REPOST: Re: Plustek OptikFilm 7200
in [Scanners]
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From: Wilfred on 17 Mar 2005 11:24 rafe bustin wrote: > Has anyone heard of or used this little beastie? > > It's a 35 mm film scanner advertised as 7200 dpi > optical. > > There are scan samples on the web, here: > > <http://www.plustek.com/film/tornado.htm> > > Most amazing is the price: under $200. > ($189 at TigerDirect.) http://tinyurl.com/5pbzw -- Wilfred van der Vegte. Replace 'invalid' with my first name to reply by e-mail
From: Bart van der Wolf on 17 Mar 2005 14:31 "rafe bustin" <rafeb(a)speakeasy.net> wrote in message news:reposted.0.qceg311vopho47275mnkbvndv52p68j4rn(a)4ax.com... > On Wed, 16 Mar 2005 09:32:49 +0100, Wilfred > <invalid(a)vandervegte.com> > wrote: > >>rafe bustin wrote: >>> Has anyone heard of or used this little beastie? >>> >>> It's a 35 mm film scanner advertised as 7200 dpi >>> optical. >>> >>> There are scan samples on the web, here: >>> >>> <http://www.plustek.com/film/tornado.htm> >>> >>> Most amazing is the price: under $200. >>> ($189 at TigerDirect.) >> >>http://tinyurl.com/5pbzw > > > OK, so the thing measures out at 2900 dpi. > No surprise. That just happens to be the > same number that Phil Lippincott assigned > to the LS-8000 on his "scannerforum" years > ago. The 'test' I have seen from Phil Lippincott was seriously flawed, in favor of his own brand. His judgements since that, have for me devaluated to being misleading and of little value :-( It is quite simple to test the true performance by scanning a slanted edge test target, or an image of such a target. > A real, measured 2900 dpi for $200 is > a major achievement. Yes, although I'm allergic to lies about specifications. > I wonder how the Minolta 5400 would test out > with these same USAF 1951 test targets. > Has anyone tried that? Is there publicly > posted info on how to interpret these targets? The USAF 1951 targets are not suited for testing discrete sampling systems like scanners or digicams. Slight (mis-)alignment with the sensor array can easily double or half the results. The ISO proposed a method based on a slanted edge, which allows to derive the MTF curve of the system. http://www.xs4all.nl/~bvdwolf/main/foto/Imatest/SFR_DSE5400_GD.png shows the response curve of the (my) scanner alone. The combined response of camera lens+film+scanner compared with (too) many other capture devices is given in http://www.xs4all.nl/~bvdwolf/main/foto/Imatest/SFR_Graphs.png , although the scan results do assume the use of decent lenses, tripod, mirror lock-up and, (in this case) Provia film. Different film or technique obviously gives somewhat different results for all capture devices mentioned. The slanted edge target (SET) and how to make one has been discussed in this group and has been mentioned in combination with the program one can use to evaluate it, Imatest (www.imatest.com). Bart
From: rafe bustin on 17 Mar 2005 23:51 On Thu, 17 Mar 2005 20:40:12 +0000, Kennedy McEwen <rkm(a)nospam.demon.co.uk> wrote: >What I would like to see is a proper measurement of the resolution of >this beast - in fact, a decent assessment from someone who is fairly >capable and independent. > >For a scanner that promises so much, it has a remarkably quiet user base >- whether complaining that it fails to deliver or shouting the praises >that it does at such a low price. ;-) > >Has anyone actually seen one of these units? I haven't seen one. I only learned of its existence a few days ago. There are a couple of scan samples here: <http://www.plustek.com/film/tornado.htm> and I have to admit these are surprsingly good, in terms of the detail I can see. I can't believe the 7200 dpi claim, at least not from what little I've seen. But I believe it's an amazing little beastie at $189. Considering I'd spent over $2K (combined) for my first two film scanners, and only got 2700 dpi from the better one... I'm a bit peeved, in fact. Grab tornado_1.psd and tornado_2.psd from the URL above. Tell me if you think your Nikon might have made a sharper scan. rafe b. http://www.terrapinphoto.com
From: HvdV on 7 Apr 2005 03:41 Hi Bart, > > > > http://www.xs4all.nl/~bvdwolf/main/foto/Imatest/SFR_DSE5400_GD.png shows > the response curve of the (my) scanner alone. The combined response of I see your response goes beyond the Nyquist frequency of the digitized image; how do you measure that? I can image you're using the diagonals in the spectrum, or do you combine results from different scans at different positions? Also I noted that your 50% MTF is at 60 cy/mm whereas in the results you published on http://www.jamesphotography.ca/bakeoff2004/scanner_test_results.html a 50% MTF of 23.8 is given. Can you explain? What was the test object in your 'scanner alone'? razor edge? > camera lens+film+scanner compared with (too) many other capture devices > is given in > http://www.xs4all.nl/~bvdwolf/main/foto/Imatest/SFR_Graphs.png , That plot represents quite some work! -- hans
From: Bart van der Wolf on 8 Apr 2005 20:57
"HvdV" <nohanz(a)svi.nl> wrote in message news:7c428$4254e41d$3e3aaa83$9858(a)news.versatel.net... > Hi Bart, >> http://www.xs4all.nl/~bvdwolf/main/foto/Imatest/SFR_DSE5400_GD.png >> shows the response curve of the (my) scanner alone. The combined >> response of > I see your response goes beyond the Nyquist frequency of the > digitized image; how do you measure that? By oversampling the sensor element's response. A slanted edge target of adequate size allows to take (a statistically useful multiple of) about 10 samples at different overlap positions per pixel. When you realize that the Nyquist frequency limits reliable resolution to (pixel dimension)/2 cycles per image dimension, it (hopefully) explains why oversampling allows to measure beyond Nyquist (which helps to value/quantify the aliasing tendency). > I can image you're using the diagonals in the spectrum, or do you > combine results from different scans at different positions? In fact, a slanted edge target allows to produce an accurate (oversampled) Line Spread Function. The MTF is just the Fourier Power Spectrum of the first derivative of that LSF. So, basically all that is needed is an accurate Edge Spread Function for the image dimension of interest, and some math. > Also I noted that your 50% MTF is at 60 cy/mm whereas in the results > you published on > http://www.jamesphotography.ca/bakeoff2004/scanner_test_results.html > a 50% MTF of 23.8 is given. Can you explain? That was due to: 1. A less than perfect target capture/slide, like caused by less than perfect focus for the lens used to capture the image (or the lens I used just performs better than Jim Hutchinson's). 2. In the Bakeoff 2004 you get a combined lens+film+scanner imaging chain result, and in my "scanner alone" the non-scanner image is as close to perfect (neither camera lens aberration nor focus error or camera shake) as can be realistically expected. > What was the test object in your 'scanner alone'? razor edge? Yes, a razor like edge mounted at a slight slant in a slide frame. So camera lens+film MTF was eliminated, and only the edge quality was limiting the scanners' MTF. >> camera lens+film+scanner compared with (too) many other capture >> devices is given in >> http://www.xs4all.nl/~bvdwolf/main/foto/Imatest/SFR_Graphs.png , > That plot represents quite some work! It's not too bad, although using a program like "Imatest", and MS Excel for the summary graphs, really helps ;-). I used to use an ISO provided example program for the SFR evaluations, but Imatest (www.imatest.com) is much more convenient, and it provides several other useful image quality evaluations. Bart |