Lighting set up (for 65mm MP-E and twinlite MT-24x)

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Graham46
Posts: 132
Joined: Thu Dec 18, 2008 7:31 am
Location: Harford County, MD

Lighting set up (for 65mm MP-E and twinlite MT-24x)

Post by Graham46 »

I have never posted to this section before-- Was just browsing at some of the other members unique and detailed explanations of their set ups and thought I would jump on board.

The set up used in my lab is simple but highly effective. The total amount of items used include a Canon 5d mark ii, a canon 65mm MP-E, a canon macro twinlite MT-24x flash, a unique focusing rail controlled by a lead screw, two articulating arms to control the flash heads, and some styrofoam to use for a diffuser. Here is a shot of the core parts
Image

Id mainly like to discuss the lighting set up, but feel free to ask any questions about the entire rig. As you can see in the first image, there is an insect mounted to a pin which is placed in some clay on top of what we call "the stage". The stage is surrounded by a ring of styrofoam to keep the flash units below from making any direct contact. The main idea used here is bounce flash-- The flash units are below the subject facing up and are fired into the above styrofoam cup causing the flash to blanket back downward evenly. In this image below, notice how we can move the flash units forward and backward (to correspond with the movement of the 65mm as we zoom in or out) by loosening the screw and sliding the brass piece along the rail. The black knob on the arm holding the flash head is for tightening the position of the arm when you have it where you want it.
Image

The styrofoam cup is the most important part, and we have gone through several iterations to come up with the current model. It is attached to the outer ring of the 65mm itself, held in place by 3 pennies (the ring around the lens is the same size as the width of a penny, it fits very nicely). The other interesting thing about the cup is that we replaced the bottom to provide even more reflection coming from the direction of the lens. Because the diameter of the actual lens behind the glass is so small, we could afford to replace part of the styrofoam to act as a reflecting disc without photographing any part of the cup itself.
Image


The lights can be positioned in any way, and the cup moves with the lens, so you get the same distribution of light whether youre at 1x or 5x. We also have different size styrofoam rings (or "skirts" even) that go around the stage to keep the light from hitting the subject directly, and bouncing it into the cup overhead instead. Here is an image produced from the set up, and then stacked in ZS and photoshopped to remove the mounting pin.
Image

Thanks for looking!
Semper cogitatio
Graham

morfa
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Location: Stockholm, Sweden
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Post by morfa »

Thank you for posting this Graham – seems like a well thought out and flexible setup.

A couple of questions spring to mind:

1. I don't recognize those articulating arms, where did you get them? I presume they're hydrostatic like the manfrotto ones?

2. What's the thinking behind the small openings cut out in the wall of the cup?

/John

Arron
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Joined: Mon Dec 07, 2009 2:21 pm
Location: Sydney, Australia
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Post by Arron »

Hi Graham. I like your setup. I was wondering, though, whether the smooth black background is as taken or whether it has been touched up in photoshop ?
cheers
Arron

tonygt19
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Joined: Sat Feb 16, 2008 12:50 pm
Location: PA and MD,USA
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Articulating arms, holes in cup and black background

Post by tonygt19 »

Hi,
Graham works in my lab at Aberdeen Proving Ground, MD and since the questions just asked are about some equipment that predates his arrival in the lab I can go ahead and fill in some of the information for him.

The articulating arms are simply called "Holdit" arms made by Noga and found at <http://www.holditarm.com/>. They are used extensively in cinematography to position lights and other accessory devices on heavy cameras. They are purely mechanical and have the extremely useful ability to fix all 3 joints with a single tightening knob. Loosen the knob slightly and all joints become repositionable, tighten and they all become fixed. Our pair was cannibalized from an extra set on our Automontage system which is now rarely used. These arms are screwed into square brass tabs we drilled and tapped to fit the base screw of the arm. The brass tabs slide in side slots on the rail when the screw is loosened to position the arms alongside the sample. They grip the slot edges tightly when the screw end is tightened to fix the arm and flash heads in the desired position.

The cup was designed to provide an overhead global illumination to enhance the imaging of textures and structures sometimes obscured by harsh direct lighting. The side holes were put there to allow insertion of small fiber optic lights to especially highlight or backlight difficult structures such as fine black hairs on antennae on a black background.

The smooth black background is intentionally produced as taken by placing a square of black velvet cloth with its nap pointing toward the lens a foot or two behind the focal planes of the stack. It is positioned at the end of the rail and reflects virtually no light to the lens. Those of you familiar with the Canon 65mm Macro know that it practically makes its own black background even in a well lit room because of its extreme sharp angle of focus.

Hope this helps,
Tonygt19
Tony

augusthouse
Posts: 1195
Joined: Sat Sep 16, 2006 1:39 am
Location: New South Wales Australia

Post by augusthouse »

Interesting explanation of the lighting concept; bounce all light onto the subject and highlight specific features with FO when/where appropriate. What light source do you use with the FO/fiber optic lights?

Lighting in the sample image is very smooth. Have there been more images taken with this setup uploaded to the forum and/else could we see some more samples? :D

The extra disc on front of the MP-E appears to be acting as a type of Lieberkühn Reflector. :-k

The setup 'legs' are intriguing. Are these are a permanent feature, or is this arrangement normally used on a flat surface, whilst retaining sufficient clearance for positioning of the articulating arms?

Thanks for sharing details regarding the setup.

Craig
To use a classic quote from 'Antz' - "I almost know exactly what I'm doing!"

AndrewC
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Post by AndrewC »

Nice lighting, thanks for sharing :) I tried something similar myself a while ago but just could not get it to work the way I wanted which was to have more directional light from the front. What I was trying was the reflector in the same plane as the front of the lens and shooting the light towards the camera so it bounced back on the front of the subject. Seems the technique is called a Lieberkühn Reflector but I just could not kludge it together :cry:

What I should have tried, and indeed have on my "project" list is a partially reflective cone around the subject, narrow end towards the objective, shoot light in from the side, bounce it towards the camera and then bounce back to the subject off a reflector next to the objective. For some reason I was trying with the light source behind the subject.
A unique focusing rail
You can't just say that and walk away ! What is unique about it ?

rgds, Andrew

Graham46
Posts: 132
Joined: Thu Dec 18, 2008 7:31 am
Location: Harford County, MD

Post by Graham46 »

Craig

Thank you for your comments. The model of the fiber optic light is a Schott DCR III, which has two long flexible lights that are about 1 cm wide at the opening. Although I had not posted any images recently, I went back to the technical and studio forum (I post almost exclusively there since all my subjects are dead) and pulled up some links to previous posts for you:

Fly:
http://www.photomacrography.net/forum/v ... php?t=7922
Mud Wasp:
http://www.photomacrography.net/forum/v ... php?t=7709
Green Horned Beetle:
http://www.photomacrography.net/forum/v ... php?t=7583
Deer Tick with mouth parts:
http://www.photomacrography.net/forum/v ... php?t=7562

I checked out the link to the reflector, looks like a very similar principle. Cannot say Ive heard of that person until now. I asked Tony and he was aware of that reflector and based his design on it, but added a small flap on the bottom to direct more light toward the center of our subjects since no light would be coming from the hole. As far as the legs are concerned, they might not be as large on future models of this set up, but the downward angle of the rail is important. The stage moves towards the lens as the lead screw is advanced, and gravity prevents "backlash" in the lead screw in between turns. The screw was purchased at Home Depot, so its not perfect, but the minor wiggle from the lack of straightness in the screw is corrected once the images are aligned in the stacking software

Andrew,
Thank you for your comments too. I would certainly keep trying with your project and just try aiming the light in from all angles until you find whats best for you. Maybe try adding a polarizer to your lens and compare those results as well.
As for the uniqueness of the rail, I say that because it was not purchased, it was machined by hand. Inside the long piece of aluminum is a lead screw which has a moving "key" fixed at one position on it. The key fits perfectly into the stage, and a rotating disc at the front of the rail controls the movement of the key. One full rotation of the disc is equal to a 1 mm advancement. When working with very small subjects, you can turn the disc as little as you want, sometimes taking 12-15 pictures before making a full rotation.
Semper cogitatio
Graham

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