drtic1
A7_EF2002_600_f56_02498.jpg
This shot was taken with Sony A7, Metabone Smart Adapter III, Canon EF 300/2.8 L IS, Canon TC 2x II and another Canon TC 2x III. Resulting lens has thus focal length of 1200mm at f/11,2. The EXIF can't record the second TC, because it is not reported. From three tested cameras -A7, A7r and NEX7 (resulting focal length in terms of FOV was funny 1800mm), the A7 capture was the one with the least motion blur. I used gimbal head and heavy tripod, but camera shake wasn't the only problem. Looking at the LCD on the cameras with focus peaking on, with lens stabilization switched off and lens switched to manual focus, I saw the focus "breathing" from sharp to very blurred.
At the first moment I was not sure what is going on, but suddenly I realized that focus breathing happened due to hot air that was comming from the passing cars in front of the focus plane. That hot air, simply blurred the image to unexpected extent.
Significant problem with A7r was shutter vibration that completely ruined sharpness, while with NEX 7, due to the extreme magnification, it wasn't possible to keep it steady enough.
A7_EF2002_600_f56_02498.jpg
This shot was taken with Sony A7, Metabone Smart Adapter III, Canon EF 300/2.8 L IS, Canon TC 2x II and another Canon TC 2x III. Resulting lens has thus focal length of 1200mm at f/11,2. The EXIF can't record the second TC, because it is not reported. From three tested cameras -A7, A7r and NEX7 (resulting focal length in terms of FOV was funny 1800mm), the A7 capture was the one with the least motion blur. I used gimbal head and heavy tripod, but camera shake wasn't the only problem. Looking at the LCD on the cameras with focus peaking on, with lens stabilization switched off and lens switched to manual focus, I saw the focus "breathing" from sharp to very blurred.
At the first moment I was not sure what is going on, but suddenly I realized that focus breathing happened due to hot air that was comming from the passing cars in front of the focus plane. That hot air, simply blurred the image to unexpected extent.
Significant problem with A7r was shutter vibration that completely ruined sharpness, while with NEX 7, due to the extreme magnification, it wasn't possible to keep it steady enough.