In my last article, I talked about different sensor formats and their various advantages and disadvantages. It led me to a question. Why don’t lenses get labeled with the FF equivalent field of view instead of constantly calculating it?
What do I mean?
Full frame is the yard stick by which all other formats are measured. A 50MM field of view on a full frame sensor is considered 50MM. If you have a 50MM lens on a Micro 4/3 sensor, it’s equivalent to a 100MM full frame field of view. So why not just label the Micro 4/3 lens 100MM? It would be a heck of a lot simpler. Our lead image is a great example of this. Three different lenses all 28MM full frame equivalent at their smallest zoom. (Edit: The OM System lens is actually 24MM)
Is it simpler?
It depends on your perspective. There is an argument that it’s too confusing for new photographers. I’m not sure how making all lenses use the same parameters and baseline off of full frame is harder than constantly multiplying your lens focal length by your sensor crop factor. If 33MM APS-C is 50MM full frame equivalent, mark it 50MM.
Depth of field is different due to sensor size. OK. So a 50MM APS-C lens and a 50MM full frame lens have a different depth of field. Much easier to discuss than 33MM vs 50MM and depth of field. The same thing applies to aperture, etc. Doing math to calculate focal length is never easier than reading it off the lens barrel.
I’m not intending to describe the technical side of this argument.
This isn’t a technical argument that I am making; there are articles that get into pixel count, diagonal cross section, etc. The consensus when you look through those is that the equivalency holds up. So why aren’t we doing it? One argument is that the focal length is a mechanical measurement for the lens. Hyperbolically, they claimthat if we labeled the lens with the equivalent focal length, the whole lens measurement process would collapse. Then put both, 24 4/3 and 48 FF, or be smart enough to know the label is for the user of the lens, and the sensor sized measurement is the crop factor. Make manufacturers do the math.
What are your thoughts?
Do you care? Does it matter in the end? Did you know this was even the case? Share below!