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Old 2nd August 2019
Walti Walti is offline
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Re: If Sensor Size Doesn't Matter, Why Buy a Bigger One?

Hi Henry

There are differences in performance between the 4/3 and 35mm sensors and systems.

Focal length, as you know there is a crop factor of 2 meaning that a 4/3 lens focal multiplied by 2 gives the equivalent field of view to the 35mm equivelent.

Depth of field, because you are using a shorter focal length to get the same field of view the depth of field also changes and this is easiest thought of as a crop factor too, so an f stop on a 4/3 system will give a depth of field the same as the f stop on a 35mm multiplied by 2, which for sport and wildlife is great, but for portrait work is a problem, so you can now get f0.9 lenses for the 4/3 system to compensate for this. So a photo taken on a 4/3 system at f2.8 gives the same DOF as one taken at f5.6 with a 35mm system

Sharpness, I really don’t know whether the smaller pixels give a sharper image or not, someone else will have to advise!

Low light performance, the performance of the 4/3 system does lag behind the 35mm system for low light but is catching up. That’s all to do with pixel size and the amount of light actually focussed onto the sensor, but it’s a personal choice as to whether the performance is good enough for you! It certainly is for me! Interestingly some of the comparisons of sensor performance put the current 4/3 devices in the same league as 35mm so it’s not going to be long before there’s equivalency between the two systems.

Defraction. The smaller pixels mean that diffraction is a potential issue with the 4/3 system, and I note that Olympus have changed their advice since the recent firmware updates for the OM1ii changing from f8 to f11 as their recommended defraction free f stop!

I think I’ve covered everything, but I’m sure others will chip in!
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Last edited by Walti; 2nd August 2019 at 07:49 AM. Reason: little mistake corrected!
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