Adjust brightness of iMac as 2nd monitor

I have a 2012 MacBook Air plugged into an older iMac via mini Display port cable. (Not thunderbolt).
How can I adjust the brightness of the iMac? The Displays system prefs doesn't have a brightness slider for the iMac screen. And the brightness keys on the keyboard only adjust the Air's display.

The iMac controls don't work ?
from: Using a 27-inch iMac (Late 2009 or Mid 2010) as an external display
Use the keyboard of the 27-inch iMac to adjust display brightness and sound volume and to control media playback of applications running on the 27-inch iMac in Target Display mode. Other keyboard and mouse input is disabled on the 27-inch iMac while it is in Target Display mode.

Similar Messages

  • New iMac loses 2nd monitor

    My new Imac 21 - i7 - Lion - dual monitor (connected with thund-hdmi adaptor) has a strange behavior.
    Everything works fine, but when the system goes in power saving mode, on coming back sometimes the second monitor becomes gray (working but no wallpaper), sometimes comes back normally, but ALWAYS all applications windows goes back to the main imac monitor.
    I've tried to switch of the 2nd monitor and the behavior is the same. So is not a power saving problem.
    It seems that the imac always autodetect monitor situation on the fly and moves windows back to the main monitor.
    The problem is that the "moving windows back function" seem to be faster than monitor detection.
    Is there a way to say to lion: "I always have two monitor, please don't change"?!?
    thank you for help.

    I suspect it may be the adapter.  I would recommend trying the one Apple recommends here or trying another connections such as a VGA or DVI assuming the monitor has that type of connection.

  • New iMac and 2nd Monitor

    is it possible to connect a regular monitor (HDMI) to the new iMac?
    If not, is there some other way to use two monitors?

    You could use a Thunderbolt to HDMI adapter

  • Connect iMac as 2nd monitor?

    I'm using my new 13" macbook pro and I'm hoping that someone can instruct me how to set up my iMac (2.33 GHz Intel Core 2 Duo) so that I can use dual monitors?

    ScreenRecyler is your only option, and I wouldn't even bother installing it.
    I was trying to do the same thing as you, can gave that software a try and it DID work, but it was very laggy and not really usable. I even tried setting it up on its own network connection using firewire and then gigibit Ethernet directly between the two machines and although the did improve, it was still too slow to smoothly scroll a web page or play a video without the frames breaking up.
    So sorry, but there is no way.

  • 27" ACD as second monitor -- cannot adjust brightness

    I've connected a 27" LED ACD to my 27" iMac as a second monitor, but the keyboard commands for adjusting brightness do not affect the cinema display. I understand a common cause for this is that the USB isn't connected, but mine is and I can verify it is working because I have an external HD connected to the USB port of the ACD, and the iMac recognizes that it is connected.
    Also, if I go into Display Preferences then I do see the Brightness slider for the second monitor. This is currently the only way I can adjust the brightness of that monitor.

    True, Unless there's a shortcut for that, the only way to adjust the brightness of the second monitor is by using the display preferences . same here with a MBP / 27" display.

  • IMac does not detect correct resolution of 2nd monitor

    I am attempting to use my 42" LG HDTV as a 2nd monitor for my iMac. The native resolution for the LG is 1920x1080 but the iMac only allows me to select up to 1600x1200. It seems to think that the LG is a smaller screen than the iMac as well and my images are stretched. The monitors are also disproportionate, for example, if I expand a window so that there is an inch of space on all 4 sides on my iMac it will overwhelm the screen of the larger monitor so that only about 2/3 of the window is visible. It's as if the iMac thinks that the LG is in 4:3 display mode.
    I am using a mini-DVI to VGA adapter. How can I get full resolution from my 2nd monitor?

    The (analog) VGA connection is limiting your resolution. Idealy a (digital) Mini-DVI to DVI adapter and a DVI cable should allow the full resolution in Extended Desktop Mode.

  • Connecting a 2nd monitor to my 27" iMac

    Hi All, I am looking to buy a 2nd monitor to go with my 27" 2.9 GHZ iMac (purchased May 2013) and wandered if anyone could provide some advice on the best way to connect it through a thunderbolt port and is there anything I must ensure the new monitor has or certain specifiction. i am looking to buy a 27" monitor to sit aside my current one. Thanks in advance for any help.

    Unless it's an Apple Thunderbolt display or some other Thunderbolt disply you simply connect a MiniDisplay port to (VGA, DVI or HDMI) depending on what the external display has and connect it up. The System Preferences - Diskplays and setup the setting the way you want. This is the ONLY way it will work. There are hundreds of Youtube videos that show you how, here is one example:
    http://www.youtube.com/watch?v=iKkPmJ1lZ4Y

  • 1 Lightning port as both 2nd monitor AND storage SSD? - 21" 2011 iMac

    Hello!
    I am considering picking up my first SSD drive for use as a work horse for streaming video and audio for my prosumer use.  My 21" 2011 iMac only has the one lightning port, which I plug my old 19" LCD monitor into for the extra screen real estate.  Not wanting to bottleneck the SSD speed by connecting it to USB 2 or even FireWire, does such a throughput device exist that would allow the one lightning port to support both  my 19" display as well as a mounted, external SSD drive?  I know that the lightning port had an expandable future, but I'm not sure if this is possible.  If it IS possible, I would imagine doing so would still be expensive.  Thanks a bunch!

    Haha, THUNDERBOLT!   Sorry, mate.  I must have been thinking of the newer iPad/iPhone connector.  Goes to show you how much mind I've paid to apples new port.  Anyway, that's great news.  Thank you.  I was pessimistic about their being enough bandwidth to fully support my 2nd monitor in addition to the top notch speeds of an SSD.  I was curious to know where there might be any sacrifices one way or another.

  • Imac not recognizing 2nd monitor

    On cold startup,  why do I always need to unplug and replug thunderbolt mini display to vga adapter for imac to see second monitor ?
    Once I do this, the 2nd monitor is recognized.  If I restart, 2nd monitor is recognized.
    thanks.. I am worried that the port will be compromised with all the unplug/replugs.
    Btw... the "detect displays" function doesn't resolve this issue. 
    thanks for any help!
    ~john theaker
    windsor ontario canada
    iMac 2.8gz quad core 17
    Samsung monitor
    mini

    Hi John,
    I really have no idea, but as a test, hold alt key at cold startup, let it set on that screen for maybe a minute or two, then click the startup volume or hit enter... any change?
    Also, if you log out & back in does it show up?

  • Losing connection to 2nd monitor when iMac sleeps

    I have a 2nd monitor connected to my 21" iMac (late 2013) with Mavericks via displayport/thunderbolt port to HDMI. I had the same one with the same link connected to my old 2010 Macbook Pro, and I never saw this.
    What happens is when the computer goes to sleep, all of the windows on the second screen move to the iMac, and my Wacom tablet even goes from being mapped to ONLY my second monitor to being only mapped to the iMac!
    This is kind of driving me crazy, and I have searched and Googled and just can't find a solution.
    Any ideas would be rad. Thanks.
    David

    Try a reset >    Mac OS X: How to reset the printing system

  • IMac 24" and adjusting brightness.

    Hello. I have this fancy (and great) iMac 24". Only annoying thing is that when I try to adjust brightness, it just does not "adjust" brightness. Difference between "none" and "full" brightness is close to nothing. I have so far zap Prams, deleted prefs, turn green and shouted that I am Hulk - any ideas?
    I know that there is Shade and other small apps to do this. But Brightness-control should efeect as...well... a brightness control.
    Sooooo...any ideas how to get a working brightness control by keyboard?

    Yeah, I have. And system preference panel.
    When I press F1 or F2 to adjust brightness I have this normal response in display (picture). I dont know whats the right word for it but I mean the white brightness slash hovering on my iMacs desktop. You know, when You press volume controls there is a picture of speaker and when you press brightness there is a picture of rising sun.
    Anyways, I get that. BUT THERE IS NO VISIBLE CHANGE IN BRIGHTNESS BETWEEN HIGHEST AND LOWEST.
    Same thing via System preferences. Brightness slider has the same lack of adjustment.
    Sooo, any ideas? Where could be the problem?

  • How do i adjust brightness on second monitor

    how do you adjust brightness of the second monitor ?? just upgraded the graphics board to ati radeon 5770 and added a second monitor -

    Never mind - found the answer inside the answer to someone else' question - the USB was not plugged in which provided the nice slider

  • RGB settings unexpected​ly reset when adjusting brightness on HP2509b monitor

    I am trying to modify the RGB values and brightness settings of my HP2509b monitor so that the the images on my screen more accurately reflect the prints that I receive from my photo lab.  
    After I modify the RGB settings so that the White Balance on my screen matches the print pretty closely I then attempt to lower the brightness to adjust that setting more closely to what I see on my print as well. Upon reducing the brightess by only 1 value, my RGB values instantly reset to the 6500K preset.
    WHY????

    Thomas,
    the free GMB program Calibration Tester shows the
    contents of the graphics card LUTs.
    Altogether three programs, mentioned here on p.20:
    http://www.fho-emden.de/~hoffmann/measgamma10022004.pdf
    If the luminance settings of the monitor are above
    the target value e.g.100 cd/m2 for a calibration
    by instruments, then the graphics card LUTs are
    trying to reduce the luminance (old example in the
    doc, also p.20), for instance from 110 to 100 cd/m2.
    Such a case would reduce the resolution a little.
    As tested by Eizo CG19:
    The adjustment of the monitor by monitor menues
    doesn't affect the graphics card LUTs. In fact,
    the calibration by GMB ProfileMaker5 guides the
    user to adjust the monitor dynamically/interactively
    so, that the LUTs contain finally almost no correction.
    In this sense the old example above wasn't perfect.
    This is the classical method, which I'm applying as
    well to Eizo CG19, though this monitor offers a
    calibration by ColorNavigator, based on monitor-
    internal LUTs with 10 or 12 bits per channel
    (leaving the graphics card LUTs at identity y=x).
    For certain reasons I'm not using this feature.
    One reason: then it would be impossible to have a
    look at the contents of the LUTs.
    Theoretically the result should be better for high
    resolution LUTs, but I wasn't able to detect banding
    or posterization after applying the classical method.
    Best regards --Gernot Hoffmann

  • IMac monitor goes dark; 2nd monitor ok

    I have a dual monitor setup on my iMac (2009) running Snow Leopard (10.6.8).  The iMac monitor had been working great, but now it goes to a black screen.  I am able to access it briefly (for about a second) by lightly pressing the power button on the back.  The iMac monitor flashes on briefly when I do this and I'm able to quickly click on user.  I used this same method to open Settings and drag it over to the 2nd monitor to change the display setting to Mirror mode, so I'd have access to the dock on the 2nd monitor (Dell 2007WFP). 
    I have tried the following so far:
         checked cables
         restarted by powering off, pressing on/off button for 5 seconds, unplugging for 15 seconds.
         booted in Safe Mode
         reset PRAM (I believe this was reset, but I don't know for sure because I couldn't see anything on the monitors.)
    Other information:
         2.66 GHz Intel Core 2 Duo
         8 GB 1067 MHz DDR3
         NVIDIA GeForce 9400
    Thank you in advance for help with this issue!

    Replacing FBDIMMs would be today inexpensive and worth doing.
    No one knows if heat is an issue without your using thermal sensor monitor. Probably want to up the default fan speeds while at it.
    And because you don't have Lion+ then even more reason to setup a small maintenace volume on another drive with OS X basic system for repairs. In fact you should always have a bootable backup or two  you can rely on.
    Restarting may work, or it  may be you have now new issue with corrupt fies or directory that a safe boot even is no guarantee of fixing.
    When in doubt, try a clean new OS install on another drive.
    And FBDIMMs: $25 for a 2x2GB set on Amazon.com
    You want to get  the most out of what  you have, a small investment  in RAM,  maybe recycle those drives for 2-4TB units. And an SSD will have system responding better and perform better.
    My guess, the 5870 wasn't needed and was overkill and a 5770 for almost  half would have been more than adequate.

  • Best 2nd monitor for iMac Intel 20"

    A few months back I stumbled upon a great article comparing Apple and 3rd party monitors that could match up well with the iMac Intel 20".. of course I can't find it now that I'm using actually using this iMac. I'm curious to hear your experiences/views on 2nd monitors that match up well for this specific computer. Thanks

    There is a MiniDVI output port on this iMac. Simply purchase one of the following adaptors and configure the dual display in Apple menu > System Preferences... > Displays. (The options appear when you connect the display):
    Mini DVI - DVI
    Mini DVI - VGA
    Mini DVI - Composite/S-Video.
    DVI will also certainly provide the best picture quality but the exact choice of display depends on your budget and intended usage. For example budget LCD displays are inappropriate for work that requires colour accuracy.
    Your iMac will support displays with the following resolutions:
    Digital resolutions up to 1920 x 1200.
    Analogue resolutions up to 2045 x 1536
    mrtotes

Maybe you are looking for