Andy Reed
New Member
Hi,
I’d like to get an idea of whether I’m in the ballpark for light levels but unfortunately don’t have access to a PAR meter. I’ve been wondering whether there are any alternative methods of getting a rough gauge of light level.
Would it be feasible to use the metered result of photographing a reference which is known to be at a given PAR as a basis for adjustment? Lets say someone knew the PAR measured at a certain piece of coral in their tank and photographed that coral using a 100mm macro lens at f2.8, 1/100th sec and ISO 1600. That photograph would have a certain RGB histogram. Does it make any sense that if I were able to adjust my lights to yield the same histogram under those settings, then I have achieved roughly the same PAR? I would expect the result to depend upon the reflectivity of the subject so maybe it would be necessary to use a common subject as reference rather than a coral.
Please accept my most likely very crude understanding of PAR. I may be missing something critical to this and I’m keen to learn whether this kind of approach could provide a rough guideline. At the moment I have no idea whether I'm even close.
Many thanks,
Andy.
I’d like to get an idea of whether I’m in the ballpark for light levels but unfortunately don’t have access to a PAR meter. I’ve been wondering whether there are any alternative methods of getting a rough gauge of light level.
Would it be feasible to use the metered result of photographing a reference which is known to be at a given PAR as a basis for adjustment? Lets say someone knew the PAR measured at a certain piece of coral in their tank and photographed that coral using a 100mm macro lens at f2.8, 1/100th sec and ISO 1600. That photograph would have a certain RGB histogram. Does it make any sense that if I were able to adjust my lights to yield the same histogram under those settings, then I have achieved roughly the same PAR? I would expect the result to depend upon the reflectivity of the subject so maybe it would be necessary to use a common subject as reference rather than a coral.
Please accept my most likely very crude understanding of PAR. I may be missing something critical to this and I’m keen to learn whether this kind of approach could provide a rough guideline. At the moment I have no idea whether I'm even close.
Many thanks,
Andy.
