what is the meaning of stop down?

Discussion in 'Beginner Questions' started by skye_lee, Apr 8, 2009.

  1. i know what is f numbers it's the size of the aperture.
    but when it says (in photography lesson (book or magazine) "f4 stoped down to f16" what is that mean?
    set my lens aperture at f4 then what?
    please help me.
    thanks in advanced.
     
  2. It simply means to set the aperture to a smaller number. But remember you have to set the ISO or shutter speed accordingly to compensate. Hope this helps.
     
  3. Regarding: "f4 stoped down to f16"
    "f4" id's the lens (it's max aperture", and "stoped down to f16" means to set it to f16.
    The expression "stop" comes from past cameras with apertures that were opened/closed to preset metal tangs, or stops.
     
  4. .
    "Stop down" ALSO usually means "stop down metering", which means lens aperture setting must be manually stopped down to your specific choice of actual aperture for each shot in order to allow the in-camera through-the-lens metering to calculate an accurate exposure, and is required for proper automatic corresponding shutter speed setting for your chosen ISO sensor sensitivity when using non-camera-linked lenses such as old 42mm thread or other old manual aperture operation lenses on new Pentax KA mount cameras, cameras that otherwise "talk" to and know how to predict and operate modern electronic lenses that are designed to work on them. Modern automatic lenses don't need to have their apertures stopped down in order to meter properly. We often say:
    • Q: Can I use my dad's old film camera's manual lenses on my new DSLR?
    • A: Yes, but be prepared to use manual stop down metering (and a dark viewfinder that's hard to accurately focus through when the lens is stopped down to your choice of a taking aperture for each shot).
     
  5. It's also a bit confusing that higher numbers mean smaller apertures. The number on the aperture ring is actually on the bottom of a fraction: it's f/4 or f/16, where f is the focal length of a lens; so on an 80mm lens, f/4 means the aperture is 20mm and f/16 means the aperture is 5mm. So when you have a lens that maxes out at f/4 and you set it to f/16, you have stopped it down by changing to a higher number.
    If this seems confusing, that's because it is :)
     
  6. Like everyone mentioned, stopping down means to adjust the aperture. Not sure how familiar you are with aperature, but it is the opening of the lens. Depending on how big the hole is, or the f stop, you either let more or less light in. The smaller the F, the bigger the opening. So a f/1.4 would be an extremely big opening, while at f/22 very tiny.
    That is how exposure works. When you're in low light situation, you want more light to come in so your image would be bright, but when outside on a sunny day, less light in.
     
  7. Well said Andrew Lynn, this is another Lynn, Lynn Jones.
    The first couple of days teaching fundamentals of photography, I always ask if the students rember taking fractions in the 4th or 5th grade, I get stunned silence. As you have clearly stated, an f stop is merely the denominator of a fraction of the focal length, the numerator of which is 1. The same is true regarding shutter speeds.
    As you say, the smaller the number the bigger the opening and vice versa. About 15 or so years ago, I sprang the same fraction of F question on more than a dozen photo instructors and they didn't know the answer, now they do!
    Lynn
     
  8. Skye,
    Just to be sure, because there are a few possible answers, could you give the complete sentence or context from that remark in the photo book ?
    I suspect, is it as Mendel said, it has to do with a lens and what the photographer set it to. For instance, ...
    I can take out my 180mm f2.8 lens and ,based on how much light is in the scene, and what I want to do, I can twist the dial on the lens down to f16. That is called "stopping down to f16" from it's max open value of f2.8. It's called "stopping down" because each number is an f-stop. So, if adjust the lens f-stop down to what I want, I have "stopped down". Does that make sense ?
    Of course the REASON to do that is to get a lot more things in focus than I would get , if I set it to f2.8.
     
  9. oh i get it. first of all, thank you to all of you for your kindly explained.
    i did know what is f/number (stop) means few classes and other books i read didn't said like " at f4 stop down to f16" what i was confused on this sentence was "at f4" my photography classes teachers were never said it that way. they all said "stop down to f4, or f5, or f 16, and etc not like "at f4".... "to f16". now it's all clear to me what was that means. thanks everyone. oh and i don't have the book with me... i'm very poor guy who couldn't afford to buy a photography lesson book i had to went down to barn and noble to study it. when i read that line " at f4..stop..f16" i was like...
    "......." "......" "huh???" "at 4??" lol.
    thanks everyone.
     
  10. .
    Skye,
    "Photography" is never ending learning you're getting into. There is no "one" right answer that works for everything all the time, for instance:
    Earlier: "... Of course the REASON to [stop down to f/16] is to get a lot more things in focus than I would get if I set [the lens aperture] to f/2.8 ... "​
    Allow me to "BUT" in here:
    No. Stopping down the lens aperture does "deepen" the subject field plane of acceptable focus, BUT it also extends exposure time requirements at the same capture sensitivity, and so for moving subjects and hand held cameras, that might cause less accurate focus as we'd increase the risk of capturing movement, BUT with flat subjects, the additional depth of subject field focus may not be necessary, and the decrease in the image-signal-to-diffraction ratio at smaller apertures may cause the resulting image to lack clarity, BUT some image distortions due to the lens aberrations may be reduced with smaller "stopped down" lens apertures, and so the image focus may appear clearer at smaller lens apertures, BUT you could also raise capture sensitivity (ISO) when using smaller lens apertures to permit using faster shutter exposure times, BUT that might increase capture noise (film grain, electrical noise) so the image focus may appear less clear, BUT if the subject field plane of focus or the image plane of focus shifts at different lens apertures, then if you do not refocus after stopping down, the resulting image may appear less clearly focused (hence Zeiss/Contax had a focus bracket feature, but that also accommodated auto focus anomalies), BUT ...
    See? It's never ending. There's no "one" right answer.
    That's why we call the science and craft of photography ... an ART !
    Enjoy, have some fun, ask as much as you can, the remember, Skye, that whole web world is your encyclopedia, and Google is your table of contents, and there are many places like this one, but also Wikipedia is a place you can leave your notes behind for others to learn from and comment on as you go.
    Share some pictures!
    .
     
  11. James  Dainis

    James Dainis Moderator

    Take photos of players at a baseball game and is is science and craft. Take a photo of a crumpled hot dog wrapper and it is Art (especially if you call it "Humanity" and charge $1,500 per print).
     
  12. .
    James, I beg to differ ... THIS is art, nothing but "artistic" decisions made by an artist. Scientific quality craft choices, sure, but "art" nonetheless:
    http://www.vintagephotos.com/Babe_Bows_Out.jpg
    The Babe Bows Out / Item #1
    Pulitzer Prize Winning Photograph
    by Nat Fein ©

    http://www.vintagephotos.com/Nat Fein Babe Bows Out Page.htm
    (16 X 20 Fiber Base Silver Gelatin Print, Signed by Pulitzer Prize Photographer Nat Fein
    Limited Edition of Eleven $16,000 Call 1-845-353-5866)​
    Hmm ... there's a meaning of "stop down" for ya, Skye!
    .
     
  13. James  Dainis

    James Dainis Moderator

    I remember reading one time how Fein described why he took that shot as he did. There were too many photographers in front of the Babe so he was forced to take the shot from the back. Sometimes artistic "decisions" are forced upon people.
     
  14. I am big fan of Automobile photographs.
    here are some pictures i took at 08 LA autoshow
    and i do love landscape as well so, i 'll share more of my landscape photographs later on.
    thanks guy!! and i hope you guys like these pictures and let me know if there are things i need to correct!
    http://i217.photobucket.com/albums/cc247/Hantastic1030/2008%20Nov%20LA%20Autoshow/_MG_5341.jpg
    http://i217.photobucket.com/albums/cc247/Hantastic1030/2008%20Nov%20LA%20Autoshow/_MG_5346.jpg
    http://i217.photobucket.com/albums/cc247/Hantastic1030/2008%20Nov%20LA%20Autoshow/_MG_5385.jpg
    http://i217.photobucket.com/albums/cc247/Hantastic1030/2008%20Nov%20LA%20Autoshow/_MG_5385.jpg
    http://i217.photobucket.com/albums/cc247/Hantastic1030/2008%20Nov%20LA%20Autoshow/_MG_5523.jpg
    http://i217.photobucket.com/albums/cc247/Hantastic1030/2008%20Nov%20LA%20Autoshow/_MG_5545.jpg
     
  15. Skye,
    Well.... since you asked.... your name is rather BIG for the size of the shots. Since you also used a fancy color patern on your name, it catches the viewers eye as much, if not MORE than the subject matter. Back down the font size and keep the color simple and professional.
    What camera/lens did you use for these shots ?
     
  16. .
    John, here's some of the EXIF from Skye's last shot:
    Make - Canon
    Model - Canon EOS DIGITAL REBEL XT
    Orientation - Top left
    XResolution - 300.00
    YResolution - 300.00
    ResolutionUnit - Inch
    Software - Adobe Photoshop CS3 Windows
    DateTime - 2009:03:21 12:35:58
    WhitePoint - 0.31
    PrimaryChromaticities - 0.64
    YCbCrCoefficients - 0.30
    YCbCrPositioning - Co-Sited
    ExifOffset - 356
    ExposureTime - 1/13 seconds
    FNumber - 5.00
    ExposureProgram - Manual control
    ISOSpeedRatings - 400
    ExifVersion - 0221
    DateTimeOriginal - 2008:11:29 05:36:58
    DateTimeDigitized - 2008:11:29 05:36:58
    ComponentsConfiguration - YCbCr
    ShutterSpeedValue - 1/13 seconds
    ApertureValue - F 5.00
    ExposureBiasValue - 0.00
    MeteringMode - Average
    Flash - Flash fired, compulsory flash mode, red-eye reduction mode
    FocalLength - 18 mm
    UserComment -
    FlashPixVersion - 0100
    ColorSpace - Unknown (0xFFFFFFFF)
    ExifImageWidth - 900
    ExifImageHeight - 600
    InteroperabilityOffset - 1076
    FocalPlaneXResolution - 2855.84
    FocalPlaneYResolution - 2859.11
    FocalPlaneResolutionUnit - Inch
    CustomRendered - Normal process
    ExposureMode - Manual
    White Balance - Auto
    SceneCaptureType - Standard

    Thumbnail: -
    Compression - 6 (JPG)
    XResolution - 72
    YResolution - 72
    ResolutionUnit - Inch
    JpegIFOffset - 1202
    JpegIFByteCount - 0​
    .
     
  17. omg peter, wow...
    any way, i used sigma lens (18-200 mm f3.5 - f6.3 OS) with canon xt.
    and for the name wise, i put my name there so ppl won't steal them from me.
    i've seen some ppl using my photos for their advertisement before. so i started to put my name on it one of my Photographer friend told me to start putting name on them... none named pictures are all saved seperatelly.
    other then that, is there any suggestion? such as, little bit more to left or this angle up or down and etc.
    thanks again.
     
  18. but and yes, i will take your sggestion as well. that way, my photos will looks for proffesion. thanks.
     

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