Wednesday, June 23, 2010

DxOMark Lenses on Bodies Measurbation Paradise! :-o

Here you can go and enter another paradise of measurbators! (but actually might be a new hell for true photographers! ;-D) A step-by-step guide below!

1. Go to:-
http://www.dxomark.com/index.php/en/Lens-with-Camera/All-tested-lenses

First of all, you can select the "Filtered View" if you like. I think this can be useful when the test database continues to grow;

2. Choose the Lens Model and then the Camera Body, then you can see the "Overview" of a summary (on scores);

3. Go to the Individual Tab to view different page/test results of "Resolution", "Transmission", "Distortion", "Vignetting" or the "CA";

4. There are Sub-Tabs to see/access to all the test data at different Focals (for zooms) and different Apertures. Just choose it, appropriate charts and graphs will be shown. There are also "Field Map" representations, which are simply a plot of the image frame with different colours to represent the results and different performance aspects measured.

With doing the above four steps, dig into different sub-tabs and choose different focal/aperture combinations and then compare different lens/body and so on, you will be a true qualified measurbator! Congrats! But before you are to do this endlessly, do remember time will always be not enough and is killed very quickly as such!

Two quick observations, btw:-

1. High resolution bodies do have a clear edge for obtaining higher scores, especially for the aggregrated mark of "Lens Peak Score".

2. Full Frame cameras perform better, even for the same pixel count and equivalent effective 135 focal length and FoV.

Besides, some more quick reading notes and remarks:-

1. "TStop" is just the actual f-stop measured for the lens (wide opened) at specific focal length, the EV stop differences against the specified ones at different focal lengths are represented at second plot chart below.

2. The MTF charts should be read as they always should, it is just a plot of the Modulated Transfer Function (the difference between the levels of Black and White) against the (different) Spatial Frequencies. Normally, MTF 50% is the default threshold for measuring Resolution, but of course a different MTF value can always be chosen, no matter it is higher or lower. Of course, should the set MTF threshold is set to be higher, the Resolution results drop and vice versa.

3. The measured "Resolution" of lp/mm (line pairs per millimeter) is NOT normalised for the sensor size and format but just a physical measure on the actual resolution regardless of the sensor size. On the other hand, another commonly used (but newer) resolution measurement unit LW/PH (Line Widths per Picture Height) is normalised. So, this should be something that you should be aware of. Just say with exactly the same resolution figure for both an APS-C combo and a Full Frame combo, indeed the FF just outperforms the APS-C as the resolution of the APS-C is needed to be "magnified" just for the same printout and viewing size of the "same" picture.


Read Also:-

Useful Lens Review Links

A New Measurebators' Paradise!

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