Stay at home
- Aug 16, 2012
There's a nice discussion about "reach" 10 years ago on dpr: "Reach" is a colloquial term for the ability of a lens to "pull in" detail from a distance. It doesn't have an official photographic definition. https://www.dpreview.com/forums/thread/2944342A STORY
A man took his 12 year old daughter out to take some photographs. They had two cameras, one with what is called a Full-Frame sensor, and the other had what is called a Crop sensor. The stood behind a fence, looking at a house in the distance. The man gave his daughter the Full-Frame camera and had her look through the 300mm lens at the house. "It's still kinda small," she said.
The man put the same lens on the Crop camera. "Here, try this one," he said.
She looked through the camera and said, "Hey. the house looks bigger with this camera! It's like I'm closer; like my arms were reaching farther out in front of me!"
"Yes," said the man, "it's like you have greater reach."
"Oh, I understand," said the 12 year old.
"That's because you are still too young to be stupid," said the man, grinning.
Your story illustrates well the confusion between reach and field of view. If the viewfinder of the crop has the same magnification as the FF, then the image will appear larger and closer, which is nice for the 12 year old or someone using the camera as telescope because it is looking at a narrower field of view. But, for the photographer who wants to see the detail in the image, then the resolution of the sensor is crucial. A 20 Mpx 7DII will give a larger image in the viewfinder than for the same lens on a 50 Mpx 5DS, but they give as near as dammit the same detail when you process the image and crop the FF. A 32 Mpx Canon 90D and M6II with its 1.6x crop factor outresolves and gives more reach than a 20 Mpx Olympus micro 4/3 with its 2x crop factor with the same focal length lens. But, the Olympus will have a narrower field of view and bigger image in the evf.