someone told me that a 180 degree shutter on a motion picture camera would be the same as a 1/48 shutter on a 24p camera, at 24 frames per second. Giving that, would going to 1/45 or 1/36 shutter speeds be approximating the look and feel of a shallower angle on film (like a 90 degree shutter would be 1/24, etc) or would it be like a 1/60 or 1/120 on 24p would be like approximating a "shallower" angle on film?

 

I don't know what "shallower" means -- it's not a term I use. I refer to a closed-down shutter angle as a "narrower" angle. A 180 degree shuuter angle is a half-circle spinning in front of the film gate, so that the frame is exposed 50% of the time. If you are shooting at 24 fps, then it means that your frame is exposed for 1/48th of a second. If you close the shutter down by half from 180 to 90 degrees, then your exposure time is cut by half again, to 1/96th of a second at 24 fps. So on a 24P digital camera, you'd use something like 1/100th of a second to approximate the look of a 90 degree shutter angle at 24 fps. The other factor is that video does not usually need a shutter at all, so at 24P, you have the option of shooting at 1/24th of a second, which is not possible with a film camera running at 24 fps. However, you do get twice as much motion blur per frame that way.

 

>Comparing shutter angle to shutter speed on a digital 24p camera is confusing to me. On the 24p camera using, say a 1/15 shutter does not give you a full 24fps. However, at 1/24 or 1/48, et. al. it does provide 24fps. Is there a similar connection to shutter angle and frames-per-second on a motion picture camera?

 

This is basic logic (or math...) If you are taking a picture 24 times a second with a camera, how can you physically have exposure times longer than 1/24th of a second? You'd have to break the laws of physics and nature and enter a different space-time continuum... Any digital camera that allows exposure times longer than 1/24th of a second has to be shooting slower than 24 times a second and somehow using a frame buffer or something to write out 24 frames per second to tape.

 

>Last on shutter angle/slash/shutter speeds. Does switching from a standard angle such as 180 degrees to a different angle change the way you would expose film? For example, would a change from 180 to 90 give you an extra stop to compensate for, or no? Would going from 180 to 45 mean two stops of exposure difference? Are you losing a stop (darker image at same iris opening) or gaining a stop (brighter image at same isis opening) all other things being the same?

 

Correct, you lose a stop going from 180 to 90 degrees and another stop going from 90 to 45 degrees.

 

>f-stop is light entering the lens (used on photography and video) and T-stop is.... I think a more exact way of measuring light after it goes through the lens and comes out the other side?

 

The f-stop is a based on a physical measurement -- it's the ratio between the size of the iris and the focal length of the lens. However, due to variations in light loss from internal reflections, etc. they decided to measure the actual amount of light transmitted through the lens and correct the f-stop mark on the barrel to compensate so that "f/2.8", let's say, gives you the same EXPOSURE as another lens set to "f/2.8" -- however, since the f-stop is based on physical dimensions of the lens, they decided to call this "corrected" f-stop mark a "T-stop" ("T" for transmission.) Just think of a T-stop as a more accurate f-stop, so read the f-stop on your light meter and set the T-stop on the lens.

 

>A photographer told me recently that no-one uses ASA speeds in photography and it is all ISO speeds.

 

ASA and ISO use the same numbering system so it doesn't matter. It's just that the American Standards Association became the International Standards Organization at some point. I don't even think they exist anymore -- now it's ANSI I believe. Anyway, manufacturer use the same numbers but call them an "E.I." now (Exposure Index) because it allows them to tweak the rating somewhat as they see fit for optimal results. But more or less, saying 100 ASA, 100 ISO, 100 EI all mean the same thing.

 

>What does a 100, 200, or 500 speed film mean in terms of look and sensitivity to light?

 

The higher the number, the more sensitive the film. 200 EI is twice as sensitive as 100 EI, or the equivalent of one f-stop more sensitive.

 

>For example, why go 7218 vs. 7212 or 7217? Do you expose differently for each one?

 

Of course, 7218 is 500 EI, 7212 is 100 EI and 7217 is 200 EI. This is basic photography....