Latitude

Discussion in 'Exposure Discussion' started by Xander Fischer, Apr 24, 2011.

  1. Xander Fischer

    Xander Fischer Member

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    Hey APUGers,

    This is my first post... (!)

    So, I'm actually a "filmmaker" (editor, to be precise), but I have an obsessive fetish for 35mm still photography on the side. Now, in motion picture 35mm film, we shoot with a stock like Kodak's Vision3, which can pack a whopping 14 stops of latitude. After learning a long while back that this wonderful exposure advantage over almost all digital formats (up until cinema cameras like the RED MX and EPIC came around) is not the case with ANY 35mm still film. But hey, I would LOVE if someone proved me wrong on that one.

    Anyway my question is this: Which 35mm color negative film has the most exposure latitude and/or dynamic range? I find that Ektar and Portra tend to yield the widest range, but I haven't shot charts with all the stocks I shoot with, so I can't say for sure. Obviously latitude gets wider when you up the ISO, but I don't want to shoot anything over 400 unless you have a REALLY good developing process that consistently provides awesome grain structure.


    SO (to reiterate): Which 35mm color negative film (preferably under 800, unless you can convince me otherwise) has the widest exposure latitude/dynamic range?

    Sorry to be so long winded... bad habit of mine.

    X
     
  2. 2F/2F

    2F/2F Member

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    Hi,

    Welcome to the Website.

    Can you really miss the proper exposure by 14 stops and still get a usable image with motion picture film? (And if you do, who actually messes up that severely? Nobody you want working for you; that's who. :D)

    Pretty much all color negative films have very good overexposure latitude. Underexposure is pretty limiting, relatively.

    As for dynamic range of the film itself, it is also very broad with any color negative film. Getting all of that range onto a paper is the challenge. (To get the most contrasty situations onto paper requires masking, which involves a lot of tedium and a pretty hefty learning curve in the grand scheme of things. Most people do not do this.) Generally speaking, the less contrasty the film, the better it is in this regard, as large differences in brightness are rendered closer together in terms of negative density than with contrastier films. Your "professional" film choices (now, after recent discontinuations) for slower films are Portra 100, Ektar, and Fuji Reala. Unfortunately, neither of these is a "subdued" contrast/color film (like Portra NC or Fuji S are). Portra and Reala are pretty "standard," and Ektar is contrasty. Hopefully Fuji will get around to repackaging its 160S as 160NS and getting it back to the U.S. (like they said they would when they discontinued 160S and 160C over a year ago).

    In short, I would use Fuji Pro 160S or Portra 160NC while you can still get them from retailers. Once they are gone, I would try Portra 100 and Reala.

    Same for 400 films. Use 400NC while you can still get it. After that, Portra 400 or Fuji Pro 400H.

    The choices are very limited. Portra 100, 400, 800, and Ektar are what Kodak makes now. Reala and Pro 400H are what Fuji makes, and Reala is only imported once per year TMK. (Or at least what they have decided to sell in the U.S.A.; they may make more products for their home market.)
     
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  3. Xander Fischer

    Xander Fischer Member

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    Well, you need that ammount of latitutude (well, it's ideal, anyway... if you have $800 for a 1000' roll) because even very will lit scenes can have a very wide range from the brightest highlights to the darkest shadows, and basically, you WANT to capture detail in ALL the ranges, because you're going to be scanning the final cut at 4k when you do the online edit (color, effects, etc.) It's mostly for the color grade, and the characteristic curve extends WAY further into the shadow reigon than any still film does (about 4-5 stops!). Kodak says in text that it goes 14 stops, but the actual curve that they provide, I only count about 10... I dunno, most people say it's 14.

    Anyway, about still film latitude, thanks for the reply. I hope I get a variety of answers, but yeah, due to the cessation of many awesome stocks, it's not surprising that we some of the answers have changed. I think you're right about Portra NC... shame they had to make the new "hybrid" bullshit-- I wanted the option!! We all did! I guess for now, I love Ektar, but I'll have to do shoot some charts if I can get my hands on some NC 400/100 to compare it with.


    Thanks for your input!

    X
     
  4. 2F/2F

    2F/2F Member

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    I understand that. But that sounds like dynamic range, not latitude. Latitude is the ability to dig a usable product out of technically flawed (i.e. improperly exposed) film. It changes based on the dynamic range of the material, but they are not the same thing. http://en.wikipedia.org/wiki/Exposure_latitude
     
  5. Xander Fischer

    Xander Fischer Member

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    You're right, thank you for clarifying. I thought they were used interchangeably, but it's good to have my head on a little straighter now.

    Dynamic range is measured in f/stops though, so I guess what I'm wondering is how many stops of dynamic range an average film has, and which film has the most dynamic range.
     
  6. Bruce Watson

    Bruce Watson Member

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    Really? What makes you say that? My understanding, such as it is, is that Kodak based the previous crop of still photography color negative films on Vision 2 motion picture emulsions. I'm assuming (danger Will Robinson!) that the current crop is based on Vision 3.

    When tweaked and optimized for still photography, I wouldn't think they'd go through a lot of effort to make still film worse -- what would be the point?

    All that said, I did make a photograph five or six years ago (so two versions of Portra back from the current one) of a white flower in full mid-day sun in June. Measured 10 or 11 stops from shadow detail to highlight detail. And didn't show any kind of color cast or interesting artifacts.

    That's the highest scene brightness ratio (SBR) I've ever found in my normal work. Then again, I'm not shooting inside a dark building wanting to keep the windows from blowing out either.

    As to proof, I think it's incumbent on the one who wants it to do the testing. Have at it, should be interesting.
     
  7. MattKing

    MattKing Subscriber

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    The cinematographic film stocks are made to print to film, not paper. Projected film is capable of a higher SBR than a "paper" print - thus the greater dynamic range.

    In addition, the process of printing to film stock involves an inherent increase of contrast. As a result, the initial cinematographic negative film stock is designed with a lower inherent contrast than film designed for printing to paper.

    As I understand it, an optical "paper" print from a cinematographic negative film stock will be very flat - you will record the dynamic range, but won't reproduce it in an attractive manner.
     
  8. Xander Fischer

    Xander Fischer Member

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    Yeah, you start off the grade with a logarithmic curve, so you're right, it's suuuuper flat, and then you basically pick and choose what you want in the color grading, and then (if you have a ton of money to spend on a film-out delivery) then you correct it all to match perfect with your print stock (which, I think you're right about being more contrasty).

    Anyone have anything to add about STILL film dynamic range though?
     
  9. Xander Fischer

    Xander Fischer Member

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    Yeah, it's not that it's worse, it's just for a different purpose. Like Matt King said, cinematic film stocks are designed to be very very flat. Like, if you were to scan the ungraded stock unknowingly, you would probably think something was fucked up it would be so flat. It's designed to capture as much detail as possible, then you basically grade it in post to bring out/reduce the image and mold it to be what you want it to look like. Basically.
     
  10. 2F/2F

    2F/2F Member

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    Still color negative film itself has a huge dynamic range. Even b/w negative film does. I would say based on experience that with skilled exposure, development, and printing, 14 stops can be squeezed onto the paper from a b/w neg. without even having to be an exceptionally skilled printer.

    I would guess that the "14 stop" statement that you have been hearing refers to how many of those stops can actually be squeezed into a scan, or the print films currently in existence. (Though who does analog editing and goes straight to print films now? So it must refer to scanning.)

    I think the dynamic range of some still films themselves must be at least 16 stops. I guess this because if you have a fairly common 10 stop brightness range that falls perfectly into place from maximum black to paper white onto your photo paper without manipulation, and your negative can print fairly normally at up to six stops overexposed (as tested by Photo Engineer here on APUG), it would seem to state that the film itself has a dynamic range of 16 stops before you start compressing the high tones severely enough to have second thoughts about the usefulness of the negative.

    So, the film itself has extraordinary dynamic range. Again, the problem, and what really matters, is not how much the film can capture; it is getting it all onto the paper. To pull all of that range out of the neg and onto the paper, you are going to have to do some heavy manipulation in printing, which is more involved and more difficult with color than with b/w. With b/w, most photographers without much experience can overexpose and pull back a negative very easily to get at least two stops reined in; you can get even more if you resort to more involved methods. Then, in printing, most can easily burn another stop or more. Those who are good at burning can easily get more than that. Then, add in what can be done with masking by those so inclined and able. With color, however, you only have burning and masking, and 1/2 stop of pulling, so it is harder to squeeze all that range onto the paper at the "amateur" level of printing skill.

    In other words, the way I see it, negative film has so much dynamic range that the cases in which it, and not ones own printing ability, is going to limit one are few and far between. In other words, shoot away, and practice digging that dynamic range out of the negative and onto the paper, as opposed to worrying about the gruesome technical details of the material.
     
  11. Xander Fischer

    Xander Fischer Member

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    Well, they generally shoot on 35mm, then scan at low res to do the "offline edit," then when they have the final film all cut, they go back to the original negatives, and they scan only the footage that made it into the final film at 4k (which resolves to something around 3k, I think) to prepare for the "online edit," where effects and color correction are done. And, actually, if it's got a really big budget (like 80%) of the movies you see in theaters these days) they will do a "film-out" after they color correct/do all the effects on the 4k-scanned final cut. Finally, when all is done and the final cut with sound and everything is done, they use a film recorder (a very expensive machine that generally uses lasers or RGB lights to burn the high res digital image onto the print stock. Distributing in a digital medium is obviously much cheaper, but a lot of theaters are still lagging on digital projectors, so film-out is often the way to go if you want to reach a wide audience.

    The 14-stop business does refer to the dynamic range (again, thank you for your corrections) of the actual stock that your shoot on. Like I said, you can kind of think of the color correction stage as "selecting" how much or how little you want out of that range, but it depends on how much you're paying for your online scans.

    Agreed, it is better to just shoot away and see what you get, but I guess I just want to be able to zone out specific stocks accurately... that would definitely take some testing of individual stocks though, and I'm not sure how to go about measuring. It's all about composition and subject matter I suppose, but I get a strange masochistic pleasure from technical immersion-- the tools do not make the artist, but if an artist understands his tools, he'll be able to use them much more effectively.

    X
     
  12. hrst

    hrst Member

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    Portra line has lower contrast thus a bit more dynamic range than Ektar. Portra 400 may have a bit more than Portra 160. However, even Ektar has very much for all practical purposes, don't listen to internet legends that "you must nail down the exposure with Ektar like slide films", that is 100% bullshit.

    So, it would go Portra 400 > Portra 160 > Ektar for the Kodak line, I suppose. But in any case, I would select the product on other criteria because all of them provide enough dynamic range to suit practically all purposes.
     
  13. Markster

    Markster Member

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    EDIT: Let me preface this with "I'm an amateur here, but ...."

    I would personally classify Ektar as a narrow latitude film. The image will display if under or overexposed, but the side effects show the quality diminishes even though individual details remain (read: the colors go off, and quickly).

    So while I like it for now, I consider it very narrow. I have heard good things about Portra and under/over exposure there.

    I do not like Reala, as the latitude is almost nonexstent IMO when exposed according to the light meter. You get the narrow window of correct lighting, pitch black shadows with no definition, and blown out highlights, all in the same picture. It boggles the mind.

    I'm personally working my way up to testing more film types. I picked up a roll of Kodak UC 400, and after that it's off to Portra 400 to test. That's about all I can really suggest now: Get single rolls here and there, and just shoot them! Make notes after you get them developed and tally a list of what films you liked and disliked.