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Struggling to grasp the exposure triangle

Discussion in 'Photography & Camera Basics Forum' started by Marnie, Feb 12, 2018.

  1. Marnie

    Marnie New Member

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    Hi everyone! I’m excited to be a member of this forum!
    I only just started taking pictures last week. I’ve never had a camera before and I just got my first DSLR, a Nikon D3400.
    So far I’ve just been shooting in auto mode, and playing with the aperture priority and shutter speed priority modes(which I’m terrible at), but I’ve read that you should aspire to shoot with the manual mode. I’m struggling with it a bit. I’ve been researching and I understand what aperture is, for controlling the depth of field. I understand shutter speed is used to blur or stop motion. All I understand about ISO is that it can make pictures noisy and you should aim to keep it low if you can. What I’m struggling to grasp is how they all work together, and how to get them to. How do you get the right balance? Are they all supposed to be equal? I mean, at the equivalent amount of stops as each other? How do stops actually work?
    I’m also not actually sure how to control the ISO, when I control the shutter speed in manual mode the ISO seems to change with it.
    I hope I’m making some sense and I hope I don’t sound silly! Any advice would be so appreciated.
     
    LYNN GRIFFITHS likes this.
  2. rebel06

    rebel06 Without a cause Moderator

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    Hi Marnie and welcome to the forum .. . give me a min to digest your post and I will try and help
    Paul
     
  3. Roger S

    Roger S Crazy Canuck Administrator

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    Hi. I'll try to get back to this when I get b
    On my computer instead of this phone.
     
  4. Marnie

    Marnie New Member

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    Thank you! That would be great. Sorry the post is so rambling!

    Thank you! I really appreciate it
     
  5. rebel06

    rebel06 Without a cause Moderator

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    Ok... I would try and master aperture mode first before you try and move on to manual mode.
    Mike Browne has a good way of showing things on his you tube channel ... take a look here ..
    Oh and don't worry about asking us questions, we are a friendly lot and are eager to help
    Paul
     
  6. tenchy

    tenchy Rain maker Administrator

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    We have a resource for this. Check out the basics link in my signature, it will take you to a list of resources, and if it's not on that list you can browse the resources.
     
  7. Marnie

    Marnie New Member

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    Thank you so much! Maybe I’m rushing a bit, I’ll start focusing on aperture mode and watch that video.
    Thank you again, it’s good to know that I’m okay to ask questions

    Oh, sorry! I’ll have a look at those resources, thank you
     
    Last edited by a moderator: Feb 12, 2018
  8. DonS

    DonS Stuck in Toronto Moderator

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    Mike Browne is great at explaining things in a simple way. That said, it sounds like you have your ISO set to Auto.
     
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  9. Snips

    Snips Always on

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    Filling a jug of water. Imagine filling it to the brim is a perfect exposure.

    Narrow aperture is turning the tap on slow and water falls out slowly through the small hole. If you open the tap fully (wide aperture) water comes out quickly. Slow/fast shutter speed. If you turn the tap off too soon the jug doesn't fill so you under expose. If you turn the tap off too late you overfill the jug and over expose. You can choose to open the tap a little and wait for longer (slower shutter speed) or open the aperture (tap) fully and wait for much less time. Whether you fill it slowly or quickly doesn't matter because as long as you stop when the jug is full you get perfect exposure.

    In simplistic terms, if you're using a wide aperture for an outside portrait for example where you want to blur the background you'll need a fast shutter speed to prevent over exposing the photograph. If taking a landscape you'll want a narrower aperture and a slower shutter speed to prevent from under exposing.

    ISO (film speed in the old days) is the third part of the triangle. If it's too dark or you want more speed then upping the ISO will bring more light in but the image will become more grainy. The lower the ISO the better the image quality. If you want good image quality (low ISO) but there's not enough light, that's when you invest in a tripod so the camera can be open for several seconds.
     
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  10. gaelldew

    gaelldew Always on Premium Member

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  11. Roger S

    Roger S Crazy Canuck Administrator

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    Photography Life has a great article showing the relationships between Aperture, shutter and ISO, HERE.

    That means your camera is set to Auto ISO in the menu. You can change that default if you want to.
     
  12. MikeB

    MikeB Always on Premium Member

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    Most photographers wouldn't know how to answer your questions as they learn by doing rather than understanding the details behind their actions. And, that has no effect on their ability to take great photos. Knowing the details doesn't necessarily make any difference to the quality of your images.

    As mentioned above there are some excellent tutorials available on how to photograph. By your questions, you seem to want to know why things work.

    Photography has some of the most esoteric and obscure nomenclature owing to the fact that its history is so deep - the Exposure Triangle includes many of those odd terms.

    The Exposure Triangle is based on the idea that, given an amount of constant light, there are three aspects of exposure that you control to get the correct exposure - ISO, shutter speed, and aperture.

    ISO (refers to the International Organization for Standardization). For sensitivity to light ISO adopted the ASA standards (American Standards Association).

    Film is sensitive to light and records an image when exposed. The level of sensitivity is determined by the manufacturer and identified as a given ISO sensitivity. For example, ISO 25 means the film is less sensitive to light and therefore requires more light than ISO 400 which is more sensitive to light.

    Unlike film, a digital sensor has a base sensitivity to light (usually ISO 100 or ISO 64) with the ability to adjust the image data electronically to simulate greater ISO sensitivity. The simulation is performed on the electronic data captured which includes image data and electronic noise. Increasing the ISO is simply boosting the signal. The problem is that as image data is boosted so is the noise data. At some point, different for each camera model, the noise becomes more and more obvious.

    So, ISO represents a film's sensitivity to light and ISO for digital sensors represents a simulation of sensitivity above the base level.

    Shutter Speed
    The length of time the shutter is open to let in light is referred to as shutter speed. The shorter the time (faster speed) the less light gets captured. As you slice up time to shorter and shorter slices, less action can occur during the slice - we freeze action, but we let in less light. A slower shutter speed lets in more light but action in the scene will be blurred.

    Aperture
    The first cameras used thin metal plates with a hole in it to let in light - they stopped all other light, they were called "stops". Different diameter holes, and each a separate stop, different apertures. There is an adjustable diaphragm in today's lens that increases in diameter (opens) to let more light in, or decreases in diameter (closes) to let less light in. The opening through which the light is passing is the aperture. In addition to controlling the amount of light hitting the sensor, it also is the primary means of controlling depth of field (the secondary means is subject to camera distance). Depth of field is affected due to the angle of incidence of the light allowed through the aperture - the larger the aperture, the more angles of incidence and shorter the depth of field. The smaller the aperture, the fewer angles of incidence and the longer the depth of field. That is why a pinhole camera has unlimited depth of field. The odd F-Stop nomenclature is based on the ratio of the aperture diameter to the focal length, that is why the larger the f-stop number (bottom part of the ratio) the smaller the aperture. It was adopted because it actually improved discussions regarding light and its constant value across an area (on film or sensor).

    Two legs of the Exposure Triangle (shutter speed and aperture) control the amount of light striking the film or sensor and the third leg, ISO, relates to the sensitivity to light (or its simulation). Each affects exposure. However, each has an additional affect that one has to take into consideration: Shutter speed affects blurring or freezing action; Aperture increases or decreases depth of field; and, ISO affects image quality (grain with file and electronic noise with sensors).

    There is no "balance" that you are trying to achieve with the Exposure Triangle. Rather, you are trying to balance image quality with your desired depth of field and the motion occurring in the scene with the amount of light you have available and for that the Exposure Triangle is informative.
     
    Last edited: Feb 12, 2018
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  13. fmw

    fmw Active Member

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    Sounds like you have some good explanations of the exposure triangle. Exposure is adjusted by any, some or all of the three points of the triangle. I will just add this:

    Aperture adjustments affect depth of field (how much of your subject is in acceptable focus from front to back.) Wider apertures produce shallower depth of field and narrower ones produce deeper depth of field.

    Shutter speed adjustments affect motion blur - either your motion or that of the subject. Faster shutter speeds produce less blur and slower ones produce more.

    ISO affects digital noise in the same way that film speed affected grain back in the day. Lower ISO produces less noise and higher ISO produces more of it.

    Those are the trade-offs. You set the one that addresses the challenge the subject presents and the other two compensate to produce the exposure you want. Sorry of it this was confusing. It is one thing to know what the triangle is and another to know how to use it.
     
  14. steve b

    steve b Always on Premium Member

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    There's some very comprehensive info on this thread, Marnie. Maybe too much to take in, even enough to frighten you off. Read the manual on basic settings over and over, in the meantime carry on in auto, eventually you'll want to break away from auto everything, ISO set to 400 would be a good start, that will cover most bases.
     
  15. LYNN GRIFFITHS

    LYNN GRIFFITHS Member

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    hi marnie, i am also a newbie, and like you am struggling, but i think with the help from these kind helpfull people on here and also, on our part, patience!!!! we will hopefully get there. i too am trying aperture, etc. i have been out this morn again just taking a couple of shots, its the focus i cant seem to get right, but, hey, we can enjoy learning.!!
     
  16. fmw

    fmw Active Member

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    There you go. It is far easier and less expensive to do the practice on modern digital cameras because you don't have to buy film and processing. You can shoot to your heart's content, learn what learned, keep what you like and toss the rest. The memory cards can be erased and used over and over.
     
  17. gaelldew

    gaelldew Always on Premium Member

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    Just keep practicing with Aperture Lynn, use auto ISO then all you need to worry about is the shutter speed, when you are more used to the camera we will have to get you using Back Button focus. Another thing what are you using to process your shots afterwards?
     
  18. arteta

    arteta Always on Premium Member

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    Some really good information. In some ways it's quite simple but because there's so much information out there, not just about the exposure triangle but most areas of photography, that it can almost seem quite daunting

    Take small steps working on your exposures and it'll all fall into place.

    Watching videos is great but practice is better

    My personal opinion on what modes to use, and others may feel different about this, but is to practice in the semi automatic modes namely aperture priority and shutter speed then when you feel more confident, learn how to use manual
     
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  19. paulmag

    paulmag Always on Honorary Life Member

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    Its easy........................

    The film or sensor needs a certain amount of light to capture the image so you use a small hole (aperture) for a long time (Shutter Speed) or a big hole for a shorter time .................if neither of those gives you the desired exposure then you can either use a different speed of film or setting of ISO on your cameras sensor.

    The longer the exposure the less able the camera is to capture sharp detail in moving elements in the frame this may or may not be desirable depends on what you are trying to get frozen action in say sports or silky smooth blurry clouds and water.

    Its all a compromise depending on what the lighting and subject matter is.

    The big trick is to practice .............with a digital camera this is very cheap to do and just costs in battery charging time.

    That said I use Aperture priority when not using manual as the Depth of field control is more important in my photography than the shutter speed
     
  20. LYNN GRIFFITHS

    LYNN GRIFFITHS Member

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    many thanks for your replys. yes, i think it has to be , practise, practise, practise, when i think i have done a bit better i will post some more pics. thanks to all.
     
  21. rebel06

    rebel06 Without a cause Moderator

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    @LYNN GRIFFITHS Dont forget that your lens will have a minimum focus distance so don't get too close or you wont get focus.
    Paul
     
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  22. LYNN GRIFFITHS

    LYNN GRIFFITHS Member

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    thanks paul. i have just put a couple more pics on .they are from last year.
     
  23. GHK

    GHK Well-Known Member

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    This may seem a funny question, but your answer will determine my next response.
    Do you know anything about Boyle's Law?
    GHK
     
  24. DonS

    DonS Stuck in Toronto Moderator

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    I had to google that myself. Not sure how you are going to apply it here. I am curious.
     
  25. hooferinsane

    hooferinsane EXIF Seeker Super Moderator

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    Three variables in that too (brought back memories of chemistry/physics) Not sure how that might apply here as above, except changing one variable will change the others
     

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