speed booster corner sharpness

[scho]

Just a followup on the SB sharpness issue I was having with my Contax C/Y lens on the NEX 6. I tried to find a decent adapter to test the lens on my D800e, but no luck. One would only macro focus and other had a cheap glass element. I was able to test the Contax lens on my Leica M9 and the Contax 28 Distagon that gave me blurry corners with the SB had no problems on the full frame M9. Couple of full frame images linked below. Guess I will be sending the SB back to HK for adjustment or replacement.

Leica M9 with Contax 28 Distagon

Leica M9 with Contax 28 Distagon

 

[Vivek]

Thanks for sharing, Carl but this (as you very well know) is not a fair comparison.

The M sensor can take anything because of the special microlens array it has.

 

[scho]

Thanks for sharing, Carl but this (as you very well know) is not a fair comparison.

The M sensor can take anything because of the special microlens array it has.

Vivek,

True, but I still think that my copy of the SB is not performing correctly. I am also now finding blurry corners and edges on a Contax 50 as well. I am returning it with a request for replacement.

 

[Vivek]

That should not happen, Carl. Hope you will get a better replacement.

 

[Taylor Sherman]

It's clear in the SB whitepaper that it increases center sharpness and decreases edge/corner sharpness. However I don't think that means things should be "blurry", just never as sharp as the center, no matter what lens/aperture you're using.

 

[SKueh]

It's clear in the SB whitepaper that it increases center sharpness and decreases edge/corner sharpness. However I don't think that means things should be "blurry", just never as sharp as the center, no matter what lens/aperture you're using.

Very true. If we look at the MTF charts (figures 6, 7, and 8) present at the white paper, the relative contrast is quite low at the carner compared to the center, m4/3 is slightly better than the NEX. Of cause these charts are measured at max. aperture of the three Nikkor lenses. We wish they will published the perform of the SB at other aperture settings, but again, this is what they want to advertize about the greatness of the SB.

The did come to a conclusion on the corner performance of the NEX SB. On page 7, the last paragraph states: Quoted " 4) the Sony NEX version in the extreme corner of the NEX format has similar MTF to the original lens in its original image corners." Unquoted. In other word, if your lens has a bad corner performance on full frame, using a NEX SB will have the same result at the corner. Please note that the image heigh of a NEX corner is only 14mm.

 

[Lonnie Utah]

TINSTAAFL.