Why are my #$%%@!! Photos Not sharp?!

Discussion in 'Photography Beginners' Forum' started by pgriz, Dec 28, 2010.

  1. pgriz

    pgriz Been spending a lot of time on here!

    Jul 30, 2010
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    Warning. 'nother long post.

    Is it you? Is it your equipment? Is it your technique? Or is it karma?

    Let’s look at some of the things that can affect picture sharpness:
    1. The lens itself
    2. A filter in front of the lens
    3. Stuff on the lens
    4. Whether VR/IS is on or off
    5. Camera shake
    6. Camera vibration
    7. Subject movement
    8. Focus placement (AF vs. manual)
    9. Brightness of scene
    10. Contrast of target
    11. Sensor position
    12. Shutter speed
    13. Lens Aperture
    14. Minimum focusing distance
    15. The focal length of the lens
    16. Diopter adjustment
    17. Space-time warping

    Usually, if the pictures are not as sharp as expected, the first suspect is the lens. Salesmen love this. “Ah, whadda ya expect? It’s a kit lens. Now if you want to take great pictures you need the 48-126mm f1.9 IDM SX FUS lens which is only $1,690.99 on sale one day only. All the big boys and girls use this lens.”

    Chances are… it’s not the lens. But what could it be? Let’s explore.

    Suspect #2 on the list is the filter at the front of your lens. It could be slightly warped, or made from inferior glass, or screwed on too tightly… and can distort the image just enough to create a softness. It could be due to chromatic aberration (the prism effect that separates red from blue). So it you are trying to determine why your photos are not sharp, take off the filter and put it aside. If doing that did not improve the picture, then it probably wasn’t the filter. But don’t put it back on just yet.
    Next suspect in the lineup is… the old “stuff on the lens” trick. That can be lint, dust, residues from dried liquid of unknown origin… Fingerprints, lipstick, chocolate, bits of food… Yep. Stuff on the lens does affect the image. But not as much as one would think. However, just to be sure, check that your lens is clean. If not, give it a gentle cleaning. Picture better yet? If not, let’s proceed to Suspect #4.

    Now VR/IS (Nikon: vibration reduction/Canon: image stabilization) is supposed to be your friend, magically rescuing pictures taken under dim conditions and making them look… well, sharp. However, like some of your high-school frenemies, this “pal” can also lead you astray. If your camera’s on a tripod, you don’t need VR/IS. Turn it off. Otherwise, it will jiggle around, trying to see if you’ve moved the camera yet, and result in creating blur on its own. Not all VR/IS do this, but why leave it as a suspect? Turn it off and eliminate the possibility.

    It turns out that suspect #4 was trying to prevent suspect #5. Which is camera shake, caused by the fact that most of us are made from gelatinous protein matrix draped on a mineral/protein framework, controlled by various organic sensors and biofeedback mechanisms. When we hold the camera, we vibrate/oscillate/gyrate despite our best intentions, and the camera moves. However, the simplest way to fix this is to put the camera on a solid surface, like a tripod. Which we should do as we try to figure out what is causing the softness in our photos.

    But even the support of a sturdy tripod won’t be enough (sometimes) to stop the camera from moving. That’s because the mirror which allows us to see the scene in our DSLR, needs to move itself out of the way to let the light reach the sensor. And “mirror slap” can cause the camera to bounce a little. So, to minimize this, you can use mirror lockup, and remote shutter releases to lock the mirror so that it doesn’t contribute to picture fuzzies. This should take care of suspect #6.

    Of course, if the subject moves while you’re shooting it, you’re potentially going to have a blur. That’s why using your pet as the target usually doesn’t work. So, for testing sharpness, select a non-moving, fixed, stationary, stable target. That should eliminate suspect #7.

    Our next suspect is the usual culprit. Many photos are not sharp because they are not in focus. How is that possible, you ask? My camera has a gadjillion focusing points and phase-locked sensors. It is the pinnacle of sensor technology. Perhaps. But if the camera’s deciding what to focus on, one thing it hasn’t yet mastered is reading your mind. So it focuses on whatever is closest or brightest, or whatever algorithm has been programmed into it. Which is probably different from what YOU wanted to have in focus. So eliminate suspect #8 by turning off the camera’s autofocus and do it manually. If you have live-view, then you can use this to achieve critical focus. If you don’t, then there are other techniques and methods. But take responsibility for your picture and focus it on the target yourself.

    If you can’t see the target, that can be difficult. So help yourself, and make sure that the target is brightly lit and that you can SEE it clearly. This then eliminates suspect #9.

    The twin of #9 is low contrast. It’s hard to focus when it all looks more or less the same. So replace your low-contrast target with something with sharp edges and very high contrast between parts. A target like shown on Norman Koren’s site (www.normankoren.com) will do well.

    Suspect #11 is almost never present. This happens if you’ve dropped the camera or gave it the equivalent of a concussion, and the sensor moved within its frame. If this does happen, send it back to the camera doctors and let them fix it. Chances are… this is not the reason your shots are soft.

    Suspect #12 is the second most common reason why photos are not sharp, when shooting hand-held. The rule is that for 35mm cameras, the slowest shutter speed which you can shoot reliably is about the reciprocal of the focal length. So a 30 mm lens can be safely used with a shutter speed of 1/30 sec, and a 200mm lens should use at least a shutter speed of 1/200sec. On crop cameras, the focal length needs to be multiplied by the crop factor, so that a 1.5x crop with a 200mm lens will have the equivalent of a 300mm lens on a 35mm camera, and will need a minimum shutter speed of 1/300 sec. However, for testing purposes, you can eliminate this suspect by putting your camera on a tripod OR using a flash which issues a very brief flash of light.

    Lens aperture (suspect #13) plays a role because lenses are not all equally sharp across the aperture range. Many are soft at the open end (due to chromatic aberration and other effects), and at the high aperture value range (F/22 and up) due to diffraction effects. So for getting the sharpest photos, the usual rule is to use something in the middle of the range (f/8-f/11). Of course, the more expensive the lens, the better the overall performance, and the more even performance across the aperture range.

    Suspect #14 is a “duh” type fellow. If you try focusing on something that is too close (closer than the minimum focusing distance of the lens), you’re just not going to get it into focus. So if you’re testing for sharpness, make sure your target is far away enough to make the minimum focusing distance an non-issue.

    Focal length is not a suspect for prime lenses, but can be for zooms. The zoom lenses are not equally sharp across the focal length range. However, determining the location of the sharpest point is an exercise left best for the well-equiped optical labs. Just be aware of it as a possibility if pictures taken at one focal length are sharp and not so much at a different focal length.

    Sometimes, the reason the pictures are not sharp is as obvious as the nose on your face. Did you correctly adjust the diopter value of your viewfinder? If you can’t see a clear picture, you’ll never be able to focus correctly. Eliminate suspect #16 by making sure you’ve dialed this in correctly.

    And finally, after all that… there is a 0.00001% chance that your pictures are not sharp because of localized space-time warping. If not, then it’s your lens.

  2. Compaq

    Compaq Been spending a lot of time on here!

    Aug 29, 2010
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    this is great - and funny!
  3. cnutco

    cnutco No longer a newbie, moving up!

    Aug 31, 2009
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    Dang... now I need to find a 48-126 mm f1.9 IDM SX FUS... :lol:

    Nice write up!


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