p.1 #1 · Quantum vs Speedlight - Your thoughts on results?
Hey, I recently posted for some advice about Quantum vs speedlight flashes. I had a few moments to a Quantum t5dr + Canon 600EX and I'd appreciate some opinions on the light differences, please.
Both flashes were in manual, which I'm new to, so I don't know 100%. Consequently I every so slightly tweaked the 600EX images to try to match the Quantums. The Quantum images are unedited.
Do you feel there's a significant difference in the light quality? A Quantum win? Speedlights are more convenient so if there's no great difference perhaps they're a better option.
The images seem pretty close to me in the light, but I don't know if I'm not seeing the differences. Certainly when using the wide angle diffuser with the Speedlight, which was needed to avoid too much of a narrow light, it does drop the power a fair bit which might be a point, the Quantum's were used with the diffuser and were barely breaking 1/32, the Speedlights 1/16 with the diffuser I think.
However, I'll be using the flash as a fill - I'll be using a continus fresnel as the main light source, so I don't need the light to be all I use, hence why I'm looking to compare the fill quality.
p.1 #2 · Quantum vs Speedlight - Your thoughts on results?
The Quantums have more power than the Speedlites, and so there can be noticable differences there if you're working in bright ambient light. Indoors, the differences are less obvious, especially given the high IQ possible at previously difficult ISO settings when using today's DSLRs.
As for the "quality" of the light, in traditional terminology that refers to the hardness or softness of the shadows produced by a light source, and that depends on the size of the source and the distance from the subject. The Quantums are very flexible in that regard because of their bare-bulb design, but appropriate use of modifiers can level the playing field quite a bit if the Speedlites have enough power after modification.
You can definitely get the "look" you're after using Speedlites just as easily as using Quantums or Profotos or any other light with the right education and experience.
p.1 #3 · Quantum vs Speedlight - Your thoughts on results?
Thanks for your reply!
Here's another one with my buddy as I wanted to see if things would be different with a person(!), 5dmk3/Tamron 24-70 at 70 so relatively close, manual flash with both set to be pretty equal.
From the below it seems to be the 'look' is pretty even with both.
It seems to suggest it comes down to, as you suggest, an issue of utility and power versus, in this case, the light specifically?
p.1 #4 · Quantum vs Speedlight - Your thoughts on results?
Since you plan to use the flash as fill here are some perceptual aspects about fill and illusion of 3D in 2D photos to consider.
In natural lighting fill isn't really noticed because in most cases it is omni-directional which makes it diffuse. The closest we can come to duplicating that "wrap-around" fill effect is to bouce the fill off the back walll near the ceiling of a studio or room on location, creating 100% reflected "spill fill" off the walls and ceiling. The next best option for a "natural" fill pattern is placing a direct fill source near the camera axis as you did in your test to minimize the shadows the camera sees and create a large footprint which bounces off ceiling and walls adding the omni-directional "spill fill" wrapping fill vectors.
In many cases spill off the ceiling and walls from the other lights (key, accent, background) will also created spill fill which needs to be taken into account in the lighting strategy and exposure. For example many beginners by huge umbrellas, use them in their living room, then find the lighting bland and difficult to control because of so much uncontrollable "spill fill".
A fill source near chin level with a face will project shaddows straight back. Inverse-square fall off will make the fill brighter on tip of the nose than the ears. The closer the fill light is to the nose the greater the rate of fall off and front>back gradient in the filled shadows. That of course assumes there isn't a lot of "spill fill" being added from the sides. Personally I like to use centered fill because it creates lighter, less distracting shadows on the nose and "hides" the ears perceptually by making them darker and less likely to attract attention. Many, especially those using reflectors, put the fill on the side opposite the key light but I find that makes the ear brighter than the nose and if placed too far behind the face created unfilled low spots on the front of the face.
A "given" with centered flash fill is it will create a second, unnatural catchlight in the eyes. As with refectors some used very large fill modifiers will place fill to the side as a strategy to eliminate the second catchlight in the eye. But as noted that will wind up making the nose shadow darker than that on the ear and can create unfilled voids in smile-lines, the base of the nostril on the fill side, the inside and corners of the mouth.
Years ago when comparison testing a new 22" dish with a med. SB I was lazy and just swithed the two as key and fill and discovered by accident that the dish was a nearly perfect fill modifier for my shooting space. Because of it's flat dish shape it spilled light off the ceiling walls in addition to straight ahead creating a more natural "wrapping" fill effect. Used back around 8' from the subject under the raised camera at chin level it created few visible shadows as a tiny secondary catchlight dead center in the black pupils which was very easy to retouch. I've been using my dish for fill that way ever since.
But a problem with any flash are the other specular highlight clues they create on the face. When lighting is flat, such as in your examples, the brain doesn't get many shadow clues to use to discern 3D shape, so it relies on where the specular highlight are seen, knowing from experience they are seen on the higher parts of objects, relative to the source of the light.
A factor that makes single flash on camera flash shots seem unnatural is the absence of any natural downward "key" light shadow clues on the side of the nose and the fact the specular reflections from the face on the face wind up lower on the cheeks, chin, forehead, tip of the nose, etc. than with natural downward sources. To some extend a chin-level direct fill source will create the same undesirable, unnaturally low highlight shape clues. But in two light key /fill scenarios the downward key light highlight clues higher on those parts of the face make the fill clues less noticable and "fake" looking. Part of the solution starts by ensuring the subject has a freshly washed oil free face and isn't wearing make-up or lotion that creates unwanted reflections.
But for some situations such as a portrait of an athlete after a workout intentionally creating specular highlights will create the illusion of better defined muscles. When shooting furry and feathered animals sources which produce specular reflections back into the camera will create a better illusion of soft fur / feathers than a diffuse source. A shiny silver umbrella or SB with silver lining and no diffusion panels is an ideal fill source in those situations.
Outdoors in backlight the fact the flash creates catchlights in the eyes is a plus because without them the eyes will look dull and lifeless by comparison. Even when a face is tilted up into the skylight to get it past the brow and eyes the sky is so large there is not the well defined 3D shape revealing catchlight on the upper half of the eyeballs. A flash catchlight dead center doesn't look natural either and create the same unnatural "too low" clues on other parts of the face.
The better single flash strategy outdoors, and indoors, is to raise the flash above the head of the subject so it creates more naturally downward shadow and highlight clues on the face, but keep it centered to avoid any dark unfilled sideways directional clues from the flash. That's the underlying cause and effect behind the use of a flash bracket: it raises the flash high enough to create natural modeling clues, but not so high the brow shades the eye when used from around 8ft from the subject.
As for Quantum vs. Speedlight: Same hammer, different size. Back before the availability of battery/inverts for studio lights Quantum filled a niche for wedding and other location shooters who needed portability but more power for formal protraits with modifiers and tasks like large groups in dark church altars or bright backlight outdoors. The same flash could also be used on a bracket, but it was load to carry around all day. So it was a less than ideal compromise between form and function. Nowadays it's easier to carry two "hammers" for a job like a wedding: battery/inverter powered mono-lights for the big tasks requiring more power than speedlights, and lighter speedlights for the reception shots where mobility and ease of use where the priority.
Back in 2004-2005 when switching to the Canon DSLR system I considered going with Quantum but instead opted for a set of four studio lights / modifiers and a pair of 580ex flashes for location work. I haven't regretted that decision.
p.1 #5 · Quantum vs Speedlight - Your thoughts on results?
Simple answer. Light is light if not counting duration, power, and color ...which probably isn't an issue with either of these.
You will not find a difference in the two lights other than power but that's oh so slight depending on what you're doing. At least to me the only real difference is using modifiers, and the available controls (DSLR controlling a 600).
This isn't the same as comparing something like two types of apples. One might be tart while the other is sweet. This may make the difference for the one you purchase.
