sharpness and focal length.

Discussion in 'Photography Beginners' Forum' started by domromer, Aug 11, 2007.

  1. domromer

    domromer TPF Noob!

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    Hello this is my first post. I just bought a nice new d80 after a using the canon is3 for a few years. I'm having some difficulties getting sharp photos.

    I understand the general rule that for hand holding a shot, your shutter speed should be at least equal to your focal length.

    What about while using a zoom lens. My current lens is a 18-135mm. If I were to shoot a subject at 28mm, should my shuttterspeed be at least 1/30th or does it need to be what the maximum focal lenth of the lens is? So even though I'd be shooting at 28mm I would need to be at 1/160th.

    Also is this rule the same for flash photography?

    Thanks for any help you can offer. The learning curve is steep from my old point and shoot!
     
  2. WDodd

    WDodd TPF Noob!

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    You are correct in that the general rule is 1/the focal length that you are currently shooting at. Ex. 50mm = at least 1/50.

    You shouldn't have to worry about the shutter speed when using a flash in most situations because the point of the flash is to give you enough light to get your shutter speed up higher.

    If you are shooting in dimmer situations try boosting your ISO or using a larger aperture (lower f number) to get your shutter speed up. Or shoot on a tripod!

    And welcome to the forum!
     
  3. Garbz

    Garbz No longer a newbie, moving up!

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    Don't forget the 1.5x focal multiplier. If you mount a 50mm on the D80 shoot at 1/75th is the rule of thumb

    But "rule" is very general. Some people can do better others can do worse. It comes down to how steady you can hold the camera.
     
  4. domromer

    domromer TPF Noob!

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    So even though my lens my go to 135mm, if I'm at 50mm. I only need to be at 1/50th.

    Last night when I was shooting w/flash I noticed my shutter speed was 1/60th. The rule would still be the same right? Even with flash I'd need to be shooting at 60mm or less with that shutter speed?
     
  5. WDodd

    WDodd TPF Noob!

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    Yes even though your lens is 135mm long at its longest, if you are only at 50mm 1/50th would be fine. Garbz reminded me of the crop factor which would make your 50mm equivalent to 80mm on a 35mm camera so at least 1/80 would probably be better.

    As far as using a flash, you would still use that same rule of thumb so as not to have shake the flash should just allow for enough light where normally this would be impossible.
     
  6. Alex_B

    Alex_B No longer a newbie, moving up!

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    Often forgotten!

    Also, this rule is not made for pixel peeping on the screen ... but for a medium print size at an average viewing distance.

    oh, different levels of booze and coffein can heavily influence your ability to hold the camera steady by the way ;)
     
  7. WDodd

    WDodd TPF Noob!

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    Is there a recommended level of either? Or some sort of combination of the 2 I should be using? :lmao:
     
  8. deanimator

    deanimator TPF Noob!

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    For longer exposures, I usually recommend one large beer. During the consumption of this beer check your equipment and begin to discuss composition, art and stuff with whoever will listen. Place your camera on the glass for a nice improvised tripod and hence a stable exposure. Coffee should be consumed next, either during the long exposure or as a pretext to chat to the nice waitress again.
     
  9. domromer

    domromer TPF Noob!

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    Thanks for all the info. I'll put it to use shooting this morning. I think I'll just double the focal lenght rule so I'm safe. Plus I've always had very shaky hands.
     
  10. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    Using flash can and does change the equation. The burst of flash is very fast, probably equivalent to a shutter speed around 1/10,000. You could have the shakiest hands ever, and get a sharp flash shot, even with a very slow shutter speed.

    However, every flash shot is really two exposures in one. One is the flash exposure and the other is the ambient exposure. So if there is enough ambient light to cause some exposure, you may get blur. Combine that with flash and you can get some funky results with a sharp flash exposure and a blurred ambient exposure.

    Also, take note that the flash exposure is determined by the power of the flash and the aperture of the lens (not the shutter speed). The ambient exposure is determined by the aperture and the shutter speed.
     
  11. domromer

    domromer TPF Noob!

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    ugh, flash is confusing. I have the sb-600. I'm trying to wrap my head around the flash diastances and stopping fast moting in the forground while still looking natural and preserving details in the background.
     
  12. Groupcaptainbonzo

    Groupcaptainbonzo TPF Noob!

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    I always find that when TAKING my photos the less of either/both makes for better results.... However, Funnily enough when VIEWING my images I find that the more alcohol I have present in my bloodstream, The better they appear. Not only that, but, others seem to agree that my pictures get better after a few ....
     

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