bing_shen1

I don't know it is just me or else. When original 5D was first announced, I felt the "wow" effect. I don't have the same feeling as I saw the 5DII samples. It surely has less noise than the orginal. But the noise is less nature looking. Do you think that we should start to judge the quaility of noise as we judge the quality of brokeh?

Perhaps there is invisible ceiling of image quality, as some has indicated that we are starting to count photons and electrons now.

For any lens that a DSLR uses, f11 to f8 was regarded as sweet spot for the max resolution in practice. This fact implies that the aberrrations are important and degrade resolution at lower f-number, AND diffraction-limited resolution is usually (if not always) not archievable for low f-numbers. You can argue that it is not the case for P&S - a smaller light circle maybe. But the quantum noise would kill the resolution way earlier before approaching sensor/lens resolution.

A non-aberration lens at F11 is pretty much what you can get for the max resolution that a lens can get in practical terms. My statement is based on the data presented in the article, nothing more, nothing less.

Here is the quote from the article:

"It represents a realistic, not too demanding case. Consider a 35mm system with a lens at f/11. At best, the maximum resolution you will get is equivalent to 16 MP, even if your camera has 22 or 25 MP. In the case of an APS-C based system the limit goes to 7 MP, and 4 MP considering a Four Thirds format. Stopping down to f/22 the limit of the effective resolution of the 35mm based system goes to 4 MP!"

Keep in mind that he is talking about a perfect lens without any aberrations.

http://luminous-landscape.com/tutorials/resolution.shtml

Interesting article in case you didn't see it.

It looks like the current DSLRs' sensors are out-resolving lenses to their diffraction

limits. The max pixel counts needed for a full frame is 16M and 7M for APS-C.

Any thoughts?

http://digibbs.tech.163.com/bbs/nikon/251.html

Above is a post in Chinese. It was saying that Nikon 18-200 at 200mm has much

larger field of view than 70-200 at 200mm. The equivalent focal length at 200mm

end for 18/200 is about 110mm.

Even I don't own Nikon gears. It was my first time to hear this. I was quite

shocked. Could owner of 18-200 and 70-200 let me know that this is total BS?

Best!

Just got mine couple of days ago. It does have the phenomeno you mentioned. It getting worse when I face the lens straight down. But if I face it straight up, zooming from 24 to 30 becomes a little too easy - I am afraid that it would creep by itself. I am suspecting that gravity has something to do with it.

I am going to have it exchanged. It focuses beatifully though.