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Helicopter
 

Helicopter

Metallic blue helicopter in flight against a blue sky with cloud. Motion blur on rotors
(Day, Exterior, Full)



Photo Information for Helicopter

Taken with Canon Canon EOS 650D

  • 200 mm
  • 1/1600
  • f f/3.5
  • ISO 100
View all photo EXIF information

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Tad under exposed, noisy sky, shutter speed too fast - looks like its stopped and falling from the sky! Also needs to be editorial unless you can remove serial number from underside.

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Ah - good point about the rotors. I need more blur not less!

 

Re: Noisy sky - I'm exporting from Lightroom and I'm not sure what the SS max file sizes are. My first effort was a 20Mb jpeg with (allegedly) 0% compression, i.e. 100% quality but I guess it was too big because the SS server rejected it. The current version was 3.5Mb when I uploaded it and I'm not sure if SS does further compression on it.

 

Is there a "best practice" for uploads?

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I don't understand the comments "noise" , "noisy" .. as I see it often from experts.

Can any one explain what noise is all about, why it happens and how it can be de-noised?

 

Appreciate your inputs.

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Hi Ari - if you zoom in on my first image (as I clearly failed to do!) you can see that the blue pixels in the sky actually vary quite considerably in brightness giving a speckled effect. This usually happens when the ISO / gain is too high and the sensor isn't getting enough light to calculate the "proper" colour and/or brightness value. This image was shot at a low ISO but the shutter speed was very high (1/1600) because I'd been shooting a motorbike race and just lifted the camera to snap the chopper as it passed overhead.

 

The end result is the same, not enough light on the sensor. If I'd shot at a lower speed as Steve suggests above then I'd have more light on the sensor and therefore a less noisy sky and the bonus of blurred rotors to give a sense of movement.

 

To "fix" (actually just reduce the effect) I used the "noise reduction" facility in Adobe Lightroom which effectively averages colour and/or brightness in a group of pixels. This has a side effect of reducing detail. The correct solution is to shoot at the correct speed and exposure so instead of ISO 400 and 1/1600 I should have used ISO 100 and 1/400. Alternatively 1/400 at ISO 200 would let me lose one stop from the aperture and get a bit more DOF.

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Thanks a lot Derek. It's a very good explanation on noise. Possibly,it's same as the signa-to-noise ratio, if I'm not wrong.

What I didn't know earliervand learnt from yiur explanation is that one can see the "noise" only when one zooms in on the picture i.e at 100% expansion.

Then to avoid or reduce noise, in auto mode,can I zoom in on the farthest object first ( assuming a still photo) and see if any pixeliation, and if no, then zoom out and shoot the picture. Will it be a good practice and yield a noise-less or less-noise picture without modifying the ISO exposure and Shutterspeed settings.

 

Thanks for your inputs.

 

Ari

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Ari, the reviewers look at your image at 100%, so it is best if you do the same. At the same time, check the noise (which is most apparent in large same-density color areas.) And you can check focus and color fringing, etc.

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