Brand New Reflector for Sale

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#2
hey rbraithewaite,

how is your diy projector going? and which projection panel are you using as i was interested in the sharp 1150 that you got off ebay recently, but i thought the price was a bit too high for a bare panel without any cables :xeye: but i am interested in seeing what people in the uk have managed so far, i am still awaitng my nview panel😀 so hopefully i could get started soon🙂
 
#3
Hi there,

The unit's going pretty well at the moment - had a few hiccups but it should hopefully be running later today! The only real problem I had was realising that I needed the metal halide lamp positioned parallel to the fresnel, panel etc. and not at right angles pointing towards them - hope that makes sense. Also realised the importance of getting the distances between everything correct! I've basically opted to base it on a standard overhead projector design for which I've stripped an old ohp. So mine looks like a giant ohp but with a 400 watt metal halide lamp (seriously bright). Anyway, when it's finished I'll put up some photos of how I've gone about it in case it's of help to anyone.

Yep, you're dead right, I paid over the odds for the Sharp QA-1150 panel but as the Proxima 846 was taking an age to arrive from the US I was desperate to get on with the build. Although it had no cables I bought a power supply new off the web for £12 and built the VGA cable for another £12 using wiring diagrans posted on another thread. In fact, I'm going to put in on ebay during the next couple of days if you're interested?

Cheers, Rich
 
#4
I have just gone the easy route and bought a overhead projector, its pretty decent as its 3500 lumens and it seems to be bright enough for my room anyway, but the nview panel i mentioned arrived damaged due to the courier no doubt throwing it about, as the rear glass was shattered and thus all the pieces of glass were scratching against the rear of the lcd screen, which is a shame as it was in immaculate condition, now i have big black blotches all over the projected image, although the nview is quite bad in relation to vertical scan lines that appear at the hint of any movement in the picture, i was pretty happy with the image displayed as it was quite sharp. Maybe i will have to get another panel but im trying to get the seller to help me claim something out of the courier. and also have you got your sharp 1150 and 1200 panels working yet? as you were looking for the psu for them in your earlier threads, and your proxima, how long have you been waiting for that as it seems like thats the only place i could get hold of another panel from:xeye:
 
#7
Hi,

I'm also working on a projector in the UK and have been doing so for about six months now. Up until last week I was working solely on my upright 'from scratch' projector. My design is a 400W MH with a custom ellipsoid reflector built from polished aluminium. My LCD panel is a 3M 5600, 640x480, 100:1 contrast, custom built interface cable - its not really fast enough for action films, but is definitely bearable. My objective is a 8" diameter f=400mm PCX. Yes, its rather big.

Last week I took delivery of an OHP that I bought from ebay almost 3 months ago just for the fresnels - within that three month period i got my hands on a couple of spare OHP fresnel sets, but decided to take delivery of the OHP anyway. I stuck my panel on top turned it all on, and all of a sudden it seemed like all my hard work over the last six months had been dashed! I'm sure that feeling will disappear once all three supplied bulbs have gone!

Im now considering retrofitting the ohp - it would make other things much easier (focusing, calibration etc.) if I can do it. The only problem is the size of the MH bulb, and possibly heat transfer problems.

rbraithwaite, if I had seen your reflector auction on ebay three months ago I would have been jumping for joy, I must have spent three or four hours looking for something suitable!
 
#8
I know exactly what you mean. Over the last couple of months I have been slowly building myself a projector. I assumed with the 400 watt MH lamp, Proxima +846 panel, etc, etc it would be amazing, super bright and far superior to any ohp.

However, after numerous redesigns and tweaks it still palls in comparison to using my ohp (a 3M 9550). Not only is the ohp infinitely better quality, it was much much cheaper, at £50, was ready to use immediately and is a damn sight smaller! I don't think the majority of people, and until recently this did include me, realise how complex and well designed a good quality ohp is, e.g. the triplet lens is awesome in comparsion to any plano-convex lens you can buy on the cheap. Why on earth did I think I was smarter than than 3M?

Guess I'm just a bit frustrated with the results of all my efforts to date. Think I'll wait a few days to summon up my energies to tackle it some more - back to the drawing board I'm afraid!

Best of luck to the rest of you, Rich
 
#9
Built vs. OHP

I know what you mean, Rich. I too had thought that building one from parts would be superior to a plain ol'OHP! After spending hours trying to figure out reflectors and such, I'm having such good luck (and ease) with using the OHP that I'm not sure that its the best way to go. I've got a question for you though, do you find that you have a better picture (in terms of color tone, etc...) with the MH bulbs than you do with the halogens that come in most older OHP's? The reason I'm asking, my OHP has a 600W halogen that seems plenty "bright" enough, but I think due to its color temp that its making my picture reddish/yellowish. I've been contemplating and gathering the parts to switch it over to Metal Halide, but didn't know whether it was worth the effort. Anyone have any side by side comparisons with halogen vs. metal halide run through the same system??
 
#10
My ohp is a fairly new model so perhaps I don't have the same problem as you. However, the focusing lens has a blue filter on the outside which I beleive compensates for the yellowish colour of the light output (I guess it's like indoor photography where artificial lighting makes your photos yellow). I reckon you can simply correct it by buying an appropriate filter from a decent camera shop., e.g. I bought a blue filter for taking indoor photos for my SLR and it cost about £12. Also, they come in a variety of sizes to fit a variety of lenses so you should be able to find one that would do for your ohp.

Hope that might be of some help?

Rich
 
#11
Thanks, Rich

Mine doesn't have any color filters on it. It's a pretty old OHP. I'll do some research into those filters and see if one might help my situation. I may still switch have to switch to metal halide, but would like to avoid the trouble if I could. I wonder how much the filter would reduce my lumens output? Very interesting....Thanks for your help, Rich, I'll start investigating down this path now. Randy
 
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