Up to My Glass

[Loose Canon]

I thought I’d do some recreational photography. In other words just shoot for the experience and for fun since it’s been a little while since I've had the chance.

This is not by any stretch a nice piece of glass. Instead just a cheap little flower vase. But I was more interested in lighting it and that was the point of the shoot.

For this one I wanted dark field highlights, then add additional lighting. I used a medium softbox as a background. Flagged it with a white card to get the edge highlights. I wanted something a little different than straight dark field so I bounced a controlled (gridded) light off of the white flag that was in front of the softbox to the bottom surface (opaque black plexiglass), and that reflection in turn added the backlighting to the glass.

The reflection from the bottom surface can be seen peaking out from behind the glass on the sides. The background/white card is far enough away from the subject and I shot it at a little higher angle so the background would be well out of the frame.

I converted it to B&W and then added some split-toning for giggles!





So I thought that was getting pretty close to what I wanted because next I wanted to add a splash of color on a dark field. But the trick was going to be retain the white edge highlights without them blowing to color. Same setup with the bounce light gelled. I got a bit of color in the top rim highlights (only) but the highlights were there and that was the important part. I de-saturated those in post. The rest of the highlights remained white.

I found it interesting that I didn’t get any color in the glass's reflection. The colored light field didn't extend far enough toward the camera to produce a colored reflection.





Next I used the same set but removed the grid from the bounce light. Again trying for white rim highlights. As expected a got a bigger colored light field and again I got colored highlights on the top rim, more so than the first, which I left this time. I also got some color in the glass's reflection because the light field extended far enough forward.

I got some vignetting in the bottom two corners of the frame due to the light falloff, which was desirable for me. I added some more vignette in post, especially in the top corners of the frame.

[Mike Buckley]

Very nice job, Terry. It's a lot of fun at least for you and me to do this kind of stuff and there is no limit to the amount of creativity that can be done.

I like the first one best, mostly because it simply appeals to what I like. In the second and third images, some of the brighter mid tones in the glass and its reflection are displaying color probably caused by prismatic diffraction. For me, those colors compete with the nice color that you added by your lighting setup.

You mentioned that the subject is "just a cheap" vase. I enjoy photographing cheap glass because its imperfections create patterns of light that can be very interesting. This subject is a great example.

What are the approximate size of the vase, the distance from camera to subject and focal length?

[Loose Canon]

The vase is 8” high Mike and the diameter of the top rim is 3-1/2”.

Distance from camera to subject is 51”, and shot at 165mm.

Guess it wouldn’t be too hard to just de-saturate any unwanted color reflections. I did it once on the top rim anyway in post. I’m not sure I could have avoided it on set, but I didn’t try either!

[Mike Buckley]

You can avoid color reflections by changing the setup but prismatic diffraction is very different. My experience, as relatively limited as it is, is that changing the setup or the position of the glass subject can eliminate a particular area of diffraction but will create a new area. I don't remember photographing a clear glass subject that didn't create at least a tiny amount of prismatic diffraction.

Rather than desaturate the unwanted color, you'll have more control over the result if you convert to monochrome through a filter or channel mixer.

Thanks for the info about the various dimensions. It's very encouraging because it proves that if I remove my past requirement to use a background that equals the field of view, I can use longer focal lengths and different positions of the camera relative to the subject even within the small size of my makeshift studio. Doing so would provide the option of creating different compositions without experiencing perspective distortion that we discussed recently.