ISO, Apperture and Shutterspeed WHAT?

Discussion in 'Photography' started by Jaco Schoeman, 21 Jan 2011.

  1. Jaco Schoeman

    Jaco Schoeman MASA Contributor

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    Photographic guru's...

    I need your help...

    I have recently bought the Fuji Film HS10 bridge camera. It has all the functionality as a DSLR, shoots in RAW etc. etc.

    Here's the spec:

    FinePix HS10 / HS11 | Fujifilm Global

    Now, shooting the kids whilst busy pulling the dog's tail etc. is one thing, but taking photos of gorgonian polyp's is another.

    I am really struggling to get my head around this whole ISO, Apperture and Shutterspeed thing.

    I have seen the movies, read google but there are no real advise out there on how to take good aquarium photos.

    Taking into consideration my water is much more blue than it is white due to more actinic light, what are the basic rules then of taking nice photos of coral, and then of fish?

    Should I use Macro Functions, what ISO should I use, Shutter Speed etc?

    I know there are no real ABC answer here as there are many factors, but where do I start. What is a good average ISO, average apperture etc to use?

    Thank you!!!
     
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  3. mariusmeyer

    mariusmeyer

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    Basic explanations of terms.

    Aperture
    Aperture determines the amount of light that comes into the camera. It is displayed on the camera as an f-stop. The higher the number of the f-stop is the less light comes into the camera. For instance an aperture of f2.8 lets in a lot more light than f11.

    ISO
    ISO is the light sensitivity of the camera sensor. The higher the ISO setting of the camera the more sensitive the sensor becomes to light. Example. ISO100 is less sensitive than ISO400. Changing the ISO to be more sensitive has a negative effect of photos as the quality of the photo deteriorates. So we try and use the lowest ISO we can in order to get the best possible quality pictures.

    Shutterspeed.
    Shutterspeed is the amount of time (in seconds) that the camera sensor will be exposed to light when taking the photo. Shutterspeeds can be as long as 60 seconds and longer and as short as 1/8000th of a second. When the shutter of the camera is open the camera must not move and the subject must not move, otherwise you get blurry photos. So in order to get crisper images we need to use as fast a shutterspeed as possible because the shorter time the shutter us open the less change there is for movement.
     
  4. mariusmeyer

    mariusmeyer

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    Now for the relationship between those settings.

    A smaller aperture (higher f-stop) will reduce the shutterspeed.
    a bigger aperture (lower f-stop) will increase the shutterspeed.

    When we photograph our tanks, especially fish, we want the fastest shutterspeed possible. If the shutterspeed is too slow then the fish will be blurred due to movement. For a fast moving fish a shutterspeed of 1/100th of a second should be good. The faster the fish moves, the faster the shutterspeed needs to be.

    Now for ISO. If we increase the sensitivity of the sensor (from ISO 100 to ISO 200 / ISO 400), we force the camera to make the shutterspeed faster otherwise the image will be over exposed (very bright). This will enable us to get a crisper image.

    If your camera has a aperture-priority setting, you can use this as a start. Set the aperture to f8 or f11. Focus on what you want to take the picure of. If the shutterspeed is too slow, then change the ISO. Change the ISO to ISO 200 and try again. Up the ISO to 400 or higher if the shutterspeeds are still too slow.

    Hope this will help. Some other time I will write something about depth-of-field, which is the amount of stuff that is in focus in the picture. This is influenced by changing the aperture.
    __________________
     
  5. TankMaster

    TankMaster

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    Very good explanation but the one key factor that affects ISO/Shutter speed/Aperture is . .Available light . .

    The available light will determine what ISO/Shutter/Aperture you use.

    TM
     
  6. Jaco Schoeman

    Jaco Schoeman Thread Starter MASA Contributor

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    Thank you. That makes a littlebit more sense now...

    In lamens terms am I right in saying:

    ISO is how much light hits the lens. Shutterspeed determins how quickly the lens closes and captures the light (image) and apperture really only determins the focus and depth of field?

    I also understand that "shooting from the hip" with shutterspeeds of more than 100 is a NO-NO.

    Am I right at saying then that (with all white light on as well) a good starting point to workfrom is;

    ISO: 200-400
    Apperture: F8 - F11
    Shutterspeed: 1/100th or more

    Now tell me if I understand right. If that shutterspeed is too slow, instead of increasing shutterspeed, I rather lower the ISO to i.e 100 (yet more light might be needed of course...)
     
  7. Max98

    Max98

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    I am a bit clueless as well but as I understand the it a higher ISO makes the lens open time shorter, so it results in a less blurred image, but the image gets more grainy.
     
  8. TankMaster

    TankMaster

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    No no no .. ISO . .increases the sensitivity of the image sensor to light. ..

    Shutter speed . . .increases or decreases exposure time. .

    Aperture . . . . the 'iris' of the lens. .opens and closes to allow more/less light through the lens to hit onto the image sensor . .

    An easy way to see how it works is to set your camera to Av . .and see what shutter and ISO the camera chooses for the given lighting conditions. .

    A few months of playing around. . then you will be able to master the Manual mode

    TM
     
  9. Reef Maniac

    Reef Maniac MASA Contributor

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    Not quite...

    ISO is a measure of the LIGHT SENSITIVITY of the sensor or film - a low ISO setting will require more light to properly illuminate the photo, whilst a high ISO setting would enable you to take a properly exposed photo at a lower light intensity. Unfortunately, higher ISO also results in more "noise", and there is thus a practical maximum ISO, which depends on the quality of your camera sensor.

    I don't have any experience with your camera, but I would guess that it would be OK up to ISO 800.

    Shutter speed, as you quite correctly say, determines how quickly the lens closes (actually, most shutters are behind the lens, but it's perfectly OK to see it as being part of the lens if that help you to better understand...)

    With all other settings being the same, a slower shutter speed would result in MORE LIGHT getting in through the lens, which will give you a lighter photo. A faster (or "higher") shutter speed will result in less light reaching the sensor, and this will result in a darker photo.

    Shutter speed also "freezes" the movement of objects - using a slow shutter speed when photographing a moving subject will result in that subject looking blurry, whilst a fast shutter speed will result in a crisp, "frozen movement" photo.

    Aperture controls the depth of field (and thus what is in focus behind and in front of the subject that you have focused on), but it ALSO controls how much light enters the lens (just like the shutter speed). A smaller aperture (higher number, e.g. f/16) will block most of the light entering the lens, and will thus only allow a small portion of the light to pass through the lens and onto the sensor, resulting in a darker photo. A large aperture (small number, e.g. f/2.8) blocks very little of the light entering the lens, thus allowing most of the light to pass through the lens and on to the sensor, resulting in a lighter photo.

    The "trick" of good exposure is to mix all three variables to give one the correct exposure whilst meeting the other criteria of depth of field and eliminating blurriness:

    • Use higher ISO (400-800) when taking pics indoors (or of your tank), and lower ISO (100-200) when taking pics in sunshine (outdoors)
    • Use higher shutter speed when photographing moving objects, and a larger aperture to compensate for the loss of light caused by the higher shutter speed.
    • Use a smaller aperture to increase depth of field, and decrease shutter speed to compensate for the loss of light caused by the smaller aperture.
    Our tanks are actually illuminated pretty dimly when compared to outdoor illumination, even on a cloudy day (I battle to get enough light with my 3 x 400W MH's...) You will thus have to use a high ISO, large aperture, and as slow a shutter speed as you can (without it being so slow that the moving fish are blurred, or that your hand movements causes blur...).

    I notice that your camera has a 30x optical zoom (equivalent to 24mm - 720mm of focal length on a 35mm camera) - this could also be a source of your difficulty in taking good pics of your fish, as the focal length of your lens also affects the amount of light transmitted, and the amount of "camera shake" induced when shooting hand-held. A good rule of thumb is to keep the shutter speed faster than 1/focal length, although a good image stabilizer could halve that. On maximum zoom, you would thus have to keep the shutter faster than 1/720th of a second (or 1/360th of a second, assuming the IS is doing it's job...) to eliminate blur, but that would most likely result in very dark photos. Your only way around this would be to mount your camera on a tripod, increase the lighting, or use a wider angle (shorter focal length, less "zoom").

    Hennie
     
    Last edited: 23 Jan 2011
  10. TankMaster

    TankMaster

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    Basically the same thing I learned in my 1st year of studying professional photography. Once you see an actual (Visual) presentation about Exposure, everything becomes a breeze. I will advise you to check YouTube for some tutorials on camera exposure. Photography is very hands on and it will take time to get the theory but actually doing it makes theory, common sense.

    TM
     
  11. Jaco Schoeman

    Jaco Schoeman Thread Starter MASA Contributor

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    Thank you all... I have played around with the camera this weekend after understanding ISO, Shutterspeed and Apperture a bit better. And I must say I am truelly impressed with the camera's performance. It took some exceptional macro shots, and I even captured a finch a shutterspeed of 4000 and ISO 200 which was quite a nice photo!!!

    After "mastering" the daylight photogrpahy I went to the tank, just to realise the obvious - the light just isn't enough... Even though I have a T5 actinic only; I knew that it would not be enough for a good photo, as it all is just too dark and blue. I added 10000K LED's, and a 12000K T8, yet this still was not enough.

    My question then would be this, if I had to get a MH of around 12000K, would this help? Is it the "whiteness" or the "brightness" of the light that comes to play in aquarium photography?

    PS: I did however manage to get one or two decent photographs though...
     
  12. mariusmeyer

    mariusmeyer

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    its the amount/brightness of light that is important. The colour representation can be fixed afterwards if you shoot in RAW by adjusting the colour temperature.
     
  13. Jaco Schoeman

    Jaco Schoeman Thread Starter MASA Contributor

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    So then using a MH for example to light up the tank would work in words. I will give that a go and see what the results are.

    Thank you for your assistance!!!
     
  14. Singularity

    Singularity Hmmm amper!

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    are you zooming when you are taking tank pics ? Reason i ask is becuase your lens when zoomed has an apreture of 5.6, this could make it difficult, try to take some pics at the wide angle and at f2.8, then crop the pics and see if they look ok, should bd fine if it for forum posting etc, not such a good idea if you want to print the pics
    Posted via Mobile Device
     
  15. Jaco Schoeman

    Jaco Schoeman Thread Starter MASA Contributor

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    Thank you!!!

    Yes, in some instances I zoom. The camera has a Super Macro facility that does not allow to soom. Under the Macro function you can zoom yes..

    I will try then not to zoom, and work with a f2.8.

    Will let you know... ;)
     
  16. Tony

    Tony

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    Back in the day when we were shooting on Fujichrome Velvia (ISO 50) and provia (ISO 100), the lower the ISO rating the richer and more detailed the picture would be but one would have to use a faster lens like a 2.8 aperture to allow more light in to compensate for the slower film to give shutterspeeds of 750-1500, especially for wildlife photography. The slower film would afford one the opportunity to blow up pictures to incredible sizes without it ever becoming grainy. Bear in mind that a 400mm 2.8 lens was a massive bugger which we used for wildlife photography. I still cant get over the detail that those films used to hold. Using a 10 times loupe to analise the slides one could see an individual hair in a lions ear if the picture was sharp. None of my digital cameras give me that detail without pixellating
     
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