Hi,

I would like to know if anybody practically compared the bulb with same wattage and different CRI values (say 65 and 90)? How does a lower CRI bulb performs as compared to lower CRI value as far as color rendering is considered? Do we see a huge difference in picture quality?

Thanks,
Milind

It will depend somewhat on the lamp. In my pro lens PLOG, I have comparison shots of the older Ushio 400W PS lamp (4000K colour temp, 65 CRI) and the newer LL T15 lamp (6500K colour temp, 90 CRI)

Both work very well, and from the viewers perspective, both looked great. The PS lamp is marginally brighter, so some of the colour looked richer, particularly in brighter scenes. Skin tones looked slightly better/warmer. The 6500K lamp had better blues in the image, and seemed to have a nicer white balance, but skin tones looked a bit pale.

Thanks Supra.

I am posting link to pictures in your PLOG for quick reference.

http://www.lumenlab.com/forums/index.php?s...9344&st=197

Supra

your use of "marginal" seems to cover a wide spectrum. So my question to you is, would it be worth it to you to source a ps lamp(at this time I don't even know if they are still available) if you were currently using the newer t15 lamp? The brighter has me slightly intrigued

Btw, my post to you in that last thread was meant to be a pm... very sorry for putting that out publicly.

My guess is you would say a z06 is "marginally" faster than a kia spectra

Uh, If you were trying to make me angry with that last comment... Meh, whatever.

I own both lamps. Those photos were taken with a Nikon D80 with the settings manually set so that they'd be identical. The pictures were taken about 1 hour apart (20 minutes for the lamp to cool enough that I could remove it without burning myself, and then 30 minutes to fully warm up the replacement lamp.) I'm pretty sure that this is all in the thread.

For what it's worth, I was evaluating whether it was worthwhile to "upgrade" to the better CRI/colour temperature lamp.

I put a luxmeter up against the screen with both, and there's a 4-6% increase with the Ushio PS vs the LL. I'll assure you that the difference is entirely invisible to the naked eye. (This was after those photos, by the way, after the 6500K lamp had a similar number of hours -- or at least a similar timespan in service.) So would I "upgrade" a perfectly good 6500K lamp for the marginally brighter PS lamp? Probably not. The extra dozen lumens or so isn't a very good return on investment. (That's with my LCD, most people DON'T get 250 lumens projected, so it's more like 5 or 6 lumens on that case.) For $50, I can probably do something that will give me a much better return in lumens and image quality. (Or whatever the cost of a lamp is where you live.)

I'll also assure you that in both cases the image is entirely satisfactory when you're sitting down in front of it. Neither I nor my friend (Who owns the aforementioned Nikon D80) could really tell that anything had changed until looking at the pics again. (And I had to check the sequence numbers to tell which was which, since I mislabeled the folder initially.) For what it's worth, my friend with the camera is one of those guys who spends an hour making sure that the colour on his projection is just so.

As for faster... No, I would say that my car was "marginally faster" after I upgraded the intercooler, air intake and intercooler pipes. I spent the money on that, though that was less for "faster" and more for less chance of detonation destroying my engine. (The upgrade increased manifold pressure by a little less than 1PSI, and was probably worth an extra 10-15 horses. Marginally better. I could have acheived the same gain in performance for "free" by turning the knob on my boost controller about 1/3 of a turn.)

no I was trying to make you laugh thats why I put the .

Just sarcastic, I am extremely sarcastic and I forget that that does not come through in a forum with text when people have no clue who I am I am a fool for that.

My marginal comment was from that diy vs commercial thread that I got locked like a noob.

Thanks for the honest opinion, I will not look for a ps lamp.

As for your car I did not follow that thread but would like too. You and I both know that boost psi is merely a measurement for how restrictive your intake is. I have found a common occurance with forced induction is poeple upgrading there intake pipe to a mandrel bent unit and "freaking" when there boost goes down. Most of the time a test drive will allow your seat of the pants dyno to tell you that it is indeed makeing more power.

Just quick stuff, sorry again for derailing a thread

I don't trust my "seat of the pants" dyno much, since it's subject to the same influences as my eyes seeing a "brighter" or "better" image. When I did my AG strip, for example, I did indeed think that the image was brigher, but a test with the luxmeter said that it was not. Effectively zero gain in brightness. Maybe a couple of my 9 point measurements were higher, but a couple were lower, too, so it's all within margin of error. The colours looked better, too, but a photograph of the desktop before the AG strip (with the scratch visible) with my camera on the same settings as compared to an "after" pic, and if it weren't for the scratch, I'd never be able to tell which was which.

I do know what you mean though. Upgrade the exhaust system in the car, and boost pressure goes down, because the car is moving the same volume of air out of the intake with more ease. Therefore it's using more air to burn more fuel and making more power, but a lower pressure. (That happened to me when I installed my upgraded exhaust system too.)

Anyway, quick answer to the question, take a look at the comparison pics, and decide what the better CRI is worth in objective terms. I'd say that from a SUBJECTIVE standpoint, it's moot, and in OBJECTIVE terms, it's a "marginal" improvement. (Yes, that was poking fun.) What I see when I look at those comparisons is that there are a couple of scenes that look better with one, and a couple of scenes that look better with the other, but neither one is clearly superior in all cases. Note also that your results may vary, depending on your particular LCD.

I just looked in my spare projector parts box, i have a ps lamp that I bought when i built my first 15"(oops). When I upgraded to the 10.6" I bought the 6500k Lamp. I am happy with the results so I do not think I am going to switch them out. I think the lamp only has 200 hours on it though so it will be a good backup in 10 yrs LoL

As for the boost, right, just a measurment of the psi in the intake tract, which could be lowered by a free flowing exhaust or intake or heads etc. So with two cars with the same motors and the same super charger or turbo setup(meaning same volume of air leaving the unit), the car with the lower boost level will be faster almost always. One exception could be if one car had an intercooler and the other did not

As for your pictures, I actually could live with any of them so I am not going to change my lamp, although I have been flirting with the idea of buying a 575w setup, although with my 400 and my dalite highpower it is plenty bright, so I think the only thing that could be changed would be the black level with a 575(perhaps I am terribly wrong

As for the "seat of the pants" Most people can tell a hp boost of 10hp or more on their own car, but your right not to go only by seat of the pants. I remember when the ls1 was first released in the f-bodies and we pdi'd the first batch we all thought that it was WAY slower than the lt1. This was simply because the motor has a much broader torque curve so you never got that mega pull that the lt1 had around 3000rpm. We had lots of arguments those first few hours until we finally got off our butts and put two side by side. The ls1 pulled 3 car lengths by 80 and that ended that argument. The ls1 car was also a trans am and the lt1 was a camaro so the ls1 car actually had about 500 pounds on the lt1 which was ultra impressive at the time.