it is said that full frame aperture equivalent of 2.8 to aps-c is 4.2. does it mean that shutter speed of aps-c is one stop slower that full frame on the same aperture? given the same focal length equivalent e.g. aps-c 23mm and ff 35mm.
it is said that full frame aperture equivalent of 2.8 to aps-c is 4.2. does it mean that shutter speed of aps-c is one stop slower that full frame on the same aperture? given the same focal length equivalent e.g. aps-c 23mm and ff 35mm.
Crop factor equivalency for apeture is referring to the perceived depth of field with a different lens, not the brightness.
An f/2.8 lens will shoot as fast as f/2.8 does, no matter what you put it on.
do you mean that aps-c has an advantage over full frame on in terms of shutter speed?
for example, I am shooting at 35mm at 1.4 with 1/80s on full frame at the exact same light situation where I use an an APS-C sensor at 23mm at 1.4 will I get 1/80s?
if yes, 1/80s on APS-C will more less subject motion blur?
You’ll get 1/80s with the same blur since you have the same field of view. Depth of field will be different though, the FF will be shallower.
If you stop down the FF to f2, then you’ll get similar depth of field, but then you’ll have to raise ISO to compensate.
No, just the opposite. It won’t matter which body you put the lens on, it will operate the same way. The “equivalent” you’re chasing only pertains to FOV
100iso on full frame does not equal 100iso on aps-c. The numbers are the same but the actual amplification on iso is not transferable across cameras.
You can see this by looking at noise of the same ISO number on different size sensors, there would be more noise on smaller sensors.
https://photographylife.com/equivalence-also-includes-aperture-and-iso#iso-and-equivalence
But what is this “speed” or “fastness”? The f-number is not just some abstract unit, but it’s tied to physical reality.
To answer to that one needs to understand that this “fastness” refers to an exposure time (or shutter speed) one can use to achieve desired image quality. Thus f/2.8 on one format does not equal f/2.8 on another.
In principle f/4.2 on FF, f/2.8 on APS-C do an identical job - they give the same image quality (noisewise) with the same exposure time, the depth of field is the same and the blur from diffraction will be the same.