New K5 user (from D7K). Low light focus issues.

Started May 19, 2012 | Discussions thread
il_alexk
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Re: New K5 user (from D7K). Low light focus issues.
In reply to Megascolex, Aug 4, 2012

Apparently you missed the following statement from the guy:

"Yes, I compared them at the same focal lengths and aperture. My D7000 never missed focus in these indoor low light situations with either lens. It did use the focus assist lamp in each case. My K5 rarely ever used the focus assist lamp (it is turned on in the settings) and I have a lot of misfocusses as seen in the pictures. I do have the corresponding D7000 pictures too, but I didn't bother posting them"

Megascolex wrote:

If you focus under tungsten light and shoot under tungsten light you won't have a focus problem. If you focus under tungsten light and shoot under flash light you will have front focus regardless of the brand of camera. It is law of physics.

That's why other cameras use AF assist in low light. The AF assist of K5 is unpredictable.

Lights of different wavelengths diffract at different angles. Red which has long wavelength diffracts most. On the other end of visible spectrum violet with short wavelength, diffracts least. Hence the phenomenon of sun appearing red when very low in the sky, then turning yellow and white. Middle school physics.

K5 can also miss a focus even without flash when the same wavelengths is used both for focusing and and for capturing the image.

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Cheers,
Alex

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