Amiga and BENQ BL912 / BL702A Monitors - Page 2

eXeler0 · 05 November 2015, 21:08

Quote:

Originally Posted by ReadOnlyCat

You are correct. PAL Amigas have indeed a 4:3 image ratio.
It is only the resolution ratio which is 5:4 (320/256 = 5/4).

A monitor/TV's ratio has nothing to do with resolution and everything to do with physical dimensions.

The shape of the monitor sets the physical limits for the image aspect. But then there is Pixel Aspect.

For example..Old CRT widescreen TVs had the same resolution as normal TVs even though the Image Aspect was different (16×9). What also had to be different was the pixel aspect - meaning the actual shape of the perceived pixels. (And in fact it was variable.) Middle of the screen had one pixel shape while outer edges would use wider pixels.. so the image looked distorted. Normal TV showed widescreen with black borders.

Whatever resolution Amiga coders used for games could probably be 320x200, 320x240 or 320x256.. (to name a few low res variants). There could be a bunch of reasons for using lower resolutions none of which are related to the max resolution of the monitor.

Nostromo · 05 November 2015, 21:36

A very nice person actually took the time to draw a perfect circle in deluxe paint and then measure the circle in width and height, and he confirmed that these are exactly 1:1

jbenam · 06 November 2015, 11:05

Awesome!! Now I just need to get one...

Tyball · 06 November 2015, 15:16

Interesting. I might just get one if prices drop. I measured the visible screen of my 1084 monitor and it measures 27 by 20 centimeters. So, that's 4:3.

Jope · 06 November 2015, 17:48

So indeed, the Amiga's resolution is 5:4 but back in the day we watched these with 4:3 screens, so the Amiga's pixels were not square.

If you draw a perfect circle in a non laced mode on a 4:3 screen, it will be stretched on a 5:4 screen.

Nostromo · 06 November 2015, 17:52

So technically, the Amiga picture is displayed properly on 5:4, not 4:3...

Jope · 06 November 2015, 17:54

No, when it was designed, the screens were 4:3, the graphics were drawn for those screens too.

About the rectangular pixels:
"Q: Why are the pixels 10% higher than wide?
A: The hardware came out that way, and it would have been a pain to do it any other way due to sync-rate-multiple timing constraints." [1]

Add to that that the early games were done on NTSC machines, where 320x200 filled the 4:3 screen. Then they were taken to Europe where we had machines that were not able to switch to a 320x200 mode, only 320x256 all the time and the graphics were squashed to the top of the screen with a 56 pixel high blank rectangle on the bottom. :-D

.. so what IS the right way to view Amiga graphics.. :-)

[1] http://textfiles.com/computers/amihist.txt

Nostromo · 22 November 2015, 20:31

I got my Benq 702a at last, very happy with it. If interested I wrote a review about it:

http://insertdisktwo.com/2015/11/21/...for-amiga-use/

TheDarkCoder · 28 November 2015, 19:34

Thanks for your interesting review, Nostromo. There is one thing I'd like to ask to you and other guys having these monitors. Would you recommend them for use with a Cybervision 64?
Indeed I have several CRTs and I am happy with them for normal usage. However I also have an Amiga with a Cybervision 64, so I would like to use it with a unique monitor to show both Amiga modes and Cgx modes. Some CRTs (multisync) allow the trick but do not offer very good specs for the very hi-res Cgx modes. So my hope is that the BenQs could be better

luy32 · 30 December 2015, 21:51

Quote:

Originally Posted by Nostromo

I got my Benq 702a at last, very happy with it. If interested I wrote a review about it:

http://insertdisktwo.com/2015/11/21/...for-amiga-use/

what happened with the link ??

This webpage is not available

Predseda · 30 December 2015, 22:05

Works fine for me.

turrican9 · 10 January 2016, 10:06

So I have two of these on the way. I will just quote a post I made into this thread

Quote:

Originally Posted by turrican9

So I have ordered two of these and already got 2x RGB to VGA adapters from amigakit. From the pictures and one video it looked like the image quality on these are excellent using Amigas native RGB.

I have the Indy AGA MK2 for my Amiga 1200 with a Phillips 17" LED 5:4 screen with DVI connection and set a custom resolution of 720x576 for gaming. Also have the Indy ECS in both one of my A500s and Amiga 600. These I use with an old 19" LG 5:4 LCD from 2004. These solutions gives excellent picture for my Amigas and gaming needs. however, none of them supports 50Hz. But I dont notice much tearing and scrolling in games are good enough.

So how are the BenQ 702A screens using RGB compared to my above solutions? I know it should be smoother scrolling due to 50Hz but I wonder how it will look compared to my above solutions. I noticed from pictures that the RGB seem to make some vertical scanlines which looked really good.

My biggest reason for ordering these is so I can connect any Amiga without a scandoubler and for smooth gaming

turrican9 · 13 January 2016, 00:17

So got the first of the two BL 702A monitors I ordered today. What a great monitor for my Amigas. The scrolling in games are just perfectly smooth, pictures and colours look amazing and there is something special about the RGB picture compared to using Indy scandoublers. This is as close as you get to a good CRT connected with scart and with the benefits of a LED screen. I just love it. No need for CRTs or scandoublers with this setup.

eXeler0 · 13 January 2016, 02:38

Quote:

Originally Posted by turrican9

So got the first of the two BL 702A monitors I ordered today. What a great monitor for my Amigas. The scrolling in games are just perfectly smooth, pictures and colours look amazing and there is something special about the RGB picture compared to using Indy scandoublers. This is as close as you get to a good CRT connected with scart and with the benefits of a LED screen. I just love it. No need for CRTs or scandoublers with this setup.

And it's cheaper than Indivision ; -)

Higgy · 13 January 2016, 09:08

I bought the BL912 mainly to also have a DVI port for Raspberry Pi etc.

I do get quite a bit of interference/artifacts, like vertical banding on the screen. Noticable on big plain colour areas like black borders or Workbench. Adjust 'pixel clock' on monitor changes them a bit.

Anyone else get it? I am using the AmiKit AMIGA-VGA adaptor with cut down 25-pin D-sub. I will try and get some photos. I am hoping my adaptor is ok?

But yes, scrolling and everything else is great. No artifacts around moving objects like when using a GBS-8200.

amigoun · 13 January 2016, 13:54

Have you set the pixel clock of your BL912 to 94? This will completly eliminate vertical banding.

turrican9 · 13 January 2016, 16:12

From what I can tell the pixel clock setting will vary a bit from BL702A to another BL702A. I had to put my pixel clock to 88 and Phase clock to 30 + to get a perfect picture. Even though 90 was the recommended pixel clock for Amiga use. Also seen others needed other values like 92. So from what I can tell it will differ a little bit and you just have to try and find the right setting. you will notice when you hit the right number because the picture goes to perfect. Also, I had some problems finding the right value. But after I had reset the screen settings and then adjusted the pixel clock again, I got the perfect picture.

I think this will go for the BL912 too.

Edit: Got my second BL702A today, so will test it later. I think it was important to buy two of these because these particular monitors will not sell forever. And finding a LED 17" 5:4 screen that works perfectly with Amigas RGB (manage 15KHz, 50Hz and at the same time have a perfect picture) is not easy.

amigasith · 13 January 2016, 21:24

Quote:

Originally Posted by turrican9

I think this will go for the BL912 too.

True. I ordered a BL912 a while ago and for my monitor, 90 was the perfect value for the pixel clock setting. Once I managed to find the right value, the picture turned crystal clear. Absolutely amazing

I also like its "Low Blue Light Mode", which is supposed to be healthier for your eyes. While I cannot tell whether this is actually true or not, the picture is - for my liking - really pleasing to the eye.

turrican9 · 13 January 2016, 22:31

So I connected my second BL702A to my Amiga 1200 using RGB to VGA adapter. Here the black was not as black as on my Amiga 500 which I have my first BL702A connected to. Also, on the Amiga 500 I had to adjust the pixel clock to exactly 88 and Phase to 30 and got a crystal clear image with no vertical lines. On my 1200 on the other hand I ended at pixel clock 92 and Phase around 30. But I did not get rid of those vertical lines I've seen in alot of pictures around Amiga forums. So I did not manage to get as crystal clear image from my 1200 (still not a bad picture, but not as good as my A500) as I have on my Amiga 500. Will switch the monitors, adapters and confirm. Will also test it on my Amiga 600 and maybe my two more Amiga 500s to look for differences.

khph_re · 13 January 2016, 22:53

Will these monitors support doublePAL? also on the 19 inch version, is there a way to connect my c64 as well?

06 November 2015, 17:48	#25
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,862	So indeed, the Amiga's resolution is 5:4 but back in the day we watched these with 4:3 screens, so the Amiga's pixels were not square. If you draw a perfect circle in a non laced mode on a 4:3 screen, it will be stretched on a 5:4 screen. Last edited by Jope; 06 November 2015 at 17:53. Reason: why did I write 3:2 when I wanted 4:3

06 November 2015, 17:54	#27
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,862	No, when it was designed, the screens were 4:3, the graphics were drawn for those screens too. About the rectangular pixels: "Q: Why are the pixels 10% higher than wide? A: The hardware came out that way, and it would have been a pain to do it any other way due to sync-rate-multiple timing constraints." [1] Add to that that the early games were done on NTSC machines, where 320x200 filled the 4:3 screen. Then they were taken to Europe where we had machines that were not able to switch to a 320x200 mode, only 320x256 all the time and the graphics were squashed to the top of the screen with a 56 pixel high blank rectangle on the bottom. :-D .. so what IS the right way to view Amiga graphics.. :-) [1] http://textfiles.com/computers/amihist.txt Last edited by Jope; 06 November 2015 at 18:17. Reason: Added the quote about the pixel shape..

13 January 2016, 09:08	#35
Higgy Registered User Join Date: Jan 2014 Location: Somerset, UK Posts: 547	I bought the BL912 mainly to also have a DVI port for Raspberry Pi etc. I do get quite a bit of interference/artifacts, like vertical banding on the screen. Noticable on big plain colour areas like black borders or Workbench. Adjust 'pixel clock' on monitor changes them a bit. Anyone else get it? I am using the AmiKit AMIGA-VGA adaptor with cut down 25-pin D-sub. I will try and get some photos. I am hoping my adaptor is ok? But yes, scrolling and everything else is great. No artifacts around moving objects like when using a GBS-8200. Last edited by Higgy; 13 January 2016 at 09:09. Reason: added 'vertical' banding

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05 November 2015, 21:36	#22
Nostromo Registered User Join Date: Dec 2008 Location: The World! Posts: 454	A very nice person actually took the time to draw a perfect circle in deluxe paint and then measure the circle in width and height, and he confirmed that these are exactly 1:1

06 November 2015, 11:05	#23
jbenam Italian Amiga Zealot Join Date: Jan 2009 Location: Italy Age: 36 Posts: 1,910	Awesome!! Now I just need to get one...

06 November 2015, 15:16	#24
Tyball Registered User Join Date: Feb 2007 Location: Netherlands Posts: 82	Interesting. I might just get one if prices drop. I measured the visible screen of my 1084 monitor and it measures 27 by 20 centimeters. So, that's 4:3.

06 November 2015, 17:52	#26
Nostromo Registered User Join Date: Dec 2008 Location: The World! Posts: 454	So technically, the Amiga picture is displayed properly on 5:4, not 4:3...

22 November 2015, 20:31	#28
Nostromo Registered User Join Date: Dec 2008 Location: The World! Posts: 454	I got my Benq 702a at last, very happy with it. If interested I wrote a review about it: http://insertdisktwo.com/2015/11/21/...for-amiga-use/

28 November 2015, 19:34	#29
TheDarkCoder Registered User Join Date: Dec 2007 Location: Dark Kingdom Posts: 213	Thanks for your interesting review, Nostromo. There is one thing I'd like to ask to you and other guys having these monitors. Would you recommend them for use with a Cybervision 64? Indeed I have several CRTs and I am happy with them for normal usage. However I also have an Amiga with a Cybervision 64, so I would like to use it with a unique monitor to show both Amiga modes and Cgx modes. Some CRTs (multisync) allow the trick but do not offer very good specs for the very hi-res Cgx modes. So my hope is that the BenQs could be better

30 December 2015, 22:05	#31
Predseda Puttymoon inhabitant Join Date: Mar 2007 Location: Tromaville Age: 46 Posts: 7,540	Works fine for me.

13 January 2016, 00:17	#33
turrican9 Registered User Join Date: Apr 2015 Location: Norway Age: 47 Posts: 893	So got the first of the two BL 702A monitors I ordered today. What a great monitor for my Amigas. The scrolling in games are just perfectly smooth, pictures and colours look amazing and there is something special about the RGB picture compared to using Indy scandoublers. This is as close as you get to a good CRT connected with scart and with the benefits of a LED screen. I just love it. No need for CRTs or scandoublers with this setup.

13 January 2016, 13:54	#36
amigoun Registered User Join Date: May 2010 Location: Czech Rep Posts: 599	Have you set the pixel clock of your BL912 to 94? This will completly eliminate vertical banding.

13 January 2016, 16:12	#37
turrican9 Registered User Join Date: Apr 2015 Location: Norway Age: 47 Posts: 893	From what I can tell the pixel clock setting will vary a bit from BL702A to another BL702A. I had to put my pixel clock to 88 and Phase clock to 30 + to get a perfect picture. Even though 90 was the recommended pixel clock for Amiga use. Also seen others needed other values like 92. So from what I can tell it will differ a little bit and you just have to try and find the right setting. you will notice when you hit the right number because the picture goes to perfect. Also, I had some problems finding the right value. But after I had reset the screen settings and then adjusted the pixel clock again, I got the perfect picture. I think this will go for the BL912 too. Edit: Got my second BL702A today, so will test it later. I think it was important to buy two of these because these particular monitors will not sell forever. And finding a LED 17" 5:4 screen that works perfectly with Amigas RGB (manage 15KHz, 50Hz and at the same time have a perfect picture) is not easy.

13 January 2016, 22:31	#39
turrican9 Registered User Join Date: Apr 2015 Location: Norway Age: 47 Posts: 893	So I connected my second BL702A to my Amiga 1200 using RGB to VGA adapter. Here the black was not as black as on my Amiga 500 which I have my first BL702A connected to. Also, on the Amiga 500 I had to adjust the pixel clock to exactly 88 and Phase to 30 and got a crystal clear image with no vertical lines. On my 1200 on the other hand I ended at pixel clock 92 and Phase around 30. But I did not get rid of those vertical lines I've seen in alot of pictures around Amiga forums. So I did not manage to get as crystal clear image from my 1200 (still not a bad picture, but not as good as my A500) as I have on my Amiga 500. Will switch the monitors, adapters and confirm. Will also test it on my Amiga 600 and maybe my two more Amiga 500s to look for differences.

13 January 2016, 22:53	#40
khph_re Registered User Join Date: Feb 2008 Location: Northampton/UK Posts: 525	Will these monitors support doublePAL? also on the 19 inch version, is there a way to connect my c64 as well?

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