Different lighting

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clarnibass
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Different lighting

Post by clarnibass »

Hi

I'm taking photos of a few things that according to the translator are "fossils". They look basically like small stones. I think the combination of those things not having much texture plus the very diffused lighting is causing them to look almost a bit blurry... but I'm not completely sure if more contrasty light would help.

They are not that small, magnification is only about x1.5.
I'm using my regular Nikon 105mm lens which is sharp and I re-verified the sharpest aperture.

Light setup was my most regular one, two flashes, one on each side and front. There was a cone diffuser and two sheets to diffuse from the sides too.

Second photo is a 100% crop. Contrasty areas look ok. Other parts looks a bit "smeary". Maybe it's just the fossil texture itself that is coming out like that?

Thanks

Image

Image

enricosavazzi
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Post by enricosavazzi »

The subject is most likely a hand-made carving, not a fossil. In the style of ancient Egyptian scarab amulets, but I have no idea whether authentic.

Your detail picture seems to show some kind of dirt in a groove carved into the stone. Perhaps foreign matter lodged there with time, or perhaps glued in place to make a recent carving look ancient.
--ES

clarnibass
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Post by clarnibass »

Thanks. I'm not sure what it is, the person who owns it said it was a fossil and gave some other details about it.

What looks like some sort of grain is probably some texture plus usual noise from a stack. Anyway I'm most concerned about the general lack of detail in some areas and maybe others with more experience can suggest whether different lighting can help or I shouldn't bother.

ChrisR
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Post by ChrisR »

Somewhere I have some pictures I took of a child's collection of common fossils such as ammonites, which came out very much flatter than they appeared to be when in the hand.
I found that using a raking light, red from one side and green from the other, brought out the relief very effectively. I used two cellphone screens with "color torch" apps, as light sources.
(cf Hoffman modulation contrast.)

I agree, fwiw, this scarab looks man made.
Chris R

ray_parkhurst
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Post by ray_parkhurst »

Looks to me like too much diffusion. I see this same kind of washed-out and "almost blurry" look when I use a full ringlight on coins or other flat-ish objects. You will need to strike a balance between lack of diffusion causing too many over-exposed hotspots vs lack of shadow detail eliminating the visibility of surface topography.

Try not to have lights coming from opposite sides of the specimen. Orthogonal lighting is best, as it minimizes the illumination of shadows created by the other light, and yet gives good fill-in. Aesthetically, it's best to light from "above" as if the lighting were from natural overhead lights, or from the sun. I would suggest two diffused lights coming in at 10:30 and 1:30, around 100mm from the specimen, and at between 45 and 60 degrees from horizontal. This "CDE" (Clock Distance Elevation) coordinate system exactly defines the placement of the source, similar to the XYZ system. Below 45-deg will cast longer shadows from the topographical features, while above 60-deg will shine more direct reflections to the sensor. The 100mm distance is suggested for small sources such as Jansjo LEDs with minimal diffusion, but if you use a larger source such as a diffused flash, move it farther away until its "size" (the 4th lighting dimension) is about the same (angular span) is about the same as a lightly-diffused Jansjo.

Dalantech
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Post by Dalantech »

ray_parkhurst wrote:Looks to me like too much diffusion. I see this same kind of washed-out and "almost blurry" look when I use a full ringlight on coins or other flat-ish objects. You will need to strike a balance between lack of diffusion causing too many over-exposed hotspots vs lack of shadow detail eliminating the visibility of surface topography.
Yup, the light is too "flat". Try using a key (one light at 12 O'clock) and fill (one light at 3 or 6 O'clock) configuration, and don't have both light sources hitting the subject from the same angle. For objects that have a lot of texture (that you want to bring out) a light that's low on one side will help. Found a video that shows the technique

I use a key and fill approach for my macro work.

clarnibass
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Post by clarnibass »

Thanks, I'll try all of that.

Re the "time", in relation to what do you mean by 10:30, 12:00, etc.?
You could look at a "clock" round the subject, which is basically around the lens too, but it could also be "higher" or "lower".
That is, if we consider the "clock" as if it's around the subject, then 12:00 would be just above in the photo, but actually would come from the side of the subject. In that 12:00 I could then also raise and/or enlarge the light.
Not sure if I explain that clearly...

ray_parkhurst
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Post by ray_parkhurst »

clarnibass wrote:Thanks, I'll try all of that.

Re the "time", in relation to what do you mean by 10:30, 12:00, etc.?
You could look at a "clock" round the subject, which is basically around the lens too, but it could also be "higher" or "lower".
That is, if we consider the "clock" as if it's around the subject, then 12:00 would be just above in the photo, but actually would come from the side of the subject. In that 12:00 I could then also raise and/or enlarge the light.
Not sure if I explain that clearly...
Think of the "clock" as forming a circle around, and in same plane as, the subject. 12:00 comes from "above" the subject. For a horizontal system, if your angle from horizontal is 90-deg, at 12:00 the light would come literally from above the subject. If the angle from horizontal is 0-deg, then the light would come straight down the optical axis.

clarnibass
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Joined: Fri Jun 10, 2016 11:33 pm

Post by clarnibass »

Thank you. I ended up positioning the two lights in terms of angles, using two diffusers. Tried no diffuser first, definitely better with more contrast, but too harsh specular highlights. Then started playing with the flash distance and diffuser distance to find the best positions. The first version definitely was too diffused.

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