On 10/11/2025 at 2:48 PM, CaolIla said:

  On 10/11/2025 at 2:33 PM, Luko said:

  On 10/11/2025 at 1:13 PM, CaolIla said:

The idea is putting some reduction in the tube and why not some extension with lens in it.
BUT there is a BUT with a lens when the distance is the focus length the light is like a donut because the tube of the retra a circular.
I need to but a diffusor on the retra side...

More than a diffusor that you need but rather a fresnel lens of something equivalent, the problem without any converging lens is that all the power will be lost. (That's what happens with the crappy Scubalamp snoot which is only equiped with a diffusor device, used it on one trip, never again, back to Retra snoot now) .This is why the Retra snoot is for me the most efficient one : you see for instance there is a sweet spot according to the distance you aim at your subject, the "halo" of the snoot will get sharper whenever you're on the ideal distance.

Diffusor or fresnel lens it is more or less the same... I'm using a fresnel on my other snoot.

Hi @Luko

I made a test to explain the donut

No lens no difusor only a small output

14 hours ago, CaolIla said:

No lens no difusor only a small output

Disclaimer : I am replying to you but am afraid that we are completely out of the OP topic, sorry for that.

So far I can notice you have 2 problems : one is the black hole inside the light which I guess is the signature of the circular bulb, the other one is that you have a light "fall off" spilling outside of the snoot hole (the outer ring of subdued light around the main light).

For me, it's due to the absence of a condenser lens that would both diffuse the circular light into a flat light and make the light converge to a focus point this avoiding spill off. We (my guide and myself) usually take continuous torch lights when we do macro, that we use when I need precise lighting other than the main snoot light or when two snooted lights are needed.

All of these small torches are equiped first with a lens like this one https://www.uwcamerastore.com/weefine-optical-collector-with-m52-for-smart-focus-6000?gad_source=1&gad_campaignid=21961101493&gbraid=0AAAAAD6tS_h9daR4-OxoqiVVd9_zdO1Lf&gclid=CjwKCAjwr8LHBhBKEiwAy47uUpyg-mpCh6yNn1-WSBCsL9CNJP9mI_UhLEkk2WRtWjKc90Kuc_xbshoCXKoQAvD_BwE

then screwed onto the condenser a plain metallic black funnel to reduce the light spot. However it wouldn't work without the condenser, which is the most important piece.

Just to show you the difference, I snapped 4 images of my mousepad with a tirch light, the condenser and a funnel.

A= full mousepad image lit by the torchlight, B= condenser on, the beam is reduced and condensed, C= condenser and funnel on, exactly what you expect from a snoot, even though I was not aiming at the sweet spot distance, not much light loss, same distance as withe condenser only D= funnel but NO condenser, I had to put the light much closer because of the loss of light, light spills outside of the main focus point, you cannot clearly see it but when I put the light close there are distinctly patterns of the LED light inside the main focus point.

@Luko


With a torchlight it is easy to visualize the result... and it is easy to achieve the goal: have a small spot

It works also good with the LED in the center of the Retra strobes... but a flash from the circular light is not as easier.

1) the need of a longer tube is necessary

2) a lens /fresnel or a concentrator as you name it is important to concentrate the light

3) with a lens with circular or only a LED you will have good "picture" of the light sources when you are at the focal length... that is the main problem. With a circular flash light you will have a bright disk with the dark center.

I made several test "Difussor" with frosted glas or such glasses

I made folowing construct
Light/strobe -> Diffussor --> 1 or more lenses with different focal --> tube with special internal shape to avoid the parasite reflexion --> and why not a lens for a last light concentration

It is not easy to make a compact solution I still exploring in different direction.
Target: Light, easy to (re)build, compact and not expensive.

In the tube a try with good results this shape

important printed with a black mat filament to avoid a maximum of the reflexion and have a nice boundery beetween the black and white zone on the picture.