COLORRIGHT works better with flash than competition

[Doug_Kerr]

Hi, Drew,

Originally Posted by drew

There are issues with its use for stringent measurement.

Which are what?

Depending on where I click on the whibal I can get a pretty good variety of readings.

Any chance that the illumination on it wasn't uniform? Often happens when it's close to another object.

Maybe your WhiBal's reflective spectrum isn't uniform across its surface. You have a reflective spectrophotometer (as you have pointed out, I don't) - you could look into that. What a scoop if you could prove that your WhiBal was "mottled".

Best regards,

Doug

I appreciate this test. Doesn't look that bad to me, either.

Now let's see the expo product.

That's the whole point here.

There is no good way of taking an incident reading with a flash attached. Expo recommends locating a mirror or a wall and blasting the flash back from the reflection to get a reading. So it is a reflective reading. It is a fair comparison. The mirror suggestion is just to overcome the underexposure I suppose, but certainly wouldn't mix the ambient light in well. Try shooting them both the same way off the subject 5 or 6 feet away as any normal person might do, not using a mirror.

Also, why try and suppress the ambient light. Let it in a la a normal reception shooting situation.

I much prefer flash used as "fill" rather than as a single key light. Much too harsh for my taste.

Maybe your WhiBal's reflective spectrum isn't uniform across its surface. You have a reflective spectrophotometer (as you have pointed out, I don't) - you could look into that. What a scoop if you could prove that your WhiBal was "mottled".

The WhiBal is that of the colleague pictured (Braulio Polanco). Perhaps I will check it out.

Although, I'm not trying to down anyone else's product. I am simply trying to point out the strengths of this one. In my mind the WhiBal doesn't really compete with the COLORRIGHT. Two very different tools. One might almost say, complementary.

The Expo people can always come back and say, well, we can set manual exposure with our tool and you can't. True.

For me, I would much rather have the tool work in a natural and intuitive way, than to be able to take a manual exposure reading. ymmv.

[Doug_Kerr]

Hi, Drew,

Originally Posted by drew

I appreciate this test. Doesn't look that bad to me, either.

Now let's see the expo product.

Nope. Not suitable for that form of combat.

There is no good way of taking an incident reading with a flash attached.

A reliable way is to use a gray card.

Expo recommends locating a mirror or a wall and blasting the flash back from the reflection to get a reading.

That would probably work.

So it is a reflective reading.

Certainly not in the same sense. The light is not reflected from scene surfaces.

That technique actually lets the diffuser pick up the incident light (although that has to be bent around to make it work if the flash is on the camera.)

Do you not understand that in the so-called "reflected light" technique, what the camera measures is influenced not only by the chromaticity of the incident light but also by the reflective chromaticity of whatever is in the "view" of the diffuser? That's why what the camera measures is not in any consistent way the chromaticity of the incident light, which is what we need to know to do white balance color correction.

Also, why try and suppress the ambient light. Let it in a la a normal reception shooting situation.

In many cases when I use flash I suppress the ambient light. I certainly almost always do so in studio portrait work (whether with a single flash unit or multiple ones) - and that shot was an example of that. One reason I do that is to avoid the problems of serious mixed light (which can't really be overcome by any WB correction).

Of course one could test in any number of ways.

We'd be glad to do any kind of tests you'd like. Our rate is $175.00 per hour for me, $125.00 per hour for Carla.

By the way, I found the data on how the color temperature of a 550EX varies with the flash output level. Here is the data:



Best regards,

Doug

[Doug_Kerr]

Hi, Drew,

Originally Posted by drew

Although, I'm not trying to down anyone else's product.

You go about that in a funny way.

I am simply trying to point out the strengths of this one. In my mind the WhiBal doesn't really compete with the COLORRIGHT. Two very different tools. One might almost say, complementary.

True. So why do you bother to suggest that readings taken from the WhiBal are erratic (of course perhaps as a result of noise in the image). You toss stuff like that about so casually.

I'm waiting for you to reveal that Erik Sowder's grandmother was a thespian.

The Expo people can always come back and say, well, we can set manual exposure with our tool and you can't. True.

True. So what.

For me, I would much rather have the tool work in a natural and intuitive way, than to be able to take a manual exposure reading. ymmv.

Well, my ExpoDisc works in just as intuitive way as the ColorRight. Or are you talking about the WhiBal? It's had to keep track.

Well, in any case, we aren't going to pay attention to anything said about the ColorThing any more, no matter how silly.

And we don't think at all any more about cosines, except when our granddaughter tells us that her husband has been laid off and she can't make the payments on her student loans anymore.

So hang in, my friend, you're doing an amazing thing. As Carla always says, "Never confess - you might get off on a technicality."

Or in this case, a non-technicality.

..._._

Best regards,

Doug

So hang in, my friend, you're doing an amazing thing. As Carla always says, "Never confess - you might get off on a technicality."

Or in this case, a non-technicality.

Wow, Doug. Why the tone?

Certainly didn't mean to offend.

Are you suggesting I need to confess to something in regards to the fact that the COLORRIGHT clearly works much better with flash?

Much different tone than the one you posted over on opf earlier shown below.

This is in regard to Drew's assertion that the higher transmission of the ColorRight diffuser is advantageous in a flash situation.

I had said that the metering would produce the same mix of flash and ambient photometric exposure for the test shot and the actual shot regardless of the transmission of the diffuser. Thus there would be no consequence of the diffuser transmission.

Drew points out that in a Canon EOS camera, operating in P mode, the metering system will not invoke a shutter speed slower than 1/60 sec or an aperture smaller than f/4. Thus, in many low ambient situations, the "ambient component" is underexposed.

Any "attenuation" of the light during measurement (from less than 100% transmission of the diffuser) will not change the flash component of the mix (since the ETTL flash metering system will bump the flash output to still produce the standard photometric exposure from the flash), but the ambient photometric exposure will not stay constant (since the shutter speed and aperture are already at their limits under P mode).

Thus the "measurement" exposure will be "flash-rich" compared to the actual exposure, typically leading to an "overly blue" incident light WB chromaticity determination (and thus an "overly yellow" corrected image).

This phenomenon is enlarged by greater attenuation (lower transmission) of the diffuser. Thus, in an ambient plus flash scenario, with a low ambient (as is typical for indoor flash situations), and with the Canon P mode in use, a greater transmission for the diffuser would in fact be advantageous.

The same would pertain if we used M mode for the flash work (as I often do).

Sorry I didn't think of that.

But I've drawn Drew into an actual technical discussion! I'm proud of ya, kid.

Best regards,

Doug

And we don't think at all any more about cosines, except when our granddaughter tells us that her husband has been laid off and she can't make the payments on her student loans anymore.

Sorry to hear that, Doug.

Didn't mean to be offensive. Hope you and Carla have a good evening.

Drew