How much important are the MTF numbers in the real world photos?

I did this test as a poll to investigate what is the meaning of the MTF numbers out of the test charts.

It's a user test - made carefully, and with a level of accuracy as good as a simple/ordinary (i.e. non-scientific) setup and technique allow.

The methodology:

I shot seven photos with the same exposure value, with a Pentax K200D camera and a Pentax SMC DA 35 mm Macro Limited lens. This lens is rated as An optical Paragon by Mike Johnston and Carl Weese (I need to say, I agree), but some people (a lot of?) disagree.

Apertures: f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22

The target was illuminated uniformly (checked with a lightmeter) and the focus was locked - the sensor alignment was virtually parallel to the target.

Camera on a tripod, 2s mirror lock and remotely triggered.

Capture mode: RAW - DNG.

Processing: each DNG file was opened with ACR 4.5. All photos were processed in the same way, including same amount of sharpness. An EXCEPTION was made for the vignetting correction.

All files were saved as 16 bit uncompressed TIFF.

After done, all TIFFs were opened in the Photoshop CS3, and each file was processed with a different amout of "fine-tuning-sharpen" i.e. Smart Sharpen/Lens Blur - but very conservative, around 50 to 100% /0,1 to 0,2 pixel radius for 5 files  - only 1 file required a slight bigger amount. 

It's important to remember, that were applied the same sharpening during the conversion. The purpose of the  fine tuning-sharpen was to find the best setting of subjective visual sharpness for each file,  specifically in the area of the "hair" of the playing card with the "King" (center of the frame). That is to say, the "hair" of the "king" was the parameter for the "standard" sharpness.

No one other edit was made.

The six files from f/2.8 to f/16 were scrambled, tiled vertically and Print Screens of six  selected 100% crop areas was captured and saved as 95 JPGs quality.

According the Lens Reviewer Website Photozone.de the MTF numbers for this lens, tested in a K10D (same sensor of the K200D) is:

These numbers generate a lot of discussions about the image quality in the web forums, (I specially read most of the messages of the  DPReview's Pentax SLR Talk, of the  Photo.net Pentax Forum and of the Pentaxforums)

After all the discussions the question remain:

- Whats the real importance of the MTF numbers by a photographer point of view?

My brief conclusion: f/22 is pretty bad for this lens and the MTF number confirm that - I threw away it for the test.

Ok, and about the other numbers? For that particular scene, it might be surprising.

Old page of the Round 1.           Round 2 here.