DLP vs LCD

captainarchive · 08-04-2009, 1:12 PM

Having had a Panasonic PTAE 200E for several years now, I'm thinking about upgrading to a HD projector. I've never had a DLP pj and was thinking about getting an Optoma HD65 as it's in my price bracket. I don't really want to pay too much more than £600. However I've read some people have a problem with eye strain with DLP pjs which is of concern to me. I wouldn't want to buy a pj and suffer from using it and there's no where locally where I can audition a pj. I'm not aware of any LCD pj's at the same price as the the HD65so are there any decent ones at a similar price point? If not how common is the eye strain issue?

kbfern · 08-04-2009, 1:59 PM

It's not so much eye strain as whether you will see the rainbow effect or not.You need a demo to find out.

Even if you see it, unless it is very frequent sighting of rainbows it will probably get less over time as the brain will compensate.

As stated earlier get a demo,go to a retailer who sells pj's and take a look or you may find a member locally who will give you a demo of their pj.Where are you? maybe someone will offer,I am in the midlands and would be happy to give you a demo.

captainarchive · 08-04-2009, 2:36 PM

Thanks for the offer kbfern. But thinking about it I'm going to be in Derby at the weekend, are there any shops there I can demo a projector.

wild_quinine · 08-04-2009, 4:26 PM

Quote:

Originally Posted by kbfern

It's not so much eye strain as whether you will see the rainbow effect or not.You need a demo to find out.

Even if you see it, unless it is very frequent sighting of rainbows it will probably get less over time as the brain will compensate.

I probably don't know enough about projectors to comment. I'm an AV layman.

But it seems to me that the 'Rainbow effect' is the scandal of the industry. When I was first looking for a projector a few years ago I was assured that only a very small percentage of the population could see this mystical rainbow effect - and not just by some salesman, but by many reviews and supposedly impartial sites on the internet. Hell, you can check wikipedias articles on DLP projectors, and the rainbow effect is only mentioned as being a problem with 'older' projectors. The figures I'd seen originally suggested that - maybe - 5% of people would suffer from 'rainbows'.

So I bought a 2nd Gen DLP projector, with 2x colour wheel. And I found it utterly unwatchable.

I would just have assumed that I was one of the (un)lucky few, given what I'd read. But then something strange happened: every single person who sat down in front of it actively complained about the rainbows.

I didn't need to prompt them, they weren't looking for anything, they didn't know what my projector was, how it worked, they didn't know I wasn't happy with it, they weren't asked to comment. Every single person was awash in rainbows.

I got rid of the damn thing immediately.

It is entirely possible that the technology has come a long way, that my projector was a POS, that there was something wrong with the model, that lighting conditions weren't optimal and 101 other things.

And maybe with modern DLPs, even the budget ones, the 'rainbow effect' has really, honestly, been 'virtually eliminated'.

But I was so appalled at how much BS there was surrounding the issue that I've now been put off for life. I wouldn't get another one now if they came with free spare bulbs and ice cream.

kbfern · 08-04-2009, 4:46 PM

They have come on a long way since the dlp machines you mentioned.For a start the speed of the wheel is now 4x/5x even 6x and the amount of segments also makes a difference.

I don't see that many people these days complaining about it in relation to how many are sold.Those that see it often say it gets less obvious as time goes on.

Don't be put off as dlp has may advantages over LCD with only the one drawback of rainbow IF you can see them.

And one more negative I supose is that most don't have lens shift unlike LCD pj so that means they are a bit more fussy where you can place them in relation to the screen.

I had an LCD before my current PJ and find the dlp pj has a more vibrant filmlike quality and no screen door effect.

captainarchive · 09-04-2009, 9:27 AM

Anyone live near Derby who can recommend a shop I can visit to audition a pj?

Dav1dF · 09-04-2009, 9:36 AM

The rainbow effect is generally associated with older projectors since they use less colour wheel segments etc. But, this also plagues newer projectors as well, as manufacturers are trying to make DLP mass market by bringing the cost down. One look at a sub £1k DLP projector will show this. You have to spend closer to £5k to eliminate RBE, but even then, those that are susceptable to it are still likely to see it.

kbfern · 09-04-2009, 9:57 AM

David I don't agree that you have to spend £5k to eliminate it.I spent £495 on my Planar 7010 projector and very rarely see rainbow.

I have seen a Optoma HD70 and HD65 which also only gave of mild RBE and these are cheap <£600 pj's.

Slow speed and the number/arrangement of colours on the segment wheel seem to determine how much you will see RBE.

You either see rainbows or you don't and some that do see them frequently and can cause nausea.Some only see occasional flashes as I did initially but after watching a few movies my eyes/brain have become accustomed to RBE and now see maybe a couple of flashes during a 2 hr movie.

Siamese Cat · 09-04-2009, 10:39 AM

I don't agree that you have to spend £5k either. Nothing like.

My first projector was an NEC LT75z with a 2x colour wheel. I used to see rainbows pretty frequently as did my wife and regular visitors to see a film. About 4 years ago I upgraded to a BenQ PE7700 which has a 4 or 5x speed wheel, I forget which. I can't remember seeing a rainbow since, nor can any of the people that did see them on the NEC. However I also have to say that even when I did see a rainbow it didn't bother me that much.

The BenQ cost about £1500 and that was 4 years ago. It would be significantly less now.

Have a demo with a pj that has a wheel of reasonable speed to see how it affects you.

It seems that the individual susceptibility to a) seeing the rainbow effect and
b) how irritating you find it varies widely. However I've never heard of nor seen a properly conducted study of the problem. In the absence of such a study any opinions you read are going to tell you more about the individual reaction to RBE rather than it's prevalence. What we can say for sure is that projectors with slow colour wheels will show the effect much more than those with 4x or faster wheels. The speed of a colour wheel is easy to check from specifications.

wild_quinine · 09-04-2009, 11:22 AM

Quote:

Originally Posted by Siamese Cat

In the absence of such a study any opinions you read are going to tell you more about the individual reaction to RBE rather than it's prevalence.

I don't disagree, but for me this is a reason to avoid, rather than approach, DLP tech.

I will come clean here: I couldn't cope with the rainbows. Every time one appeared it felt like my eyes were being jerked across the screen to a new focal point that simply wasn't there. It made me feel sick.

And I should note that past experience is no guide to how likely you are to get sick because of rainbows. I am not a sickly person. I have a damn near iron stomach. I don't get travel sick, I don't get motion sick, I can eat almost anything... I did get seasick once, so I'm not impervious or anything; but the waves were twenty foot high. Boy, I was a totally different kind of full colour projector that night, I've got to tell you.

Anyway: the point I would like to make is that, although I could not cope with the DLP projector I bought, and had to get rid of it, I would probably have tried another at some point were it not for the opinions-presented-as-fact and other bull poop surrounding the issue.

I took advice from what I think of as all the right places and it simply wasn't truthful, or accurate. And so now the only evidence I would trust would be that of my own eyes, in a demo. But even then, I don't know how things would be at home, or over prolongued periods, or at different settings.

So I'm done with DLP, and the reason is not my strong reaction - although I did have one - it's that I couldn't get good information about this, and I'm not sure I can even now. Once bitten, on that front.

Heck, just take a look at the wikipedia page on DLP projectors, and watch it glossing over stil current issues. It reads like it could have been written by Texas Instruments.

Siamese Cat · 09-04-2009, 1:28 PM

I wonder, wild quinine, if you had a faulty dlp projector. Your reaction was clearly very strong but I really don't remember reading of anyone having such a strong reaction to a modern projector. What was the projector that caused you such a problem?

The DLP versus LCD topic is one that has been discussed for years and years and there are loads of people who have chosen to go the dlp route for a better picture. It is now rare to read of people who are bothered by the rainbow effect. As i said in my last post I've never seen anything on the scale of the incidence nor on how alienating it is but I suspect that both are now quite rare.

That said I do of course accept that for some the rainbow effect is completely unnacceptable. I do remember a thread - years ago - in which some of us were speculating as to the reason for this, was it to do with the eye or the brain. We ended up accepting that we hadn't a clue!

I have to say that when people see my projector in action for the first time I have never - not once - had anyone mention rainbows unprompted. They used to with the NEC. When prompted I have only had one person agree he'd seen one. Just one. Ever. Not scientific, I know, but quite a lot of people have seen it.

Usual reaction... Wow, where can I get one of those followed by what does it cost.

Ivojo · 09-04-2009, 1:41 PM

The closest I've ever come across to an explanation is our differing flicker fusion threshold (worth Googling). It's the frequency at which our eyes stop seeing pulsing light and start to see solid light and varies from person to person.

I've been a bit unlucky with this as I've started suffering from the rainbow effect later in life. I don't consciously see it very often but I do find even 4 and 5 speed 7 segment DLP projectors a strain to watch for more than about an hour without a break.

Dav1dF · 09-04-2009, 1:43 PM

Quote:

Originally Posted by kbfern

David I don't agree that you have to spend £5k to eliminate it.I spent £495 on my Planar 7010 projector and very rarely see rainbow.

As I have already said, some people are more prone to it than others, so the figure will vary. For me, having installed and viewed many projectors, I've found that I can see RBE on virtually all DLP projectors below £5k, so are out of my shortlist of possibles.

Quote:

I have seen a Optoma HD70 and HD65 which also only gave of mild RBE and these are cheap <£600 pj's.

Having installed a HD65, I have to admit the RBE was too much for me to live with.

Quote:

You either see rainbows or you don't and some that do see them frequently and can cause nausea.Some only see occasional flashes as I did initially but after watching a few movies my eyes/brain have become accustomed to RBE and now see maybe a couple of flashes during a 2 hr movie.

Agreed, but for some, it's annoying to the point of even seeing it twice in a movie is offputting.

How much RBE is noticable is not only down to low PJ spec, but also how far from the screen the PJ is. A PJ which is situated further away from a screen is normally not as bright, making for a lower contrast ratio when compared to a PJ that is closer to the screen. The PJ coser to the screen shows RBE more.

captainarchive · 09-04-2009, 4:28 PM

This reminds me of an issue we had at work with people being sensitive to flourescent strip lighting. We had another team merge with ours and the people who joined us previously worked in an office with tradition lightbulbs. When they moved into our offices two people started to suffer from eye strain and headaches. H&S concluded it was down to the flourescent lights. Out of 11 people they were the only two who were suffering. Fortunately it was possible to accomadate them in an older part of our building with lighbulbs and their headaches stopped.

jacko5 · 09-04-2009, 5:01 PM

Quote:

Originally Posted by Ivojo

The closest I've ever come across to an explanation is our differing flicker fusion threshold (worth Googling). It's the frequency at which our eyes stop seeing pulsing light and start to see solid light and varies from person to person.

I've been a bit unlucky with this as I've started suffering from the rainbow effect later in life. I don't consciously see it very often but I do find even 4 and 5 speed 7 segment DLP projectors a strain to watch for more than about an hour without a break.

That is exactly my experience and I am of mature years (sounds better than old) and my tolerance has decreased to the extent that I was forced to part with my Sharp XV-Z21000, not due to rainbows, I only saw the odd one. My problem is eyestrain. I have put more hours on my Sony HW10 in 4 months than I did in a year with the Sharp.
I am hoping that the problem will not be present when the 3 LED single chip DLPs eventually come out.