1. I've been looking to get a second 24 inch LCD monitor to connect up to my main Mac system as a secondary screen in a dual monitor setup. While my HP LP2475W will remain the my primary screen, but I wanted to be able to get reference material (manuals, documents that I responding to by e-mail, etc) up on a separate screen. It would also allow using Lightroom in dual screen mode, although I've never really felt the need.

    It so happens that I found a very good deal on a Samsung BX2450 from an on-line store, with free next-day delivery. The Samsung BX2450 is a new-generation "green" display with an LED backlight. A quick internet search revealed that the BX2450 got high marks from almost all owners. The only negatives I found was fiddly touch sensitive buttons, and that there is a known incompatibility between the BX25450 and the ATI (now AMD) graphics driver on Windows if you connect the BX2450 up with a HDMI to HDMI cable (the BX2450 doesn't have any DVI inputs, just HDMI). Apparent if you use a DVI to HDMI cable, there isn't a problem. But, for my purposes that was fine - mostly I work on a Mac anyway, and if I do need to connect to one of my Windows boxes, using a DVI cable is fine. So I went ahead and bought the BX2450.

    The rest of this post is my experiences in using and calibrating the BX2475. It's written very much from an imaging and photographic perspective. Those interested in gaming performance - response times and the like - should look elsewhere.

    First impressions and construction


    First impressions were positive - the BX2475 looks good, and has a stand that, while it looks a bit fragile, actually seems to support the display as well as as my (much) more expensive HP unit. The BX2450 also appears to to live up to its green credentials - the power supply is external, and about the size of an iPhone. In fact, the whole display is light in weight - it was easy to carry around, and get in position on the desk.

    Initial power up was fine; the BX2450 immediately showed as a second screen under OS X, with the correct resolution, etc.

    The bad news: you can't adjust the height of the display. At all. There however is a tilt function.

    The second piece of bad news is that all the software is Windows only. Not a single piece of Mac software - not even a display profile.

    The "just be aware of" news - the BX2450 appears to essentially be an HDMI TV, rather than a computer monitor, even if you set it to "PC" mode. Now that doesn't make a lot of difference but be aware that there are some funnies: you will see the resolution listed as 1080p, rather than 1920x1080, and the display seems to identify itself as a HDMI TV rather than anything else. So you will see an "Overscan" checkbox in the Mac Display preferences which you won't for a normal monitor. Don't try to switch that off, btw - the display will no longer show a picture(!) This identification issue probably also explains the Windows HDMI issues that others have found.


    Calibrating the display

    Although the default setting on the display were ok, certainly better than some other displays I've seen, the first thing I looked at was how to calibrate the display. Now I didn't buy the BX2450 to display images; that's what the wide gamut LP2475 is there for. But as a I spend a lot of time looking at images, and specifically looking at the color rendition of images, bad color bothers me. I was also interested in how accurate a display I could get from a low-cost LCD display with LED backlighting. So I got out my trusty X-Rite Eye-One calibration device, and set to work. Here's the quick summary of my experiences:

    • First thing that I had forgotten was the X-Rite's Eye-One Match 3 software doesn't actually support calibrating to two monitors. Now you'll see a lot a stuff written on the internet that this is because "you can't have two calibrated displays on one display board because there's only one LUT in hardware", etc. Nonsense. Any modern OS will happily let you run two different calibrated displays from one video board. This is just a limitation of the Match 3 software. Solution: temporarily disconnect the primary monitor, and use the secondary as the primary while you calibrate. OS X will automatically keep track of which profile applies to which monitor, btw.
    • Second thing that I found out was that the touch sensitive buttons on the BX2450 really are as fiddly as claimed.
    • Third thing I found is that the BX2450 (or maybe the combination of the BX2450 and the Eye-One puck) doesn't like to be calibrated to a D55 (5500K) white point. While you can calibrate to that, the resulting display is truly horrible; the brighter parts of the image are ok, but the darker parts get a massive red color cast - totally unusable. So I ended up calibrating to a D65 white point. 
    • Fourth thing I found out was that setting any of the Red, Green or Blue controls to more than 50 is not a good idea; when you generate a profile you get nasty discontinuities in the gamma curves, indicating that the display becomes non-linear. The process I followed was firstly to set the BX2450 to what Samsung call a "Cool" color tone, which was close to D65. Then I manually adjusted to D65 as measured by the Eye-One using the RGB sliders, taking care that no color control went above 50. For reference, the settings I ended up with were Red:20 Green:20 Blue:50 
    • As with most displays, the default brightness was way to high; I set it to 34 on the slider, which corresponds to a 110 cd/m² setting, my preferred LCD value.
    The end result of this was pretty good. It's almost impossible to give any idea of color rendition on the web, but visually comparing the BX2450 to my LP2475, the BX2450 stood up pretty well for images with relatively small color gamuts. Specifically, for sRGB images, which are what almost all JPEG files use for a color space, the calibrated BX2450 looked nearly as good as the LP2475. Interestingly, to my eyes, the difference was more a slight lack of contrast in the shadows, than any major difference in color rendition.

    The BX2450's gamut

    The problem for the BX2450 of course, and the reason why the LP2475 costs several times more, is gamut - how broad a spectrum of colors can be displayed. A quick look at some raw images rather than JPEGs from my Nikon and Sony cameras showed a very different story; the LP2475 was able to display better reds and greens.

    Here are the gamuts of the LP2475, the Samsung BX2475, and the sRGB gamut for reference. 


    Bottom line - the BX2450 doesn't come anywhere near the gamut of the LP2475, especially as regards greens, but also in reds. Compared to the sRGB gamut, the BX2450 is actually pretty close, but is just a bit less capable on both the greens and reds. Which is consistent with what I found looking at actual images - sRGB images are ok, raw images that have wide color gamuts, not so ok.

    Conclusion

    The bottom line is the following: if your imaging needs are limited to looking at JPEG images, or web surfing, the BX2450 will serve you fine, and if you have a hardware calibration device, you can get quite acceptable color if you stick to a D65 white point. Also, the BX2450 will be a good choice for those that create websites, or artwork that will primarily be seen on the web - in that case the similarity of the BX2450's gamut to sRGB is actually an advantage.

    In the role that I'm using the BX2450, and given what I paid for it, I've very happy - it does exactly what I bought it for, and does better than I had anticipated in terms of color accuracy.

    However, if you're a serious photographer that deals with raw images, the BX2450 is not for you, at least as a primary monitor. Firstly, the color gamut isn't wide enough. But the real show stopper is the issues I had trying to calibrate the BX2450 to a non-D65 white point. That may not be the fault of the BX2450 - it may be that my Eye-One calibration device isn't up to dealing with LED backlights. But for whatever reason, if you're serious out photography, you need a monitor that will calibrate reliably with current calibration devices.
    4

    View comments

  2. David Kennard has posted an interesting article and mini-tutorial on using CornerFix with the Fuji IS-Pro camera. The IS-Pro is a specialist camera that is sensitive to both infrared and ultraviolet light - in fact, rather than the usual four channel Bayer array sensor, the IS-Pro's sensor has eight channels in a 2x4 arrangement, requiring that DNG files be in linear raw format before CornerFix can correct them. What David is doing is using a combination of filters and CornerFix to make the Fuji IS-Pro usable for normal photography as well. David goes through the process step by step, discussing settings in detail, and provides some really good examples. The article is here.
    0

    Add a comment

  3. Google recently converted my Chromasoft website (as distinct from this blog) from the old Google Pages format to Google Sites, as they are doing for all Google Pages sites. The website is where all the reference material for the various things I blogger about here are. So, for example, there is:

    • Calibration test image (synthetically created "perfect" versions of the Gretag Macbeth 24-patch test chart);
    • A spreadsheet with color space information;
    • More information about dcpTool;
    • Some papers I wrote on color spaces.

    The automatic conversion was reasonable, but messed up formatting a few places. So I've taken the opportunity to refresh the site with a new, cleaner format, and also to make use of some of Google Sites features that weren't available in Google Pages. E.g., the navigation widget, which replaces the previous "hard coded" navigation links.

    The site is here: http://sites.google.com/site/chromasoft/
    0

    Add a comment

  4. As mentioned in this post, I just did a fresh install of Ubuntu 10.04 "Maverick Meerkat". I mentioned two fairly major problems I had with the Ubuntu installer in that post. I also had another problem, but this one isn't Ubuntu related.
    I had chosen to install from a USB key, but what I had forgotten is that the motherboard in the PC is a Gigabyte motherboard, and it doesn't like booting from USB. This is a common problem with Gigabyte motherboards - just Google for Gigabyte and "boot from USB", and you'll see many variations of "can't boot from USB", "won't boot from USB", "unable to boot from USB", etc, etc. What happens is that the motherboard just completely ignores the USB key; effectively, it's like it isn't there.

    Unfortunately, there isn't a solution to be found in any of those posts. Or at least I ran out of patience before I found one, although it's clear that the problem is to some extent USB drive dependent - Gigabyte motherboards seem to like some drives, others not. So rather than continue to go through endless posts that don't offer solutions, I started playing around. What I found was:
    • With any other drive in the machine, even if the boot from the drive was disabled in BIOS, the Gigabyte motherboard would still ignore the USB key and boot from the other drive;
    • With all other drives physically unplugged, boot would fail with a "Insert boot disk and press enter" message. The light on the USB key didn't even flicker at any point in the process, indicating that the USB key wasn't even being seen;
    • However, that was where things got interesting. What I found was that if I then unplugged the USB key, and plugged it in again, then pressed enter, the USB key was recognized, and the machine booted.
    Now this is a step in the right direction. If you don't have any other bootable drives in the machine, then you can just follow that procedure.  Problem is what if you do have other drives in the machine? In my case, the intention was to install Ubuntu on a dual booted drive, so having a bootable drive in the machine was required, and the there wasn't any way to get to the "Insert boot disk" prompt - the machine just booted from the drive I wanted to install Ubuntu to.

    The Solution

    Thinking about this, the USB key only being recognized if it was unplugged and then plugged in again suggests that somehow, if the USB key is inserted at the time the machine is powered up, the motherboard gets into a mode where it doesn't recognize the key and it gets ignored until a operating system driver starts up. But later in the boot cycle, the motherboard does seem to be able to recognize it. So what I did was simple:
    1. I started the machine with the USB key unplugged;
    2. Once the machine had got through the first parts of its boot sequence, I plugged the key in, then hit the F12 key to bring up the boot menu. And on the third try, there the USB key was, on the list of hard drives. And it booted fine!
    Two thing to note here - what I found worked, for me anyway, was to plug the USB key in just after the BIOS displayed the list of PCI devices, and just as it gave its "Verifying DMI pool" message. Secondly, note that the USB key appears on the list of hard drives.

    Now I must admit, plugging the USB key in during the boot sequence is neither elegant or reliable - you'll probably have to try it a few times - but it worked for me.
    85

    View comments

  5. So I use Linux occasionally for software development stuff e.g., pcdtojpeg will run on Linux. I'd skipped Ubuntu 10.04 because (a) the release got a pretty bad name for reliability and (b) I was busy professionally, and with pcdMagic and CornerFix, so anything on Linux wasn't featuring anyway. But having gotten both pcdMagic for Windows and V1.4.0.0 of CornerFix out the door, I decided that an upgrade was called for. I decided on a fresh install, as Ubuntu's upgrade process can't skip releases, and I wanted to change the drive format to EXT4 anyway. Well, it wasn't an easy process - I ran into two fairly major bugs in Ubuntu's install mechanism:

    Ubuntu 10.10 "Maverick Meerkat" install bug 1

    Problem one was a "SYSLINUX – Unknown keyword in configuration file" error.What I'd decided to do was to boot from USB. So, as the Ubuntu download page recommends btw, what I did was to use the the Ubuntu "Create bootable USB Key" feature. Only I used it under my existing Ubuntu installation, which was 9.10. There's an Ubuntu bug description here, but in summary the problem is that the version of Syslinux (which is what actually boots the USB key) that old versions of Ubuntu place on the USB key isn't compatible with the configuration file that comes with the 10.10 ISO image. So instant crash. Irritatingly enough, looking at Ubuntu's own bug tracker, this was identified as a bug back in July, but nobody bothered to fix it, although I'd rate it as a showstopper. So far as I can tell, there are two solutions:
    • Create your Ubuntu 10.10 bootable USB key using Ubuntu 10.10. That's a bit of a catch-22 situation, but it may be an option for people with access to a friend's Ubuntu 10.10 installation or whatever.
    • Edit the /syslinux/syslinux.cfg on the USB key to remove the "ui" keyword, which is what causes the problem. This is the solution that I used.
    Ubuntu 10.10 "Maverick Meerkat" install bug 2

    Problem two was a crash in the very early part of the install.The symptoms of this are:
    1. If you're in the graphical install mode (the full screen purple screen), the install just hangs. The little dots keep moving, but nothing happens.
    2. If you hit esc, you get a "getpwuid_r(): failed due to unknown user id (0)" message, as documented in this Ubuntu bug report.Again irritatingly, this bug is known. Even more irritatingly, as the bug report makes clear, the error message is entirely misleading - it can result from any number of underlying problems.
    3. So, what you have to do is to get a real error message. The way to do that is to keep Ubuntu out of the graphical install, and have it give text error messages. You do that by hitting F6 as soon as the purple screen comes up, then editing the command line to remove "quiet" and "splash". Then press enter to have your new command line run.
    4. What I then got was the real error: "Buffer I/O error on device fd0, logical block 0".If you know that fd0 is the floppy disk, this tells you what you need to know. Turns out that although the machine doesn't have a Floppy, I had "Floppy disk" enabled in the BIOS of the motherboard (which is the default), and Ubuntu just can't deal with a non-existent floppy. Disabling the Floppy in BIOS solved the problem.
    Comments on Ubuntu later.....



        3

        View comments

      • There's a new version of CornerFix out, V1.4.0.0. The new release extends CornerFix beyond M8s, M9s and S2s to allow images from just about any camera to be corrected - e.g., Sony NEX, Sigma DP series, etc.

        This is prompted by the many requests I've been getting from numbers of people for CornerFix to be made compatible with various new large sensor cameras, especially the Sony NEX series, for which there are now a lot of lens adapters available. However, given the size of the NEX sensor, and the characteristics of, for example, the Voigtländer (Cosina) 15mm f/4.5 lens, the same color vignetting as happens on the Leica M8 becomes inevitable. And of course, there's no Leica style "self coding" option on the Sony NEX.

        So rather to continue to respond to requests to update CornerFix to each camera, I decided to make CornerFix more general. Now in fact, CornerFix always was quite general - it was just set up to warn about "Unsupported camera model" if it came across any camera I hadn't tested on. But usually, CornerFix would get it right anyway.

        What the new version of CornerFix does is to look at the characteristics of the DNG file itself, and decide whether it can be processed. So it will now work with very nearly any DNG file, regardless of whether the file came directly from a camera, or was converted from the camera manufacturer's raw format with Adobe's DNG Converter. The only restrictions are that the DNG has to have either Bayer sensor or "Linear Raw", aka RGB, data in it. Which covers about 99.9% all cameras out there, btw. So, all you have to do to use CornerFix with a Nikon, Canon or whatever is to convert your raw image to DNG, then use CornerFix as usual.

        At the same time, CornerFix also has a new website. The website has detailed instructions on how to use CornerFix with converted DNGs, etc.

        Downloads are still from the usual place: CornerFix Files on SourceForge.net
        0

        Add a comment

      • So, pcdMagic for Windows is out. pcdMagic converts Kodak Photo CD images into more modern formats such as JPEG and TIFF. But unlike all the other solutions out there, it actually gets the color right.

        The original pcdMagic, which was Mac only, shipped back in February. At the time, I said there would never be a Windows version. Well, 9 months later, there is. The Windows version is a quite a bit different to what I built for the Mac, however. What I found with the Mac version was that there were two distinct groups of people using pcdMagic:

        First, there were the pro photographers, the high-end "art" print shops and advanced amateurs - folks that know their photography, and are using pcdMagic because it's really the only Photo CD conversion solution available that actually gets the color reproduction right. Probably a third of the users of pcdMagic for the Mac fall into that group, judging by the organization names. These are people that can talk about ProPhoto color spaces, etc.

        But there's also another group of users - folks who just want to get their images back the they remember them. These users neither know or care about color profiles, but they do know that the images as converted by the various free packages on the Web just look wrong. pcdMagic for Windows is built to make life easier for them, while still providing all the color profiles, etc in the background. So pcdMagic for Windows is built as a drag-and-drop application. All you have to do is to drag-and-drop any Photo CD file on the window, and it gets converted. Batch operations - just drag-and-drop a group of files. All the color profiles, etc, etc are done in the background. But pcdMagic for Windows is still a seriously powerful piece of software; although its a lot simpler to use than the Mac version, the only features it's missing relative to the Mac version are sharpening (easy to do later if you want), and the option to convert to DNG.

        For those interested in the technicalities, pcdMagic for Windows is a C# and WPF application. Reason being that WPF brings some useful color management capabilities to the table.
        0

        Add a comment

      • There's a good article by Marco Noldin on his blog where he discusses an issue relating to DNG color profiles with hue twists that I haven't touched on in this blog. I've pointed out the issues that you can get when trying to recover images that were for whatever reason badly exposed, or had their expose adjusted for purposes of ETTR. However, Marco points out an additional risk - in some profiles the HSL tables are quite coarse, and as a result can cause posterization.  dcpTool allows him to provide a really good before-and-after example, first showing posterization with a the standard profile, and then showing no posterization using the same profile just edited via dcpTool to remove the table.

        The post is in Italian, but Google Translate does a pretty good job, so it's well worth the read, as is his companion article here.
        0

        Add a comment

      • Jeff Hapeman has posted a good tutorial on using CornerFix, going into the detail of how he uses CornerFix in conjunction with the Leica M9 and Voigtländer 12mm and 15mm wide-angle lenses. Good reading for anyone just getting started with CornerFix.

        You can find the tutorial here:
        Jeff Hapeman's CornerFix tutorial
        0

        Add a comment

      • Two new articles on ETTR have recently been pointed out to me:
        • There's a long discussion on ETTR on Photo.net, here.
        • And also, probably in response to the discussion, an article by Jeff Schewe.
        In both discussions Jeff puts up a spirited defense of ETTR. For those interested in the pro and cons, both are well worth the read. Jeff's position and my position aren't actually as far part as some of the posters in the Photo.net article seem to believe - as mentioned in my original blog post, there is a place for ETTR - it's just that the circumstances in which ETTR is useful are a lot narrower than most ETTR proponents believe. The root cause of that is that a lot of ETTR proponents don't actually understand ETTR. To quote from Jeff: "ETTR can aid you along those lines...if you understand how to use it (some apparently don't)".

        I do have a bit of a problem with Jeff's article however, where he provides examples of ETTR apparently providing significant noise benefits. The problem is that he doesn't compare against is the simple option - just changing the camera's ISO setting. Pretty good bet all the improvement in noise performance he shows can be duplicated, a lot more simply, just by decreasing ISO.
        0

        Add a comment

      Popular Posts
      Blog Archive
      About Me
      About Me
      My Photo
      Author of AccuRaw, PhotoRaw, CornerFix, pcdMagic, pcdtojpeg, dcpTool, WinDat Opener and occasional photographer....
      Loading