Ubuntu 18.10 – Sound changes from Optical Audio (On Motherboard) to HDMI (Onboard Graphics – Intel) at random

I’ve been running Ubuntu 18.10 on my media center since January. It’s been working fine until recently where it keeps changing the audio device from the Optical/SPDIF Output (to my sound bar) to the HDMI audio from the onboard graphics. I have no idea why, and changing it back within the settings menu works fine.

I’ve tried using pavucontrol to force using the correct audio device, and it seemed to work for a couple hours. But it switched back again.

I’m completely at a loss, I haven’t had this happen before. Any help would be appreciated.

High resolution photography with C API and optical zoom

I am currently looking for solutions to take high resolution photos of objects via a dedicated software. (The software will be developed by myself.) Therefore I am looking for ideas for cameras, where:

  • The camera has a full API (settings, focus, exposure, etc…) available in C/C++. (Similar to the Canon EOS-SDK)
  • The camera supports an optical zoom via the API. (The objects vary between 3m and 0.5m in size, I would like to zoom in for the smaller objects to capture them with max resolution)

As far as I know the Canon cameras (EOS) do not support optical zoom via their API, all I would be able to do is to crop the image in the SW hence simulating a digital zoom.

Do you have any suggestions, which products I should look at closely? (I am not much of a photography expert)

Thanks in advance,


Why is the depth-of-field preview in the optical viewfinder of my Canon 500D inaccurate?

I have noticed that in my Canon 500D, the depth-of-field preview in the optical viewfinder is inaccurate with large aperture settings.

If I press the DoF preview button, there is very little difference between, say, f/1.8 and f/3.5. In particular, pressing the DoF preview button with f/1.8 vs. f/2.8 seems to make no difference at all.

Obviously, there is a huge difference in the photo, and certainly I can also see the same difference if I use live view (LCD screen) and the DoF preview button. And even with the optical viewfinder, the DoF preview button seems to work as expected with smaller apertures (say, the difference between f/4.0 and f/8.0 is clear and what I see in the viewfinder matches what I see in the photos).

What is going on? Exactly what limits the performance of the DoF preview button with the optical viewfinder, and what is the largest aperture with which it still produces “correct” results? Are there differences between different camera models regarding this aspect?

After a lot of googling, I was able to find this page which suggests that the focusing screen in the optical viewfinder might be the limiting factor:

“Oddly, these modern screens get no brighter when you’re using a lens faster than f/2.8. Try it: put on an f/1.8 or other fast fixed lens and flick the depth of field button. You’ll see no change in anything until you stop down to about f/2.5!”

Sounds familiar – but the above quotation is about Canon 5D, which is obviously a very different thing from my 500D.

I also found this page which is specifically about 500D, but the discussion thread seems to give few conclusive answers.

VMware ESXi 6.0 – How can I pass-through (add) my Mac Pro’s optical drive to a VM (running OS X Mountain Lion)?

Bit unconventional I know, but I am running VMware ESXi 6.0 on my old Mac Pro 1.1. If you don’t know what that is then (no offense, but) you won’t be able to help me. The Mac Pro host has a “super drive” as its optical drive for CDs & DVDs.

I am trying to use VM pass-through to get my physical optical drive passed-through to the virtual machine. However, I have added the device to the VM and enabled pass-through, but still do not see it in the VM. What could I be doing wrong here? Thanks.

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Unable to trigger my Speedlite YN565EXIII via optical trigger using a Canon 750D (Rebel T6i)

I own a Rebel T6i and a Speedlite Yongnuo YN565EXIII. I’ve tried several times to trigger the flash off-camera (on a tripod with a softbox) and I’ve had some very unsatisfactory results.

With the speedlite on a tripod I’ve set it to ETTL slave mode (Sc mode). On the camera on the camera I went to Flash Control >Built-in flash settings in there I’ve set the following settings:

  • Flash firing: Enable
  • E-TTL II meter: Evaluative
  • FLash sync. speed in Av mode -> 1/200
  • Channel: 1
  • Group: A

Here’s a image of the flash settings as it is right now: Flash Settings

On Buillt-in flash settings I have the following:

  • Flash mode: E-TTL II
  • Wireless func: (Set to the icon of the dedicated flash only)
  • Channel: 1
  • Firing Group: All
  • Exp. Comp: 0

Here are some images of my camera settings:

First screen: First screen

Second screen: Second screen

I have the sensor turned to me as I take shots of my speelite on a tripod. I’m literally taking pictures of the optical sensor:

Here’s how the speedlite it’s positioned: Speedlite position

I think its important to say that Im shooting on full manual mode. Now to the problems.

1) Most of the times when I use the pop up flash to trigger the speedlite, the built-in camera goes off, however the speedlite isn’t triggered, even though I’m pointing the built-in flash directly to the sensor at a distance of around 1.5 meters (about 5 feet I guess). The speedlite goes off on an estimate of one time every ten attempts. The batteries are new and I wait about 5 seconds between each new attempt.

2) When the speelite goes off, most of the time it doesn’t affect the exposure of the image. It’s like, it’s out of sync with the camera or something like that. My room it’s pretty dark, and even when the speedlite goes off the image it’s completely dark.

3) Sometimes (a good amount of times) the pop-up flash of my camera doesnt go off even though its set to go off and my room it`s completey dark. Does the built-in flash has a recharge time or something like that?

I’ve also tried using the speedlite (and built in flash) on manual slave, instead of E-TTL slave, but got the same problems.

Im trying to learn off-camera flash techniques and I was relying on the optical trigger, as I dont have a wireless one, so if anyone has a suggestion on how to fix this I`m eager to try.

How to switch MacBook Pro back to Normal Digital Audio Out from Optical Audio Out?

I have a Late 2011 MacBook Pro (2.2 GHz Intel Core i7) for six years which means no Apple Care or Warranty. One day, Just after a Normal Boot the Audio was not coming and the Audio was permanently muted but since I heard a lot about these issues on MCP from this era I did a small research on google and found these two websites, one from Apple and another from Joseph Hall’s Blog. Joseph’s Solution worked a dozen times and never did again. I tried the Toothpick method(Stick a nonconductor inside the audio jack) as said on the Apple Forum but no luck. After some further research, I figured out that the switch between Optical and Digital is something which the IC in the motherboard controls. Now I can only hear the output from a headphone or via Airplay (Apple TV). Should I change the motherboard in order to hear the sound? Thank You!

PS: This is not a duplicate and if you think so then please leave a comment below and I’ll clarify it. I’ll try my best to make the question more clear for every user.