Lumens, what is enough

[Dax]

I have been wanting to post this for a little while now, but have been in the middle of trying to update my room a little and this did not get the chance. While my room still needs a few additional tweaks, I am now set up to the point where I can play again and get back to testing and enjoying my sim studio.

I have read a few posts over that last couple of months questioning whether or not a projector would be bright enough and just thought that I would start a thread that allows people to post pics of what they are doing and also shows the brightness in their rooms. Hopefully this can help some people out with their projector selections and maybe help get an indication of what they can expect. I will try and add three postings here on three different projectors that I have had in my sim room with a little discussion of the set up and the amount of light in the room at the time. I will also give some comments on each projector as well.

[Dax]

Here is some pics on the projector that I am using for the moment. It’s and Epson EX9210 that is rated at 3,400 lumens (reviews of this projector note that it is very close in testing to the lumens reported by Epson. The screen resolution is 1920 by 1200, which is my preferred ratio for sim golf, as on a 16 wide screen you would have a 10 foot high image.

The price for this projector is US$780 at the time of writing, but I have seen it on sale for less and I managed to find a used one for cdn$450.

The unit sits about 15 feet away from my screen and is ceiling mounted with the bottom of the unit being approximately 89 inches off of the floor. Using the zoom feature on the projector this gives me an image that is approximately 130 inches wide and about 86 inches tall (note that the bottom of my image starts at about 4 inches from the floor).

The images below have been taken on a cloudy day with a good amount of ambient light in my room with there being no lights on. I took a picture later than from when I took the sim golf pics as I noted that the bottom of the image was sitting higher than I wanted and thus needed to make some adjustments to the numbers that I report above. Pardon the mess, but as noted I am still working on my room a bit.

Overall, I am pretty impressed with the image that I get from this projector while playing Virtual Golf 2 and find the greens and contrast ration to be good. The projector is still new and I am trying to figure out if I can go in and tweak some things further in order to refine the image. The downside for this projector is that it does not have lens shift. It does have a decent zoom ratio and also a good keystone and corner correction feature but that is about it. However, at the price that I got this for, you cannot complain.

On the lens shift, I really love this feature and remembered why when setting up the projector as I needed to spend more time on set up to get things as centred as possible and also then to square things up. I note that I am not done yet as I still need to secure my screen framing to my back wall. My other projectors with lens shift were set up in at least a quarter of the time that it took for this one.

As can be seen in the pictures, the image looks pretty good in a room with a fair bit of ambient light. However, you can see that it is a little, just a little, washed out.

[Dax]

The next projector that I had the opportunity to use and which I still own is a Panasonic PT-EZ580. This one has been discontinued since about 2018 and I believe the prices ranged between US5,000 and US$7,000 during the time that it was out.

This is a very bright projector at 5400 lumens and had a native resolution of 1920 by 1200. Unfortunately, unlike many of the newer Panasonic’s with similar brightness this one just did not have great performance in the area of contrast. Also, another issue that I found was something that can be a problem with most high lumen projectors and that is they tend to shift toward a greener image than normal in their higher settings.

I did not note this in my posting above, but I should note that none of the pictures I am taking are using the dynamic setting as I find this to throw off the colours a bit too much for my liking and it also does tend to increase the noises coming from the fan going at full tilt.

I picked this projector up used for a good price and note that I have seen one listed as high as Cdn$2,000 but think you can get it for a good amount less than that price. I am using mine now for sports viewing in a room where the lights will be kept on and while the sim image was never to my liking it does give a very good image in its current use and will get better once I have a chance to mount my screen in thy at room.

in terms of features, this one has a lot in order to easily get the image set up quickly. Vertical and horizontal lens shifts are very good and allows for a lot of flexibility and it also has the corner adjustment and keystone feature. The issue with the unit that I had was that it sat back at around 18 feet and it also weighs a lot. Given the distance, it was pretty easy to get your shadow showing. However, the great thing about these Panasonic projectors is that you can buy different lenses and one of the available lenses is a short throw and this is what I would recommend if you went down this line of Panasonic projectors. Also, the new ones that are not in the ez range but rather I think they are in the 570 range at 5,000 lumens is that they have much better contrast performance.

Overall, even when it is not in its brightest setting, this thing is a light cannon and projects a very bright image.

Note, the picture was taken on a sunnier day than that of the Epson above.

[Dax]

The final projector that I have had in my room for a short while was an Epson 5040ub. As many of you might know, this is an pixel shifting 4K projector and this should be kept in mind when viewing the images.

At the time I took the pictures, I believe I had it set up at about 16 feet from the screen. This projector is an HDR compatible 1920 by 1080 projector that is rated at 2,500 lumens that received great reviews online when it came out (it has now been replaced with a slightly brighter and better performing projector now). I believe it retailed for around US$2,400 when it was discontinued. I should note that Projector Centals testing measure the lumens on this at 3,500 in its brightest mode in their review of the unit.

I should also note it came with vertical and horizontal lens shift as well as the other adjustment features that made it very easy to set up. Out of all my projectors, this was my favourite in terms of image and everything (but price wise it is more expensive and so not the fairest comparison) but it was bought for a dedicated dark theatre room where it also performs very well.

This pic was a side by side comparison with the Panasonic on a day that was pretty bright.

[Will]

The answer is based on the room's lighting. The required projector brightness is known to be around 50 foot lamberts with some (controlled) ambient light. 16 ft lamberts is a lights-out condition for watching movies and does not apply to a golf sim room. You will be walking around and will have lights near the hitting area. Factor a safe 50 foot lamberts to estimate your needs.

A 16' wide screen requires 30% higher lumens than a 14' wide screen. Here is the math....

Assuming a 16x9 ratio projector, a 14' wide screen has 14'x7.875'=110.25. Sq. Ft.

50 ft lamberts is the goal. So....
50 x 110.25 = 5512.5 lumen projector



Seriously... this is the math.




50 ft lambert goal on a 16' wide screen?
16'x9'=144 Sq. Ft.
50x144= 7200 lumen projector

16'x10'=160 Sq Ft
50x160= 8000 lumen projector

It's all simple math, and nobody will tell you that exactly 48 foot lamberts is the target with ambient light in the room. You must control the lighting. 50 is an easy number to work with, and the room contributes everything. The 30% increase, 16' wide vs 14', in projector lumens should get your attention.

My 8000 lumen, 2160p, laser projector is played in a garage with tinted windows on a 14' wide screen. It is brilliant after the sun goes down, and holds up till late after noon, but there is a period when the light in the garage is more than I'd like. Again, 8000 lumens on a 14' wide screen is equal to 8000/110.25= 72.56 foot lamberts. You have to control the ambient and direct light in the room to get the desired results.

To add to Dax comments.... Horizontal and vertical lens shift is absolutely awesome for the golf sim application. 2160p is way too important on 14' wide and greater screens. You are only 10' away, 4k is very relevant.

"Ambient light" has to be controlled to make projectors perform. If you find that 3500 lumens works for your environment, that's great.

3500/110.25 = 31.250 foot lamberts.
3500/144.00 = 24.300
3500/160.00 = 21.875

Lastly, an overhead projector and lens throw ratio between.0.50 and 0.90 can give you a shadow free experience. This isn't a strict rule, just do the math for your situation.

e.g. 0.70 throw ratio on 14' wide screen.
0.70x14=9.8'

This lens would allow a projector to be mounted directly overhead, in a safe position, with the lens calculated to be 9.8' from the screen.

[Dax]

Excellent summary! Thank you Will!

[Will]

I need to edit the above incorrect statement.

"The required projector brightness is known to be around 50 foot lamberts with some (controlled) ambient light. "


The projector has to produce about 50 foot lamberts of luminance on the screen with some ambient light in the room.


While digging around for the right words, I found a page that better describes what I was trying to say and it even has a calculator.

https://www.projectorscreen.com/what...do-i-care.html