Interesting article on DxO about 5D III and D800 resolving power

Started Apr 4, 2013 | Discussions thread
schmegg Veteran Member • Posts: 5,768
Re: Interesting article on DxO about 5D III and D800 resolving power

qianp2k wrote:

Hans Kruse wrote:

schmegg wrote:

Hans Kruse wrote:

The diffence is quite remarkable and with a full frame 645 sensor the sensor area is around 2.6 times larger so it is to be expected that the resolution is much higher.

The size of a sensor is not the governing attribute that determines its resolving power.

If you photograph the same scene (=same FOV) which is how everybody does this kind of comparisons, then yes, it is!

Just like APS-C sensors resolve less detail than a full frame sensor with the same number of pixels.

Given the exact same detail presented to the sensor plane (which is the only really valid way to determine which sensor can resolve more), an 18MP Canon crop will resolve more detail than a 22MP Canon FF sensor.

Not if you photograph the same scene which is what DxO does and everybody else.

I think you are considering situations where the detail presented to the sensor plane is different to begin with - something that isdue to the difference in sensor size in many situations.

Every review site I know of compares resolution via shooting the same scene (same FOV). You have a different way, but this is unusual and therefore creates more confusion


If you shoot from the same distance with the same focus-length lens, you ended with two different AOV photos, two different scenes, then you compare apple to orange.

What happens is that you end up projecting exactly the same image detail onto each sensor in the comparison (providing you are using the same lens).

Then is very simple to determine which sensor has the better resolving power - you simply look at the detail that has been recorded!

In addition by shooting in the same AOV (or FOV), it just reflects how we use cameras in real world, such as you use 15mm on Canon APS-C while you use 24mm on Canon FF to get the same AOV.

However, when you do this you can make no claims about which sensor resolves more. The best you can claim is that the system (camera and lens), when used in a particular circumstance, can resolve more.

But I can easily give you a different scenario where the result will be the opposite. Which makes this type of comparison, in terms of determining which sensor is capable of resolving more detail, simply a waste of time.

For example, when shooting a portrait at, say, six feet and using the same composition in terms of AOV, a 5D3 will almost certainly out-resolve a 60D. But, when shooting macro, or BIF, the 60D will almost certainly out-resolve a 5D3.

It's just silly - the resolving power of a sensor does not vary with the shooting situation! The idea is totally ridiculous, and any test for sensor resolving power that comes to this conclusion is flawed.

What you guys are talking about is the resolving power of the system (camera and lens), not the sensor, and the comparable resolving power of two given systems (as opposed to two given sensors) is a movable feast and may very well vary depending upon the application - such as the example above.

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MOD Mako2011
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