Hello Mike
I think I was the first to try out LS4000 in mars 2001 and reported some
bad scans with curved film, and depth of field problem on my Ls4000 scanner.
I wrote that the scanner was sharp in the middle and unsharp out against the
sides and corner . Please give me a fully conclusion of your figures.
Best regard Mikael Risedal
>From: Mike Duncan <[EMAIL PROTECTED]>
>Reply-To: [EMAIL PROTECTED]
>To: [EMAIL PROTECTED]
>Subject: filmscanners: Nikon IV Depth of Field Test
>Date: Wed, 29 Aug 2001 14:18:08 -0400
>
>Using the film strip adapter SA-21 with the Nikon IV and NS3.1, I obtained
>the following focus Nos. on a relatively flat Max400 negative (Landscape):
>
>End Frame:
> L Mid Right
>Top 221 228 219
>Mid Top 217 225 217
>Mid 213 217 212
>Low 212 221 214
>Bottom 214 223 220
>
>Center Frame:
> L Mid Right
>Top 219 226 224
>Mid 206 216 218
>Bottom 211 222 223
>
>Right faces the scanner front.
>
>Next the focus was changed at the center of the negative and the SFR was
>measured at 50% response and 10% response. Note that SFR is the spectrum
>of a slanted edge and gives a more conservative number than MTF using
>sinewaves. For comparison the 50% response is 500 cycles/in using MTF and
>290 cycles/in using SFR. Also note these numbers include the response of
>Kodak Max400 and my Canon FD 50mm F3.5 macro lens stopped down to F9.5 and
>tripod mounted. The 50% SFR indicates sharpness, while the 10% SFR
>indicate resolution.
>
>Nikon Focus 50% SFR 10% SFR
>214 283.6 690
>226 238.5 580
>238 158.6 450
>
>For comparison, my Minolta Dual (SCSI, fixed focus) has 50% SFR in the
>center of the negative at 170 cycles/in and 10% SFR at 570 cycles/in. So
>the depth of field to equal the Minolta best SFR is just under +/- 24.
>Grain is soft at this limit.
>
>Mike Duncan
>
>
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