Suspect OMAX Objectives?

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Suspect OMAX Objectives?

#1 Post by Rozee » Thu Mar 26, 2020 10:18 am

Short background: Though I had some experience in microscopy in the veterinary field, it has been quite some time. A lack of medical insurance and several doctors discounting my concerns and refusing any testing, led me to buy a microscope, fungal stain, etc. Though I am quite sure my results were positive for Dermatophyte infection, embarrassment and two demeaning responses on Reddit led me to quit asking for thoughts.
But I digress, the scope I bought claimed to be an Infinity corrected with Plan Bright field objectives. I was quite shocked to see the objectives did not say “Plan”. They were blank like typical achromatic objectives. After some digging I found a post discussing this same issue back in 2016, though the company told the buyer over the phone they were absolutely plan. I then searched through google images. I found visually identical objectives being sold on OMAX’s own site, listed as Semi-PLAN and I found another identical OMAX set, on a separate site, sold as Achromatic. Interestingly, I found no set or individuals sold as PLAN. The objectives included have a black barrel, while OMAX only sells sets/individual PLAN with a metal barrel.

As I am inexperienced, testing the truth in advertising has been inconclusive. I will say they are definitely not as “sharp” as another PLAN objective I have. Even if they are “PLAN”, would you agree that these inconsistencies are cause to scrutinize the scope altogether? I appreciate any feedback offered. (I do have the ability to return)

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Re: Suspect OMAX Objectives?

#2 Post by apochronaut » Thu Mar 26, 2020 2:11 pm

Unfortunately, this bait and switch type of selling when it comes to on-line budget retailing of microscopes is not uncommon. The companies involved do not make microscopes, they have systems assembled by jobbers in China from parts sources that are often quite diverse. Years ago, in the early 90's I had some dealings with a microscope distributor in China who told me that at that time, there were "probably 10,000 microscope manufacturers in China". He included of course, assemblers too. I had a phone call through to one of them once and while I waited for him to come to the phone, you could hear his steps shuffling on a dirt floor as he approached. Either that or there were an awful lot of metal turnings on the floor.
At assembly time, if one version of objective is not available , then another is sourced. That's how the distributors get things done at the best price.

It is important to note that "plan" is not an absolute term and gets bandied around rather loosely. There is no specification for plan and some objectives marked semi-plan are in fact more plan than some marked plan. The degree of planarity should not affect the central "sharpness" of the image, nor should it affect the sharpness across approx. 50% of the middle of the field. With average grade objective lenses there will be optical distortions out beyond that towards the periphery of the f.o.v., whereas with plan objectives, the periphery will have a more corrected image. Sometimes plan objectives also have a small degree of distortion towards the periphery as well.

I would return the instrument and purchase what you actually want, with a guarantee of same, elsewhere. You might also confirm that any optics marked as plan are in fact plan to the field stop.

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Re: Suspect OMAX Objectives?

#3 Post by david_b » Fri Mar 27, 2020 11:27 am

Omax objectives can be 'metal' finish in both achromatic or plan, but the Plan objectives are marked "Plan"
The black finish is semi-plan. ... tives.html

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