Using an Olympus E-330 DSLR with a Binocular Stereomicroscope

by Ted Clarke, USA

 


My earlier Micscape article, “A Gun-Mount for Nature Photomacrography”, gave an introduction to my use of this very innovative camera. A subsequent article in Microscopy Today, “Olympus E330 DSLR for Photomicrography with Older Design Microscopes”, demonstrates how this camera can be used with an Olympus 28 mm f/2.8 camera lens held over a 10X eyepiece to record a full 18 mm FN without vignetting even though the eyepiece is not high eyepoint. The camera was mounted in my rigid macro stand to avoid blurring from shutter vibration, which has been my practice when using 35 mm SLR camera backs for photomicrography and photomacrography. I had planned to follow this with evaluation of the E-330 for scanning light photomacrography. My Modern Microscopy article on scanning light contains Photo 1 showing the head of a housefly recorded with my Nikon Coolpix 995 mounted to a 10X high eyepoint eyepiece in the bellows system. The E-330 will allow direct projection of the macro lens image onto the camera sensor without the need for an eyepiece and with twice the pixel count for a larger field size at the same spatial resolution. I have also been working with a home-made transmitted light illuminator for use with my stereomicroscope so I can look at lake water organisms with the grandkids. I wondered whether there was a way for me to use my E-330 for digital images from the binocular Meiji stereomicroscope used with the new illuminator.
 



Figure 1 (Click image to view master)

I suspected that it might be possible to mount the E-330 on the bellows rail of one of my pair of home-made fiber-optic double condenser illuminators described in my Microscopy Today article “Brightfield Illumination of Large Field Sizes”. These illuminators use an Olympus Auto Bellows as a focusing rail for their components. My previous experience with the crack-prone plastic inserts used in the Olympus Auto Bellows is described in my Microscopy Today article (p.1, p.2) “Heavy Duty Camera Bellows for Digital Imaging”. The Kodak MegaPlus 1.6i digital camera caused cracks to form in the female dovetail inserts. These were noticed before total failure occurred allowing the expensive camera to fall. Even though the double condenser application for the Auto Bellows does not impose the heavy loading of the digital camera, cracks were found in dovetail mounts after about 15 years of use. I replace all of the plastic inserts with precision machined zinc alloy ZA-12 inserts made in my home shop. Photos 2 & 3 show the front and back of the bellows rail system that I used with the E-330. The slider for the camera adapter shown in Photo 2 contains a zinc alloy dovetail insert and was initially used with the heavy duty bellows rail of my macro stand shown in my scanning light article in Modern Microscopy. The top of this slider has alignment lugs for locating my OM-1 or OM-4 film camera backs as well as the cable release adapter bases used with the Coolpix 995 and E-330 digital cameras. The cable release bracket for the E-330, shown in Photo 2, also has lugs to align the E-330 camera. Photos 4 & 5 show the E-330 mounted with its 28 mm f/2.8 lens almost touching the Meiji 10X eyepiece. My final alignment procedure was to close the aperture diaphragm of the 28 mm camera lens until the brightfield image in the camera, set for live viewing, became seriously vignetted with a somewhat an out-of –focus image of the aperture formed. Tilting of the bellows rail and rotating the bellows rail on the ˝” diameter vertical shaft was used to center the image of the aperture diaphragm and get its edge uniformly imaged. The aperture was then fully opened. The 10X live viewing from the main CMOS sensor was used for fine focusing of the microscope. The spot metering does not work in manual mode with the Olympus MF-1 adapter needed to mount the 28 mm lens. Live viewing with the CCD sensor of the viewfinder system was used to obtain the exposure readings in manual mode with no compensation with the camera set for 100 ISO sensitivity. The test object chosen was the same slide of mounted housefly wings used for my earlier article on using the E-330 with my modified Biolam and 4X. The camera suggested exposures were used to start a series of trial exposure to find the optimum exposure, about 1/100 sec in brightfield and ˝ sec in darkfield.
 


Figures 2 and 3

 

Figures 4 and 5


Photo 6 is a composite of the brightfield and darkfield images of the fly wings taken with a 0.5X reducer and the Meiji 2X objective. Some illumination unevenness is apparent towards the edge of the field. Photo 7 is a composite of the brightfield and darkfield images recorded using the Meiji 2X objective. Illumination is fairly even for this smaller field size. Photos 8 & 9 show the same wing in brightfield and darkfield recorded using the Meiji 4X objective. I am surprised to see the hair fringe resolved on the trailing edge of the wing was recorded. This fine detail is just resolved when viewing through the eyepieces. The tests indicated how well the critical focusing feature of the E-330 performs. The shutter vibration level is apparently minimal so that a very rigid stand is not needed for use with a stereo microscope. The photomicrography capability with the E-330 and my stereomicroscope is helpful but not necessary for me because both of my upright student microscopes have multimode illumination capability for 20X and 50X imaging with the E-330 mounted in my macro stand or on the enlarger stand. The modified Monolux microscope is described in my Microscopy Today article on rediscovery of darkfield dispersion staining. The dispersion staining image in that article of the entire field of Chrysotile asbestos on a reference slide was recorded with the drawtube mounted macro lens.



Figure 6 (Click image to view master)

 

Figure 7 (Click image to view master)

 

Figure 8 (Click image to view master)

 


Figure 9 (Click image to view master)

 

Comments to the author Ted Clarke are welcomed.

Micscape Editor's acknowledgement: Local pdf copies of the author's 'Microscopy Today' articles are courtesy of the author and the 'Microscopy Today' Editor.

 

 

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