These Seiko Pentax UltraThin 1.6 lenses with Surpass ECP seem to have large blemishes in the underlying AR coating. They appear as hazy or cloudy streak-like patterns, similar to a fingerprint smudge. Is this common or just a bad batch?
These Seiko Pentax UltraThin 1.6 lenses with Surpass ECP seem to have large blemishes in the underlying AR coating. They appear as hazy or cloudy streak-like patterns, similar to a fingerprint smudge. Is this common or just a bad batch?
Are the lenses new ? If so, could be stress cracks from twisting in the edger or too much chuck pressure.
I have seen this quite a bit with high index materials that have an ar coat. The cause is excess heat. The high index material has a greater expansion rate than the coating and it splits the brittle coating as it expands. Most causes of heat are leaving glasses in the car, or inadvertant exposure to frame warmers at high settings.
Lesson learned, I'd stop using them for a few years, their lenses have not proven the test of time. Oh and when they claim, Oh, "we've fixed that." Well you really should reply, our shop has been there done that, we've been burned before. Have them comp you a pair, wear them for at least 6 months, if no problems arise, than cool, at that point, maybe give a 2nd try. Really if you're a reputable shop, you can't keep looking bad because of inferior products!
but i do agree, it could be generator marks, usually meaning you can't use stock lenses, gotta grind 'em, so I might give it another whirl, but after that.... see above
Last edited by eyechick1969; 05-30-2012 at 07:05 PM.
I see his occasionally, typically chuck pressure or improper removal of the chuck after edging. Always on AR lenses and typically high Cyl jobs. I actually did this to my own lenses recently, then Barry gave me a great tip.
- Optician
- Frame Maker/Designer
- Teacher of the art of crafting handmade eyewear.
Check with your lab. It's a surfacing issue and some labs won't admit to it. The AR covers it up. I ran into it and when the lab rat told me, he got in trouble. Dull cutters and too much heat.
This is exactly what caused this, heat. More than likely from putting the entire frame (lens and all) in a frame warmer.Originally Posted by rwheeler
Agreed.
This doesn't look like any surfacing issue I've ever seen, and I have worked in a surfacing lab for 10 years. It's heat, but the kind from a frame warmer, oven or hot car. Or maybe even the kind one runs into after spending too much time in a walk in freezer. If it were chuck pressure related, it would look a litle more circular.
Wesley S. Scott, MBA, MIS, ABOM, NCLE-AC, LDO - SC & GA
“As our circle of knowledge expands, so does the circumference of darkness surrounding it.” -Albert Einstein
This is why I don't have a bead pan.
I'm curious as to why anyone would put the front of a metal frame in any kind of warmer, beads OR air...
My guess would be that they don't know any better.
I am in total agreement with RWHEELER who said that high index lenses have a greater expansion rate than the AR coating, thus when they get too hot you get that. It reminds me of transition lenses when they get age and had several expansion and contractions in metal frames, they shrink and the lenses get loose. I was told by transitions that they expand at a greater rate than the metal frames, thus shrinkage. I do know that an air warmer can do the same thing as a bead warmer, however, because it has happened to me with an air warmer. It's understandable, it's still heat.
If you get real lucky, high index lenses crack in a salt pat. Pity the labs and mfg. didn't tell us that when they first came out and we all had to learn the hard way.
It's really heartwarming to have to tell an extreemly nearsighted patient that you just broke his ultra-expensive lenses and you know he can't see to drive home. Then you can tell him you'll have him a new pair in less than a week. Just lovely.
Chip
Very common problem, always replaced under warranty. Heat crazed as many have said. Absolutely nothing to do with surfacing. Clients frequently forget about the heat issues with ALL A/R coatings...I always tell the client when picking up new ones. Surprised at how many people use hot water to clean their glasses. Or those who leave glasses in their vehicle in the summer while wearing sunglasses. All AR coatings are crazable with flash heat sources. Saunas, hot tubs, large campfires, BBQ ignition, ovens, dishwashers....the list is long.
Mike:
Don't this kind of insinuate that this ain't ready for the general Public yet? I mean us run of the mill slobs that have to work and live under real live envioronmental conditons?
How many people are gonna drive to the fishing hole in the wee hours before daylignt, and protect thier clear glasses while they wear thier polarized lenses to fish? They gonna sit in the car than reach 300+ degrees.
Chip
Chip
Agreed.
Could also be the lens being flexed, A measure a smidge to long. I would lean this way as it is a metal frame, why would it have heat applied, if they are new lenses. If lens is to wide it will pooch the middle of the lens forward, not follow the eyewire, and flex the center of the lens.
Always remember, anything that has to be replaced under warranty wasn't built strong enough to begin with.
Chip
I have used literally tens of thousands of these lenses and I have never had a single finished SV Seiko finished lens craze, either in the lab or in the real world (I've had a few Seiko progressives craze).
The mostly likely cause is heat. I am guessing these were finished SV? You don't state explicately. If it was surfaced it could be a bad tool creating too much substrate stress centrally, and the uneven subrate density inhibits adhesion.
Also, I have had a few lenses craze from using pure Alcohol when cleaning, we now mix it down to 90%.
Were they Finished or ground?
What's the tip?
Maybe the tip was "Don't bet on the horses, since I'll have Another has been scrathed from his attempt to win the triple crown in the Belmont.
That's a good tip.
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