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smokinreefer

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first off, thanks for the pics Nathan, it'll help out alot of people.
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secondly, altho i will still be using Iwasaki's on my up and coming 135, i really like the look of the Ushio's from the pics.
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Nathan1

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djt,

Here's the explaination as to why some blue fish look purple on your minitor and why when you photograph actinic bulbs they look purple on your minitor.

Your monitor (and all digital cameras) has three colours, Red, Green and Blue. Using these three colours it tries to represent the entire colour spectrum as best as it can.

So, what does it do if it is trying to represent a colour which is more violet than blue. Notice I say "violet", not "purple". The two colours are NOT THE SAME. What does it do if it tries to represent a colour wavelength below the blue phosphour. Well the answer is "IT CAN'T". So what it does instead is mix a little red with the blue and turn the pixel purple.

No monitor can represent violet or any blue below the wavelength of your blue phosphor. So yes, no digital camera can produce an accurate representation of a subject, but it can come pretty close. For example no camera or monitor can display yellow. Instead it mixes red and green, but it you were to look at the colour spectrum it would not show yellow, it would show red and green. It's because our eyes have only three colour receptors.

Have you ever wondered why some people's tanks look purple, or the actinic lighting looks pink/purple. It's because of this limitation.

So, yes, these photographs are not 100% exactly what you will see, but they are pretty close, APART FROM THE PURPLE BLUE TANG. This tang appears blue all the time in all bulb combinations. It won't all of a sudden look purple to you.

djt, you have a good question, but you are just going to have to trust me on this, it looks purple because of the monitor and/or camera, not because it really looks that way in real life.

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-Nathan

[ July 01, 2001: Message edited by: Nathan ]
 
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Anonymous

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I think I've got it. You're saying that if there's any quantity of violet in the lighting in those pics, red and blue are substituted for it, right?

Thanks,
John
 
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Anonymous

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Great job!!! It is hard for me to decide on which bulbs. I like the ushio and the sunburst. Does anyone have any thoughts on those two. Also I just bought two ballasts on ebay and was wondering where to pick up the rest of the outfit. Bulbs, and base. Any help will be appreciated.


RLTW
 

Nathan1

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djp,

You got it!
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Sounds easy the way you explain it. I tend to overkill explainations.

-Nathan

PS Using your simple explaination, it can also be said that if there is any yellow, the camera and monitor will mix red and green together thus "simulating" yellow. But let's not get too deep into that on this thread.
 

Emmitt

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Not to beat a dead horse, but how come the Tang looks blue under the Iwasaki? IMO, the Iwasaki pics are the only ones that look like a real reef. <G,D & R>
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Great work, btw. Thanks for taking the time and effort!!!
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[ July 01, 2001: Message edited by: Emmitt ]
 

Nathan1

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Here is exhaustive photos of my 75g tank lit with different types of MH bulbs WITHOUT ANY SUPPLEMENTAL LIGHTING:
All bulbs are 400W except one photo with 175W

Iwasaki 400W 6500K DL (the new type with carbon resistor) (1 month old)
Ushio 400W 10K German (aka Hamilton) (9 months old)
Sunburst 400W 12K (2 months old)
Blueline 175W 10K+ (9 months old)

Camera: Coolpix 990 3.34Mpix
White balance calibration: Sun and blue sky against pure brilliant white paper taken outdoors
Shutter speed: universally stable @ 1/60s
Apature: universally stable @ 3.1f

This means that the camera is not allowed to correct for colour, or brightness. All photos are as accurate as can be allowed with modern technology. No post colour or brightness adjustments have been made. What you see is what you get.

reef_light_comp_ani.gif


reef_light_comp.jpg


reef_light_comp_bulbs.jpg


-Nathan

[ July 01, 2001: Message edited by: Nathan ]

[ October 19, 2001: Message edited by: Nathan ]
 
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Anonymous

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I must say I am a big fan of the Iwasakis. I have a 400W on my 75g (but will get a second ASAP) with 4 2' actinics and the colour is good. I also have 4 2' 6500K tubes which I may replace with actinics when I get the new lamp. I think the actinics with the Iwasakis fluoresce the corals better then some 10000Ks I have seen.
By the way, great pics.
 

Mac1

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<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR> Actually, the hippo tang looks blue all the time under all these bulbs. The reason why it looks purple in the photos is
because some blues cannot be represented with the RGB phosphors of digital cameras and monitors, so ultra violet blue
ends up being protrayed as purple, which is not a true representation of the colour.<HR></BLOCKQUOTE>

Ummm... not to pick a fight, but I can show you a hundred digicam pics of Hippo Tangs that don't look Purple-pink. It's not a limit specific to the RGB Spectrum, more a case ofa limitation in the Tonal Range of the CCD or accompanying software.
Take it from someone who deals in RGB and CMYK(OG) for a living... it's the camera allright.

- Mac
 

kazzoo

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Very nice Nathan!
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Thank you.

It is interesting to look at the bulbs in progression, from iwasaki - ushio - sunburst - blueline, and envision seeing snapshots of a reef at increasing water depths with the iwasaki being very near the water surface and the sunburst being very deep, with the ushio somewhere in between. The blueline looks too dark.
 

playfair

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Man, your fish must be goin nutz after that test! LOL

Yeah, it's definitely the camera. RGB can be transmitted to create ANY visable color. I once read that most consumer camera CCD's have some type of balancing filter to even out it's sensitivity, or maybe to emphasize certain blues. The hippo is picking up a frequency from the ushios that causes the camera to "go nutz". Sometimes my Sony does this (especially with actinics on), but I am totally amazed and disappointed that a new 990 would do it!
 

Nathan1

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Playfair, Mac, and others wanting to know about the purple hippo tang:

Don't forget that I did not allow the camera to automatically adjust for colour at all. Usually the camera is on auto white balance, which means that it automatically changes the hue to compensate for such a situation as this.

If I had allowed the camera to correct itself, then you wouldn't see the proper colour of the light from the bulbs (it would try to make all the colours "neutral"). I purposely limited the functionality of the Coolpix 990, so don't think that it's some how flawed. This is a great camera.

Playfair, I have to disagree that a camera can represent all colours of the spectrum. It cannot represent any wavelength below the blue colour detection CCD or above the red CCD. Actually it can only detect Red, Blue, and Green. Why? Because we as humans can mainly see colour in Red, Blue, and Green, so why bother having it be able to detect colours that we can't, like yellow for example. There is no such thing as a yellow pixel; a computer monitor or digital device uses a mixture of red and green to fool or "trick" our eye into thinking that it is seeing yellow, but it's not really yellow. Some bees can see UV light that we humans can't, and so they are naturally attracted to certain flowers, in the same way we can see light that digital devices can't, such as "actinic", or "blacklight" at a party. Ever try photographing a blacklight party lamp? The result is not anything like what you see in person.

I find this topic very interesting.
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-Nathan

PS Don't let this semantic detract from the main purpose of these photos, and that is to give an "overall idea" of what these bulbs look like. I spent a lot of $$$ on MH bulbs because there was never a service like this before, so I decided to do everyone a favour and let you get an idea of what you will be getting. It may only be 99% accurate, but that's ok, your pixels don't do my tank justice!
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[ July 02, 2001: Message edited by: Nathan ]
 

srbayless

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Howdy,

Man, that is an awesome comparison.

I never new the 400 Iwasaki was that much large than the Ushio. The inner bulb looks to be twice as large as the other bulbs'. Could this explain why the Iwasaki's ouput is so much higher?

You can really see the intensity difference in the SPS in the lower left frontside. You can see alot more detail inside the coral with the Iwasaki than the Ushios.

Thanks,

Scott.
 

swreefer

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Thank you. I think I finally found a bulb that will give me the blue look I want. Time to buy a Sunburst.
 

Nathan1

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You know, one of the most rewarding thing about this post is that everyone has different taste. Some say, "thanks, I'm buying a 'such and such'!..."... I'm glad my photos help people decide.

My personal favourite is Ushio. I don't have much actinic so Iwasaki's look too darn green for me.

-Nathan
 

Mac1

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<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR> Don't forget that I did not allow the camera to automatically adjust for colour at all. Usually the camera is on auto white balance, which means that it automatically changes the hue to compensate for such a situation as this.If I had allowed the camera to correct itself, then you wouldn't see the proper colour of the light from the bulbs (it would try to make all the colours "neutral"). I purposely limited the functionality of the Coolpix 990, so don't think that it's some how flawed. This is a great camera.
<HR></BLOCKQUOTE>

Sorry man, but it's nothing you can control... the CCD is limited in the tonal range it can capture, that is further limited by the software encoded on the Camera. And I don't mean the stuff you can turn on and off like white Balance.

By the sounds of things, you don't need a primer in additive color theory, however for those that do: http://www.techcolor.com/help/rgb.html

The topic you're dancing around however falls into the category of Dynamic range more than color space...
http://www.dpreview.com/learn/Glossary/Digital_Imaging/Dynamic_Range_01.htm

And what I think you're trying to suggest, is that the Nikon is not limited in Dynamic Range. This is also very false, but an entirely different matter.

If you don't believe me, ask yourself why film photographs always seem to look so mucb "Richer" than digipics? Take it from someone who reproduces images for a living, it ain't the resolution.

- Mac
 

Mac1

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Actually, now that you've got me thinking about it (WOW, haven't used those Brain Cells since College), it's more a matter of bit depth than dynamic range... while somewhat related, they're not the same. Your Camera is only a 24 bit device... captures 8-bits (or 256 shades) of information per color... times 3 colors (RGB), gives you a total of 16 million possible color combinations... nowhere's near what's possible with all the wavelengths of visible light

- Mac
 

playfair

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Nathan, don't get me wrong, you did an awesome job (made history? lol), and I believe that all but the hippo is true to life color.

I'm not disagreeing with your explaination, as the CCD is limiting. However, a monitor or any projection device uses RBG pixels because any visable color can be created with them. For reflected colors, the same applies to Magenta, Yellow, Cyan. (The old subtractive/additive color thing). That's all I was getting at.

Hope you are gonna sell the lamps you don't want!

Oh, BTW, the only "flaw" in the test was that teh USHIO lamps were 9 months old, which by many accounts is past their useful life...
If you replace them with new ones, perhaps another set of pics comparing the 9mo old to new?
 

Nathan1

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I used the standard PFO ballast that I bought from marinedepot.com. It fires all these bulbs without any problem, except the SunBurst takes about 5 seconds to fire. The Iwasaki and Ushio come on within the first 0.5 seconds of flipping the switch.

-Nathan
 

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