Ray Flash ring flash adapter

This doesn't seem to be the right forum for this, but I don't know where to report on it, so here it is.

Here is just a grab shot of Carla on her 70th birthday with the Ray Flash ring flash adapter on a Canon Speedlite 580EX II on an EOS 40D (we were on our way out the door to birthday brunch at Bistro Louise):



Ex camera, full frame, no processing except brightness/contrast adjustment, downsampling, and post-downsample sharpening.

Doug, thank you very much for posting this...!

My concerns (after reading all comments at Strobist and contemplating the basics laws of physics) are:

* the unit seems to be unbalanced and needing bottom support, which
1) is a hassle to make and affix;
2) would then block the access to the zom/focus rings;
Did you notice this?

* the vertical light duct blocks flash's AF assist beam, which can be crucial in low-light reception/night club environment;

Your shared shot looks OOF with the focus being on a lamp shade (which would be exactly where the leftovers of the blocked AF beam would be) instead of Carla's face, which kinda supports the theory of beam blocking..

* the lighting pattern is described as "narrow" and "delivering a strong vignetting";

I don't see this on your shot, unless you have adjusted vignetting in raw tool, can you confirm?

* the red-eye effect is noticeable, if ever slightly - I would *really* like to avoid fixing it in hundreds of red carpet/night club shots which I would have to process f*a*s*t...
I can definitely see some red-eye here :-( Darn...

Can we have the link to this adapter?

Sure.
Product page
Strobist review

Doug and Nikolai,

Thanks for the introduction to this lightweight thingemjig that can be added to one's collection of camera-specific flashes.



Ray Flash: The Ring Flash Adapter
Ring Flash for Canon and Nikon Portable Flash Units

I like the idea of the device being an adapter. It's expensive at $300 but as it triggers Canon or Nikon slave units, that could still be a worthwhile saving if you already have these, I just don't like the effect by itself and if I'd want that, I'd like the light to be larger! I have only a small experience with Nikon ring flash and that was a superb performance for macro work. I have no doubt that it's as good or better than Canon flash.



This Canon ring flash is available form many stores including of course B&H and Adorama and works directly with EF 50mm f/2.5 Compact Macro, EF 100mm f/2.8 Macro (both versions), and MP-E 65mm Macrophoto Lenses (can also be used with EF 180mm f/3.5L Macro USM via Macrolite Adapter 72C). It's an Ex era flash do its best used with the film cameras, Eos 3 and 1 series as well as all DSLR's. If you have 550EX strobes, it will trigger them too..

The Macro Twin Lite, MR-14EX, gives serious close-up, nature, and macro enthusiasts a different option in macro lighting-a directional quality of light, as opposed to the rather "flat" character of the traditional ring lite. Two separate flash heads can be swiveled around the lens, can be aimed separately, and even removed from their holder and mounted off-camera. This new Ring Lite for close-up and macro shooting is loaded with features and capabilities. Now with Canon's E-TTL, it takes full advantage of the flash performance of the EOS-1v, EOS-3, and other E-TTL cameras. Circular twin flash tubes can fire at even power, or varied between them over a six-stop range, and one or more 550EX Speedlites can be used as wireless slaves along with the MR-14EX. The controller unit now has an illuminated full-info LCD panel and its accepts optional hi-capacity battery packs.

Like the MR-14EX, the new Macro Twin Lite MT-24EX is fully E-TTL compatible with all EOS bodies, including digital SLRs, and even allows Wireless E-TTL flash control with one or more 550EX and/or 420EX "slave units". It also provides easy ratio control of each flash head's output, over a six-stop range. Adoram sells it for $685.

So why is the $300 Ray adapter better than the dedicated ring flashes of Nikon and Canon? I expect the argument is that these fit on more lenses and save a little money!

The Canon and Nikon ring lights can be separately controlled right and left sides so as to add dimensionality. To me, this plus adding another flash higher to one side above the camera, or on stands, will do a better job.

I like the idea of a portable ring flash from Lumedyne. From 3 watt Seconds to 1600 Watt Seconds, this has the adjustability for most any situation; gentle fill or to overpower the sun. This is the real thing! It does weigh 2.5lb, but pair it with a Nikon D700 or a Canon 5D and it will seem to weigh far less! The lens diameter is 100mm (3.7").


Available from B&H at just $1149 and Adorama for $1199.

With a lightweight Lumedyne power pack, this makes a practical and powerful ring light that will provide real power to overcome even bright sunlight. This, unlike the Ray flash is pro gear and will allow lighting for groups with no problem and no restriction on lens or camera choice.

Actually, the 580 EX II weighs almost 1lb 1oz. So with the Ray ring flash adpater that's another 1lb 1.5 oz, we are at almost the same as the Lumedyne ring flash!

The only way to save weight, then is to use a Canon or Nikon dedicated ring flash!

Asher

My understanding of the Canon Ring Flash units - they're for dental and macro photography but the ring is too small for portrait work.

Hi, Nikolai,

Nikolai Sklobovsky said:

Doug, thank you very much for posting this...!

My concerns (after reading all comments at Strobist and contemplating the basics laws of physics) are:

* the unit seems to be unbalanced and needing bottom support, which
1) is a hassle to make and affix;
2) would then block the access to the zom/focus rings;
Did you notice this?

Click to expand...

I would say that white the rigidity of the mount is not what a pre-divestiture telephone engineer would find lovable, it is quite sufficient for normal duty.

* the vertical light duct blocks flash's AF assist beam, which can be crucial in low-light reception/night club environment;

Your shared shot looks OOF with the focus being on a lamp shade (which would be exactly where the leftovers of the blocked AF beam would be) instead of Carla's face, which kinda supports the theory of beam blocking..

Click to expand...

Good thought, but I had only the center AF point active,and there was plenty of ambient to do AF without any assist.

I suspect the focus was actually on the chair back.

That concern is a valid one, though.

* the lighting pattern is described as "narrow" and "delivering a strong vignetting";

I don't see this on your shot, unless you have adjusted vignetting in raw tool, can you confirm?

Click to expand...

I did not do any vignetting compensation in this shot.

I had planned to do a real pattern analysis, but I got off the track. Maybe "soon".

* the red-eye effect is noticeable, if ever slightly - I would *really* like to avoid fixing it in hundreds of red carpet/night club shots which I would have to process f*a*s*t...
I can definitely see some red-eye here :-( Darn...

Click to expand...

Indeed - it is not a full cure for that.

Just for general interest, note that the camera was in "portrait" orientation for this shot.

Thanks for your observations.

Best regards,

Doug

Ray Flash ring flash adapter - luminance distribution

Note that this report does not bear on the matter of the "beam distribution" of the Ray Flash ring flash adapter.

Interest has been expressed in the uniformity of the luminance of the face of the Ray Flash ring flash adapter. (I will discuss the significance of this later.)

The following image gives a basic visual presentation of the distribution of luminance (actually, the luminance-time product, but since the time variation of the flash is consistent across the face, we can fall back and think only of relative luminance) across the face of a Ray Flash ring flash adapter mounted on a Canon Speedlite 580EX II flash unit, for emission in a direction almost parallel to the camera axis.



The image was taken with a Canon EOS 40D located about 20 feet from the flash unit. (Actually, the flash unit was on that same camera, and the shot was taken in a mirror 10' from the camera!)

Among other things, the shot gives a nice insight into the arrangement of the "light pipes" in the Ray Flash unit. Readily seen are the numerous little "facets" along the rear surface of the pipes that serve to direct part of the traveling light forward ("across" the pipe) in that region.

We see, in the upper sector of the ring (generally from about 10:30-1:30 "on the clock" a very limited luminance. Then, in the next "stripe" down (to about the "beltline" of the face, a greater luminance, with the remainder of the face exhibiting slightly less luminance, with fair uniformity.

Why luminance?

We rarely hear of the photometric property luminance in connection with light sources, but rather more frequently in connection with illuminated surfaces (or self-luminous subjects) . But here I speak of the luminance of the source.

If our light source were a true point source (its cross-sectional size is inconsequential compared to the distance to an object upon which we are interested in the effect of the source), then we are intersted in its luminous intensity-time product in the direction of interest, where luminous intensity is the amount of luminous flux per unit solid angle (for a very tiny solid angle centered on the direction of interest). From here on, as a "shorthand" to save verbiage, we will not speak of the time factor, and speak only in terms of luminous intensity.

But here, we have an extended source: one whose dimensions are substantial compared to the distance of interest.

In such a case, the effect on a distant subject (from any small but finite-sized "patch" on the source) is based on the "equivalent luminous intensity" of that patch. This is the product of the average luminance of the source within that patch and the area of the patch.

[We normally hear this relationship in the opposite direction: the luminance is the total luminous intensity over a very small patch divided by the area of that patch. Here we use it the other way up.]

Thus, to consider the "uniformity" of the "output" of an extended source (in a certain direction) across its face, we must consider the distribution of its luminance (in that direction) across the face. So I speak of that.

Why do we care?

Well, suppose that our ring light had a drastic variation in luminance around its face. Then a centered circular object would not exhibit a "uniform" shadow around its periphery. (Note that non-centered objects will not in any case exhibit a uniform shadow.)

What about beam distribution

We heard it said (not by moi) that a Ray Flash installation "exhibited a narrow beam" which could result in vignetting. How is that related to what I report here?

Hardly at all. That property relates to how the luminance of the face of the flash adapter (for any "patch" of interest) varies with angle. (Recall that the image I showed demonstrates the luminance along the axis of the system.)

A different test is needed to gain insight into that property, one I have not done (even designed) yet. I hope to deal with that in a time frame less than that required to get the first reaction to my initial report on this unit.

Best regards,

Doug

Ray Flash ring flash adapater - beam pattern

I have made a primitive test of the beam distribution of the Ray Flash ring flash adapter used on a Canon Speedlite 580EX II flash unit.

In the test, a uniform-reflectance wall was illuminated with the adapted flash rig and photographed with a Canon EF 24-105 mm f/2.8 L IS lens. The focal length was 32 mm. The format size is "1.6x". The distance to the wall was about 8'.

Thus the full horizontal field of view (we will see the full frame) is approximately 38.7°; the vertical field of view, 26.4°.

The flash unit beamwidth (head zoom) was set to "24 mm". This appears to produce the most uniform illumination with the Ray Flash adapter in place.

The test image was corrected for the expected inherent vignetting of the lens using PTLens.

Here is the full test frame (after that correction, in reduced resolution, otherwise unmodified):



Note that at the distance involved here, the angular distribution of the beam should be about the same as would be experienced for greater distances to the subject as well.

Clearly, across this field of view, there is significant illumination falloff. (I have made no numerical evaluation.)

Best regards,

Doug

Wow, Doug, when you said "soon" I thought "next month", not "next day"
Thank you very much for validating my concers and for sharing the results of your experiments!
The information is absolutely invaluable!
Much appreciated!

Re: why the Ray Flash versus the Canon (or other) ring flashes. They are intended for macro work and have a low output--Guide number for the Canon MR-14EX is 46 ft. The guide number for a naked 580 EX II is 190 ft. The Ray Flash supposedly loses about 1 stop, so that would take the guide number to 190/1.414 = 135. That's quite a difference from the MR-14EX.

Hi, George,

George Slusher said:

Re: why the Ray Flash versus the Canon (or other) ring flashes. They are intended for macro work and have a low output--Guide number for the Canon MR-14EX is 46 ft. The guide number for a naked 580 EX II is 190 ft. The Ray Flash supposedly loses about 1 stop, so that would take the guide number to 190/1.414 = 135. That's quite a difference from the MR-14EX.

Click to expand...

As I understand it, the Ray Flash is not really intended for macro work but rather for on-camera illumination for portraits and so forth. Thus a larger guide number is beneficial.

Best regards,

Doug