影相邊沿的銳利度不比AF-S 17-55mm f/2.8 G差

Nikkor AF-S 17-55mm f/2.8 G IF-ED DX Review

http://www.photozone.de/8Reviews/lenses/nikkor_1755_28/index.htm

Re: not so great for my taste

the lens seems crisp to me. it's the canon imaging that's a little mushy (stronger AA filter and noise reduction)

sv
http://forums.dpreview.com/forums/read.asp?forum=1030&message=18526026

和AFS17-55mm的差別是在f2.8時中間部位的畫質Tamron17-50mm是從1850起跳,
AFS17-55mm是從1950起跳,S18-50mm是從1599.5起跳.

還有tokina的16-50也頗令人期待

http://www.photozone.de/8Reviews/lenses/tamron_1750_28/index.htm

.........On the downside the very high field curvature at wide angle settings can be a problem in some situations (flat or very deep scenes at large aperture settings).

上面這段話是什麼意思呀？謝謝

http://www.photozone.de/8Reviews/lenses/tamron_1750_28/index.htm

Verdict

.........On the downside the very high field curvature at wide angle settings can be a problem in some situations (flat or very deep scenes at large aperture settings).

上面這段話是什麼意思呀？謝謝

Photoshop PS CS2
Posted by    Steve Bingham  

Photoshop PS CS2 has: Filter - Distort - Lens correction. Then choose Lens Distortion from among the dozen parameters. This will correct just about any amount of pincushion or barrel distortion. it is an extremely powerful tool. It also corrects vignetting, chromatic aberrations, and transforms perspective.

--
Steve Bingham
http://forums.dpreview.com/forums/read.asp?forum=1030&message=17631189

用photoshop cs2 的 Filter - Distort - Lens correction 內就有Chromatic Aberation可Fix Red/Cyan fringe 或 fix Blue/Yellow fringe.

Re: How to Correct for Chromatic Aberration ( CA) with 12-24mm Lens

Photoshop CS2 has a Distortion filter called Lens Correction. It will allow you to adjust sliders to correct Red/Cyan and Blue/Yellow fringing, as well as barrel distortion, pincushion, keystone, and vignetting. I tried the CA adjustment in NC, but found the CS2 filter to do a better job.

CA can be a problem since it takes time and effort to fix, and cannot always be completely eliminated. However, don't make your decision on CA alone. I think contrast is very important in a lens. It is what gives an image that "sparkle" that is sometimes confused with sharpness.

Robin
http://forums.dpreview.com/forums/read.asp?forum=1030&message=14261572

Tamron 17-50 f/2.8 in stock at B&H  


Tamron Zoom Super Wide Angle SP AF 17-50mm f/2.8 XR Di II LD Aspherical [IF] Autofocus Lens for Nikon Digital Cameras

Mfr# AF016N700 • B&H# TA175028NAF  



Our Price: $ 449.00

http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=423716&is=REG&addedTroughType=search

http://forums.dpreview.com/forums/read.asp?forum=1030&message=18719260

Tamron 17-50mm f/2.8 test images

Stumbled into this lens at the local camera emporium. Couldn't resist, so here is another Brick (in the) Wall seen 32 different ways (4 focal lengths of 17, 24, 35 and 50mm by 8 different f/stops from f/2.8 to f/32) followed by 32 paired images taken this past afternoon from the parking lot of the camera store and killing time while my wife was shopping. Nice symmetry, huh?

See them here ...

http://www.pbase.com/jtsmall/tamron_1750



My iniitial enthusiasm is tempered with lack of sleep so here is a brief list of tentative conclusions:

1. build quality is quite good ... on par with Nikon's plasticy lenses and

2. finally a digital lens that feels like it should ... smaller (than the Nikkor 17-55)!

3. color and contrast are very good on jpgs right out of the camera w/o post processing

4. marked vignetting regardless of focal length is noted at f/2.8, better at f/4, nearly disappering by f/5.6 for all practical purposes.

I'm going to sleep on it and shoot many more images but as of now I'm thinking this one is a keeper assuming I can get past the vignetting.

http://forums.dpreview.com/forums/read.asp?forum=1030&message=18756164