apochronaut wrote:.....
I am curious too, how well centered is the Chinese 60X, an often overlooked specification that does contribute to the cost of fine objectives. Reichert used to advertise parcentering to 4 um, I believe it was, which becomes important with objectives of 50X and higher.
An interesting factor Phil', one that I'll take a look at and get back to this thread with a bit more info' concerning....
I must say the cheapo-60x was a revelation, but, as I was discussing with my Wife only yesterday, the abscence of any meaningful QC means it's a 'buy one and hope' scenario. Most certainly I think it's a case of some are good, some very good and some appallingly-bad...
Knowing what I now know from the experience of purchasing the cheapo-60x, if I received a poor one I'd send it back and 'try again', as it's clearly and demonstrably true that pretty good ones are coming from the great-big Chinese machine at that end of the market - it's just a 'hope for the best' case which can/
may actually go well
on occasion.
I also remarked to her the confidence that may be had when buying for example an Olympus-branded piece of equipment, as a company such as this has an awful lot to lose if it loses confidence of the 'big-buyers'...
There is no-doubt a level of expertise necessary to glean the very best performance from the high-end equipment and I myself have found my results with the 60x improving significantly as I've familiarised myself with it's use and characteristics. The factors involved are indeed myriad and only a measure of these are able to be controlled or influenced, especially by an amateur working in an amateur environment, such as myself and my teeny lab (living-room floral carpet included...).
I find that the majority of the time the differences between collar-settings are most noticeable between the 0.17 and 0.16, although yesterday I was examining fixed (i.e. dead & preserved with FAA) moss-leaves in a wet alcohol-based mountant (coverslipped of course) where I set the collar nearer to the 0.20 thickness for best viewing.
There's no doubt whatsoever in my mind though that the subject is a significant factor - plant sections (between say 5-12µ and well-stained) are nowhere-near as demanding in terms of pure resolution as for example the fine details of Diatoms. Having said that I find that the 60x is very good at 'focus-through' use, especially relevant with plant sections thicker than perhaps 3µ , using Lily pollen as a yardstick, as again I did yesterday.
Here's an example of subject limitation I think, the infamously unsharp chromosomes as seen within a 7µ strongly-stained slide of a section through the ovule of a Daffodil. This image is from the 60x Oly objective but is nowhere near as sharp as a Diatom image of course. This is however a major improvement from what I was able to see with the Leitz.
The cell dividing on the RH side of the image has clearly defined chromosome 'arms' and indeed the mitotic-spindles below them, at least that's what I think they are, I'm no expert.
In the context of plant section slides and light-microscopy, this is a very pleasing image indeed.
Here's a mono-version taken through an Olympus IF550 (green) filter - to me they're pretty-much identical in terms of resolution....
I've some exiting plans to return to mitosis images, probably from root-tips as the orientation of the divisions is far more organised than in for example the nucellar-tissue seen above. I plan to concentrate on the optimisation (to my ability at least) of stain choice, combination and technique. I'm actually looking forward to Autumnal declining temperatures here in the U.K. as this very hot (by our puny standards that is, where we all think we're going to die when temperatures rise above about 25 deg C here in the sunny U.K.) period is awful for sectioning...