Standard Plan Objectives v Plan Infinity objectives.

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Dave S
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Standard Plan Objectives v Plan Infinity objectives.

#1 Post by Dave S » Mon Aug 26, 2019 4:45 pm

Am I right in thinking that in terms of image sharpness the is noting to choose between either of the objectives?

I understand that infinity corrected objectives are more versatile when it comes to adding intermediate accessories, but if you want change any of the objectives, they have to be ones from the scopes specific manufacturer, whereas any standard 160mm objectives can be used with any 160mm tube length microscope.

So, I guess my question is, as an amateur/hobbyist microscopist, is there any advantage in paying the extra money for infinity corrected optics?
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PeteM
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Re: Standard Plan Objectives v Plan Infinity objectives.

#2 Post by PeteM » Mon Aug 26, 2019 7:17 pm

Probably not.

Infinity systems shine when a researcher wants to have multiple imaging methods in one scope -- the "infinity space" makes it easier and cheaper to insert polarizers, prisms, mirrors, filters, beam splitters etc. into the optical path.

To the extent the infinity systems are newer and of top quality they may also have better coatings and perhaps more precise CNC lens grinding. However, for the most part, top quality Nikon, Olympus, Leitz etc. optics from the 70's and 80's provide essentially the same image as new infinity optics costing hundreds to thousands more.

If you're buying a new Chinese scope, the infinity optics really don't cost them much more to make than new 160mm finite objectives, heads, and condensers.

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Re: Standard Plan Objectives v Plan Infinity objectives.

#3 Post by MicroBob » Mon Aug 26, 2019 7:27 pm

Hi Dave,
an expensive Plan objective like the old Zeiss 160mm ones will probably have had a generally better correction than the very much cheaper basic achromats. But for plancton objects both are usable.
For 160mm Objective you need the right eyepieces as these correct remaining colour errors and are calculated for different pick up points within the tube.
If you want to spend a real lot of money for a really good microscope of the mayor brands you would have to choose infinity as this is what they use today for everything but the most basic models. I don't think that you will have an advantage from infinity correction in the more budget friendly regions.

Since you come from photography I would suggest to choose a system where really nice objectives are available. You will enjoy what some won't recognise at all.

Bob

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Re: Standard Plan Objectives v Plan Infinity objectives.

#4 Post by Hobbyst46 » Tue Aug 27, 2019 2:05 am

Hi DaveS, the performance of new Chinese Plan 160mm and Plan infinity objectives has been commented on and/or demonstrated n recent posts. Although there has been a positive report of a 4X Plan when directly interfaced onto a camera body, the reports about their performance on a microscope vary. See for example comments by Apochronaut. I found a new unbranded 4X plan to be usable, but not for high level photography. An old Nikon plan was definitely better. Yes, the new objective was low cost, but lacked in planarity. Since my testing was done on a finite Zeiss system these results might not be general . But if upgrading to a new Chinese scope I would ask for demo of quality before buying.

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Re: Standard Plan Objectives v Plan Infinity objectives.

#5 Post by Dave S » Sun Sep 01, 2019 1:20 pm

Thanks for your input guys, informative, and appreciated, as always.
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Re: Standard Plan Objectives v Plan Infinity objectives.

#6 Post by Roldorf » Sun Sep 01, 2019 4:22 pm

Hobbyst46 has it in one. You really need to be able to see and experience what you are spending your money on.
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Dave S
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Re: Standard Plan Objectives v Plan Infinity objectives.

#7 Post by Dave S » Sun Sep 01, 2019 5:51 pm

Absolutely Alan, but not always practical, which is why I wouldn't buy second hand on e-bay, or from some distant private seller. At least when buying new i have some comeback if it is below the expected standard.

The only two places to 'try before you buy' in the UK is GT Vision, and Brunel. GT are close enough to visit, but Brunel would likely involve an overnight stay.

Of course Brunel do sell through Amazon, who have a good returns policy.

I will be contacting both GT and Brunel with a list of technical questions, relating to the models I have in mind.
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Re: Standard Plan Objectives v Plan Infinity objectives.

#8 Post by Scarodactyl » Sun Sep 01, 2019 6:16 pm

Dave S wrote:Absolutely Alan, but not always practical, which is why I wouldn't buy second hand on e-bay, or from some distant private seller. At least when buying new i have some comeback if it is below the expected standard.
Ebay's return policies are extremely generous. If something is listed as in working condition but isn't returns are pretty straightforward. Not everyone knows enough to assess the scope's functionality and repackaging is a bit of a pain, but you are absolutely not left with no recourse unless you're buying units already listed as broken or for parts.
I'm not saying you have to take this approach by any means or that other problems aren't possible, but it's not like you're SOL if someone sends you a nomfunctional scope when you ordered a working scope.

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Re: Standard Plan Objectives v Plan Infinity objectives.

#9 Post by mrsonchus » Sun Sep 01, 2019 7:30 pm

Dave S wrote:Absolutely Alan, but not always practical, which is why I wouldn't buy second hand on e-bay, or from some distant private seller. At least when buying new i have some comeback if it is below the expected standard.

The only two places to 'try before you buy' in the UK is GT Vision, and Brunel. GT are close enough to visit, but Brunel would likely involve an overnight stay.

Of course Brunel do sell through Amazon, who have a good returns policy.

I will be contacting both GT and Brunel with a list of technical questions, relating to the models I have in mind.
Regarding Brunel Microscopes, they do of course sell directly. That said, they are in my repeated experience a very good company to buy from. They will certainly not cause you any worries as regards returns I'm certain. The best way to liaise with Brunel is by telephone I have found.
The technical director is Helen, and she is both knowledgeable and helpful. The owner is Alan, who is available to speak to if you simply ask, if he's available. A very honest company indeed.
I bought my first new 'scope from them, a very nice 'SP200' infinity model, which I eventually sold-on and I now have, via a beautiful finite TL 170mm, Leitz Orthoplan, a very nice used Olympus BX40 infinity 'scope.

Brunel also sell used 'scopes, have a look over their pages you never know what you'll find!

By the way, I've no connection whatsoever with Brunel beyond that of a very satisfied customer of the past 5 years, since I first started with microscopy....
John B

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Re: Standard Plan Objectives v Plan Infinity objectives.

#10 Post by mrsonchus » Sun Sep 01, 2019 7:32 pm

Scarodactyl wrote:
Dave S wrote:Absolutely Alan, but not always practical, which is why I wouldn't buy second hand on e-bay, or from some distant private seller. At least when buying new i have some comeback if it is below the expected standard.
Ebay's return policies are extremely generous. If something is listed as in working condition but isn't returns are pretty straightforward. Not everyone knows enough to assess the scope's functionality and repackaging is a bit of a pain, but you are absolutely not left with no recourse unless you're buying units already listed as broken or for parts.
I'm not saying you have to take this approach by any means or that other problems aren't possible, but it's not like you're SOL if someone sends you a nomfunctional scope when you ordered a working scope.
Must agree....
I bought my used Olympus BX40 from a very decent chap in Spain via e-bay, with the knowledge as mentioned that they really favour buyers if any problems arise - they didn't and the 'scope arrived beautifully packaged and looking virtually brand-new and unused...
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Re: Standard Plan Objectives v Plan Infinity objectives.

#11 Post by apochronaut » Mon Sep 02, 2019 3:11 am

If you establish a budget ahead of time for brand new microscopy equipment, then you have already imposed a quality limitation on that equipment. There is very little difference between stencil brands of microscopes within price range categories, especially when it comes to the 160mm tube systems, where the optical designs are 1980's vintage and not very good ones at that.

Leaving mechanical precision and durability aside and sticking with the optical quality, one could acquire superior optics theoretically , by buying into new budget infinity corrected systems. The designs at least would be more likely to offer improved planarity and contrast , since they would be likely to take advantage of improved lower cost glass formulas and perhaps coating technology but a preset budget might preclude that option , since the infinity corrected instruments from the stencil brands are in a different price bracket, usually.

Dealers can offer some possibilities for one to spread their wings a little into used equipment that would have a guarantee attached but again, with the preset budget limitation, that would likely not be an option in most cases.

Ebay has been secure enough for some time now, that it offers the possibility to keep within a budget and as well have a guarantee, provided as scarodactyl pointed out the seller has not listed the item as for parts or as is, etc. Within that context, it seems to me to be one of the only sales venues where one can well exceed quality expectations, while staying within the confines of what they are willing to spend.

Two, more recent optics acquisitions I bought on ebay are an infinity corrected 2.5X .075 planfluorite and an infinity corrected 100X 1.32 planapo w/. iris, from the same series. These are pretty close to state of the art optics; certainly, they were so as of about 2005 or 10 . The cost of both of these was less than the cost of one infinity corrected, iris diaphragm equipped Chinese achromat on line, and had either of them been defective, it could have been returned at the expense of the seller. Collectively, the price of the two objectives probably exceeded 7,000.00 , when they were new.

For anyone desiring to own an optical setup that well exceeds the limitations of their budget, I cannot see how ebay does not factor highly in the equation.

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Re: Standard Plan Objectives v Plan Infinity objectives.

#12 Post by Dave S » Mon Sep 02, 2019 2:56 pm

As always 'apo; you speak wise words based upon extensive experience.

However, as I think I have said before, to me, micrcroscopy is not a serious hobby, but more fascinating pass time. wheres as my serious, and expensive interest is photography.

I bought the Bresser Trino to see if microscopy was something that I might like to pursue, as a pass time (not a serious hobby). What I saw with the Trino was enough to inspire interest, but I soon discovered the limitations of achromatic objectives, when imaging. As far as the microscope's physical attributes, I was more than happy with it, given the price, and I would have been happy to replace the objectives with Plan versions.

However, Bresser's support guys in Germany, whose help an advice has been nothing short of exemplary, told me that the cost of doing so, would be in the order of 500 Euros, and that the existing oculars would not be matched to them. Honest customer support, not 'salesmen'.

I would have gone with the Bresser TRM 301 which has Plan objectives (Chinese, yes I know), Kohler illumination, and very suited for DSLR use, as opposed to MicroCam. The fact that it came with Halogen illumination, was a no go for me.

If I can enjoy reasonable viewing, and imaging, that's all I want. I am not expecting the sort of image quality I get with my photographic gear, which cost several thousand pounds. That said, I have seen many microscope images posted, taken with 60's, 70's, and 80's used premium brand microscopes, which as a photographer, would leave me very disappointed in terms of resolution, and sharpness. However, one experienced microscopist told me that in general, hobby microscopists, don't stress too much about such things.
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