M42 Series Lens to M4/3 Series Mount Camera, M42-M4/3 IV PRO High Precision Lens Mount Adapter

SKU: KF06.504

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This has nothing to do with the lens, it is the image size setting (live view) on the camera. 
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In my opinion, this splash water protection is as good as unnecessary for a well-built lens. When it rains properly, you no longer unpack your splash-proof camera unprotected and even the amateur models can withstand a short shower. 
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In free fall, the autofocus would have to follow the "pull" downwards. It should be at least a Nikon 5500 or Nikon 7200. Choose a very short shutter speed, eg 1/1000. Then ran to about 25 cm and go along. Keep the background as dark as possible. Illumination with continuous light at a 90 degree angle, preferably from above