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Tuesday, August 25, 2009

F-Stop


Examining Depth of Field.


When operating a camera manually it helps to understand this...
F-Stop = diameter of the aperture / focal length. Picture below.

F Stop e.g. f/16 setting lets in the least amount of light (small diameter) and a long depth of field
F Stop e.g. f/4 setting lets in the most light(large diameter) and a shallow depth of field


Shutter Speed = how long the actual "exposure" takes.
Because I'm changing the F Stop I also have to change the Shutter Speed to get the correct exposure.
Aside from understanding that...the depth of field is what I'm interested in.

Ok, now my test of "Depth of Field".


Here's my experiment.
Using my standard zoom lens DT 18-70mm f/3.5~5.6 up-close.


F Stop e.g. f/22 gives you a longer depth of field or in other words...a longer distance in focus.
But can't see a noticeable difference between these first two pictures with this long shot of about 60 feet.
I think it's because there are too many images in this picture.
Can you see a difference ? I can't.


Shutter speed is 25th of a second and f/22 stop/aperture



F Stop e.g. f/8 gives you a shorter/shallow depth of fields or in other words...a short/shallow distance in focus.
Shutter speed is 200th of a second and f/8 stop/aperture





BUT here you can see the difference with a shorter shot of 6 feet


Again...
F Stop e.g. f/22 gives you a longer depth of field or in other words...a longer distance in focus.
Shutter speed is 25th of a second and f/22 stop/aperture
Did not use a tripod or picture would be clearer. My camera has stability control.



Again...
F Stop e.g. f/8 gives you a shorter/shallow depth of fields or in other words...a short/shallow distance in focus.
Shutter speed is 250th of a second and f/5.6 stop/aperture



So what's my conclusion?
For landscape shots...manual is not necessary.
For close-up shots where you want the background to be blurry use a small F Stop.
Also there's always different lenses, but don't feel I have a need for that now.
Although a Macro Lens might be nice.
Still learning to use a DSLR...any suggestion/advice is welcome.

My camera info is located at the bottom of side bar.

9 comments:

  1. Wow! You are entering a zone about which I have NO experience and/or desire to gain! ;-) I'm just happy taking photos with cameras that do it nearly all by themselves!

    PS I just found your last hypertufa post. How are your plants doing? Your planter looks Wonderful to me!! :-) I tried one last week and waited a little too long to unmold it. But, I think it will be okay once I get it planted. And once a little moss grows on it. :-)

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  2. I just took a photography class and finally understood F-stops. It always confused me before. I also did a post with sample pictures, mainly for myself so I wouldn't forget what I learned.

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  3. Sigh...I think I want a DSLR, but the notion of having to invest in lens is the big issue! I know a macro lens would be essential for me! It's frustrating that my fuji bridge camera has worthless instructions! Btw, your garden looks great! gail

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  4. I can definitely see the difference in the rose picture. I've read a little about shutter speed and F stop, but my camera doesn't really have much range in it since it's basically a point and shoot. It's fun learning more about cameras and trying out different settings.

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  5. Patsi girl .. your garden is looking very LUSH and beautiful in these shots !
    I want to learn much more than I know (could fit on the head of a pin ?) about photography .. I think I may get a "Dummies" book on digital photography .. BIG sigh !
    Your information was great though girl : )
    I saw the finale of Nurse Jackie ... OMG !!!! LOL

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  6. Great topic.

    Another depth of field consideration is the focal length of the lens. The depth of field is inversely proportional to the focal length of the lens. At 28mm you will have a greater depth of field than at 100mm. If I want good bokeh in closeups, I extend the lens to its greatest length. (Bokeh is what happens away from the point of best focus.) For more detail (away from the point of best focus) I shorten the focal length.
    Marnie

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  7. Now you are really into it, Patsi. I normally click on the standard feature available, like landscape, macro, portrait,nightshots etc... Only when these feature can give what I want, then I play around with manual settings. Great info, Patsi.
    Cheers
    ~bangchik

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  8. Shady,
    Can't wait to see your planter !!
    Haven't looked at mine lately...it's on the side of the yard.
    ~~
    Robin,
    The thing with using manual mode...if you stop using it you'll forget it. Like anything else I guess.
    ~~
    Gail,
    DSLR's are costly. I had a great 'point and shoot' by canon but had to send it back to company because of a defect once and the second time ....I just gave up.
    ~~
    Catherine,
    Stay with what's easy to use....it should be fun.
    ~~
    Joy,
    What are you talking about? !!
    Your pictures are CLEAR AS A BELL !
    You don't need to learn anything.
    About Jackie? Not too eventful.
    ~~
    Rosemary,
    Only helpful if you can control your camera. :)
    ~~
    Marnie,
    I've been playing around with different focal lengths and lenses but have to investigate 'bokeh '. And need a better understanding of my camera.
    Hmmmm you've got me thinking... Mucho Thanks !!
    ~~
    Bankchik,
    Manual is not needed to take a good picture.
    Do understand what you're talking about.
    I'm pretty much the same way, but use aperture or speed priority. Maybe I should try the other settings.

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Glad to answer questions when I visit you...

Making life easier is a good thing.