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Thread: K5 Dust Alert test?!

  1. #21
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    Default Re: K5 Dust Alert test?!

    Quote Originally Posted by night86mare View Post
    i also don't understand, main reason is cos can't really zoom in to check more thoroughly.
    Yes, that's the main reason I use it. If just shoot white oof bg at f22, I have to zoom in on the LCD and pan around to check for dust, which is slower and more troublesome than using dust alert. Dust alert doesn't catch some of the finest dust, but if it can't see the dust, the dust won't bother me either.
    My photos - see just some or all of it =)

  2. #22
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    Default Re: K5 Dust Alert test?!

    Quote Originally Posted by armadillo View Post
    Just test again, with my lens cover, result is 100% white, no spec of dust at all.
    I think doesn't matter what you shoot, as long you leave the camera idle for few minutes before you do the dust alert test, that will work.
    Or if you can't wait then just shoot any white background, that will work as well
    It's an interesting result, but whatever the reason (my guess is some temporary, slightly warm pixels, combined with insufficient exposure for accurate dust alert diagnosis since it's completely black), it shows that doing dust alert with the lens cover on has the potential to give you false positives. So why would you want to do it that way? A plain white (or any one solid colour for that matter) wall can't be that hard to find. Or a lamp shade (not a bare light bulb) can work perfectly well as well, just put the lens right up to the lamp shade when you press the shutter. The only important thing is to make sure that the object is close (dust alert sets focus to infinity, so go close to make things oof to wash out the details) and has no distinct change in contrast. And I'm guessing that with the lens cap on, the camera has to do a long exposure to get the dust alert frame? With a white wall at home at night, it should only be about 1s at max.

    K-5 manual pg 342:
    "Fully display a white wall or other bright subject with no detail in the viewfinder and press the shutter release button fully."
    My photos - see just some or all of it =)

  3. #23

    Default Re: K5 Dust Alert test?!

    Quote Originally Posted by Gengh View Post
    Yes, that's the main reason I use it. If just shoot white oof bg at f22, I have to zoom in on the LCD and pan around to check for dust, which is slower and more troublesome than using dust alert. Dust alert doesn't catch some of the finest dust, but if it can't see the dust, the dust won't bother me either.
    it will still show up at web size if you can see it at 2x zoom, particularly if you have a relatively smooth/uncluttered surface, e.g. water under conditions of long exposure.

  4. #24
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    Default Re: K5 Dust Alert test?!

    Quote Originally Posted by night86mare View Post
    it will still show up at web size if you can see it at 2x zoom, particularly if you have a relatively smooth/uncluttered surface, e.g. water under conditions of long exposure.
    Visible at 2x zoom, dust alert will definitely catch. Those that it misses are the more or less pixel level ones, only visible at close to 8x zoom on the LCD.
    My photos - see just some or all of it =)

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