Why “Full Frame Equivalents” matter!

Warning: This post may be a rant and definitely 100% my opinion!

Bogus camera, Seriously? Yes, that’s right!! Bogus camera! Why?

Well, imagine a camera that generates random values for focal lengths, f-stops and isos. That’s right, random!

What will those numbers mean to you? The answer: nothing!

These numbers don’t mean anything without establishing a reference point. Camera and sensor size is missing. This information is needed to understand what the photographer used. Otherwise, the information is not of value.

Different sensors, different settings, but the same result

The following photo was taken on a MFT camera. The settings used are displayed in the photo:

Micro Four-Thirds
Micro Four-Thirds

Look familiar? Yes, it’s the same orange in both pictures. This time I have listed MFT values in the photo. So now we’re getting somewhere. Again, if you don’t own an MFT camera and aren’t aware of the crop, what do these numbers mean? Nothing!

Here’s another photo taken on an APS-C camera:

APS-C
APS-C Equivalent

Wow! More numbers! We’re not done yet, there’s more!

Full Frame Equivalent

I’ve listed the values here from the above photos:

MFTAPS-CFull Frame
Focal Length50mm62.5mm100mm
f-stopf/5.6f/7f/11.2
ISO200300800

Wow, how does anyone understand this stuff? The point here to understand is that various cameras produce almost the same photo using different settings. In order to do that, you should understand the relationship between the numbers and their camera sensors.

The case for a standard scale

These numbers can be used as guidelines to new photographers who may want to take similar pictures or just to show the world the possibilities with these settings. But unless a standard scale is known, the numbers don’t mean anything!

Take for example: 50mm, 62.5mm, and 100mm

or f/stop numbers: f/5.6, f/7, and f/11.2

If a camera type/sensor type is listed, one would have no clue what the actual focal lengths or f-stops meant in terms of their own cameras.

If you haven’t caught on yet – the current standard of listing Focal Lengths, F-stops, and Iso numbers with respect to one’s camera does not provide useful information to other photographers, unless the crop-factor is understood.

Either way, please take a few minutes to watch the following videos:

To reiterate from the videos, there is a crop applied to non full-frame cameras to get to full-frame equivalents. The crops and equivalent attribute tables are show below.

Crop Factors vs. Focal Lengths, F-stops and Isos


Full Frame

APS-C

Micro Four-Thirds
Focal Length11.62
F-stop
(aperture number)
11.62
Iso11/(1.6)^2
or
~2/5
1/(2)^2
or
1/4

Full-Frame as a Standard Scale

For both film and photography, the 35mm Full-Frame sensor has been used as an industry standard. I’m calling for this to be continued with respect to not only focal lengths, but also aperture and iso values. The tables below list the equivalent values.

Equivalent Focal Lengths for different sensor types

Full FrameAPS-CMicro Four-Thirds
25mm15.63mm12.5mm
50mm33.25mm25mm
100mm62.50mm50mm
200mm125mm100mm
600mm375mm300mm

Equivalent F-stops for different sensor types

Full FrameAPS-CMicro Four-Thirds
f/1.90f/1.19f/0.95
f/3.60f/2.25f/1.80
f/7f/4.38f/3.50
f/8f/5f/4.0
f/11.2f/7f/5.6

Equivalent Isos for different sensor types

Full Frame APS-C Micro Four-Thirds
50128200
100256400
200512800
40010241600
80020483200
160040966400

As you can see, given the many sensor types available, it makes sense to standardize focal lengths, f-stops and isos. Since 35mm (full frame) is the standard, as a MFT owner, I have no problem listing both MFT and full-frame equivalent values.

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