Reefs.org Forums

[Iron]

http://www.reefcentral.com/vbulletin/showthread.php?sc2a070e6feb35cb67253e 797fb914253&threadid=28195 since this is on lighting and corals

[ July 04, 2001: Message edited by: Iron ]

[polyp]

While these pictures are very useful to make relative comparisions between bulbs, it is not meaningful to make absolute judgements about color by looking at the images on each of your respective monitors. This is perhaps why Nathan states the images provide only "an overall idea" of what these lighting setups look like. When was the last time you had your monitor calibrated? Digital cameras aside, these images will look different on every single monitor they are displayed - in many cases, significantly different.

Mac:
Bit depth, dynamic range, and white point are all going to determine the effective working color space. In order to capture a greater dynamic range, use HDR(High Dynamic Range): an image created by bracketing exposures with a camera and combining with a computer. To create and view it appropriately, check out the following link:
http://www.debevec.org/FiatLux/mkhdr/

The fellow that did the majority of coding for the toolset above works in our R&D dept.
The resulting images will be 32 bits per pixel (yes, 32 bits!). Again, it is important that your monitor is calibrated - and even so, you cannot see the full dynamic range of the High Dynamic Range image all at once (you must 'window' through it in 'stops') because a monitor simply isn't capable of displaying the full gammut of such an extended color space.

[Snailman]

It would be nice to see a pic of those Iwasakis on a ballast specifically made for Iwasakis. From what I've heard they look completely different and lose that green/yellow tint.


Chris

[john f]

Chris,
I ran them on the recommended MV ballasts years ago and found them very yellow.
Not sure about the newer Carbon resistor models on MV though.


John

[ReefQuest]

How many actintic blue pc's do you think it would take to give the IWASAKI's the same look as the USHIO's? I like the look of the USHIO's best, but also like the $59 price of the IWASAKI's!!!

Chris

[Nathan]

David,

Ok, Hmmm... that's really interesting. I guess Nikon cameras can't capture the violet blues very well then. That's odd, and kind of disappointing (since I have the CP990).

Thanks for pointing that out.

-Nathan

[ReefQuest]

It's not just Nikon. I have an Olypus 3040 and I get the purple tang effect, too, unless I use a flash! Check out these pictures of my blue maxima. The first one I used a flash. In the second picture of the cleaner shrimp I did not use a flash and you can see the difference on the clam.

[canadawest]

I'm curious why the people who said they like one lamp over another made that decision?

I would suspect that it was a purely esthetic reason? Aka - which one looks nicer to the human eye?

Isn't more important to choose based on what is best for the inhabitants? It seems obvious to me that the Iwasaki lamp is much more intense (brighter reflections off the corals in the pictures than the other lamps) and the 6500K lamp is closer to natural sunlight than the 10K lamps that are more "pleasing to the eye".

Now I know that Nathan is not using any supplementation, but wouldn't it be better for the inhabitants to utilize the full spectrum 6500K lamps with a couple actinics so that the entire range of sunlight is offered to the reef inhabitants?

I am just offering an opinion, which I will qualify by saying that while I don't yet use MH lighting, I have been studying a bit about PAR and K rating in the hopes that when I do decide to add MH lamps that I make the decision based on what is best for my corals and fish, not what is best looking to me. With that said I should also mention that I am not for/against any particular brand or type of MH lamp, just looking for other's experience and opinions.

PS.. Great job on the comparison. One of the best (and useful) apparently neutral comparisons I've seen.

[ July 25, 2001: Message edited by: canadawest ]

[David]

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>Originally posted by Nathan:
<STRONG>djt,

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.
</STRONG><HR></BLOCKQUOTE>

Hello Nathan,

I also have a Coolpix (880 for me) and I also have the same bad result when shooting blue fishes and fishes not other blue invertebrates in the tank.

Have a look at : http://membre.ara.free.fr/david/Dscn0058.jpg
or http://membre.ara.free.fr/david/Dscn0094.jpg

I think that this color problem is more linked to Nikon than linked to the technology used by numeric camera. Coolpix (880, 990, 995 ?) have the same cell (captor) as Sony DSC-S70 for example, and if you take the same pictures with a Sony then the colours will be correct.

Just have a look at pictures in :
http://membre.ara.free.fr/david/cp880

As you can see there is no problem with the Sony...

David

[SteveMH]

Hi,

Wanted to let you know that this comparison has been extremely helpful! I'm setting up MH for the first time and this information really helped. From what I understand Ushio is the same as 10,000K? I'm a little confused on that because I noticed the Blueline is also 10,000K but it's way darker. My ballast is only 175 watts. I am thinking of trying two German 10,000K's and maybe running my two PC actinics with them. Too much blue ya think?

Thanks,
Steve

[DK]

Nathan,

Pics are very interesting. How many hours have the bulbs been used? There is usually a slight color shift during the first 50(?)or so hours and then a slow change over many months. So, are all of them of a relatively similar age?

[Len]

It should be noted that the correlation between PAR rating and "good for corals" is not entirely accurate. PAR values indicate the intensity of photosynthetically active radiation, but independent spectrums are not weighted for their photosynthetic efficiency in particular circumstances. Although photosynthesis can occur throughout the PAR spectrums (400-700nm), certain organisms utilize different spectrums more efficiently, based on their photosystem and light-harvesting pigments. To say higher PAR value = better is an unwarranted statement. Spectrum is a VERY important factor to consider.

In relation to our hobby ....

The greatest coral biomass is located below 3 meters of water. Only the more resiliant species will tolerate the rigors of living in the upper strata of water. Below 3 meters, the upper spectrum is significantly attenuated. Hence, it is not implausible or illogical to suppose that over zooxanthellaes' life history, corals have become better equipped to utilize - say - 420nm then 650nm. Not all PAR spectrums are equal, but PAR values treat them as such.

The moral of the story is: do not treat PAR as the ultimate factor in bulb decision. Use it as a guideline, but realize it is only half the story. People seem to miss this point quite often.

Food for thought: if you shine a high-intensity red spectrum light (eg LED) on most reef orgnanisms, you'll get no reaction. This includes fishes, photosynthetic and nonphotosynthetic bivalves, worms, and corals. Now, if you shine a high-intensity BLUE spectrum light on these same organims, they react instantaneously to the stimuli. This anecdotal obervation is very telling.

[eaglet]

there it is thanks for all the hard work. Eaglet

[Psyduck]

I just like his tank [img]images/smiles/icon_smile.gif[/img]. Nice tank.