LouiseScot wrote: ↑Tue Jul 07, 2020 10:59 pm
"£2000 is a very generous budget within the used microscope market, and I mean very generous!
You can get a good quality used microscope with phase for less than half that with a little patience."
That would suggest that new Euromex or Motic are poor quality? My current one was relatively cheap but has served me well.
Louise
You have to look at it from the standpoint of what you are looking for and what you are getting in terms of features for your £. You have an interest in phase contrast and are concerned about the relative precision of a 1 micron fine focus compared to a 2 micron fine focus. That's primarily what I see. I think you are more concerned about the proximity of the dealer, or some kind of security related to the purchase , though. I can sell you a used 4 objective phase contrast microscope with 4 extra bright field objectives and a trinocular head in immaculate condition for 800.00, shipped to England . It will still be working well after the Motic or Brunel or Euromex microscopes are in the dumpster but would you go for that? I think not.
So, lets look at a practical solution. You already have a microscope. You don't say whether it has plan objectives or not or whether it is 160mm but I assume it is? I'm curious why you wouldn't go back to Brunel and see if a phase condenser and objectives are available for your current scope? All you need is the sleeve size for the condenser, then a condenser and matching objectives can be found. You are going to need 8 objectives or more, no matter what microscope you have because phase objectives introduce spherical aberration when used for BF and softens the image. If you buy a phase contrast microscope, in order to get high quality imaging you will only be able to use it for phase......or do you plan on keeping the current one for BF and have two dedicated microscopes? If that is the case, you don't need to spend £2000.00 on a phase microscope, just maybe 700 or so. Planachros can only take you so far. I would save the extra money you are considering spending on fancy planachros and start finding Planfluorite or planapo objectives to upgrade your existing stand, or a new 700.00 stand, whichever you choose. They require 45mm parfocal objectives. With a little patience you should be able to find 4 or even more for the money you saved , infinity or 160mm, whichever is needed.
Don't worry too much about the focus having one or two microns graduation. Largely that is just a marked graduation on a scale. Swap the knobs and therefore the graduations over from one mic to the other and the one with the finer graduation would have the finer graduation. Parts within fine focus mechanisms used to be made from finely machined steel and brass micrometer screws, needle pivots, clock gear sets. Modern ones are helical screws, orbital worms , nylon or plastic clock mechanisms but are mostly nylon or plastic The precision of movement is provided largely by damping grease, not the mechanism so much. It's only a matter of time before the lubricant fails and the mechanism loses it's precision. Chinese budget microscopes have been on the market for almost 40 years now and they were built better 40 years ago. How many do you see on the used market in good working condition? Maybe ask Brunel, they have been selling them for years.
e
I've had an oldish unbranded trinocular scope since the '90s which I've upgraded to plan objectives. However, I'd like to get a better, newer trinocular scope and one already set up for phase contrast. I've been looking at the Euromex Oxion model and the Motic Panthera cc. Both Chinese, and they seem very similar in most respects and are similar prices. I do get a bit confused with objectives options (both are infinity corrected). Obviously, I'll be using phase contrast objectives. Motic do objectives which they label UC (ultra contrast) - anyone know if that's really just marketing? They don't mark the actual objectives with UC or include it in their listing. Euromex do just 'Plan Phase', no 'UC' or similar. I'm wondering how interchangeable the different sourced infinity corrected objectives might be? Motic appear to offer more aftermarket options for objectives. If anyone has any general comments about Euromex/Motic optical and build quality, I'd be pleased to hear.