Olympus microscopes and photomicrographic equipment

Attaching a digital SLR camera to an Olympus SZ4045, SZ4060, SZ6045 or SZ1145 stereo microscope

Introduction

Canon EOS digital SLR on an Olympus SZ4045 stereo microscope

Olympus produced equipment for connecting their Olympus OM 35 mm film cameras to trinocular versions of their SZ4045, SZ4060, SZ6045 and SZ1145 stereo microscope for photomicrography. These accessories can either be adapted or replaced to allow Canon EOS, Four Thirds, Nikon, Pentax, Sigma, Sony and other digital SLR cameras to be used instead of OM cameras, with the digital sensor located in exactly the same plane as the film.

Starting from the top, you need the following 5 items:

Camera body
Lens adapter
Camera adapter
Photo eyepiece
Photo tube

The SZ4045, SZ4060, SZ6045 and SZ1145 stereo microscopes were discontinued several years ago, and so most of the items referred to on this page (including the Photomicro Adapter L and the NFK photo eyepieces) are also discontinued. The best places to find them are eBay and microscope dealers who sell used equipment.

Stereomicroscopes provide several centimetres of working distance which makes them very convenient for manipulating and dissecting specimens, but it also makes them less suitable than compound microscopes for taking photographs. A compound microscope will produce more detailed and sharper photographs, and better results from image stacking.

Camera bodies

You do not need a lens on the camera, because the photo eyepiece is designed to project an image directly onto the sensor. The best digital SLRs to use as replacements for an Olympus OM have a 36×24 mm full-frame sensor, for example the Canon EOS 5D Mark II, 5D Mark III and 6D, allowing you to carry on using the same NFK 2.5× photo eyepiece.

A cheaper option is a digital SLR with an APS-C sensor (22.2×14.8 mm), such as the Canon EOS 7D, 40D, 50D, 600D (Rebel T3i) and 1100D (Rebel T3), but the smaller sensor results in a significantly smaller field of view.

It is possible to use digital cameras with a Four Thirds sensor (17.3×13.0 mm), but the camera’s field of view is substantially smaller than the viewing eyepieces.

Vibration from the camera’s mirror and shutter can be a problem when taking photographs through a microscope. Traditional solutions include electronic flash, long exposure times, mirror pre-release, and stands that support the camera independently of the microscope.

Canon EOS digital cameras from the 5D Mark II, 7D, 40D, 450D and 1000D onwards have a Live View Silent Shooting mode that makes them particularly suitable for photomicrography. In this mode, vibration is almost eliminated, because the exposure is started electronically while the mirror is already raised and the shutter is already open. This is also referred to as EFSC or electronic first shutter curtain. EOS cameras also come with EOS Utility software that allows the camera to be controlled via a USB connection from a computer, allows the computer screen to be used for checking focus and composition, and allows images to be saved directly to the computer.

The camera body is connected via a lens adapter to the camera adapter.

Lens adapters

The lens adapter connects the camera body to the camera adapter, and ensures that the digital sensor is located in exactly the same plane as the film in an OM camera.

For Canon EOS camera bodies, new lens adapters are readily available on eBay to enable these bodies to be fitted to the top of the Photomicro Adapter L instead of an Olympus OM camera. These adapters convert the OM bayonet on the Adapter L to an EF bayonet, and exactly compensate for the 2.0 mm difference in registration between OM and EOS bodies.

Adapter for mounting an OM lens on a Canon EOS camera

Front and rear of adapter for mounting an OM lens on a Canon EOS camera

There are 3 types of adapter for using Canon EOS bodies – no chip, AF confirm chip and EMF chip. The features of the 3 adapters are:

	no chip	AF confirm	EMF
M (manual exposure, user sets the shutter speed)
Av (auto exposure, camera sets the shutter speed)
Spot, partial, centre-weighted and evaluative metering
Confirmation of manual focus by beeping and by flashing one or more of the AF points in the viewfinder
EXIF lens data fixed at 0 mm for focal length and F/0 for aperture
EXIF lens data fixed, e.g. 50 mm for focal length and F/1.4 for aperture
EXIF lens data can be changed by user

For Sony NEX, Four Thirds and Micro Four Thirds camera bodies, new lens adapters are readily available on eBay to enable these bodies to be fitted to the top of the Photomicro Adapter L instead of an Olympus OM camera.

For Minolta AF/Sony α camera bodies, there are new adapters on eBay that might be suitable for use with a Photomicro Adapter L. The adapters are thick but they include a lens, so they might allow OM lenses to focus to infinity; if this is the case, then they probably are suitable.

For Nikon F camera bodies, it is not possible to make an adapter, but it is possible to remove the OM mount from the Photomicro Adapter L and attach a Nikon F mount.

For Canon EOS, Minolta, Nikon, Olympus E, Panasonic, Pentax, Sigma, Sony α, Sony NEX and other camera bodies, new T-2 lens adapters are readily available on eBay to enable these bodies to be used with alternative camera adapters that have a T-2 fitting on top.

Camera adapters

Olympus produced the Photomicro Adapter L to allow their Olympus OM 35 mm film cameras to be used for photomicrography with trinocular versions of their SZ4045, SZ4060, SZ6045 and SZ1145 stereo microscopes. Lens adapters are easily available on eBay to convert the OM rear lens fitting on the top of the Adapter L so that Canon EOS, Four Thirds and other shallow-bodied cameras can be used instead of OM cameras, with the digital sensor located in exactly the same plane as the film. It is not possible to make an adapter for Nikon F cameras, but the OM mount can be replaced with one for Nikon F cameras.

The bottom of the Adapter L clamps on to the circular dovetail on the SZ-PT Photo Tube.

The Adapter L was originally finished in grey to match the BH microscope. The finish was later changed to cream to match the BH-2 microscope.

Alternative camera adapters

If you want to use a Pentax or other deep-bodied digital SLR, it is not easy to convert the Adapter L, but there are at least 3 sources of alternative adapters that attach to the Olympus circular dovetail at the bottom and take a T-2 mount at the top. I have not seen any of these adapters, so please contact the manufacturers to ensure that they are suitable.

1) Richard J. Kinch (Making Digital Camera Microscope Adapters) makes an adapter that maintains the proper 150.0 mm distance from the lip on which the top section of an NFK eyepiece rests to the plane of the sensor.

Richard J. Kinch’s adapter for Olympus 38 mm photoport

Richard J. Kinch’s adapter

2) Martin Microscopes produce their MBH2T adapter; this is not listed on their website so you need to contact Martin Microscopes.

3) Diagnostic Instruments produce their PA1-10A adapter.

Diagnostic Instruments PA1-10A adapter

Photo eyepieces

To project the image produced by the objective onto the sensor in the camera body, special photo eyepieces that sit inside the circular dovetail on the SZ-PT Photo Tube are used, not the viewing eyepieces.

The NFK photo eyepieces were designed for photomicrography with the LB or long barrel objectives and with stereo microscopes of the same vintage.

For digital SLRs with a full-frame sensor, such as the Canon EOS 5D Mark II and Mark III, the most appropriate photo eyepiece is the NFK 2.5×.

For digital SLRs with an APS-C sensor, such as the Canon EOS 7D, 40D, 50D and 600D, the most appropriate photo eyepiece is also the NFK 2.5×, but the smaller sensor significantly restricts the field of view.

Camera image areas with Olympus NFK 2.5× photo eyepiece

Camera image areas with Olympus NFK 2.5× photo eyepiece, relative to GSWH10× viewing eyepieces (F.N. 22)

For digital SLRs with a Four Thirds sensor, the most appropriate photo eyepiece is also the NFK 2.5×, but the small sensor means that the camera’s field of view is substantially smaller than the viewing eyepieces.

Using an NFK 3.3×, NFK 5× or NFK 6.7× photo eyepiece will result in a restricted field of view. It is not possible to use the NFK 1.67× photo eyepiece to provide a larger field of view because it is too long.

Photo tube

The SZ-PT Photo Tube has a 38 mm circular dovetail on its top surface, and the NFK photo eyepiece sits inside the dovetail.

The Photomicro Adapter L clamps on to the circular dovetail located on top of the SZ-PT Photo Tube.

The bottom of the SZ-PT Photo Tube clamps on to the top of the SZ-TRU Mirror Unit in trinocular versions of the SZ4045, SZ4060, SZ6045 and SZ1145 stereo microscopes.

The SZ-PT Photo Tube is interchangeable with the SZ-CTV adapter for C-mount video cameras.

Further information

For more information, see the following pages:

For information on how to use cameras with other Olympus microscopes, see the following pages:

Send comments or questions to Alan Wood

Olympus microscopes and photomicrographic equipment

Olympus OM system close-up and macro equipment