This is my first posting of pics taken with my “new” second-hand Meiji EMZ-5TR microscope and Schott KL1500 duel goose-neck lightsource. I am using the same Olympus SP-350 and Brunel camera adapter.
Since getting the Meiji it has taken me ages to achieve a reasonable level of parfocality with the eyepieces and camera and an "acceptable" camera set-up - it works ok but I’m still hoping to improve on quality as I gain experience.
The following three images are of an end slice of an Allende meteorite. Allende is one of the more interesting (type CV3) Carbonaceous Chondrite meteorites. It fell in Pueblito de Allende, Chihuahua, Mexico on 8th Feb 1969. A search on Google will bring up a huge amount of information about this particular meteorite and for anyone interested a top-line description can be found at http://www.alaska.net/~meteor/AMinfo.htm
Pic1 (stack of 4 images) shows the many round chondrules (see http://en.wikipedia.org/wiki/Chondrule )and other inclusions present in this meteorite. For me, most fascinating of all are the white calcium-aluminium inclusions that are believed to be some of the very first matter created during the formation of our solar system, in excess of 4.5 billion years ago.
Pic2 is from a stack of 5 images.
Note (edit to original posting): Pic3 is a more recent image taken at a lower illumination levels (as recommended by Ken) and jpg optimised to <200Kb using greater selectivity on key areas. Even so there is a noticable loss of detail from the original 800x600 457Kb image. I think it's an improvement on the original posting - thanks Ken.
Although you wouldn't think so from the apparent grain size, this chrondule is smaller than the one in pic2 at approximately 1.2mm in diameter.
Bruce
Last edited by Bruce Williams on Sun Dec 10, 2006 6:35 am, edited 5 times in total.
Some pretty good shots here from that second hand Meiji there Bruce. The first is quite excellent and the second and third seem to be slightly over illuminated and sharpened. I have had similar results with my 13TR when I over illuminate the subject being photographed with my Sony DSC-W5, so I just dim the light a bit and cut back on the sharpening. My biggest problem was getting proper focus through the 10XWF eyepiece I had installed in the photo tube of the 13TR, however, through trial and error I finally achieved the desired result. I think however that a 10XWF laboratory eyepiece would probably give even better results, in that it would probably deliever more light and a larger image (FOV) to the camera.
Yes I'm sure you're right about the over illumination Ken and I'll take your advice and try using lower illumination on a set of new pics. I think too that maybe some of that oversharpened look is probably due to my inexperience with setting up the light sources.
I'm certainly not finding it easy to achieve pin-sharp focus and have been amazed (and frustrated) by just how "critical" that sweet spot is. It only takes the slightest turn of the focus knob to move right through focus.
Pic1 was cropped from an image at minimum Meiji zoom (no downsizing and 50/1.2/0 USM)).
I didn't apply a great deal of USM on pic2 (50/1.2/0 on the downsized image) and 80/1.2/0 on pic3 (straight crop). These images were at maximum zoom on the Meiji.
I had a real problem getting the images under 200Kb for posting (at 800x600 they were all three originally > 400Kb out of Photoshop).
I used XAT Image Optimiser but because the "important" detail covered the whole image I was unable to effectively use selective compression. I'm (mentally) working on some jpg optimization ideas for my next meteorite posting.
I have often noticed in subjects of high reflectivity that if one moves the source of illumination back away from the subject and slightly reduces the intesity of the source, the images come out with a much more even amount of illumination. Digital cameras seem to be much more sensitive not only to light but to motion or vibration unlike their film counterparts. For example, butterfly and moth wing scales were a nightmare when I first started to try and photograph them but after time and with many trial and error images, I found out that the reduction in light intensity and the nearness of the illumination source in realtion to the subject being photographed with the Meiji made a great deal of difference in the appearance of the wing scales, they seemed to look more natural when I or after I, backed off a little. Another thing you might find more useful is a fluorescent ring illuminator, like the Micro Lite FV 1000 ($350.00US). Fluorescent illumination gives a much more appealing look to rock and mineral subjects, as the light is softer and more like daylight, however if a white background is placed behind the subject being photographed, the reflected light of the fluorescent illuminator, back into the twin objectives of the Meiji, gives the image a milky look or appearance.
Well I am not sure as to how everyone else may view your redoing of the image but I think there is a marked improvement overall . However when it becomes possible, I would think that a fluorescent light source would be most benificial when it comes to photographing subects such as these through the Meiji. Steve does a lot of mineral shots and he could probably give you much better direction on this than I but these do look better in my opinion.
As for these camera adapters, I am not too keen on them since after wasting a good deal of money on them and not getting the results that I wanted but that is a matter of preference. Personally I like the Orion SteadyPix camera bracket, also advertised as an adapter, positioning the camera over a regular 10X wide field eyepiece installed in the photo tube.
Ken Ramos wrote:Steve does a lot of mineral shots and he could probably give you much better direction on this than I but these do look better in my opinion.
Sorry for the late reply guys. Been really busy through December and only been keeping an eye on the macro/close-up forum.
I have found that a stronger light source is better. I've always used halogen. Initially a 50W halogen desk lamp, and in more recent times, a 150W halogen light source with twin goose necks. The most obvious benefit is that I no longer burn myself! But I've also found that the stronger more focussed light is better. Still have some issues with metallic minerals but I find that the goose necks give me enough flexibility to still have enough light, but to be able to reduce glare. I can buy a ring adaptor for my light source but haven't yet got round to it (funny how you're always looking for a round tuit!).
One "drawback" of the halogen is that I usually have to do minor colour adjustments, but I usually find that the Auto Color Adjustment in Photoshop is sufficient.
I use an Olympus scope and a Sony DSC-P150 camera btw.
Hmm...seems that your results are quite different from mine there Steve. I once employed the use of much brighter illumination but the images looked quite harsh on rocks and such with lots of reflective particles and then I backed off the light a bit and got better results. Fluorescent illumination seemed to really work much better for those subjects vice the halogen though. Now I am thinking that it might be the cameras we are using. Both of us are Sony DSC users, I am assuming from your post but different models. The sensors of the two cameras maybe different or and thus accounting for our varied results and then again we are using different scopes, you an Olympus and I a Meiji. So then again it maybe the configuration and type of equipment we are using is making the difference. I am sure there is a "Partridge in a pear tree" there somewhere. Merry Christmas!
Thanks for the advice guys - it seems that experimentation and experience with different subjects could be the route to take.
The main problem I am experiencing is glare.
There seem to be so many variables to work with ie, light source intensity, distance from subject, position, angle (individually for the 2 goose necks) and the use of the Meiji's own adjustable light. I've also read about folks using cut up ping-pong balls as diffusers and of course there is reflected light.
At the moment (with no experience of using artificial light in traditional photography) I am using (possibly faulty) common sense and crossing my fingers ...and of course modifying the set-up based upon results.
Once I've set up the lights and the magnification on the Meiji, I do a custom white-balance set-up (quick and easy on the Olympus SP-350) with a piece of white card, which in the main seems to produce reasonably accurate results.
Which reminds me, I could use some advice about positioning the head units on the goose necks. On the Schott KL1500 the heads can be moved relative to the end of the fibre optic cable. At the moment I have them set to give the (almost) brightest, but just slightly difussed, disc of light. Is there a scientific "sweet spot" that I should be using?
Can't say as I know of any "sweet spot" there Bruce, most of my dealings with photographing through the Meiji has been through trial and error, playing with the white balance settings on the camera and such, pretty much the same as what you are doing. The ping pong ball thing seems to work pretty well for some folks.
About the lighting, I'm not sure this will help but I'll give it a try. Sorry about the length -- I couldn't figure out how to make it any shorter. Grab a snack and read carefully, I guess.
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It helps to imagine yourself to be shrunk tiny, standing on the subject.
From that viewpoint, what does the illumination look like?
If most of the light comes from a narrow angle -- a light source that is apparently small but bright -- then the illumination is "harsh", or "directional". It will cast dark shadows with hard edges. If the camera sees that illumination reflecting from a shiny surface, then the reflection will be small and bright. Direct sunlight on a clear day is harsh/directional.
On the other hand, if the light comes from a wide angle -- a light source that is apparently large but dim -- then the illumination becomes "flat", or "diffuse". It will cast lighter shadows with soft edges. If the camera sees that illumination reflecting from a shiny surface, the reflection will be large and not so bright. Outdoor light on a foggy day is flat/diffused.
Most light sources are intrinsically small and therefore directional. To make diffuse illumination, you either bounce the light off a big reflector, or shine it through a big diffuser. In either case, whatever portion of the reflector or diffuser is lighted up, becomes another light source from the standpoint of the subject. Typically the reflector or diffuser covers a wide angle (from the standpoint of the subject), so that light is a lot more diffuse than the original source.
The light coming from your fiber optic heads will be very directional unless the heads are very close to the subject. To get a feel for this, hold a toothpick near the subject and see how sharp and intense the toothpick's shadows are. (There will be two shadows, one for each light source.)
Most good illumination is a combination of directional and diffuse components. The trick is to balance the relative amounts, and to adjust the position and size of the directional sources.
In terms of image quality, the absolute light level does not matter, except for low-order effects like noise accumulation for long exposures.
However, most rooms provide a fair amount of diffuse illumination just from light bouncing off the walls. When you turn down the brightness of any added directional sources, you increase the proportion of diffuse illumination. Many subjects, especially shiny ones, look better with diffuse illumination. I'm pretty sure this is why Ken's recommendation to reduce the brightness works for him.
Another way to get more diffuse illumination is to explicitly add some. Ken's other suggestion, to use fluorescents, makes sense here in terms of using a larger and therefore more diffuse light source. But there are other ways involving diffusers and reflectors.
White pingpong balls are made of very good diffusing material, meaning that however much light goes in, most of it comes out again, at pretty much all angles.
So, you can add some nice diffuse illumination -- from the standpoint of a small subject -- by shining light onto a big chunk of pingpong ball material that is very close to the subject. You can also create somewhat directional illumination in a wide range of sizes and positions by simply illuminating smaller portions of the pingpong ball.
There's nothing magic about a pingpong ball except that it's small, white, diffusing, and quite durable. (Eggshells were the classic tool for macro lighting, but they're not so great for "durable".)
Sometimes pingpong balls are too small, in which case other diffusers like paper, white fabric, or white-painted plastic can be used in just the same way.
In general, with 3D subjects you need some diffuse illumination to keep shadows from going black, and you need some directional illumination to let the user infer shape from shading. If the subject has shiny parts, then it also helps to have some very small (highly directional) source positioned so that the camera can pick up its reflections as "catchlights". Without some bright spots that are recognizable as reflections, the viewer can't tell whether a surface is matte or glossy.
As you say, there are a lot of variables to play with. If I were feeling mathematical, I might say there's at least 13 of them. That's x, y, and z plus two tilts, plus lens extension, for each of your illuminator's two heads, plus illuminator vs room brightness if there's enough ambient light to matter.
Surrounding the subject with a pingpong ball cuts the count a bit. Let's see...each head will illuminate a spot somewhere on the pingpong ball, and you can characterize the spot by latitude, longitude, radius, and brightness, but the ball will exclude ambient light, and, uh, only the relative brightness of the two spots matters, so, um...gee, we're down to only 7 variables!
Seven variables is a lot less than 13, but it's still quite a few, and it's probably too many to think that you're ever going to get the "perfect" lighting.
I'm afraid that's about all the science. Everything else is art -- a field I've never been particularly good at.
I suggest attacking stepwise -- think in terms of one main light, fairly directional, plus one fill light, fairly diffuse. Using the pingpong ball, that means placing one head very close to illuminate a small area of the ball, and pulling the second head back to illuminate a much larger area. But some symmetric subjects look great with symmetric lighting. Again, you can often get to a good combination by moving one light until the illumination looks pretty good, then moving the other until it looks even better.
With luck, what I've written above will be helpful to understand what's going on. But there's no substitute for flying the lights around to see what "looks good".
Really appreciate the time you've given to helping out on this one Rik. In many ways lighting is as important as the microscope and the camera to achieving a good result - so I am grateful for your advice especially when it's as clearly and interestingly expressed as your posting.
Bruce, you're very welcome. I find that writing about stuff helps me organize my own understanding, so with a bit of luck and time to do it, it's a win-win situation. Good questions are precious things!
All feedback is appreciated, by the way. If suggestions don't work, or ideas are hard to understand, or just plain don't make sense, be sure to let me know, OK? Sometimes I write nonsense, and once in a while I don't notice until it's pointed out.
