APS-C IMAGE QUALITY VS fULL fRAME AT TESTING

Started Feb 24, 2013 | Discussions thread
qianp2k Forum Pro • Posts: 10,350
Re: I can help.

Great Bustard wrote:

qianp2k wrote:



So let's understand what "resolution" really mean to us? If is there crop factor and penalty from crop magnficaiton (enlargement)?

http://www.josephjamesphotography.com/equivalence/index.htm#lensvssensor

In short, the resolution as a function of sensor size and pixel count can be summed up as follows:

  • For a given lens sharpness, the difference in resolution (lw/ph) between two systems will be between the ratio of the sensor heights (enlargement ratio) and the ratio of picture height in pixels (linear pixel density). The sharper the lens, the closer the balance will be to the ratio of linear pixel density, the less sharp the lens, the closer the balance will be to the enlargement ratio.

LOL, I know you like to point to your own bible. Anyway according to common knowledge base, for a crop sensor to overcome the penalties from crop magnification or enlargement a much better lens and lots more pixels are needed. In reality however more then often such "perfect" lenses don't exist or impossible to be manufactured.

http://en.wikipedia.org/wiki/Crop_factor

However, the lenses specifically designed for smaller formats are often sharper than the lenses designed for larger formats.

Not sure if this is true. Please give me a sample what Canon EF-S lenses are better than EF lens counterparts? 17-55/2.8 IS vs 24-105L? 60/2.8 macro vs 100/2.8 macro?

Whether or not this is enough to overcome the difference in sensor size depends on the specific lens-sensor combination, and, of course, whether or not we are comparing at the same AOV and DOF.

Such test must based on the same AOV when you frame the subject into the same FOV. DOF is not an issue as it's a technique related not impossibility such as you can use on tripod. FF can achieve any deep DOF and can achieve more than crop without suffering diffraction but crop cannot achieve the same shallow DOF as from FF. In another word, FF has better control in DOF than crop. No mention in many scenes DOF is not even an issue.

Anyway DXOMark confirms 12mp FF outresolves 18/16mp APS-C (that's DXOMark's conclusion). Still wait and see if the new 24mp APS-C outresovles 12.8mp 5Dc as I have not found DXOMark has tested 24mp APS-C sensor-lens resolution that I can use for a comparison. I will not be surprised 24mp APS-C does.

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