"the sweet spot"

gvfgvf Registered Users Posts: 356 Major grins
edited May 7, 2015 in Technique
Ever use a film camera? Or a Digital on Manual?: "The Sweet Spot"

Speed: 125; Aperture f/8

for day shots, gets anything no matter the light unless some real extreme, set it and leave it.

(I had some 1950 film cameras - there was a red dot on the ring for this setting)

Comments

  • kdogkdog Administrators Posts: 11,680 moderator
    edited April 26, 2015
    You left out ISO. Exposure is specified by three variables, not two.

    The Sunny 16 Rule gives a general guideline for exposure in direct sunlight as follows:

    ISO: 100
    Speed: 1/100s (or 1/125)
    Aperture: f/16

    So in order for your settings of 1/125s and f/8 to work in direct sunlight, you would need an ISO of 25. No digital camera that I know of goes to an ISO that low, although some films do.
  • pathfinderpathfinder Super Moderators Posts: 14,694 moderator
    edited April 26, 2015
    "f8 and be there" -- but like kdog was suggesting, lots more choices and opportunities today.

    I do regret that our modern DSLRs don't offer us ISO 10 or 12 or 20 - might be quite useful at times.
    Pathfinder - www.pathfinder.smugmug.com

    Moderator of the Technique Forum and Finishing School on Dgrin
  • alaiosalaios Registered Users Posts: 668 Major grins
    edited May 1, 2015
    So what did you do at film age being constant at f/8. Does this hold for any lens or almost any lens? I have used some aps-c cameras and I think their sweet spot is f 4 or f5.6
    Alex
  • gvfgvf Registered Users Posts: 356 Major grins
    edited May 4, 2015
    pathfinder wrote: »
    "f8 and be there" -- but like kdog was suggesting, lots more choices and opportunities today.

    I do regret that our modern DSLRs don't offer us ISO 10 or 12 or 20 - might be quite useful at times.

    The choices don't always help, sometimes, but they can also distract from the eye and light. You can make the same choices with shutter speed and aperture changes . Actually, many names of exposure choices are only that anyway, just playing around with speeds and f-stops or apertures in reality.
  • gvfgvf Registered Users Posts: 356 Major grins
    edited May 4, 2015
    alaios wrote: »
    So what did you do at film age being constant at f/8. Does this hold for any lens or almost any lens? I have used some aps-c cameras and I think their sweet spot is f 4 or f5.6
    Alex

    I think it's for the average 50mm lens but not sure. One old folding camera I used shot 6x9, negatives the size of a business card, had a 3.5/100 lens, Zeiss, (great lens) and worked on that too.

    But different lenses and cameras would have various "sweet spots" I assume. In old cameras it will say what it is in the directions, or put a red dot on the spot in speed and aperture rings.
  • pathfinderpathfinder Super Moderators Posts: 14,694 moderator
    edited May 4, 2015
    Alois, I think "f8 and be there" came from street shooters and photojournalists that were shooting black and white negative film, and were more concerned with grabbing an image ( not missing a shot ) than getting the correct exposure. Exposure could be helped by altering the developer time later in the darkroom.

    F8 and be there did not come from large format landscape shooters.

    I think the phrase is from the 1930s. Google suggests the phrase may have originated with WeeGee - http://www.adorama.com/alc/0013109/article/f8-And-Be-There
    Pathfinder - www.pathfinder.smugmug.com

    Moderator of the Technique Forum and Finishing School on Dgrin
  • gvfgvf Registered Users Posts: 356 Major grins
    edited May 5, 2015
    kdog wrote: »
    You left out ISO. Exposure is specified by three variables, not two.

    The Sunny 16 Rule gives a general guideline for exposure in direct sunlight as follows:

    ISO: 100
    Speed: 1/100s (or 1/125)
    Aperture: f/16

    So in order for your settings of 1/125s and f/8 to work in direct sunlight, you would need an ISO of 25. No digital camera that I know of goes to an ISO that low, although some films do.

    No you don't, 100 speed film is fine on that setting for most day shots. If it's incredibly bright or conversely dark you play with a stop or two with both speed and aperture, no big thing. It's for average day lighting, not extremes, the setting, and easily alterable if you hit an extreme. Digital doesn't have ISO (ASA), that's film speed, has zip to do with digital - unless it be some produced "look" digital manufactures. But film is film and digital is digital, ISOs don't refer to digital.

    Best
  • kdogkdog Administrators Posts: 11,680 moderator
    edited May 5, 2015
    gvf wrote: »
    Digital doesn't have ISO (ASA), that's film speed, has zip to do with digital - unless it be some produced "look" digital manufactures. But film is film and digital is digital, ISOs don't refer to digital.
    Digital cameras most certainly do have ISO settings. The setting specifies the sensitivity of the sensor to light, the same way that ISO in film does.
  • gvfgvf Registered Users Posts: 356 Major grins
    edited May 5, 2015
    kdog wrote: »
    Digital cameras most certainly do have ISO settings. The setting specifies the sensitivity of the sensor to light, the same way that ISO in film does.

    Yes, true, but ASA and ISO were about film speed, digital is still digital and does not react to light as film does. But I take your correction. There are settings for ISO with digital.
  • kdogkdog Administrators Posts: 11,680 moderator
    edited May 5, 2015
    gvf wrote: »
    Yes, true, but ASA and ISO were about film speed, digital is still digital and does not react to light as film does.
    Given that the brightness values for digital ISO were chosen to mimic the same brightness as on film, in what way do you find them different?
  • gvfgvf Registered Users Posts: 356 Major grins
    edited May 6, 2015
    kdog wrote: »
    Given that the brightness values for digital ISO were chosen to mimic the same brightness as on film, in what way do you find them different?

    Digital does not involve a direct impression of light on a medium on which it leaves an image of itself, it mimics a direct effect by manipulating information from sensors. It manufactures an approximation of light, an imitation of it. It's more a computer than a camera, the latter basically a box with a pin hole letting light in to leave a "stamp" or impression on a light-sensitive material at the rear of the box, with the amount of light that enters he box controlled by leaving a cover for the hole off for a certain time and then on covering the hole to block more light from entering. If you could also shrink and expand the size of the hole that would be an additional way allow a lot or only a little light to enter the box and hit the light-sensitive material at the rear creating an image on it.

    In digital, once the light hit the sensors, you would see nothing. No one can see information.
  • puzzledpaulpuzzledpaul Registered Users Posts: 1,621 Major grins
    edited May 6, 2015
    gvf wrote: »
    Digital does not involve a direct impression of light on a medium on which it leaves an image of itself, it mimics a direct effect by manipulating information from sensors. It manufactures an approximation of light, an imitation of it. It's more a computer than a camera, the latter basically a box with a pin hole letting light in to leave a "stamp" or impression on a light-sensitive material at the rear of the box, with the amount of light that enters he box controlled by leaving a cover for the hole off for a certain time and then on covering the hole to block more light from entering. If you could also shrink and expand the size of the hole that would be an additional way allow a lot or only a little light to enter the box and hit the light-sensitive material at the rear creating an image on it.

    In digital, once the light hit the sensors, you would see nothing. No one can see information.

    By what means do you see this 'direct impression' of light on film ... without processing the film, and thus adding some degree of subjectivity to the captured image?

    pp
  • gvfgvf Registered Users Posts: 356 Major grins
    edited May 6, 2015
    By what means do you see this 'direct impression' of light on film ... without processing the film, and thus adding some degree of subjectivity to the captured image?

    pp

    Yes, well the image is seen on the negative, processing brings out the chemical image on the film "stamped" by exposure to light, but it doesn't create it.

    It's a one-hop connection from light to image, and another hop as light (darkroom) gives us the image seen through the lens, least on an SLR. Otherwise as seen by the eye through the focusing lens with light entering "the box" through the taking lens.
  • puzzledpaulpuzzledpaul Registered Users Posts: 1,621 Major grins
    edited May 6, 2015
    gvf wrote: »
    Yes, well the image is seen on the negative, processing brings out the chemical image on the film "stamped" by exposure to light, but it doesn't create it.

    It's a one-hop connection from light to image, and another hop as light (darkroom) gives us the image seen through the lens, least on an SLR. Otherwise as seen by the eye through the focusing lens with light entering "the box" through the taking lens.


    Well, you've probably got a considerable advantage over me with this topic, as I never did any film processing ... negs either went to a shop in town (so's I got a replacement) or slides back to kodak,when I shot film.

    However, as I understand things, light may well have impacted on the film's emulsion layer ... but whatever was there couldn't be seen (by a std. mk1 eyeball) without that film being processed.

    If it could, then I presumably could've opened the back of the camera (after shooting a roll of film), pulled it out of the container ... and checked to see if I'd got my pics correctly exposed and focussed etc (which was rare)?

    As I see it (pun not intended) ... whatever might be stamped on the film (using your words) is useless - for all practical purposes- unless it's processed ... is that not the case, or is my ignorance in this topic total?

    pp
  • kdogkdog Administrators Posts: 11,680 moderator
    edited May 7, 2015
    gvf wrote: »
    Digital does not involve a direct impression of light on a medium on which it leaves an image of itself, it mimics a direct effect by manipulating information from sensors. It manufactures an approximation of light, an imitation of it. It's more a computer than a camera, the latter basically a box with a pin hole letting light in to leave a "stamp" or impression on a light-sensitive material at the rear of the box, with the amount of light that enters he box controlled by leaving a cover for the hole off for a certain time and then on covering the hole to block more light from entering. If you could also shrink and expand the size of the hole that would be an additional way allow a lot or only a little light to enter the box and hit the light-sensitive material at the rear creating an image on it.

    In digital, once the light hit the sensors, you would see nothing. No one can see information.
    In terms of exposure, which I believe is the topic of your thread, they are equivalent. They both conform to the ISO standard for adjusting the sensitivity of the camera to light. The same settings on a manual camera will work on a digital camera. You said so right in your original post. You just left out ISO which I corrected you on. I'm not sure how this thread got so off topic.
  • gvfgvf Registered Users Posts: 356 Major grins
    edited May 7, 2015
    Well, you've probably got a considerable advantage over me with this topic, as I never did any film processing ... negs either went to a shop in town (so's I got a replacement) or slides back to kodak,when I shot film.

    However, as I understand things, light may well have impacted on the film's emulsion layer ... but whatever was there couldn't be seen (by a std. mk1 eyeball) without that film being processed.

    If it could, then I presumably could've opened the back of the camera (after shooting a roll of film), pulled it out of the container ... and checked to see if I'd got my pics correctly exposed and focussed etc (which was rare)?

    As I see it (pun not intended) ... whatever might be stamped on the film (using your words) is useless - for all practical purposes- unless it's processed ... is that not the case, or is my ignorance in this topic total?

    pp

    There is an "IT" though, whether you need chemicals to see "IT" or don't. (you do). And the "IT" unseen - or seen in the negative, is the effect of light.
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