Comparing Olympus 4/3lenses to FX "Full Frame" offerings

Started Jan 25, 2014 | Discussions thread
Great Bustard Forum Pro • Posts: 39,710
Noise as a function of DOF.

Doctor Lecter wrote:

"So larger formats gain their noise advantage over smaller formats by using a more shallow DOF for a given shutter speed."


Did you just make that one up? You did, didn't you.

In fact, not only did I not make it up, but it should be intuitively obvious. That is, the wider the aperture (entrance pupil) diameter, the more shallow the DOF and the more light that will pass through the lens.

Larger formats gain a noise advantage because they are larger. Period. End of story. There is a larger surface area that produces more information, be it film or digital. Sort of like a computer hard drive. A 1TB drive can hold more data than an 80GB drive.

The larger size of the sensor comes into play, directly, only for base ISO shooting. For example, a person shooing a scene at 12mm 1/200 f/5.6 ISO 100 on 4/3 would shoot the scene at 24mm 1/50 f/11 ISO 100 on FF for the same DOF (assuming 1/50 is fast enough to mitigate motion blur).

In this case, the larger sensor can use one-fourth the shutter speed resulting in four times as much light falling on the sensor, and it is because the sensor is 4x larger that it can absorb 4x as much light without oversaturating.

However, in lower light, where the photographer would use a higher ISO to increase the LCD playback / OOC jpg brightness of the photo, to get less noise, the FF photographer would often choose a wider aperture (e.g. 50mm / 1.4 = 36mm on FF vs 25mm / 1.4 = 18mm on 4/3), but this would also result in a more shallow DOF.

It's pretty simple.

It is, isn't it?

You'll get there... you're almost grasping these basic concepts.

In your particular case, I'm not so convinced. However, I'll make every effort not to give up hope.

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