My working microscope for over two decades has been a Zeiss Photomicroscope III slowly built up with phase, DIC and fluorescence when funds and the opportunity arose. It is showing its age and exhibits the foibles noted for this era with an increasing number of delaminating optics - eyepieces, objectives and the binocular head. In 2019 my brother Ian and I started to look around for a modern stand with infinity optics and decided on a Nikon Eclipse E800. This was a research stand released in the 90s but now becoming offered for sale at a fraction of their likely new price when institutions decide that a shiny new model is required with more bells and whistles.

The table below summarises key features of the Eclipse Ex00 models likely of interest to enthusiasts seeking some features and upgradability not featured in the more edu' orientated E100 and E200 models. The MicroscopyU website has a splendid Nikon's Museum of Microscopy where each model released in the 90s has a page describing in more detail the features and design philosophy of the model. The table uses this site as source and relevant brochures / manuals for models where available. All models listed have fluorescence and phase facilities. The Universal C-CU condenser fits all for phase, DIC and darkfield.

Model / release year	Stage - rotating	DIC	Filters	Lamp	Eyepiece, field of view / mm	Comments
E400 / 1997	Basic, no bearing, no centring	No. Quintuple nosepiece.	Two filters can sit on field lens.	6V 30W external	22	Substage fixed
E600 / early 90s	Basic, no bearing, no centring	Yes, Sextuple nosepiece with slots for prisms.	Filter cassette, with ND filters, blue, green, diffuser.	12V 100W external	22	Substage detachable.
E800 / 1996	Bearings, centring	Yes, Sextuple nosepiece with slots for prisms.	Filter cassette, with ND filters, blue, green, diffuser.	12V 100W external	25	Substage detachable.
E1000/1000M / 1997	Bearings, centring	Yes, Sextuple nosepiece with slots for prisms.	Filter cassette, with ND filters, blue, green, diffuser.	12V 100W external	25	Substage detachable.  Extensive automation. 1000M has 1X macro capability.

Which model? The enthusiast seeking a stand with upgrade options may be more likely to choose an E600+ model with a more powerful lamp, filter cassette and DIC potential. For longer term reliability, other enthusiasts may share my wariness of heavily automated stands, in this range the E1000. I briefly owned an E600 stand so was able to compare with the E800. The E600 rotating stage was basic, metal acting on metal and spent some time exploring plastic bearing sheets to improve.

The E600 and E800 have similar upgrade potential, the most notable difference was bulk and weight. The E600 was readily moved by one person, the E800 is too heavy even stripped down and is a two person carry. The E800 did feature screw in carrying rods but often lost as in this example. In 2019 I opted for the E800 as a good centring stage was desired and preferred its more open design.



The Eclipse E800 and E600. Useful tools - 1.5, 2, 3 and 4 mm hex long screwdrivers.

Optics The microscope stands from the 90s onwards to the present uses the extensive CFI60 infinity objectives with 60 mm parfocal distance. The Nikon Objective Selector is useful in assessing the range. Objectives bought new, especially the more exotic ones, can be very expensive but can often be had for much lower prices sold used e.g. on eBay. Private sellers tend to have lower prices.

Shipping experience The bulk and weight of stands like the E800 can be their undoing if shipped despite good packing. I would not recommend an overseas purchase and if at all possible, collect. My example was badly damaged in transit requiring negotiation of a discount (not owning a car, collect was not an option within the UK). The stand internal lamp lens was cracked and replaced with a close match from Edmund Optics. The substage pinion had snapped. Curiously this was an OEM spare from a US dealer suggesting this was a weak point on the model. The binocular head had sheared off the head and inspection shows a porous alloy that may be prone to damage. The dealer was able to replace the entire trinocular head with another but each head is made parfocal with a stand and some lack of parfocality remains.

If do buy with shipping, advise: Stage taken off and focus racked down; trinocular head removed and the binocular head well supported in separate packing.

Upgrading Building up a stand for DIC or fluorescence can be more expensive if carried out piece by piece. It can be more cost effective to seek another stand already fitted with most items sought. This was the case after buying the E800, an E600 DIC fitted model came up for sale to buy, swap out the DIC system and a functioning E600 passed on. Quite recently an E800 model fitted with an impressive selection of objectives with DIC and out of date confocal system was offered on eBay UK. The auction was subsequently altered presumably by a potential buyer's request just to offer the objectives and DIC items for a small fraction of the cost to build up piecemeal.

Documentation The E800 operating manual can be freely downloaded from various sources. Unusually the service manual is also available to purchase, such manuals from the author's experiences are rarely available (see Resources). This does make use of specialised tools for some alignment procedures but provides a valuable insight into the E800 repair, maintenance and construction.

E800 tour Size; depth ca. 53 cm (incl. lamp), width ca. 35 cm, height ca. 46 cm to eyepieces, ca. 59 cm to photo port. Weight, estimate over 25 kg fully equipped.



The E800 has a dedicated ergo head. A design philosophy cited for the Ex00 range is ergonomically placed low level controls for easy reach. The single filter on right when in use is for blue daylight correction. Like other modern stands, the field iris is controlled from the right hand knob on the base. The plastic bevelled cogs in my stand had split requiring a resetting of the cogs to ensure full iris travel. The access panels above the nosepiece are for the epi / fluorescence modules. The epi lamp fitting and lens is not fitted as standard at the back. A magnification changer module was available to insert above the nosepiece. This is a feature I miss coming from the Zeiss Photomicroscope where it is fitted as standard. I am keeping an eye out for one but it does not seem common. A sophisticated photographic block was also part of the system offering multiple 35 mm camera back ports as well as vertical. The nosepiece has slots above each objective for the matched DIC prism if installed.
A set of long hex screwdrivers (earlier above) with handles is recommended for the stand as the trino' head and lamp top require tools longer than typical Allen key pocket sets.

 



The lamp choice is selected from the front knob. The E800 did have some optional electronic controls for some modules using the serial port. The DIC system uses the de Sénarmont method and seen fitted on the field iris. The shear is adjusted by rotating the graduated linear polarising filter beneath a fixed alignment quarter wavelength retarder. The Nikon MicroscopyU website explains the principles and claimed benefits. This includes providing a low ergonomic control of the DIC effect.
A disadvantage of this DIC approach is that no room is left below the substage. On the Zeiss Photomicroscope where the DIC effect is adjusted by a universal slider above the objectives there is plenty of room below the substage e.g. for a flashgun set to one side with semi-silvered right angle mirror on the field lens to allow flash imagery with DIC of live aquatic organisms.


 



The filter cassette offered ND filters, a green interference filter and lamp filament diffuser. The latter increasingly important with low mag objectives. The 12V 100W halogen bulb is pre-centred and does not offer the alignment controls seen on the Zeiss Photomicroscope lamphouse. Unlike for the Zeiss Photomicroscope the bulb is horizontal above a lens and right angled mirror; bulb removal and centring by eye is easier. The lamphouse port has an interference type heat filter. An optional diffuser 'D' forms part of the filter cassette (see below). The manual recommends ether a Philips 7724 or Osram HLX 64623 bulb. I prefer the former as the datasheet notes it has a slightly larger filament 5 x 3.1 mm cf 4.7 x 2.7 mm.

 



The Nikon Universal C-CU condenser offered DIC, phase and darkfield(?). The bar swings out the upper lens for lower mags. This is shown fitted with a Ph2 ring and the earlier L, M and H DIC prisms. The green 'Dry' labelling indicates this is the set for the dry NA0.9 condenser top. Another set was required if the condenser featured the NA1.4 oil top. This is one of the Eclipse series weaker design aspects in my opinion, requiring much extra expense if wished to upgrade to exploit the max NA of oil objectives. For higher NA work I have the Achromatic-Aplanatic NA1.4 condenser with no support for phase / DIC (above right). It has no filter tray.

The transmitted / epi (not fluoro') power supply shown right sitting on top of that for a Zeiss Photomicroscope III has no control functions bar the mains switch. The cables / connectors are proprietary and believe some of the stand lamp controls act via internal PSU electronics. If a PSU is missing it is straightforward to add some external cables from the lamp to a desktop PSU with both rated up to ca. 8A for the 12V / 100W halogen lamp. Or an LED retrofit could be considered.

The PSU has failed once in over three years of use. A 2SK1192 MOSFET failed. This was diagnosed with my brother Ian's help (the 'sparks' of the family) and a replacement fitted myself. There is an internal fan (a tad noisy on mine but reminds me it is on) and the unit requires good air circulation.

Understanding the DIC system? Aspects of the Eclipse Ex00 and later x0i DIC systems continue to puzzle me, this is my current possibly flawed understanding so comments are welcomed! The system for the Nikon Ex00 stands is described in the manual for the Nikon C-CU condenser (see Resources below). There were three L, M and H main prisms for the condenser system across the NA range of objectives as described in the table on p.27. Nikon's newer Eclipse x0i models had N1, N2 and NR prisms for the condenser. Both condenser systems had a set of sliders for DIC compatible objectives. The L,M.H system had both PF and PA sliders for some objective mags. Apart from the 10X plan apo which uses a PF10X the prism labelling suggests PA and PF were for the plan apo and plan fluor objectives respectively for a given mag. See notes in the Resources about using PF / PA sliders with various objectives from useful comments from online forum members who responded to my query.

When inspecting used DIC compatible objectives for sale they can be labelled with either or both as suited for N, M systems. My understanding from this labelling is that the CFI60 objectives remained unchanged but the objective labelling reflects when the optic was made. So if an objective is labelled either in the N or M series the correct prism pairing in the range owned should be fine. This is my experience with objectives owned with labelling spanning the two series. What are not compatible from a valuable Facebook group discussion with an owner of both systems is that the condenser and the objective prisms need to be from the same series but have seen a matched older system on x0i microscopes.

It can be worthwhile adopting a 'try and see' approach for DIC with an objective. I own the plan achro 50X NA1.0 oil which is not stated to be DIC compatible but gives useful DIC with an objective / condenser prism pairing in the L,M,H series.

Photography The camera - relay options from the Ex00 system diagram can be rather baffling. Matching cameras can be expensive if seeking the ideal relay adapter. I just use a standard across makers adapter for photo port. It is a lensless 37 mm OD to C-mount fitting with a Sony NEX5N body for colour images, accepting the vignetting which is cropped out. For studies in monochrome with near UV or near IR I use a ZWO ASI178MM astro' type camera with 1/1.8" sensor. This only covers the centre of the visual field but useful for diatom dotting type studies. As remarked earlier, a feature I miss is the magnification changer fitted as standard on the Zeiss Photomicroscope.

Using the Nikon Eclipse E800 and the Zeiss Photomicroscope III I have used both systems side by side since buying the Nikon in 2019 and both have valuable roles. The Zeiss is fitted with fluorescence with homebrew LED modules, incident epi DIC (as well as transmitted like the Nikon) and own a high NA darkfield condenser, features I'm unlikely to be able to afford for the Nikon with increasing prices and now VAT on EU imports as well as for the US. Despite its foibles, the Zeiss remains my go-to scope for many studies and the less cluttered substage is more amenable to homebrew studies. I decided to equip the Nikon with mainly used planapos when funds permitted to be the 'sports car' model of the two. These optics are excellent of course but hand on heart for many studies prefer the lower NAs of the Zeiss Neofluar and plan achros as they offer more depth of field for single image work, I rarely have the patience to image stack. The Zeiss has the wider range of phase as well, only the 40X plan fluor on the Nikon is phase.

One aspect that need to be wary of running the two side by side is focussing, especially at high mags. Rotating the Nikon focus knobs towards the user moves the stage down, to me the more intuitive action for focussing the objective away from the slide. On the Zeiss it is the reverse.

On 'brass and glass' and the humble LOMO Biolam My brother Ian made an interesting remark on using the Nikon which I agree with. Both of us have owned some very fine brass microscopes from the late 19th / early 20th century by Ross, Beck, Swift, Powell and Lealand, Watson. They had much smaller field of views at the eyepiece but excellent corrected low mag objectives and some very competent high mag / NA optics. We still feel that such models can often provide the most visual 'image wow' of prepared slides e.g. of a blowfly tongue test subject at low mags or a diatom at higher mags; the subject details can be appreciated in one focus plane and apparently crisper as a smaller field with at the time common sub 10X mag eyepieces. Imaging does not require as much stacking, if any. When using the modern 25 mm FOV eyepieces with high NA optics at low or higher mags there is often a need to visually explore focus planes with larger image which to us can lose some of that 'wow factor' elicited from the older scope optics. The modern widefield optics models can come into their own when studying live samples of aquatic life when chasing live subjects.

We occasionally dust down a LOMO Biolam, my first proper scope bought over 40 years ago. The 20X NA0.65 apo and 30X NA0.90 water immersion with the sub 10 mm FOV eyepieces can provide for us just as much if not more 'image wow' for diatoms as the serious modern optical firepower of the Nikon system.

When bought in 2019 the E800 was less common on the used market, but in the past few months in particular there have been a number of E600, E800 examples offered on eBay UK, often by the dealers that clear universities and institutions. This is to the benefit of the enthusiast where items can be a fraction of their used price but a pity when a fully working stand is often seen stripped to sell for parts.

Resources, active at the time of writing February 2024. If a link fails, try a Google search for other host sites using the exact document titles given below.

Nikon Microscope E800 Instructions hosted on the Micro Video Instruments, Inc site
Nikon C-CU Universal System Condenser Instructions hosted on the Micro Video Instruments, Inc site. Dated '96? so for the Eclipse Ex00 series.
D-FL Epi-fluorescence Attachment hosted on the Micro Video Instruments, Inc site.
Nikon Microscope E800 Repair Manual can be purchased from the Laboratory Optical Service, Inc website.
CFI 60 Objectives for Nikon Eclipse Series Microscopes with thanks to Stephen Challener for providing a link to this valuable document on the Facebook Nikon Microscope Users Group. A useful forum to ask queries. This describes the correct prism for each objective mounted in the nosepiece.
This states that PA series prisms should be used for the 20X and 40X plan apos. I possess the PF prisms which match the plan fluor 20X and 40X objectives also owned.

A query on the photomacrography.net - amateurmicroscopy.net group provided a valuable response to my query from an owner of the PA series who noted they give "better relief effect, especially with very 'flat' samples" than the PF series (thank you to responder 'Boron'). On my own set up the PF prisms do seem to give competent if not optimal DIC for many samples when used with the plan apos.

Thank you to Rafael Martín-Ledo who shared his valuable experiences in the above Facebook group on which objective sliders has given very good results for DIC with different objectives. He noted (shared with permission, thanks).

"My experience:
- With 10X Plan Fluor I use PF10X: very good!
- With 20X Plan Apo I use PF20x: very good!
- With 40X Plan Fluor I use PA 60 Oil: very good!
- With 40x Plan Apo Oil I use FL 40 W: very good!
- With 60X Plan Fluor dry I use PF/PA 100 Oil: very good!
- With 60X Plan Apo WI I use AP 60 WI: very good!
- With 100X Plan Fluor I use the PF/PA100X Oil: very good!"

Nikon Eclipse TE2000 Differential Interference Contrast Attachment Instructions hosted on the University of Montreal website. To date this is the only manual have found that describes the later 'N' prism DIC system albeit for the inverted models.

 

Comments to the author David Walker are welcomed.

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