For older lenses such as a straightforward angulon, yes it's lower, but for Super Angulon and newer it's much close to 35mm and MF lenses than it used to be.
Some of the work I'll be doing is archival and therefore I have no choice, but for my personal work I'll certainly take the time to evaluate the the most cost effective resolution. When I was doing this some years ago I found that resolution had a great affect on rendering of tonal transition. Wide dynamic range and tonal transition are LFs great strength in addition to raw resolution, so I don't mind trading file size and time to preserve that. On Wed, Jan 6, 2016 at 1:14 PM Michael Below <be...@judiz.de> wrote: > 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 >>> >> > ------------------------------------------------------------------------------ > _______________________________________________ > Darktable-users mailing list > Darktable-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/darktable-users >
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