Wrong F Stop

Discussion in 'Digital Photography' started by AirborneAngel, Jun 28, 2009.

  1. AirborneAngel macrumors 6502

    Sep 8, 2007
    Los Angeles, CA
    Alright, so the other day I had been shooting really close up shots and had my f stop cranked all the way down to 5.6 (on aperture priority,) I then went on to shooting landscapes and left the f stop cranked all the way down at 5.6 (when it should have been up at f10 or f11) the photos came out very soft.

    My question here is, did they come out soft because of the fact that I used 5.6 or for another reason? Also, what would be the best way to correct this in photoshop (apart from an unsharp mask or a high pass filter w/ blending modes.)

    That day I was shooting with a Canon Rebel XS 1000D with the kit lens.
  2. leighonigar macrumors 6502a

    May 5, 2007
    Is it not simply that at f/5.6 the depth of field is shallow, especially up close, and so almost nothing is in focus? You can't really correct this. Post an example.
  3. HBOC macrumors 68020

    Oct 14, 2008
    it might be able to be corrected in PS or whatnot, but how soft are we talking? Did you shoot in RAW? Shooting in RAW usually renders softer images straight from the camera.

    That is why i always shoot in manual. One time i was out shooting fireworks, and somehow my ISO got dialed up to 800 or something. Sucks when you get home and have great firework shots, but soo noisy. Really can't do much, unless you spend a bunch of time cloning and such...

    I mean you shot at f/5.6? That isnt too bad, maybe a stop or 2 more open than ideal. Was it done in mid day?
  4. AirborneAngel thread starter macrumors 6502

    Sep 8, 2007
    Los Angeles, CA
    Alright, here's the shot (I did shoot it in RAW in addition to JPEG) I realized that my only problem wasn't the 5.6 aperture, but also the fact that I had my autofocus set on "select autofocus" as opposed to "automatic autofocus," dumb mistake.

    I just hope I can save the shot somehow.

    Link: http://img31.imageshack.us/i/img3743x.jpg/
  5. toxic macrumors 68000

    Nov 9, 2008
    i've no idea what it focused on...and i think that's the problem. the lens isn't anywhere near that soft.
  6. Abstract macrumors Penryn


    Dec 27, 2002
    Location Location Location
    I think that the shutter speed must have been slow, and that your photo isn't soft. What probably happened is that everything in the foreground moved slightly, and since your camera is using really slow shutter speeds, your camera picked up some of that movement. Remember that a pixel is usually several micrometers/microns in size. Surely there are things in the image that may have moved while you were taking the photo.

    Were you using a tripod?
  7. Gold89 macrumors 6502

    Dec 17, 2008
    Exif shows:

    Camera Model: Canon EOS DIGITAL REBEL XS
    Lens Name: EF-S18-55mm f/3.5-5.6 IS
    Exposure Time: 1/1000 sec
    F-Number: f/5.6
    Exposure Program: Aperture Priority
    ISO Speed Rating: 200
    Lens Aperture: f/5.7
    Exposure Bias: 0 EV

    Shutter speed shouldn't be a problem at all at 1/1000th massively surpassing any 1/focal length = minimum handheld rule. I would try stopping down the aperture to roughly f9, I would also try and avoid too much pp until your straight from camera shots are sharp. :)

    Also a tip when shooting landscapes I find it is easy to bracket each shot by -1/0/+1 and then having the option to pick and choose your shot when you return to the computer. :)
  8. QuantumLo0p macrumors 6502a


    Apr 28, 2006
    What was the focal length? Won't longer focal lengths have a shorter depth of field than using a shorter focal length on the same lens?
  9. Ruahrc macrumors 65816

    Jun 9, 2009
    If you're wondering why the grass in the foreground is way blurry, yes it's because you used f/5.6, or not necessarily because you used f/5.6 but rather did not seem to focus correctly for that aperture. Doubtful you can do much about this.

    If you're wondering why the image is a little soft, it is likely a combination of things. Maybe your lens is giving up a little bit of sharpness at f5.6 whereas it would be a little better at f/8 or f/11. Also the focus point seems to be way too far back (look in the middle of the image on the horizon, there are a few trees that are pretty well focused, but way in the background) combined with the larger aperture that caused much of the picture to be a little soft due to depth of field.

    Next time consider the use of hyperfocal technique, it may help. Just chock it up to learning experience.

  10. iBookG4user macrumors 604


    Jun 27, 2006
    Seattle, WA
    I edited it a bit, but it is pretty soft. If you want to print it you'll want to keep the size pretty small. It is a bit sharper now, but it's not going to get any sharper than this without getting the oversharpening halos.

  11. HBOC macrumors 68020

    Oct 14, 2008
    As a rule of thumb, for me atleast, I always use a tripod, especially when it is dark out, like in your photo. I usually always use ISO 100, or lower, unless ofcourse it is not feasible.

    As some pointed out, i think it is a lack of focus on any one object. I always noticed that my 30D had problems with low light, and pair that with a slower lens, and you have that infamous AF hunt noise.

    what was the focal length? I would shoot at f/11 most likely for this scene..
  12. AlaskaMoose macrumors 65816

    Apr 26, 2008
    He should have used f/11 to f/16 for landscapes. Even with a wide angle lens set to 12mm I still use f/11 for most of my landscapes. A 50mm lens doesn't give much room up close.

    I used around f/16 for this one, with the lens from 12-24mm:

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