Hi all,
I've got my lens reversing ring and have been experimenting with the different lenses I have to see how using this method compares with normal fitting. ( I'll post some results later).
To get an accurate estimate of the relative quality of each lens I felt I need to use a subject side diffuser. I don't have any ping pong balls at the moment, so I made one from a translucent white plastic drinking cup.
This is what the diffuser looks like in use.
I was very surprised at the amount of difference there is between the two images, with and without the diffuser. Take a look at these images. Obviously the top image is the one with the diffuser.
Whilst I prefer the top image from the point of view of judging the technical quality of one image against another, I also quite like the image without the diffuser. I'm sure there are subjects out there that would look better without the use of a diffuser.
I suppose the moral of the story is that the subject dictates the setup and not the other way round. In this case, it is possible that the use of a diffuser could ruin a good image.
FYI. The two test images were taken with my 105mm nikon macro lens reversed on a Pentax bellows and with a set of extension tubes fitted. The field of view at the subject is approx. 11 mm.
What A Difference A Diffuser Makes.
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georgedingwall
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What A Difference A Diffuser Makes.
Last edited by georgedingwall on Wed Mar 05, 2008 1:42 am, edited 1 time in total.
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rjlittlefield
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George,
Thanks for posting these pictures and bringing up this topic.
I was shocked to realize how much improvement good diffuse illumination can make with some subjects.
When I finally broke down and bought a halogen fiber illuminator, one of the first experiments I tried was to stick a beetle under the microscope and light it up with the fiber tip. It looked nice and bright, but otherwise pretty much what I was used to.
Then I stuck in a pingpong ball diffuser, cranked up the brightness to compensate -- and quite literally gasped! I was completely unprepared for so much improvement, despite 40 years of reading and playing with various lighting schemes.
The fiber illuminator and white-ball diffuser is now part of my standard arsenal for direct viewing too, not just photography.
--Rik
Thanks for posting these pictures and bringing up this topic.
I was shocked to realize how much improvement good diffuse illumination can make with some subjects.
When I finally broke down and bought a halogen fiber illuminator, one of the first experiments I tried was to stick a beetle under the microscope and light it up with the fiber tip. It looked nice and bright, but otherwise pretty much what I was used to.
Then I stuck in a pingpong ball diffuser, cranked up the brightness to compensate -- and quite literally gasped! I was completely unprepared for so much improvement, despite 40 years of reading and playing with various lighting schemes.
The fiber illuminator and white-ball diffuser is now part of my standard arsenal for direct viewing too, not just photography.
--Rik
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georgedingwall
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Hi Rik,
They seem to do the job for now. They have about half a stop of variability in the light output, and HF seems to cope with that OK.
Do you think I would get any significant improvement in lighting quality by re-considering the fibre light.
Since I posted the image of my diffuser set, I've had to do a modification to it. The way you see it above, the subject is introduced near the rear of the cup throught the hole you can see.
That's OK for the 105mm lens. When I put my 35mm and 50mm lenses on the setup, the subject was too far away to bring into focus. So I've had to put a new hole near the front on the opposite side, so that I can bring the subject into focussing range.
Unfortunately, while I was drilling the new hole, I knocked off one of the wooden supports for the diffuser, and I now have to wait for the areldite to dry before I can continue with my testing.
Isn't life a bundle of laughs.
I looked at a fibre optic illuiminator sometime ago, but was put off by the price. That's when I went into the attic and got out my old studio lights.rjlittlefield wrote:George,
Thanks for posting these pictures and bringing up this topic.
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The fiber illuminator and white-ball diffuser is now part of my standard arsenal for direct viewing too, not just photography.
--Rik
They seem to do the job for now. They have about half a stop of variability in the light output, and HF seems to cope with that OK.
Do you think I would get any significant improvement in lighting quality by re-considering the fibre light.
Since I posted the image of my diffuser set, I've had to do a modification to it. The way you see it above, the subject is introduced near the rear of the cup throught the hole you can see.
That's OK for the 105mm lens. When I put my 35mm and 50mm lenses on the setup, the subject was too far away to bring into focus. So I've had to put a new hole near the front on the opposite side, so that I can bring the subject into focussing range.
Unfortunately, while I was drilling the new hole, I knocked off one of the wooden supports for the diffuser, and I now have to wait for the areldite to dry before I can continue with my testing.
Isn't life a bundle of laughs.
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rjlittlefield
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Boy, doesn't that story sound familiar!georgedingwall wrote:Unfortunately, while I was drilling the new hole, I knocked off one of the wooden supports for the diffuser, and I now have to wait for the areldite to dry before I can continue with my testing.
Isn't life a bundle of laughs.
I've been there and done that -- and much worse!Um, maybe "significant but not striking"? If I recall correctly, you're already using those big fluffy softboxes. Placed close to the subject, they should give you a lot of the directionless character of the white ball technique. Cover the top and bottom of your workspace with white paper or crumpled aluminum foil and it should get even better. It's probably also easier to get the light "just so" using fiber, since you can see directly what it's doing and not have to rely on pictures or dim modeling lights.I looked at a fibre optic illuiminator sometime ago, but was put off by the price. That's when I went into the attic and got out my old studio lights.
They seem to do the job for now. They have about half a stop of variability in the light output, and HF seems to cope with that OK.
Do you think I would get any significant improvement in lighting quality by re-considering the fibre light.
But given what you already have, I'd certainly not rush out to buy a fiber illuminator for stacking.
--Rik
George
As far as I understand it, the principle of lighting subjects remains the same whatever their scale. Scale is the key, as the subject size shrinks you need to shrink the size of the lights in relation to it to retain the same character of illumination.
We tend to think of lighting on the human scale (portraiture) and name lights accordingly, forgetting as subjects deviate from the human scale the effect of the same light will too. For instance a floodlight for portraiture will become a spotlight if used to light the side of an ocean liner and a spotlight in portraiture will become a floodlight when photographing a beetle. This is why camera type flash guns often produce better lighting in macro photography than studio flash, simply because their flash tubes and reflectors are smaller.
If you are using the lights direct and not behind a diffuser you need to shrink or "snoot"** your lights in size to retain the same proportions to the subject as the appropriate light in portraiture has to the sitter to retain the same lighting characteristics. That is where fibre optics come in, they are the spotlights in insect portraiture when ordinary flash has now become the floodlight.
**See:- http://www.lumiquest.com/lq891.htm
As Rik says, you can use crumpled aluminium foil strategically placed within your diffuser to put back some of the specular highlights lost through diffusion if you require. You have to look through the viewfinder and move it around until you get the effect you are after. Do not use uncrumpled foil as it simply acts like a mirror, but crumple the foil up into a ball then smooth it out with your hand to produce a sheet of the size you want with a dimpled surface.
DaveW
As far as I understand it, the principle of lighting subjects remains the same whatever their scale. Scale is the key, as the subject size shrinks you need to shrink the size of the lights in relation to it to retain the same character of illumination.
We tend to think of lighting on the human scale (portraiture) and name lights accordingly, forgetting as subjects deviate from the human scale the effect of the same light will too. For instance a floodlight for portraiture will become a spotlight if used to light the side of an ocean liner and a spotlight in portraiture will become a floodlight when photographing a beetle. This is why camera type flash guns often produce better lighting in macro photography than studio flash, simply because their flash tubes and reflectors are smaller.
If you are using the lights direct and not behind a diffuser you need to shrink or "snoot"** your lights in size to retain the same proportions to the subject as the appropriate light in portraiture has to the sitter to retain the same lighting characteristics. That is where fibre optics come in, they are the spotlights in insect portraiture when ordinary flash has now become the floodlight.
**See:- http://www.lumiquest.com/lq891.htm
As Rik says, you can use crumpled aluminium foil strategically placed within your diffuser to put back some of the specular highlights lost through diffusion if you require. You have to look through the viewfinder and move it around until you get the effect you are after. Do not use uncrumpled foil as it simply acts like a mirror, but crumple the foil up into a ball then smooth it out with your hand to produce a sheet of the size you want with a dimpled surface.
DaveW