cgardner
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 p.1 #3 · Leica lenses shots - looking for suggestions on light use | |
There's "creative" and then there is "natural". When you learn how to do the latter is easier to figure out how to do the former. 
Phuang3's example is a good one of what natural modeling looks like on an 3D object because was taken with one natural source. Note the differences. Your lighting, which appears to be coming from two more or less equal lights from opposite sides is creating to bands of highlights with a dark stripe between. His has one band of highlight on part of the lens closest to the single source.
When looking both images the viewer's brain needs to match the contrast clues in the 2D photo with memories of patterns seen in person. Which looks more familiar and natural? The one with the most natural looking modeling clues created with highlight placement.
There are no "rules" for lighting but there is cause and effect perceptually of how the viewer will react to the patterns the light creates, both highlights and shadows. Since natural light comes from above at an average downward angle of about 45° we are accustomed to seeing highlights on the top half curved surfaces at the point on them closest to the source, with shadows (if visible on light object/background) falling downward towards the ground...
http://super.nova.org/MP/Comp3.jpg
http://super.nova.org/MP/Comp6.jpg
On black objects the shadow clues are not seen so the brain discerns shape almost entirely from the highlight clues...
http://super.nova.org/MP/Comp6black.jpg
If the clues — where the highlights are placed and their intensity — aren't naturally downward it make the 3D shape of the object more difficult to recognize. It will be recognized, it will just take longer for the view to "get" what it is and often there will be a undefined nagging feeling that something doesn't look "right" about it...
http://super.nova.org/MP/Comp6blackReversed.jpg
The "not right" reaction is due to the lighting angles and the clues it creates not matching those we see objects in natural light all the time. When you look at a photo and think, "That looks odd." it's because your brain was expecting "normal" and got something different.
You asked about using light creatively? Knowing how to create natural modeling clues with lighting to trigger a "looks normal" reaction you can intentionally and predictably mess with the brain of the viewer and create that "wow, that looks different" response by changing up the highlight and shadow clues. For example in the second black-on-black illustration the lighting direction is the opposite of normal.
In terms of lighting strategies there are five basic ingredients to the recipe:
http://super.nova.org/MP/Comp6blackText.jpg
Other terms are also used, so call them what you like if you disagree with my labels but understand the ROLE each plays. One of the more confusing things about lighting is that the same lighting instrument changes role and sometimes has more than one depending on where it is placed. In terms of basic cause and effect with photography there are two basic roles: revealing shadow detail (fill) and creating highlights and the illusion of 3D shape in a 3D rendering (key, rim, accent) and 3D space (rim, background). In lighting books I read and learned from the terms "accent", "rim", "kicker", etc. all describe lights creating highlights on the object which are secondary to importance to the main or "key" modeling source or to differentiate whether the light is hitting the front of the object (key) or the sides (accent / kicker) or from the back (rim).
As for the roles? Due to the short DR of a digital sensor the two basic ingredients you need to record a full range of tone and detail are:
fill - raised shadows to where camera can record detail in them
key light - creates frontal modeling over the fill
When a single direct source is pointed at an object "key" light the camera, due to it's limited DR can't record detail everywhere. The photographer can expose for highlights but loose shadow detail or expose for shadows and loose highlight detail, or as averaging exposure meters do expose the middle grays correctly and loose a bit of detail on both ends.Adding fill allows the photographer to set the desired aperture for DOF desired, then by adding fill from the direction of the camera put enough flat and "clueless" light on the object so the camera can record detail (i.e. register a signal) from the blackest parts of it. Why should fill be "clueless"? Look at the differences between your lighting on the black lens, Phuang3's and my illustrations. Your second light, the fill source, is creating the second confusing highlight clue on the object.
With something matte surfaced like an egg or a face it is possible to shine a fill source directly at the object from just over / under the lens (to keep it flat and even everywhere are reach the deep depressions the camera sees) without seeing the refection of the light. But on a shiny object the specular reflection will be seen.
In Phuang3 shot by the window the fill came from the light from the window bouncing back onto the front side from the walls and ceiling of the room indirectly. If using artificial lighting you need to create that same type of indirect omni-directional fill to avoid a fill light reflection. One way to do it is to bounce the fill light backwards behind the camera onto a white wall which will then wrap it around the room evenly, similar how skylight works to fill and reduce contrast on sunlit objects outdoors.
If lighting the lenses I'd start by setting camera f/stop for DOF then turn on just my fill and bounce it off various parts of the room until in the test shots I take I see detail recored everywhere but with no, or as few as possible highlight clues from the fill. Here's a trick I've learned. In a situation like that where you can't totally eliminate the specular clues from the fill place the fill light so it creates even fill but the highlight from it winds up in the same place as the key or an accent light, or somewhere that is easy to retouch. Some solutions for fill are counter-intuitive. A huge SB for fill will create a big reflection, but a bare bulb fill will flood a small white room with light from all directions but create a pin-prick reflection that is easy to retouch out of the object. Remember its not just the direction / quality of the fill light that matters it's also the clues that it creates and ideally it should be "clueless".
After setting fill for "neutral" clueless recording of shadow detail the next task is setting the key light to create 3D shape on the front. Placing it 45° higher and 45° to the side is a good starting baseline for evaluation because that's where the sun is in the sky relative to things on the ground at 10AM and 2PM and the perceptual baseline most have for "looks normal" lighting.
With black-on-black we may find the lenses disappearing into the background. That's a function of how dark the background is and how much further it is from the key and fill lights used so far. There are several ways to address that problem:
1) Use a lighter toned background for better natural contrast
2) Use a background light to create separation
3) Use rim light from behind to define overall shape and create separation
4) Add accent lighting from the sides to define and nuance the shape
5) Any or all of the above.
A few years ago a guy posted his first attempt at a maternity shot using typical portrait lighting with key light in front at 45° which works great for modeling a face, but made his wife's belly look like a blimp. To illustrate an alternate strategy I grabbed a similarly shaped egg and put it in my kitchen window. Rather than using front "key" lighting as the primary modeling source I let the "rim" lighting from behind about 135° to the lens axis do that...
http://super.nova.org/MP/Egg.jpg
The window faces north and it was in the morning so the light was indirect but directional from the NE as seen from how it wraps around the 3D shape of the egg. With just the natural light my camera couldn't handle the contrast and record the amount of detail I wanted on front so I grapped a square silver reflector and held it above and to the left of the camera. I didn't hold it exactly centered because I wanted the reflector to act as "accent" light and "fill", doing basic job of fill to allow the camera to record more detail on the shaded side, but also creating some subtle modeling on the front. Not a well defined "key" light modeling clue as in the illustration, something more similar to what you see when an object is close to a reflective surface. That same strategy works well for maternity shots because it reveals the smooth round shape in a way that doesn't make it look huge because it is mostly seen in shadow and the brain will focus more on the edges which are highlighted.
When lighting anything you should first think in terms of goals such as defining 3D shape naturally, or not, and how the viewer's brain will react to the highlight and shadow clues. Understanding that it will be obvious where to put the light to create those clues. In that regard it's a bit like magic. In planning an illusion the magician first needs to understand what the audience will expect to see, then do that with his left hand, while switching the empty hat for the one with the rabbit in it with his right.
If you create an image with seen by eye natural 45° downward lighting with one dominant highlight the reaction to the lighting will be neutral because it seems perfectly normal. When you deviate to far from that natural looking baseline of lighting clues it may confuse the viewer and cause difficulty in them relating to the object because it doesn't "look right" compared to how it might sitting in front of a window in natural light. That's can be a good or bad thing depending on the reaction you wanted in the mind of the viewer when seeing the photo.
Like I said there are no rules, only cause and effect. The basic goal in a photograph is to create on some level an emotional reaction. A photograph is like looking through an open door when the lighting clues mimic nature. Yours are more like looking through a window filled with glare, the lighting being other than natural looking gets in the way of processing the content.
Part of the problem is the double highlights and the other is the fact that the highest, closest part of the lens to the camera where I'd expect to see natural light created a highlight is instead a dark stripe. The clue are more or less opposite what I'd expect to see in natural lighting.
My suggestion? Find a north facing window and set up similar to Phuang3's shot, then try the rim lighting strategy I used in my Egg example using the natural light and a reflector. Then with those two shots as a comparison baseline try to recreate the same looks, now mindful of where the reflections are falling on the objects and how the number, placement and brightness affect the perception of "normal" 3D shape.
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