A simple modular diffuser for field work

morfa · Post by **morfa** » Sat Sep 11, 2010 6:21 am

I just made a post on my flickr blog about the latest version of a type of diffuser I often use for hand held macro shooting in the field. The purpose was mainly to have something to point to when people have questions about flash diffusion. I won't include the entire thing here but I'm posting a few pictures with brief descriptions along with some samples.

The diffuser mounted on the Zeiss Luminar

The raw material: a white plastic yoghurt bottle with screw on cap

The "modular system": the screw caps acts as mounts, custom fitted to the lenses, and the diffusers themselves are easy to mount/unmount as well as being interchangable between different lenses

Demo samples:

Full story here: http://www.flickr.com/photos/johnhallmen/4978832703/

Please let me know if you have any thoughts or suggestions!

RogelioMoreno · Post by **RogelioMoreno** » Sat Sep 11, 2010 8:23 am

John,

Very nice, I like it.

Thanks for sharing.

Rogelio

PaulFurman · Post by **PaulFurman** » Sat Sep 11, 2010 9:08 am

Clever! Especially the screw cap adapters.

That material looks fairly opaque but I guess a translucent milk jug type plastic doesn't provide enough diffusion or the flash is strong enough to overcome?

rjlittlefield · Post by **rjlittlefield** » Sat Sep 11, 2010 9:14 am

I like this a lot. You get broad diffuse illumination and the light dims gradually toward the edge of the diffuser so you don't get those hard-edged reflections that scream "flash!".

--Rik

Bob^3 · Post by **Bob^3** » Sat Sep 11, 2010 9:18 am

That's a very elegant solution, John. The advantages for field work are very clear to me:

Even though the diffuser is small and portable, the illumination covers a wide angle because it is so close to the subject.

It can be rotated to obtain a better light direction for a particular subject.

It produces very natural lighting much like is seen in images captured under cloudy skies---as can be seen in the reflection in the eyes of the jumping spider. In fact, I like this effect much better than the full "wrap around" diffusers that pruduce a circular reflection with a "hole" in the center that can make eyes appear to have pupils. In my opinion, this concept would also be valuable for studio setups.

Inexpensive---materials essentially free, at least if you happen to like that particular brand of yoghurt!

I haven't seen that brand for sale in the US. So the might be able to do some business selling your empties on eBay!

Thanks for posting your creation. It gives me some good ideas.

Bob^3 · Post by **Bob^3** » Sat Sep 11, 2010 9:40 am

PaulFurman wrote:That material looks fairly opaque but I guess a translucent milk jug type plastic doesn't provide enough diffusion or the flash is strong enough to overcome?

In my experience, the problem is usually not getting enough light throught the diffuser to illuminate the foreground subject, it's properly lighting the bg. With this solution, it looks like the flash can be tilted to direct most of the flash energy to the bg to help balance the the exposure (if the bg isn't to far away).

morfa · Post by **morfa** » Sat Sep 11, 2010 11:49 am

PaulFurman wrote:PaulFurman wrote:
That material looks fairly opaque but I guess a translucent milk jug type plastic doesn't provide enough diffusion or the flash is strong enough to overcome?

I see what you mean but I can't say I've had any trouble with underexposure – not even with a small flash gun like mine, low ISO and a small effective aperture.

I wouldn't go as far as saying that this material provides the optimum balance between transmission and diffusion but I've often had trouble with either too opaque or too transmissive materials.

Like Bob mentions a lot can be controlled by positioning and angling the flash unit.

Another thing to point out is that this solution provides some control over another lighting aspect: by positioning the flash unit very close to the diffuser you get a pronounced hot spot and the shadows get more defined – the light looks less diffused. Move the flash away from the diffuser and the light distribution over the diffuser surface becomes much more even, the shadows softens and the diffusion effect becomes quite pronounced.

wiebe · Post by **wiebe** » Sat Sep 11, 2010 12:20 pm

Excellent idea, I might give this a try as well.

seta666 · Post by **seta666** » Sat Sep 11, 2010 2:52 pm

The system is very clever, the results awesome. What I like most about it is the ability to change the difusser shap with little effort.
Do you still use your old Ice-cream cup diffuser for field work? I mean the V2 with no ring shadows
Regards

AndrewC · Post by **AndrewC** » Sun Sep 12, 2010 2:27 am

Bob^3 wrote:..... In fact, I like this effect much better than the full "wrap around" diffusers that pruduce a circular reflection with a "hole" in the center that can make eyes appear to have pupils. In my opinion, this concept would also be valuable for studio setups.

...

In a studio with a "floating" subject you need to provide a a lightsource from below. Either a wrap around diffuser where you are actually bouncing light off the bottom surface or using a diffuser arch with an appropriate reflective floor. In John's great examples light is bouncing back up from the natural floor, just as it would naturally.

There does seem to be something special about yoghurt drink plastic - unfortunately mine have rip off foil tops so have to get wedged on with foam padding. The screw top solution is much better

I'll have to persuade my son to change brands !

morfa · Post by **morfa** » Sun Sep 12, 2010 4:43 am

seta666 wrote:Do you still use your old Ice-cream cup diffuser for field work? I mean the V2 with no ring shadows
Regards

Yes, at least as much as this one! Sometimes I prefer the less even light from the beautydish diffuser and not all bugs are happy with the "giant yoghurt bottle embrace" :-)

Barry · Post by **Barry** » Sun Sep 12, 2010 4:56 am

Looks as a good field solution!
In these nice sample pictures I dont see any flare - but I wonder if you strongly diffuse the light (flash far from plastic) if this isnt an issue? Perhaps the direction of the light is mostly away from your lens, but some light may cause weak flare problems?
(I often wonder the same for microscope objectives and pingpong balls)

Regards,
Barry

morfa · Post by **morfa** » Sun Sep 12, 2010 5:02 am

Barry wrote:Looks as a good field solution!
In these nice sample pictures I dont see any flare - but I wonder if you strongly diffuse the light (flash far from plastic) if this isnt an issue? Perhaps the direction of the light is mostly away from your lens, but some light may cause weak flare problems?
(I often wonder the same for microscope objectives and pingpong balls)

Regards,
Barry

Good point Barry – forgot to mention that!

If you look closely in the pictures you might be able to see something black at the inside base of the little diffuser attached to the chrome Componon lens? I've covered the innermost part (on the inside of the threaded part) with black "light trap" flocking. This is highly effective and makes the diffuser double as a lens hood – much less flare with the diffuser than without it in some cases.

Bob^3 · Post by **Bob^3** » Sun Sep 12, 2010 3:23 pm

AndrewC wrote:In a studio with a "floating" subject you need to provide a a lightsource from below. Either a wrap around diffuser where you are actually bouncing light off the bottom surface or using a diffuser arch with an appropriate reflective floor. In John's great examples light is bouncing back up from the natural floor, just as it would naturally.

Absolutely! So when I can't get to my favorite outdoor location (in addition to shooting "floating" preserved subjects) I also enjoy the challenge of shooting live subjects in the studio on natural substrates, with natural backgrounds. Low "keeper" rate sometimes, but fun!