How a CROP Sensor Affects APERTURE Performance (VIDEO)

Like many photographers using APS-C cameras you may be thinking about “moving up” to a full-frame model, while sifting through all the pros and cons before pulling the trigger. There’s a long list of variables to consider, including one that may not have to your attention.

Most of the comparisons between crop sensor and full-frame cameras concentrate on image-quality benefits, higher resolution, and a greater freedom to crop images when necessary. Other frequently discussed concerns include the impact of full-frame sensors when using wide and telephoto lenses, and the typical greater size, weight and cost.

There’s also the fact that most of the lenses you own (other than older glass from the days of 35mm) are likely incompatible with a full frame model—meaning a sizable investment in new glass beyond the cost of an upgraded camera.

There’s an additional factor that’s often overlooked; namely, the impact of sensor size on aperture performance. The tutorial below will end any confusion you may have on this issue in barely 10 minutes.

Photographer Booray Perry is also an adept instructor, posting unique tutorials on shooting techniques and interesting discussions about photo technology. He also includes a bit of humor in his lessons, so they’re also fun to watch. As you’ll see, this video was provoked by a message from a fan—questioning the use of APS-C cameras for shooting in low light.

Perry’s somewhat controversial (and tongue-in-cheek response: “How dare you sir? “Putting a full-frame lens on a camera with an APS-C sensor is like using a teleconverter, reducing the light reaching the sensor by 1.5 or 1.6. This turns your f/4 lens into something like f/6.”

His explanation is that a lot of the light passing through the lens is spilling off the unused edges of the smaller sensor. “Hence, the crop.” This is just the beginning of what is a very interesting discussion, that we’re sure will raise a lot of eyebrows. But keep an open mind, watch until the end, and then see what you think.

There’s a variety of helpful (and entertaining) advice on Perry’s instructional YouTube channel, so be sure to take a look.

And don’t miss the earlier tutorial we posted from another pro who discusses the dichotomy between how many megapixels you really need vs. how much resolution you want.