Archived posting to the Leica Users Group, 2004/10/20
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 7:14 AM +0800 10/21/04, Howard Cummer wrote: >Hi Luggers, >First a special thanks to Henning for his comments on his RD1 test >drive. As reported here previously the Epson RAW plug in has >programming to reduce vignetting on all lenses from 12mm all the way >up to 90mm. You just select the focal length and click on it and >edge vignetting is gone. Please see > >http://www.photo.net/photodb/folder.tcl?folder_id=434937 > >for an example with my 15mm heliar. Howard is right; with the Epson RAW plug-in you can compensate for vignetting, but at the expense of noise and dynamic range. What is actually happening is that the corners are being compensated after being severely underexposed. Anybody who has used a digital camera knows that RAW files have a fairly good dynamic range, but if they are underexposed by more than 2 stops the image is never as good as it could be. With the lenses tested, the corners are sometimes more than 3 stops underexposed. The corners then show lots of noise and appear muddy. I didn't use this RAW compensating option much as I wanted to see what the camera/lens combinations could do on their own. Photoshop Camera RAW has its own anti-vignetting function built in for moderate compensation, up to about 2 stops. Also, this compensation does not work with jpg files with the Epson software, which is reasonable as the compensation necessary is too severe to be handled by any method for these types of files with more limited dynamic range. In RAW mode the camera is often not able to keep up with shooting, even though the fastest you can shoot is severely limited by the wind lever. >I have tried Adrian Bradshaw's 90 APO and 50 Noctilux while visiting >in Beijing and the APO back focusses by a couple of cms in the close >range as does the Nocti, but at intermediate distances, the APO goes >progressively out of focus in relation to the rangefinder focus >point until you hit infinity and then the image is sharp. But as >reported at infinity (where my rangefinder is out) the lens cuts a >sharp image on the CCD. We didn't test the Noctilux at infinity but >by 3 meters its focus point was way off the rangefinder indication. >I do hope my replacement camera is better. If not I think, sadly - >because I like other aspects of the camera, Epson has a serious >problem on its hands about the design and manufacture of the 1:1 >rangefinder. > > >Cheers > > >Howard (in cool Beijing this morning) >_______________________________________________ >Leica Users Group. >See http://leica-users.org/mailman/listinfo/lug for more information -- * Henning J. Wulff /|\ Wulff Photography & Design /###\ mailto:henningw@archiphoto.com |[ ]| http://www.archiphoto.com