Newbie - blurring and aperture

Discussion in 'Digital Photography' started by SebZen, Sep 26, 2009.

  1. SebZen macrumors 6502

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    Apr 12, 2009
    #1
    Hi there. I just got my first camera, FujiFilm FinePix S1500. Not the best, but decent enough.

    Anywho, I tried messing around with it and all and like it. But in the manual it says that if I up the aperture (lower F-number), I'll blur the background and foreground. In the picture in the manual that demonstrates this, they have a few crayons lined up, one behind the next, and only the middle crayon is clear, the others are blurry.

    Well I tried doing this and I can't get it to work. I placed two bottles, one behind the other and tried taking pictures with different settings, including aperture at F2.8, up to 6.something. With shutter at about 50 (I tried other shutter settings as well, still clear. And anything above or below would come out over or underexposed). And with all the aperture settings, both bottles come up clearly. What am I doing wrong?
     
  2. FrankieTDouglas macrumors 65816

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    #2
    How far away from the focus point is your camera?
     
  3. SebZen thread starter macrumors 6502

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    #3
    Sorry, new to all this. What does focus point mean? The subject (IE what the camera is focusing on)? About 2-3 inches away.
     
  4. Ruahrc macrumors 65816

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    #4
    It's likely that the picture in the manual was exaggerated to show the effect, or taken with a different camera. Because of the small sensor, P&S cameras have a lot of depth of field (the "zone of focus" in front of and behind the focal point) and even an f2.8 lens will have a pretty big DoF when focused close. In order to see the effect you may need to compare for example the blurriness of a tree that is way in the background (with the bottle focused up close at a few inches) instead of a few bottles lined up next to each other.
     
  5. Grasher macrumors member

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    #5
    P&S cameras do have a lot more depth of field than DSLRs but you can cheat this a little. If you stand further away and shoot with a longer lens you can achieve a reasonably decent background blur. Telephoto lenses give you a shallower depth of field.

    I shot with a Fuji 5600 for a couple of years before moving to a DSLR. What's great about them is that it forces you learn the technical stuff well so that you can get round the limitations of the camera. For example, the aperture on mine didn't go lower than f8 so getting a slow shutter speed to shoot water trails was difficult. This forced me to learn that lowering the ISO or using a ND grad filter will also reduce shutter speed (not to mention waiting for the sun to go behind a cloud!).
     
  6. Grasher macrumors member

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    #6
    You could also try using the macro mode - I think I shot this one using the macro mode. It was done at 63mm, which is at the low end of telephoto but still demonstrates my point. You can see that the ground behind the insect is completely blurred, and even the rock directly behind the insect is slightly out of focus. Basically just play around with your camera settings.
    Incidentally, if anyone knows what this insect actually is I'd love to know. The shot was taken in the Grampian Mountains in Victoria, Australia. The insect was about 2-3 inches long.
     

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  7. SebZen thread starter macrumors 6502

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    #7
  8. emorydunn macrumors 6502

    emorydunn

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    #8
    Yeah. If you zoom in more you can blur the background even more. So sooting at 150mm will give you a shallower depth of field than shooting at 50mm.
     
  9. luminosity macrumors 65816

    luminosity

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    #9
    Until zooms are able to regularly break the 2.8 barrier, prime lenses are always going to be superior for blurring out a background. If you want to see a magnificent out of focus area, use a Nikon or Canon 200/2 lens.
     
  10. FrankieTDouglas macrumors 65816

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    #10
    Actually, long lens do not give shallower depth of field.

    They give you the impression of adjusted depth of field. They merely magnify the background, compressing a scene and pulling the background closer to the foreground. Aperture and distance of lens to focus are the only ways to adjust depth of field. With long lens, you're still seeing the exact same background, except only an excerpt of it, and really close up (and out of focus due to the other two variables).

    So given this, you can move your background object further away from your point of focus, extend your lens to its maximum, and get in as close as you can (while keeping your composition), while shooting with the smallest aperture number possible with your camera.

    Now granted, most of this will be futile. Your camera has a very small sensor. In order to fill a frame with your content, you have to step back. This, in turn, increases depth of field. The larger the sensor, the closer you can get, which narrows the depth of field more and more. The smaller, the further back you go.

    Like someone said, see if your camera has a macro function. This will help in close focusing, which should provide some of that blur you're looking for. It probably won't be like your example image, though. Shallow depth of field is something people strive for by getting expensive cameras (that have big, expensive sensors).
     
  11. emorydunn macrumors 6502

    emorydunn

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    #11
    Ok, you caught me. It will give a blurrier background though which is what is desired in this case.
     
  12. FrankieTDouglas macrumors 65816

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    #12
    It will.

    It's just that too often, people don't know how dof actually works. Incorrect advice is given, which hinders actual comprehension. If this guy is new to photography, he might as well hear the correct facts.
     
  13. emorydunn macrumors 6502

    emorydunn

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    #13
    You're right. That's probably exactly how I came to that conclusion. I still need to work on some of my technical knowledge and get all the little "facts" I've heard corrected.
     
  14. FrankieTDouglas macrumors 65816

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    #14
    The fun part about learning the technical side is that once you do, you don't need to think about it anymore (more or less, at least). Once you know how things work, it's like muscle memory, so the technical gets out of the way and you can focus on the content of your work.

    Often with students, I never go past the technical merits in early images they make. I want to make sure they get the mechanics down. It's not as exciting, but it creates a solid foundation. The content, if it's there in their head, will come regardless. They just first have to store the "boring stuff" into rote memory.
     
  15. SebZen thread starter macrumors 6502

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    #15
    Alright it's still not working out for me. I took 4 shots of the same objects.

    This one was taken on auto (ISO 400, 1/125, F3.3). Zoomed in
    This was is on manual (ISO 400, 1/40, F3.3). Zoomed in
    This one on auto (ISO 400, 1/125, F3.4). Macro
    This one on manual (ISO 400, 1/40, F3.4). Macro
    None of them are really blurry (I'm sure blurry to you guys because of quality :p but not blurry in the sense I'd like it to be). A couple are a tiny bit blurrier but I think it's because I wasn't holding it very steady.

    Is this camera not capable of the blur I'm looking for, or are my settings wrong? The picture in the manual was very convincing :) They had 5 crayons lined up a couple centimeters away from each other, and the first and last two were very blurred out while the middle one was clear.

    Here is the picture I'm referring to, it's on page 36
     
  16. FrankieTDouglas macrumors 65816

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    #16
    You're approaching it wrong. All of those items are very close to the same plane of focus (think of your focus as a line that extends horizontally along your viewfinder... everything that touches it is in focus). Even though they are staggered behind each other, it's not enough. The focus falloff is still within the range of the last one. Even a 2.8 lens on a DSLR would keep those foreground and background objects in relative focus.

    Instead of thinking left to right, think front to back. Put an object directly in front of your lens, maybe a foot away. Focus on it. Now add items, each spaced a foot behind the last one, behind your focus point. For effect, make sure part of each object covers the object behind it (just to make sure you're aligning from foreground to background).

    See if that makes a difference.
     
  17. Designer Dale macrumors 68040

    Designer Dale

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    #17
    Depth of Field

    Try this. The painted rock is the focal point of this picture. As objects in front of and behind it become farther away, they start to go out of focus. Depth of field is the zone of the picture where things are sharpest. This was shot with a Fuji 602, a point and shoot with manual settings.

    For lots of info, check out Learn/Glossary at the DP Review site in my sig.

    Dale
     

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  18. Grasher macrumors member

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    #18
    Now I'm confused (and I'm a relative newbie so very happy to be put straight). I'd read in a couple of places that longer lenses produce shallower depth of field. I used to use this knowledge to get a blurred background for portraiture when I was shooting with a Fuji 5600, which looks a bit like an earlier version of what the OP has.

    I guess my question is: when is a blurry background not due to shallow depth of field? I just took a couple of shots with identical aperture but different focal lengths and the background is definitely more blurred with the longer focal length.

    Technical stuff aside OP, give a longer lens (i.e. zoom in more) a go and see if it gives you the effect that you're looking for.
     
  19. FrankieTDouglas macrumors 65816

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    #19
    Tomorrow I'll go out and do some photographs, using the same f/stop and distance from focus point, and only change the focal length. I'll post them in here for the comparisons. But think of it like viewing an image at 25% in Photoshop. All appears sharp and in focus. Then when you zoom in to 100%, you see it's actually soft. The image did not change at all, only its magnification. Which is what a long lens does to your background.
     
  20. Ruahrc macrumors 65816

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    #20
    Go back to the 3rd image you linked to. See how the front corner of the table (the one closest to you) is a little blurry? And look at the wallpaper in the background behind the pepper. It's out of focus. Those two objects are outside the depth of field for those given camera settings. The butter and the vitamins are still in focus because they're not close/far enough away from the focus point (the pepper) to be out of focus (actually it seems that they may be slightly out of focus but it's hard to tell on a web sized shot).

    To minimize the depth of field on your camera, zoom it in as far as you can, work at the widest aperture you can, and put the subjects as close to the camera as you can get and keep them in focus (i.e. work at the minimum focusing distance of the lens). All three of these factors will work to minimize the depth of field.

    The picture in the manual probably was taken with a different camera. That kind of result usually requires a bigger sensor and a wider aperture. Doesn't mean it is expensive but shallow DoF is a property of optical physics you cannot get around. You might be able to get the same thing by following what I mentioned above, longest focal length, widest aperture (smallest number) and minimum focusing distance.

    If you can determine the dimensions of your camera sensor, if you type the necessary parameters (sensor size, focal length, focusing distance, and aperture value) into an online DoF calculator you can see the minimum DoF you are able to achieve on your camera.

    Ruahrc

    P.S. longer focal lengths do decrease the DoF. A couple of runs through a DoF calculator will show you that. If you shoot the same line of dominoes from 20 feet away using a 50mm and a 500mm lens on the same aperture, you will get less DoF from the 500mm lens. Don't get confused where typical telephoto shots have more extreme subject-background separation leading to more exaggerated DoF (example a bird with a mountain background at infinity vs. shooting a line of dominoes with a 50mm or using it for macro closeup work).
     
  21. Grasher macrumors member

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    #21
    I think this is where we're differing. I meant that I would change the distance from the focal point and use the longer lens to make the image composition roughly the same (perspective flattening aside). To put it simply, take a shot, then take a few steps back, zoom in and take another shot.

    I took a couple of shots earlier today to test the principle. Short lens was taken at 18mm, f5.6. In this shot the fence is sharp and the brickwork and trees behind are still reasonably sharp. Long lens was taken at 70mm (from about 2 metres behind the first shot, again at f5.6 and in this shot you can see that the fence is sharp but the brickwork and trees are now blurred slightly. The only processing I did was to crop the long lens shot a little to get the composition roughly the same.

    Clearly this approach isn't as good as having a wide aperture on a DSLR-sized sensor but the OP is looking for advice on the equipment that he has. This is a reasonable workaround.
     

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  22. anubis macrumors 6502a

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    #22
    Walking backwards and zooming in does not affect the DOF at all. Setting your lens focal length to 50mm and standing 10 feet away from the subject will result in the exact same DOF as setting the focal length to 100mm and standing 20 feet away.

    The OP's problem is that he will be unable to reproduce the photo in the manual. The sensor is too small, which means that he has to stand farther away from the subject with the same focal length (as compared to APS-C or FF) which increases DOF. Additionally, I doubt the OP's lens is capable of focusing close enough to achieve those results.

    http://www.dofmaster.com/dofjs.html
     
  23. run-kmc macrumors member

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    Aug 11, 2009
    #23
    Move the 50mm lens in close enough to capture the same image as the 500mm from far away, and depth of field is the same, everything else being equal. Aperture and focal distance are the only two things that affect depth of field. The only two things. The only two things. :D
     
  24. SebZen thread starter macrumors 6502

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    #24
    OK, oh well, so not capable of that kind of blur. I did get a nice blur today though by using macro mode on a bug :) Bug was clear while leaves on the ground were very blurry. Was quite a nice shot!

    Thank you all for your help but I have one last question. Say I want to capture a bird hovering in the air but I don't want its wings blurred in the picture. My understanding is that I need to up the shutter (higher number, right?), well with this camera, it seems that anything over about 60 will result in quite a dark image, and 200 is pretty much all black. What can I do about this?

    To be fair I was messing around with it in my room which doesn't have the sun shining on it, but the room is decently lit. I tried upping the ISO up to 6400 and was still quite dark. My camera's shutter goes up to 2000, so even with ISO 6400, a shutter of 2000 will be pitch black even if I stare at the sun it seems.
     
  25. fulcrum.1995 macrumors member

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    #25
    Bringing down the aperture number will compensate for fast shutter speeds.
    There is also exposure compensation that the camera should have options for
    exposure compensation will most likely show a bar with numbers from -5 to 5 with little increments that will brighten and darken your image
     

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