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  1. #11
    2F/2F's Avatar
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    Quote Originally Posted by David William White View Post
    Point of clarification (without arguing the figures quoted):

    The '7-9 stops' is a description of the total range of luminance the film is able to record, from highlights to shadows. The '-2 to +3' is the variance from nominal exposure allowed for respectable, standard prints.
    That sounds right at first....but on further thought, it cannot be. Even when not at their best-performing ISO settings, quality digital cameras can almost match that nine stop figure these days, and considering the stop or so of headroom when shooting raw and doing the equivalent of "pulling", they can (barely) exceed it. Color neg film can record far more than 9 doublings of luminance value in a scene, as can black and white film. I know that from personal experience.

    Perhaps the 7-9 stop figure is not just talking about the film itself, but factors in the conversion to a "straight" positive print on to RA paper, without utilizing special printing techniques such as burning, masking, or multiple scanning...but the film itself can certainly record a wider luminance range than that.
    Last edited by 2F/2F; 12-04-2009 at 02:45 AM. Click to view previous post history.
    2F/2F

    "Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."

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  2. #12

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    Like PE, I also use Portra VC 160. I expose it at ISO 80 to ensure 0.15 density units above film fog at a Zone I placement when exposed in shaded light. Shade light is a cooler light and has less red then direct sun light areas. Using ISO 80 insures that any reds in shaded areas such as flowers are properly recorded and do not turn muddy.

    I also have constructed a 14 stop characteristic curve ranging from Zone I to Zone XIV using ISO 80. The curve is very straight from Zones I to XII which means the contrast is constant over that range. Zones XIII and XIV exhibit a shoulder, and the curve begins to flatten which means the contrast at those Zones is reduced. However, detail at Zones XIII and XIV are still very good.

    Basically what this means is that Portra VC 160 does a very good job at approximating the brightness ranges of the human eye. If you can see it you can photograph it. With a 14 stop range, I have no need of nor do I use graduated neutral density filters. I have shot under the most extreme mid day conditions one could ever imagine and have gotten excellent results. However, I would like to qualify that statement with the following considerations:
    • I use a UV 2A haze filter. This filter is the only filter that removes 100% of the UV radiation and is designed for high altitude shooting. It is not cheap.
    • I also use a polarizer filter to help with clouds. The polarizer will remove any glare in the scene and will increase the contrast in clouds to help compensate for the reduction in contrast at Zones XIII and XIV.
    • Printing high contrast color negatives using traditional methods with a scene range of 14 stops is a topic that needs to discussed some where else. The methods can be very complex.


    Hope this helps...

  3. #13
    2F/2F's Avatar
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    Good info, Steve. Thanks.
    2F/2F

    "Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."

    - Rob Tyner (1944 - 1991)

  4. #14
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    Steve;

    Very good comments. I should add that I use the same filters that you do and leave them on my cameras all of the time. The only one that does not have the filters is my Speed Graphic unfortunately, but, you can't have everything.

    PE

  5. #15
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    So Steve,

    you expose 160vc at 80, all the time? I'll have to shoot a roll and see what its like.

    just out of curiosity, what type of uv 2a filter would you recommend? I have b+w filters on all my lenses, would a 2a from them be satisfactory? I've also heard of a company, Formatt, that supposedly makes super-duper filters(with a price to match). Have you ever heard of them?

    thanks for the info!

    -Dan


  6. #16

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    Color negative film has extremely wide latitude, but you can definitely tell when a negative has been underexposed or overexposed. It's more tolerant to overexposure than underexposure. You can get acceptable (well, sort of) negatives in the +3 to -2 range, but things get a bit washed out with overexposure and gritty, with little shadow detail, on underexposure. I've found you can treat color negative film very much like black and white film. Make sure you have sufficient exposure for the shadows, and the highlight will probably take care of themselves (except in really extreme contrast situations). Best results are usually near the rated speed, but I often give about a third of a stop overexposure to make sure the shadows are good (sometimes more).

  7. #17

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    Quote Originally Posted by DanielStone View Post
    So Steve,

    you expose 160vc at 80, all the time? I'll have to shoot a roll and see what its like.

    just out of curiosity, what type of uv 2a filter would you recommend? I have b+w filters on all my lenses, would a 2a from them be satisfactory? I've also heard of a company, Formatt, that supposedly makes super-duper filters(with a price to match). Have you ever heard of them?

    thanks for the info!

    -Dan
    Yes Daniel, I expose my film at ISO 80 all the time. This makes sense because a scene with both extreme shadows and highlights is what I shoot most of the time. The highlights expose just fine, and I get rich detail in the shadows. A scene only in bright sun is equivalent to a scene with both shadows and highlights, but without the shadows. In scenes like this I look for a shadow some where close to the scene to meter on and give it a Zone III exposure/placement (most of the time) even though the shadow is not in the actual scene I am photographing. This allows me to let the highlights fall where there may and exploit the full 14 stop latitude of Portra VC 160.

    It is very important with color negative film that you expose for the shadows just like do with b&w film and let the highlights fall where they may. This is because the shadows are the thinnest part of the negative. Do not expose for the highlights like you do for slide film otherwise you could severely underexpose the film and not realize the full 14 stop latitude of the film.

    I shoot with 5x7 and 4x10 large format cameras and use the Lee Filter system. I purchased my filter from B&H Photo, and it is a Format filter. The price for a 4X4 inch filter is $157.50. The filter has a slight yellow tint to it, and I have had no problems with it.

    The filter I purchased came with a plastic frame. I carefully remove the frame which was glued on. The filter consist of three layers of glass cemented together. I then sanded the edges and seal them with clear nail polish. The filter is thicker then the standard filter thickness and would not slide into my Lee filter holder. I hand to modify one of the slots on the filter holder with shims so that I could slide the UV 2A filter into the slot.

    Hope this helps...

  8. #18

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    Quote Originally Posted by stevewillard View Post

    It is very important with color negative film that you expose for the shadows just like do with b&w film and let the highlights fall where they may. This is because the shadows are the thinnest part of the negative. Do not expose for the highlights like you do for slide film otherwise you could severely underexpose the film and not realize the full 14 stop latitude of the film.
    Thanks that was really what I needed as I only shoot slide and B&W at the moment and that statement makes it much clearer.
    Thank you everyone for your input!

  9. #19

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    The power of color negative film lies with bold vivid light which is just the opposite of color slide film. In fact, I cannot shoot with someone who uses slide film because my needs are so different. You can see some of my work on my website at www.stephenwillard.com to get an idea of what I am talking about.

    Please note photographing a bold high contrast scene is the easiest part. Portra VC 160 can do that with easily. The hard part is printing a high contrast color negative onto paper. There are two methods you can employ. They are dodging & burning and masking. I use the masking because it can be applied to very small or fragmented areas of the image that would be impossible to do with dodging & burning. However, there are two serious problems with masking high contrast negatives. They are as follows:


    1. Ghosting - This is a term I made up to describes a vivd halo that occurs where there is abrupt density differentials in the mask film sandwich such as where mountain edges meet the sky.

    2. In order to compress the brightness ranges from extreme shadows to extreme highlights I have to create mask as thick as bricks to hold back light in the shadows long enough so that the highlights can be properly printed. These thick masks will compress the hell out how of adjacent detail with similar print values. For example, detail in a mid tone region of the print can turned to mud looking flat, lifeless, and dull.

    To overcome these two problems I have had to invent whole new masking technologies in my darkroom which took me years to do and at this time is proprietary. For this reason I highly recommend that you restrict your scenes to 8 to 9 stops at the most.
    Last edited by stevewillard; 12-04-2009 at 02:49 PM. Click to view previous post history.

  10. #20
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    Clarifying dynamic range and exposure latitude

    Terms dynamic range and exposure latitude cannot be defined without each other. For a given technology (slide film, neg film, digital) there is only dynamic range. Then, exposure latitude means the extra dynamic range for a given scene. For example, if a negative film has a dynamic range of 14 stops, and a scene you are going to photograph, has a contrast of 9 stops, you have 5 stops of exposure latitude.

    So, there is no "exposure latitude" for a given film, but rather there is "exposure latitude" for a given film AND scene.

    But, that is only a simplification. In fact, there is no perfectly linear and uniform system over the whole dynamic range. If you have 14-stop dynamic range and 9 stops of information, there are more and less optimal exposure choices to select from. And that depends on everything, again.

    Dynamic range for digital, slide film and neg film behaves quite differently.

    But I have come up with three different definitions for dynamic range, that can be used for digital or film.

    The almost linear / noiseless dynamic range -- the brightness information that shows all the very fine low-contrast detail perfectly without any contrast-increasing post-processing.

    The usable dynamic range -- all the brightness information that can carry quite fine details, so that this fine detail can be somehow seen in the final picture without contrast-increasing post-processing; or with contrast-increasing post-processing, any low-contrast fine detail can be revealed in very acceptable quality.

    The complete dynamic range -- all the brightness information the medium can record, regardless of quality and the effort needed in post-processing.

    For the good digital SLR cameras, the figures may be something like 7, 9, 11 stops. For color slide films (example: Fuji Astia 100F): 5, 9, 12. And, for colour negs..... Well, the manufacturers don't even bother to print the shoulder region in the characteristic curve in datasheets, because the linear section is already so long. The figures for color negs are something like: 11, 15, 25. This seems to agree quite well with Steve's experience.

    Today's color negs have the linear region as long as the whole dynamic range of digital, and then they have a very good and long shoulder region, that is completely extra!

    Here's a shot on Fuji Superia XTRA 400, overexposed 9 stops (thus placed almost completely on the shoulder) and contrast boosted after scanning: http://sorsa-tv.ath.cx/~antalh/tur/9ylivalotus.jpg
    Last edited by hrst; 12-04-2009 at 04:45 PM. Click to view previous post history.

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