I think the numbers are right. But you might consider if there is an image quality advantage through scanning at 8000dpi - AFAIK large format optics have a lower resolution. Are you using a special setup (aerial photography of something like that)?
Am 6. Januar 2016 13:49:38 MEZ, schrieb Laurence Rochfort <laurence.rochf...@gmail.com>: >Thanks all for the response. I'm getting some pretty huge numbers for a >4x5 >at 8000DPI using your formulas above. > >(4 * 8000) * (5 * 8000) = 1280000000 -> 1.2 Gigapixels? > >3 * 4 * 1280 * 4 = 61440 -> 61 GB RAM? > >Will it really need that much or will the tlinig you talk about reduce >that? > >Fortunately, I have access to 144GB of RAM so it doesn't really matter, >but >just curious. > > >Can I conclude that I'm unlikely to be CPU bound with a single 6 >core/12 >thread 2.4GHz Xeon? > >Thanks for all the advice! > >On Wed, Jan 6, 2016 at 12:20 PM Roman Lebedev <lebedev...@gmail.com> >wrote: > >> On Wed, Jan 6, 2016 at 3:08 PM, Michael Below <be...@judiz.de> wrote: >> > To calculate MPix from DPI use (length_in_inch*nr_dpi) * >(width_in_inch * >> > nr_dpi). >> > >> > So for 4” * 5” film at 3000 dpi you get (4 * 3000) * (5 * 3000) = >180 >> MPix >> (yes, sounds about right) >> >> > According to Roman’s rule of thumb, one image will need > 8 GB RAM. >> I should probably note that those 8Gb must not be the the total >amount of >> RAM in the system, but the amount of free ram, fully available for >> darktable. >> >> And do note that it is the lower estimate, in many cases darktable >will >> need >> *much* more. Though in many of those cases tiling will kick in and >help. >> >> > IMHO you don’t need to worry about CPU parallelism in that case, >you >> should >> > choose the slower CPU if you can avoid swapping that way. >> > >> > >> > >> > Cheers >> > >> > Michael >> Roman. >> >> > >> > >> > >> > Von: Laurence Rochfort [mailto:laurence.rochf...@gmail.com] >> > Gesendet: Mittwoch, 6. Januar 2016 12:47 >> > An: Roman Lebedev >> > Cc: darktable-users@lists.sourceforge.net >> > Betreff: Re: [Darktable-users] Benefit of more than 4 cores vs >"speed" >> > >> > >> > >> > I have no idea how many MPix. I've only ever used film, so I don't >think >> of >> > it in those terms. How can I calculate MPix from DPI? >> > >> > >> > >> > Any thoughts on CPU parallelism vs speed? >> > >> > >> > >> > Cheers, >> > >> > Laurence. >> > >> > >> > >> > On Wed, Jan 6, 2016 at 11:32 AM Roman Lebedev ><lebedev...@gmail.com> >> wrote: >> > >> > On Wed, Jan 6, 2016 at 2:19 PM, Laurence Rochfort >> > <laurence.rochf...@gmail.com> wrote: >> >> Hello all, >> > Hi. >> > >> >> >> >> I'm building a new PC with scrounged components. I have the option >of >> >> either >> >> a dual Xeon E5645 with up to 96GB RAM, or an i5-3470 with 8GB RAM. >> >> >> >> The storage is a PCIe x4 SSD. >> >> >> >> You can see a comparison here: >> >> http://cpuboss.com/cpus/Intel-Xeon-E5645-vs-Intel-Core-i5-3470 >> >> >> >> I'll mostly be dealing with medium format and 4x5 drum scans, so >TIFF >> >> files >> >> that are from 200MB to 1GB. Mostly I'll be doing crop, rotation, >colour >> >> and >> >> zone adjustment. >> > Yes, but how much MPix? >> > 50 MPix? 100 MPix? >> > >> > (very rough rule of thumb, lower estimate: for x pixel image, you >want >> > at least 3 * 4 * x * 4 bytes memory; that is, for 20MPix = 960 MB) >> > >> > If more than ~50MPix, then you *absolutely* need as much RAM as you >can >> get. >> > I doubt that GPU would be of any help at those sizes though... >> > >> >> >> >> Could people advise me on which would perform best? >> >> >> >> Many thanks, >> >> Laurence. >> > Roman. >> > >> >> >> >> >> >> >> >------------------------------------------------------------------------------ >> >> >> >> _______________________________________________ >> >> Darktable-users mailing list >> >> Darktable-users@lists.sourceforge.net >> >> https://lists.sourceforge.net/lists/listinfo/darktable-users >> >> >> > >> > >> > >> >------------------------------------------------------------------------------ >> > >> > _______________________________________________ >> > Darktable-users mailing list >> > Darktable-users@lists.sourceforge.net >> > https://lists.sourceforge.net/lists/listinfo/darktable-users >> > >> >> >> >------------------------------------------------------------------------------ >> _______________________________________________ >> Darktable-users mailing list >> Darktable-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/darktable-users >>
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