The Subtle Difference Between Lenses...gravy or mustard?
Oh, the hours I agonised over whether to choose Miranda over Exakta or if the Petri was up to the quality of the Topcon...Unfortunately there was no internet at the time so I had to get my misinformation from magazines - fortunately I had limited funds and could not afford too many of these and my level of confusion was moderately low. Nowadays I can bounce from one forum to another - from one manufacturer's website to that of their rival - and pick up enough opinion and angst to boil the water in a large pot.
Note: Time and economics have relieved me of my worries - all four of those manufacturers are cactus. I am also delighted to report that modern optical offerings do not have enough variation between makers to foster such cares.
Oh, there ARE differences. Get out your optical bench and your steam-powered MTF generator and go for your life. You'll find that you can get different numbers for sure. The numbers won't make your pictures look better, but.
You'll be able to differentiate products in each maker's catalog by price ( always a good thing...) and weight. More money and more weight means higher or lower numbers in the laboratory. Again your pictures may be annoyingly similar but at least you have different numbers.
I would also caution those people who are contemplating the purchase of lenses that are very, very expensive against doing the sort of mathematics that sets these prices against that of a Sunday roast dinner and a pint of beer. The results are unsettling - in one case I calculated that an optic was the equivalent of five and a half years of Sunday dinners ...including the pint and, on suitable occasions, Yorkshire Pudding. Strong as my desire might be to take wonderful pictures, my respect for Yorkshire Pudding with gravy is stronger.
Moral? There is none, except the purchasers of modern lenses of the modest sort can comfort themselves that they are getting a very good product and, as far as their characters will permit, can go out and be happy with them.