8mm Forum: Exactly which bulb do you buy and why

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Posted by Tom Photiou (Member # 130) on June 21, 2017, 04:23 PM:

Well, this is old and boring subject but due to problems of the past i wondered those of you who use the common A1/232 12v 150w bulb, which version do you buy, what really is the difference between the different versions and why do you or how do you decide to choose?.Andy, the one you sent me is fine, but looking on line after so many years of buying you see EFR, Phillips, Osram, xenephote and prices vary so much, from 4.99 up to super versions costing in excess of £20 each. Are they really that much different, at the end of the day 12v 150w is just that isn't it?

Posted by Dominique De Bast (Member # 3798) on June 21, 2017, 04:46 PM:

The light output depends on various factors : the lens, the support on which you project (that's often neglicted but a grey screen will not give you a picture as bright as a white one), the way the projector is designed (I noticed that some 100 watts bulbed projectors gives a brighter light than a 150 watts equiped one), the shutter (two or three blades) and yes, a bulb can make a difference : I replaced a 250 watts lamp on a Eiki by a 200 watts one and I got more light on the screen. Xenophot bulbs are reputated to give you more light. I guess you see more the difference on a projector that gives you a "normal" picture than one that already gives you full light on the screen but that's just a guess.

Posted by Winbert Hutahaean (Member # 58) on June 21, 2017, 05:30 PM:

What is the voltage output from the projector really gives the impact to the brightness.

The formula will be:

12v bulb at +12v output (a bit) will be brighter but shorter life span.

12v bulb at 12v output will be normal as designed by the manucfacturer both on brightnesa and life span.

12v bulb at -12v output will be dimmer but longer life span.

So your choice.

Cheers,

Posted by Steve Klare (Member # 12) on June 21, 2017, 05:48 PM:

When you are buying a bulb to a code like EFR, you are buying according to a specification, so they really shouldn't be that different.

I guess there are a lot of minimums among the specs. Let's say they all have to average at least 50 hours. Maybe a "better" one might average 55 or 60. The same might be said for characteristics like brightness, but I'd be shocked to hear any of them is twice as good as any of the others: there are just theoretical limits to how much they can squeeze out of the same technologies.

I use Osrams because I can get 'em cheap. When I wind up with other bulbs, 24 hours after I put them in the fact is pretty much forgotten.

Maybe side by side there is a noticeable difference, but it's not that dramatic you'd see it separately.

The internet has made buying lamps a breeze. 10 years ago I'd go into a camera shop and buy an EFP or EFR and pay 25 bucks and have to pick it up in a week. Now I go to a web based seller and pay well under 10. I buy enough for a couple of years at a time and long before I have a lamp crisis! (Usually when I've reached my last spare.)

Posted by Winbert Hutahaean (Member # 58) on June 21, 2017, 06:38 PM:

quote:
When you are buying a bulb to a code like EFR, you are buying according to a specification, so they really shouldn't be that different.

Steve, this statement is from the manufacturer side. Yes this should be giving the same result.

But each of us here has different projectors which have various voltage output. Although, it is designed for a certain voltage output, but due to several problems, the output can go high or low. If the projector goes a bit higher, the EFR bulb will be brighter (but has shorter life).

So for me it is not about the brightness that we should care of, but the white level (what should I say here?).

I have tested different bulbs, and they give different tone (read: temperature). Some has yellowish (cheap bulb), some really white (like sun bright) and some has greenish white tone. And I believe this will relate to the Kelvin...which will give impact to the price.

cheers,

Posted by Tom Photiou (Member # 130) on June 22, 2017, 01:40 AM:

Great replies and thank you. The reason why i asked was simply,as Steve states,the internet does offer so many compared to 20 years ago. The prices range from 4.99 to 25 per bulb and i thought will there be consequences if i bought 10 of the 4.99 bulbs or should i opt for a better branded one for around £7 or £8. In the past i have always been a firm believer in you get what you pay for,however, why would any purchase one for 24.99 but i guess they must do.

Posted by Maurice Leakey (Member # 916) on June 22, 2017, 02:38 AM:

I'm nit-picking here. The A1/232 operates on 15 volts and not 12 volts as stated.
If your screen is not too large I would suggest going for the cheapest lamp as any 150 watt lamp should give quite an adequate picture.

Posted by Brian Fretwell (Member # 4302) on June 22, 2017, 02:44 AM:

There was only one brand I had trouble with (I haven't seen it for years) called Flekta. The lamps failed before the filament burned out as the connections to the pins weren't welded very well and parted company in use. I assume this was due to repeated heating/cooling nd expansion/shrinking at the join.

Posted by Tom Photiou (Member # 130) on June 22, 2017, 06:53 AM:

Maurice, corrected, 15v, my error, [Embarrassed]

Have to add to Brian's comments to, Talking to well known repair specialist some time ago, he made an interesting comment, the bulbs by all manufacturers today dont seem to be anywhere near as sturdy, (pin wise), as they were 10/20 years ago. Since he said that you only have to look at tiny pins and they do just seem to bend so easily, i know they were never like steel poles but the quality of them just isn't there like it use to be. A bit like everything today i guess. [Wink]

I think we will stick with Osram though & there are some very good deals out there. [Wink]

Posted by Maurice Leakey (Member # 916) on June 22, 2017, 10:07 AM:

If quality is wanted then there would seem to be no other alternative than going for an Osram Xenophot.
Most projectors which use the A1/232 lamp have a low/high switch setting, so using the low setting will give an extended life.

Posted by Paul Browning (Member # 2715) on June 22, 2017, 11:03 AM:

Like the headlight lamps Tom, the cheap lamps use inferior leaded glass, and the branded lamps use quartz glass, far superior whiter light, plus the filament position to reflector can be compromised with a loss of focus of the spot of light through the gate to actual film plain. I have been messing with a few different lamps in these reflectors, its important to get this as best as possible, regardless of the lamp type, or else or that energy is wasted.

Posted by Tom Photiou (Member # 130) on June 23, 2017, 01:17 AM:

Great replies and thank you. The reason why i asked was simply,as Steve states,the internet does offer so many compared to 20 years ago. The prices range from 4.99 to 25 per bulb and i thought will there be consequences if i bought 10 of the 4.99 bulbs or should i opt for a better branded one for around £7 or £8. In the past i have always been a firm believer in you get what you pay for,however, why would any purchase one for 24.99 but i guess they must do.

Posted by David Fouracre (Member # 3883) on June 23, 2017, 04:52 AM:

The A1/232 lamp spec is manufactured to a standard specification, however I have in the past, fallen into the trap of so-called disco light A1/232 and these appear to be designed for more rugged handling and claim longer life. My experience with such lamps has been poor centering of filament and requiring a slightly higher voltage. This ties in with the extended life as they are under-run in most projectors. The xenophot lamps are much superior in performance I find.
Regarding the ELC A1/259 24v lamp.
Some years ago I went to show our local guides a film programme and having set-up ok,(new lamp) started the show ok. The leader countdown got to 4 and `phut`out went the lamp!
Into the spares box with apologies to audience and a quick lamp change. Repeat start up and within 15 seconds the new lamp failed!! More red-face!! This time a meter check on voltages - no problems. Third start-up attempt with a well- used lamp with "less than perfect" reflector state and then, crossed fingers for the remainder of a less than brilliant screen illumination!
My lamps had all been purchased from Derann and held as spares for some months. When I mentioned my problem to Derek at Derann, he confirmed that they had recieved a poor batch of lamps with internal spot weld problems between the pinout and filament.

I learnt from this to always run-in a new lamp for 30 minutes before a show.

Posted by Steve Klare (Member # 12) on June 23, 2017, 09:41 AM:

I was at work about a year ago and saw some familiar boxes on a cart. I took a look: Osram, EFR, Xenophot!

-being that I want to be an ethical employee (-and I really need this job...), I just put it down and wondered what on earth a research laboratory needed a projection lamp for.

Later on I found out they are used in microscopes.

It's good to know that these are being used in something built in this century!

Posted by Maurice Leakey (Member # 916) on June 23, 2017, 10:17 AM:

Steve
It also ensures that the Osram Xenophots are still being manufactured.

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