Hi Rex. thanks for your question. Shooting with the 40mm help me to reduce my shutter speed to increase the light on my image and still quick a good sharpness.

Rex Larsen February 3, 2018 - 2:49 am

Stanislas Dorange

But why f7.1 and a slow shutter speed . What about f4 and a faster shutter speed? Same exposure, faster shutter speed.

Stanislas Dorange February 4, 2018 - 9:24 pm

Rex Larsen

I am agree with you, my set up was wobbly :-)