What focal length on Sony APS-C gives the same portrait framing as an 85mm lens on full frame?
Asked 5/23/2018
4 views
2 answers
0
I use a Sony A6500 with an APS-C sensor. When people say an 85mm lens is a classic portrait focal length, they usually mean on full frame. On Sony APS-C, does that translate to about 55mm because of the 1.5x crop factor? And if I use a 55mm f/1.8, will it behave like an 85mm f/1.8 for portraits?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
8y ago
2 Answers
6
Well, sort of. There's no such thing as absolute equivalence.
In terms of angle of view a 55mm lens will give the same AoV with a 1.5X APS-C sensor as an 85mm lens on a 36x24mm FF camera.
In terms of exposure you'd need a 55mm f/1.8 to get the same AoV and exposure in the same light as an 85mm f/1.8 on a FF.
In terms of depth of field (DoF), you'd need a 55mm f/1.2 to get the same DoF from the same subject distance as you would get with an 85mm f/1.8 lens on a FF camera. The 55mm f/1.8 on an APS-C camera could only match the DoF of an 85mm lens set at f/2.8 on a FF camera.
Of course opening up the aperture to f/1.2 would change the exposure compared to f/1.8, so you'd either need to change the shutter time or the ISO to compensate.
Originally by user15871. Source · Licensed CC BY-SA 4.0
user15871
8y ago
0
Generated from our catalog & community — verify before relying on it.
Yes—if you mean framing/angle of view, a 55mm lens on Sony APS-C is roughly equivalent to an 85mm lens on full frame because of the 1.5x crop factor.
But “equivalent” depends on what you want to match:
- Angle of view/framing: 55mm APS-C ≈ 85mm full frame
- Exposure: 55mm f/1.8 and 85mm f/1.8 can use the same exposure settings in the same light
- Depth of field: they are not the same at the same f-number. A 55mm f/1.8 on APS-C gives depth of field closer to an 85mm at about f/2.8 on full frame, from the same subject distance
To match both the framing and the shallower depth of field of an 85mm f/1.8 on full frame, you’d need about a 55mm f/1.2 on APS-C.
So for portrait framing, yes, around 55mm is the right equivalent. Whether it’s the “perfect” portrait lens depends on the look you want—85mm-style framing is great for tighter portraits, while wider lenses can work better for environmental portraits.
Recommended products
UniqueBot
AI8y ago
Your Answer
Related Questions
Which lens gives more background blur on a Sony a6500: 30mm f/1.4, 50mm f/1.8, or 56mm f/1.4?
How does crop factor affect depth of field equivalence?
Why do APS-C and full-frame 50mm lenses have the same field of view on my APS-C camera?
Does an APS-C-only lens change its stated focal length on a crop-sensor camera?
Should I use a 55mm f/1.8 in crop mode to mimic 85mm, or buy an 85mm f/1.8 for my Sony A7 III?