FAQ: How can I diffuse illumination? 1: Bench setups

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NikonUser
Posts: 2636
Joined: Thu Sep 04, 2008 2:03 am
Location: southern New Brunswick, Canada

FAQ: How can I diffuse illumination? 1: Bench setups

Post by NikonUser »

[Edit AdminCR]
See also :A later result with an enlarger lens and simple diffuser: Here



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Seems that there are many ways, possibly all work equally well. Rather analogous to building a better mouse trap.

Would be useful if photos of setups were placed here, or links to setups.

My most recent incarnation is the:
Slush (slushie, slushy) cup top
The top of this cup is a clear plastic dome, 10cm diam at base, 5cm high, with a 25mm diameter hole at the top. The barrel of a Nikon 4x CF Plan Achromat fits nicely into the top hole, but of course the hole can be enlarged and even reduced.
Covered with white paper, in this example paper kitchen towels, a slush cup top makes a useable diffuser.

Did a reasonable job on this highly reflective Greenbottle fly. Dotted line and X shows approx. position of pin and fly.
Image
NU09220
Image
NU09221
Last edited by NikonUser on Fri May 07, 2010 3:51 am, edited 1 time in total.
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives

NikonUser
Posts: 2636
Joined: Thu Sep 04, 2008 2:03 am
Location: southern New Brunswick, Canada

Ball Diffusers

Post by NikonUser »

Discussion and images of Ping Pong Ball diffusers
HERE
An alternative is a child's hollow plastic baseball, diameter 74mm.
I just bought 10 of these for $5.00 at Toys-R-Us. Outer surface is shiny so I dulled it with coarse sandpaper. Cut a hole in one end so as to make it fit over a 4x Nikon CF Plan Achromat; cut easily with a hole-cutting saw on a drill press. Cut a 25mm hole at other end.
This is a temporary set up with the ball held in place with Scotch tape.
X is approximate position of fly, T at 45 degrees is approx. position of lens.
Full frame of Blow Fly, photographed 28 October 2009, collected 2 June 2009 and kept at -17C

Nikon 4x objective @ 150mm extension, 45 frames @ 0.05mm, 2 flashes, ZS PMax
Image
NU09224
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives

NikonUser
Posts: 2636
Joined: Thu Sep 04, 2008 2:03 am
Location: southern New Brunswick, Canada

Post by NikonUser »

Charles used plastic baseballs in June 2007
SEE THIS PAGE
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives

Eric F
Posts: 246
Joined: Tue Nov 11, 2008 1:38 pm
Location: Sacramento, Calif.

Post by Eric F »

Using "Rosco Diffusion Kit" papers on a vertical camera stand setup.

Rosco company offers many excellent diffuser products (see HERE). A "Rosco Diffusion Kit" (contains 24 pieces of letter-sized diffuser papers, costing about $30 from a local retailer) makes it easy to experiment with many different strengths and kinds of diffuser materials (pieces can be combined--so the possible number of combinations is very large). My current favorite paper is "Tough Rolux #3000" but I have only tried a few combos so far! The following shows some simple ways to utilize these diffusers on a vertical camera stand.

First attempts were to use step-down and step-up adapter rings to fix diffuser to a Canon Macro Twin Lite. A 15mm high ring of poly plastic was cut from a shallow container and "sandwiched" between a 72-67mm and 58-72 ring (the Twin Lite mounting base has a 58mm thread on the outer face). A long piece (20cm) of transparent mylar was rolled into a double-walled cylinder, with a 10cm length of diffuser paper lining the inside, and this is placed into the plastic ring (67mm diam., using friction-fit only, so the cylinder can be rotated, to avoid the seam interfering with the flash, and to make it easy to switch papers). This worked OK (very easy to switch around paper types, etc.), but I still preferred a pingpong ball setup! The plastic bottle on the left is the basis for the next (and better) arrangement.
Image


Cutting the neck and most of the bottom off the bottle leaves a cone-shaped piece that that can serve as a "holder" for diffuser paper made into a cone (using a pattern similar to the one for the inside of a Beljan RMS adapter cone discussed HERE). Two methods of attaching the plastic cones are shown: one that fits snugly onto the tip of the lens (left), the other loosely around the base; the shape of the lens determines which is best. The tight one must be cut very carefully to fit properly (a Dremel rotary tool is helpful here). In each case, the diffuser paper cone must be in place before the plastic part is attached. The notches in the cones on the left are to accomodate insect pins, which sometimes interfere with close focusing (working distance with the Minolta is 6-8mm).
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The loose plastic cone in place (without the diffuser paper).
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Complete diffuser cone setup shown on stand. Placing the Twin Lites on flexible arms was the initial reason I tried the cone setup, but I've now come to prefer this system for small subjects. I believe the cones make a better diffuser than the bigger cylinders; more like a pingpong ball diffuser, but many more options possible with different diffuser papers. Of course, many other materials (even Kleenex tissue!) could be used on top of the plastic cones.
Image


Shot of a small robber fly (Atractia sp.) using #3000 "Tough Rolux" cone diffuser. Shot at 9X--head is 0.5mm wide. [Minolta 12.5 @ f2.8, 40 @ 0.02, ZS]
Image

My thanks to Craig ("augusthouse") for introducing us to Rosco products on photomacrography.net.

ChrisR
Site Admin
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Location: Near London, UK

A suggestion for beginners

Post by ChrisR »

Soften that light!
We see a lot of beginners' pics where the subject comes out rather "hot". That's to say with bright directional light, looking artificial, burning out the highlights and causing harsh, blocked shadows.
Colours can also be "blown" easily with harsh light so you get for example a lot of exactly the same colour, typically max yellow.

One of the few things on your side when close-up is that an electronic flash can be diffused a lot, and still leave you plenty of power.

It's worth experimenting with whatever subject turns you on, to see how much diffusion you like.
Flash on camera, even a pop-up, can be OK. Try investing in a sheet of white paper and two paperclips.
Make a hole in the middle of the paper slightly bigger than you need for your lens, and fold it as shown. One side's paperclip is shown, green. You can slide the folded paper through the paperclips more, to tighten the paper onto the lens, one each side.

Image

The flash is diffused through the top half of the paper, while the undeneath part provides reflected fill-in light to hold the shadows up.

You can do much the same with a white plastic bag. Make a hole for the lens and tie a knot in the bag above the lens, leaving an "ear" of whatever size you like for the light from the flash to hit, and be diffused onto the subject. The rest of the bag can be underneath for fill-in.

If you use a pop-up, the flash probably wouldn't hit the subject straight through the diffuser because the lens is in the way. With a flashgun on the hotshoe, it might well be able to, so you might need extra diffusion. A double thickness of paper!

Craig Gerard
Posts: 2877
Joined: Sat May 01, 2010 1:51 am
Location: Australia

Post by Craig Gerard »

Most of the posts in this thread relate to tabletop setups; just a suggestion; but should this thread be renamed to "How can I diffuse illumination for tabletop setups ?

A second FAQ that deals with on and off camera solutions for use in the field might also be considered , for example: "How can I diffuse illumination when photographing outdoors" It could include flash setups, diffusion of natural light, reflectors/bounce, etc.

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

Craig Gerard
Posts: 2877
Joined: Sat May 01, 2010 1:51 am
Location: Australia

Post by Craig Gerard »

Eric,

I was making some ping pong ball diffusers and decided to order an Olfa CMP-1 compass circle cutter as mentioned by Charlie in the thread "The Art of Making Ping Pong Ball Diffusers"

However, the supplier sent me the Olfa CMP-3 Rotary Compass Cutter by mistake - it was a good mistake.

I've been using the CMP-3 for making cone diffusers for objectives similar to those outlined in your earlier post in this thread. The size can be customised for a particular objective/lense and it allows the use of whatever material is best suited to the job. Rosco or Lee Filters work well with this approach, even paper has proven to be useful with some subjects.

The cones can be constructed with adequate precision to allow them to be attached with a push/fit or friction-fit without secondary support (providing the material used has sufficient rigidity).

The Olfa CMP-3 assists in cutting nice, neat circles (with practice); in this case, one for the outer diameter and one for the inner diameter. The distance between the outer diameter and inner diameter will determine the height of the 'wall' or surface of the cone. A suitable size for RMS microscope objectives would initially have an outer diameter of 90mm and an inner diameter of 40mm. Make a straight cut through the circle, slide/shape into a cone of desired inner diameter to suit objective barrel, trim most of the excess whilst leaving sufficient overlap for a narrow fastening seam. The seam can be joined on both sides with Sellotape or a thin strip of double-sided framer's tape. I've begun to trial 'Jac Paper' double-sided adhesive tape on the seam because of its stronger 'grip'.

Secondary cones made of specific gels or filters can be used to overlay the base cone.

I'll post some pictures in this thread when I have made a few more diffusers. I posted one setup shot using such a cone here. In that picture the cone is attached to the microscope objective.

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

NikonUser
Posts: 2636
Joined: Thu Sep 04, 2008 2:03 am
Location: southern New Brunswick, Canada

Post by NikonUser »

A $2.00 diffuser
Purchased in a crafts/art supply store and sold for making stencils.
Smooth and slightly shiny on one side and dull on other side; rolls easily into a cylinder. Was used in the following setup for the 2 dragonfly 'jaws' images HERE

A: Nikon focus block, with 0.001 mm tick marks, for fore/aft (x-axis) frames for the stack
B: Swift focus block, accurate to 0.003 mm, removed from a microscope sold for parts, for vertical (y-axis. or is this z-axis?) adjustment.
C: pair of RRS focus rails for left/right adjustment (not recommended for accurate and precise shifts, but in fairness I doubt that these rails were designed for this purpose. I just happened to have them). Some means to move the camera/bellows/lens left/right is very useful.
D: 18x5" sheet of plastic for stencils.

The focus block is made for vertical orientation and 'expects' some gravitational force when vertical. Elastic band below B is to try and mimic that force.

Image
Image
NU10053 NU10054
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives

Craig Gerard
Posts: 2877
Joined: Sat May 01, 2010 1:51 am
Location: Australia

Post by Craig Gerard »

The following images belong with my previous post regarding the use of Rosco or Lee Filters as diffusers:

Referring to the following images:
The 'lid' or cone of the diffuser is separate from the diffuser 'cylinder' and is attached to the lense or objective.

The 'cylinder' can be swapped-out depending on the working distance.
If I were to use a microscope objective, the working distance would be less; so, I would then use a more shallow diffuser cylinder in combination with the cone, or alternatively, just use the cone.

Same also applies for larger specimens .i.e. a diffuser cylinder with wider diameter and additional height. The need for the cone diminishes, somewhat, the greater the working distance.

Image

Image

Image

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

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