External monitor and DPI

[sal]

It doesn't work properly in Win 8.1 or rather it works, but gets screwed intermittently. In my case I have a 4k display on my desktop which is also connected to the TV which is 1080p. You can setup different scaling for the 2 displays and it works fro a while, then at some point it gets screwed, eventually i gave up trying to troubleshoot it. No idea how well it's handled in Win10

[VectraMan]

Right now my laptop is running at it's recommend 1600x900 (16x9)
My monitor is running at 1680x1050 (16x10)
So, you might say I won't see the difference between 1600 and 1680. I'll drop the monitor down to 1440x900. No stretching.
Next test - drop the laptop from 1600x900 to 1440x900 (i.e. change the ration from 16:9 to 16:10) - laptop now has black bars down either side. It does NOT stretch the output to fit the panel.

If it's anything other than the native resolution it's either got to stretch it or pillarbox/letterbox it. If you've dropped your monitor from 1680x1050 to 1440x900 then it's doing one or the other.

If your laptop pillarboxes when you drop the resolution then that's not a lot of use. If I get a 3200x2100 laptop and I put it into 1920x1080 mode (or whatever is closest) then the text will be tiny and I'll only be getting a small area in the middle of the screen!

[WTFH]

If it's anything other than the native resolution it's either got to stretch it or pillarbox/letterbox it. If you've dropped your monitor from 1680x1050 to 1440x900 then it's doing one or the other.

If your laptop pillarboxes when you drop the resolution then that's not a lot of use. If I get a 3200x2100 laptop and I put it into 1920x1080 mode (or whatever is closest) then the text will be tiny and I'll only be getting a small area in the middle of the screen!

OK, either I am not understanding you, or you are not understanding me...


You don't need to put the laptop into the same resolution as the second screen and you don't need to have them at the same ratio.


And, the letterbox bars are only to get the ratio right - it's not switching off pixels to get the resolution.
(I've just tested that to check - take the laptop resolution down to 1280x768 = 15:9 and the image almost fills the whole screen. If I drop it to 1280x720 (16:9), hey presto the screen is full, no stretching)


Now, I'm wondering if your idea of stretching and mine are different - to me stretching would imply it's done in one axis only, so you lose the original ratio.


Maybe rather than talking about this in terms of my monitors, what is the monitor you'll be connecting the laptop to? What is it's resolution and size (also that for the laptop)?


e.g. laptop with 15.4", 2560x1400, monitor = 24", 1920x1200

[VectraMan]

Now, I'm wondering if your idea of stretching and mine are different - to me stretching would imply it's done in one axis only, so you lose the original ratio.

I wondered if that's what you meant. No, stretching as in anything where the resolutions don't match, so it has to map source pixels onto destination pixels which will always result in a loss of quality. It doesn't really matter that much about a small difference in aspect ratios, unless you're trying to draw a circle.

https://en.wikipedia.org/wiki/Native_resolution

Maybe rather than talking about this in terms of my monitors, what is the monitor you'll be connecting the laptop to? What is it's resolution and size (also that for the laptop)?

The Dell laptops are 3840x2160 16:9 15.6" and the external screen is 1920x1080 16:9 21". So clearly the same text size (in terms of pixels) on both and the laptop screen will be unreadably small, or the external screen will be ridiculously large. You seemed to be suggesting changing the resolution of the laptop display, but you can't do that without making it look ropey, or perhaps put black bars all round the side which would be stupid, and either would defeat the object of having a high resolution screen in the first place.

[WTFH]

The Dell laptops are 3840x2160 16:9 15.6" and the external screen is 1920x1080 16:9 21". So clearly the same text size (in terms of pixels) on both and the laptop screen will be unreadably small, or the external screen will be ridiculously large. You seemed to be suggesting changing the resolution of the laptop display, but you can't do that without making it look ropey, or perhaps put black bars all round the side which would be stupid, and either would defeat the object of having a high resolution screen in the first place.

So, laptop pixel pitch is 10.97 pixels per mm, external is 4.17ppmm.


It's so much easier when it's the external that is higher res!
I'd suggest using the laptop for images/video and the external for text, that way you get the best from the laptop, otherwise you're paying for pixels you don't need.


I'd argue that at 15.6", you might see a marginal improvement in pixels going from 1920 up to 3840, but it would be minimal. In fact I decided to check what the recommended screen size/resolution/distance was for 4k:
4K Calculator - Do You Benefit? - Reference Home Theater


A 15.6" screen running at "4k" i.e. 3840x2160 - to see the benefits you need to be 1" from the screen! Marketing teams do a great job in getting people to buy higher res than needed.

[sal]

So, laptop pixel pitch is 10.97 pixels per mm, external is 4.17ppmm.


It's so much easier when it's the external that is higher res!
I'd suggest using the laptop for images/video and the external for text, that way you get the best from the laptop, otherwise you're paying for pixels you don't need.


I'd argue that at 15.6", you might see a marginal improvement in pixels going from 1920 up to 3840, but it would be minimal. In fact I decided to check what the recommended screen size/resolution/distance was for 4k:
4K Calculator - Do You Benefit? - Reference Home Theater

A 15.6" screen running at "4k" i.e. 3840x2160 - to see the benefits you need to be 1" from the screen! Marketing teams do a great job in getting people to buy higher res than needed.

All this is resolved by running each screen at native resolution and use UI scaling to increase the font size, windows borders etc. while maintaining the Native resolution for maximum picture quality. The problem is that in Win7 you can't scale the UI individually for each display, but only across the board, so you want to "zoom" on the high ppi display to 125% scale - it will zoom all of the displays. This is supposed to be fixed in Win 8.1 where you can assign scaling per display which should resolve the OP problem, unfortunately as I pointed out it's not working properly (shocker...). AFAIK this is properly handed by OSX, as expected, giving the fact Apple is pushing fro high ppi displays across the board.

[VectraMan]

I'd argue that at 15.6", you might see a marginal improvement in pixels going from 1920 up to 3840, but it would be minimal. In fact I decided to check what the recommended screen size/resolution/distance was for 4k:
4K Calculator - Do You Benefit? - Reference Home Theater

Yes but that's for telly, which is a bit different, and those arguments were always put forward against 1080p TVs (mostly by people who'd bought 720p "HD" TVs and didn't want to admit they were wrong).

With text and graphics it is potentially better, though I'm pretty sceptical that QHD on a 15" screen isn't totally OTT. It is the way the world is going though, and Fanbois rave about their Retina displays and it can't all be "emperor's new clothes".

[WTFH]

Yes but that's for telly, which is a bit different, and those arguments were always put forward against 1080p TVs (mostly by people who'd bought 720p "HD" TVs and didn't want to admit they were wrong).

With text and graphics it is potentially better, though I'm pretty sceptical that QHD on a 15" screen isn't totally OTT. It is the way the world is going though, and Fanbois rave about their Retina displays and it can't all be "emperor's new clothes".

I think the 24"/27" 5k displays are possibly worth it, if you are a photographer - but only because it makes image editing easier. Otherwise, I don't massively see the point.


The times you see the benefits are when you are pushing to the limits. If 95% of your life in front of the screen is posting on here or reading/writing emails, then 1600x900 will be more than adequate - even for the 5% when you're watching videos, as it will be marginally smaller than HD (and how many of the videos you watch are HD?)
And anyway, you've got the big screen for HD.


So, the question is, in what way will you benefit from the higher definition?

[MicrosoftBob]

I think the 24"/27" 5k displays are possibly worth it, if you are a photographer - but only because it makes image editing easier. Otherwise, I don't massively see the point.

Even then you're better off with a larger dedicated monitor that has a wider gamut of colours and wait for large 8k displays to become cheep

[yasockie]

Get an external 4k Screen?
the 40" Phillips is brilliant, but you can also get a 'small' 28" or 32" screen, which are too small to display text in 4k 1:1 but then you can apply the same lavel of DPI scaling on both screens.
Personally my home screen is big enough and when plugged in in, I don't use laptop screen at all.