Desicated leaf

[DanK]

I found this on a sidewalk recently, and there was no tree in the immediate vicinity that matched, so it must have blown from elsewhere. I have no idea what the species is. In any case, I thought it was interesting. Tried it in B&W because the lines and textures are the main story, but it was dull that way. This is a first edit, and I have to come back to it when I'm less tired. All C&C welcome.

[Dave Humphries]

If you still have it Dan, can you shoot more pictures?

I'd be tempted to experiment with a snooted or honeycombed light source and vary its distance from subject.
Or even gel (coloured) from one side vs the other.

Just a thought,
Dave

[DanK]

Dave,

I do still have it. I actually did two stacks so far with different lighting, varying both position and brightness.

Re gels--that's definitely not my style. But I'm intrigued by your suggestion of a snoot and honeycomb. What are you thinking of? Illuminating only part of the leaf?

Thanks

Dan

[Dave Humphries]

But I'm intrigued by your suggestion of a snoot and honeycomb. What are you thinking of? Illuminating only part of the leaf?

Hi Dan,

The intent was to make the light source small and/or directional, that this should better reveal texture - it may not work as a concept. Varying the light-to-subject distance would likely result in some part of the subject being in shadow from other parts, but equally, if the source were small and directional enough to actually behave as a 'spotlight', that could bring further opportunities - but I can't promise they'll be photogenic

Cheers,
Dave

[DanK]

Hi Dave,

This raises a basic question to which I don't know the answer. I'm sure some folks here do.

Using a snoot or grid doesn't focus light in the way a lens would. A snoot is generally made of a non-reflective black material. So, some light will be absorbed, while some will be reflected in the general direction of the subject, but not focused. So, let's say that you use a snoot but set it so that the entire leaf is still illuminated. Will this be appreciably different--in terms of the image of the subject, not the surrounding area--from simply increasing the power of the light source?

In general, I raise textures in shots like this by having one or two lights that are direct, rather than reflected, but still diffused somewhat. I vary the location to taste, and I have the primary directional light on a dimmer. I don't worry about stray light that one might otherwise block with a snoot because I have a black background that I can easily turn pure black in post, if there is too much stray light on it. In this case, I didn't really need to do that, as the luminosity value of the black background was mostly only 1.

Dan

[Dave Humphries]

So, let's say that you use a snoot but set it so that the entire leaf is still illuminated. Will this be appreciably different--in terms of the image of the subject, not the surrounding area--from simply increasing the power of the light source?

Hi Dan,

Yes, I think this was dawning on me as I was typing last night (and is clearer still this morning), that a lensed lamp (LED torch*) was probably what would be needed for what I was imagining.

* flashlight?

Whether that would be effective is also debatable, given the experience you already have with the subject matter and illumination thereof.

I'll 'stop digging' at this point and retire, having consolidated some past learning, since forgotten!

Cheers,
Dave

[Manfred M]

Interesting points Dave and Dan.

As I rarely shoot flowers, I can't comment, but I use both a snoot and a grid on a small reflector to produce raking light that produces interesting shadows. I borrowed a fresnel lens head to use a more focused beam, something that might be more useful for Dan as it can be used with continuous light sources.

I do throw gels on my lights for effect from time to time and use either a snoot or a reflector with barn doors to direct the light. In general, most of my subjects tend to be larger than the plants and flowers you shoot, Dan.

[DanK]

Interesting points Dave and Dan.

As I rarely shoot flowers, I can't comment, but I use both a snoot and a grid on a small reflector to produce raking light that produces interesting shadows. I borrowed a fresnel lens head to use a more focused beam, something that might be more useful for Dan as it can be used with continuous light sources.

I do throw gels on my lights for effect from time to time and use either a snoot or a reflector with barn doors to direct the light. In general, most of my subjects tend to be larger than the plants and flowers you shoot, Dan.

A fresnel lens should create more focused light, if I understand correctly. What still puzzles me is the impact of a snoot or grid on something that is as small or smaller than the diameter of the snoot. In the uses for snoots and grids that I have seen, it's been to limit light on parts of the image, not to create more directional lighting within the diameter of the modifiers. But maybe it does.

[xpatUSA]

What still puzzles me is the impact of a snoot or grid on something that is as small or smaller than the diameter of the snoot.

As the diameter of the light source at a given distance increases, the inverse square law has less effect:

http://kronometric.org/phot/lighting...20handbook.pdf

Page 26.

That would impact the illuminance of something, irrespective of it's size.

Or, taking the snoot as a tube of a given diameter with an homogeneous light source at one end, the illuminance of something within the lit circle does not change, irrespective of it's size.

Depending on what what meant by "impact" ...

[DanK]

As the diameter of the light source at a given distance increases, the inverse square law has less effect:

http://kronometric.org/phot/lighting...20handbook.pdf

Page 26.

That would impact the illuminance of "something", irrespective of it's size.

But that still doesn't answer my question, which is whether the use of these devices would change something other than illuminance--specifically, it would affect the visibility of textures more than simply changing the birghtness of the source. That's the question raised by Dave's post. I think the answer is no. What it does affect is the illumination of peripheral areas, but that's not of much concern to me in most cases because I can keep the background dark without these devices. (I've thought about using a snoot when the angle of the direct light lets an annoying amount of light hit the background.)

[xpatUSA]

But that still doesn't answer my question, which is whether the use of these devices would change something other than illuminance--specifically, it would affect the visibility of textures more than simply changing the birghtness of the source. That's the question raised by Dave's post.

I had edited my post while you were typing.

The visibility of textures is governed by the human visual contrast sensitivity function.

I agree that a single fixed-position source's luminance would not affect the visibility of textures. Placement of a single light source would, provided that texture is 3D or is some surface having reflectances variously proportional to angle of light incidence.

[DanK]

I agree that a single fixed-position source's luminance would not affect the visibility of textures. Placement of a single light source would, provided that texture is 3D or is some surface having reflectances variously proportional to angle of light incidence.

But it does. Imagine the following setup, which is similar to what I do in practice. The subject is textured, with ridges and valleys that are at an angle to the camera's sensor. Place a single source at a 60 angle to the line from the camera to the subject. Add a second, very diffuse light source above forward of the subject.

Now, gradually increase the luminance of the first light, starting at zero. As luminance increases, shadows increase, making the textures more visible.

In practice, that's what I do with most of my flower macros. I play with the position and luminance (or distance) of the direct light to place the shadows where I want them and make them the size and darkness I want.

Now, the question raised by Dave's post is this: what if I added a snoot or a grid to that first light? I think that as long as the unblocked area is still larger than the subject, the effect would be to slightly increase the luminance of the source but nothing more--that is, that it would have no effect on visible texture beyond what I can get by playing with the location and luminance of the source.

[xpatUSA]

But it does.

I shouldn't have tried to paraphrase your statement. I will recant thus:

I am unable to say whether the use of these devices would change something other than illuminance -- specifically, [whether] it would affect the visibility of textures more than [by] simply changing the birghtness of the source.

[Manfred M]

A fresnel lens should create more focused light, if I understand correctly. What still puzzles me is the impact of a snoot or grid on something that is as small or smaller than the diameter of the snoot. In the uses for snoots and grids that I have seen, it's been to limit light on parts of the image, not to create more directional lighting within the diameter of the modifiers. But maybe it does.

It's all about the size of the light source and what one wants to do with it. If I am shooting a larger subject, I will use a snoot or small reflector (7" - 8") to highlight a particular area in the image. The grid goes on to control the light more and give me less spill.

For a small subject, the large light source (like a soft box) will give very diffuse light. Sometimes I want that but at other times I am looking for a more edgy light that gives more localized shadows. A fresnel is a spotlight and gives more control than a snoot or reflector. I suspect I will eventually end up buying one.

[DanK]

Spillage is mostly not an issue in this case. Re more focused, edgier light: I agree, and the idea of a fresnel lens is interesting. However, an intermediate step for me would be simply reducing or eliminating the diffusion in front of that light.

That still doesn't get to the question Dave raised. It seems to me that a snoot or grid won't focus the light more; at most, it will increase luminance a bit by reflecting some light. So I still think it wouldn't have any effect (beyond possibly the effect of increasing luminance) on textures and shadows. I may well be wrong about this.

[xpatUSA]

It seems to me that a snoot or grid won't focus the light more; at most, it will increase luminance a bit by reflecting some light.

A little light (!) reading tells me that a snoot usually produces a beam of light of a certain cross-sectional area which might converge or might diverge - but only a polar diagram would tell us any more more than that. A converging beam would of course focus somewhere.

Be that as it may, I see a snoop as being no different than say a flashlight with a parabolic lens. As to whether the resulting beam falls within a subject or encompasses that subject is chosen solely by the photographer.

So I still think it wouldn't have any effect (beyond possibly the effect of increasing luminance) on textures and shadows. I may well be wrong about this.

For a subject that falls completely within the beam of light, the visibility of "textures" remains a function of the angle of the incident light.

A link offered up for rebuttal:

https://photofocus.com/photography/h...-a-snoot-grid/

Cool video ...

[DanK]

For a subject that falls completely within the beam of light, the visibility of "textures" remains a function of the angle of the incident light.

I think that's the answer, and given the other factors I've mentioned, I don't think a snoot or grid would matter for what I'm doing.

[Manfred M]

That still doesn't get to the question Dave raised. It seems to me that a snoot or grid won't focus the light more; at most, it will increase luminance a bit by reflecting some light.

No, they won't focus light any more; only a fresnel will do that. They will change the direction and quality of light, If you add them at a very acute angle so that the light "skims" along the surface, they will accentuate the shadows and highlights.

In this shot, there is a raised pattern and I used two different reflectors that were gelled and equipped with grids, just scimming across the surface. I was able to light the edge in one direction and the surface in the other.

[xpatUSA]

I agree that a single fixed-position source's luminance would not affect the visibility of textures. ...

But it does. Imagine the following setup, which is similar to what I do in practice. The subject is textured, with ridges and valleys that are at an angle to the camera's sensor. Place a single source at a 60 angle to the line from the camera to the subject. Add a second, very diffuse light source above forward of the subject.

Now, gradually increase the luminance of the first light, starting at zero. As luminance increases, shadows increase, making the textures more visible.

Sorry to say that I'm still puzzling over this. I'm wondering what properties of the shadows are increased by increasing the luminance of the first light.

[DanK]

Sorry to say that I'm still puzzling over this. I'm wondering what properties of the shadows are increased by increasing the luminance of the first light.

The light is coming from the side. The side of ridges facing the light will brighten, while the side in shadow won't, or will brighten less. Consider the limiting condition: reducing the lighting from the side to zero. The shadows disappear.