# IQ of 7d w 15-85mm Vs 6d w 24-105mm?

Started Mar 8, 2013 | Questions thread
Missed it

qianp2k wrote:

Mako2011 wrote:

ultimitsu wrote:

MAC wrote:

ultimitsu wrote:

It is intuitive. Moving further away -- in general, takes a better, more expensive optic to display the same resolution.

And with crop sensor you HAVE to move further away because you do not have enough sensor to cover the scene. This is exactly how it ought to be.

Not when comparing formats....The distance needs to be the same when comparing across formats.

Did you get it 15mm on 1.6x crop = 24mm on 1.0x crop having the same AOV (or FOV) from the same distance? What's difficult to understand?

To actually compare properly the characteristics of this discussion across formats you must...

• The photos all have the same AOV (diagonal angle of view) and aperture (entrance pupil) diameter: 50mm / 2 = 62.5mm / 2.5 = 67mm / 2.7 = 100mm / 4 = 25mm.

• The photos all have the same DOF (as well as diffraction softening) when they have same perspective (subject-camera distance), AOV, aperture diameter, and display size.

• The photos all have the same motion blur and the same total amount of light falls on the sensor when the aperture diameter and shutter speed are the same (e.g. ISO 100 on mFT, ISO 160 on APS-C, and ISO 400 on FF).

• The photos all have the same same noise when the same total amount of light falls on the sensor if the sensors are equally efficient (less noise if the sensor is more efficient, more noise if the sensor is less efficient).

• Other elements of IQ, such as resolution, bokeh, flare resistance, etc., as well as elements of operation, such as AF speed/accuracy, size, weight, etc., are not covered in this use of the term "equivalent".

DXO is an analysis site, not raw data provider. Until you can prove their analysis is wrong then please do give us a break.

So then MAC must be right until you can prove him wrong

That's what I said you only playing the game of words, nonsense.

Does illustrate a valid concept here though

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My opinions are my own and not those of DPR or its administration. They carry no 'special' value (except to me and Lacie of course)

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