sssurfer

I took some measurements and got some surprises. Here are to you for your judgement: It seems that cyclops diameter ranges from 5.9 to 7.5 mm, and magnified date windows from 3.6 x 2.4 mm to 4.1 x 3.1 mm. What do you think?

Hardly it can. Much more likely they actually are different magnifications. Or -- if you are talking about OP site pictures -- that they have been differently retouched. One of the most relevant issues, IMHO. Sorry of being not able to get the meaning out of the remainder of your post, though Surely it helps! Thanks A LOT! I'm going to take measurements on them asap. (It would be even more helpful, should anyone provide info about the real, unmagnified size of gen date windows).

At the actual point I am confident that those companies that declared themselves able to make 'our' previous lenses would be even more able in making lenses with the new, relaxed specifics. Just, let us not relax our needs about low tolerances. Ok, let's collect prices from those companies -- both archibald and finepics, both sapphire and SF11 -- and then let's take our decision.

This is an interesting point. Indeed, we took that measurement on a pic from the OP website -- that could have been retouched. I just made a new masurement on that other 104 pic I already used. The magnified width seems 4.2 mm. If the date window is 2.5 mm wide, that actually would stand for about 1.7x magnification (1.68x, precisely): Please note that, even in case our new target is 1.7x, with glass we could reach 1.6 (which would be absolutely acceptable) only at the cost of a lens so extreme in its design as the ones we were considering for sapphire and SF11 a few days ago. We just verified that that design is unacceptable due to excessive circular distortion and (possibly) halos. We already calculated that RBJ's glass lens is at 1.3x, which gives reason of it being free of distortion and halo. If we want 1.7x, we still have to go to sapphire or SF11 same way as when we wanted 2x. BTW, 1.7x is the average magnification of the last values I posted a while ago, for date windows placed at 3 mm from the lens (1.6x) up to 3.5 mm (1.8x).

finepics, keeping same dimensions as in reps but using sapphire or SF11 will just add about +0.15x to rep magnification -- i.e., from 1.2x to 1.35x. Too low, IMO. My new recommendation: Sapphire or SF11 Diameter = 6 mm ROC = 6.2 mm ET = 0.4 mm CT = 1.17 mm FL = 8.0 mm Tolerance unchanged (= 0.06 mm on ROC and CT). Those values theorically stand for 1.8x magnification on a date window 3.5 mm away (1.6 at 3mm), and for a lens sensibly flatter -- in its convex portion, not its ET -- than our previous one, without a knife edge. Sort of tradeoff between all our thoughts. Surely, a prototype would stay highly recommended. Glass is out on any calculations.

finepics, please have a look at my old post about anchor lenses on old RWG. I thought that halo was due to poorly polished edges -- but it could also be due to something else. Do you think it is due to lacking of edge thickness? It could be due be to that very domed shape. But, expecially: I grinded the Edmund's lens to about 1.4 mm. Edge chipped a bit while polishing. No problem (apart from $$$), as I just wanted to test the overall magnification of this lens. Results: higher magnification than expected. Too high. It seems that RBJ was right when he was wondering about excessive magnification. I thought a lot about it, and the only reason that I can identify is that the distance between the datewheel and the crystal is higher than we believed. Actually, that was the most critical datum to us -- and a one that we always lacked of. It seems that adding the facts that the datewheel is a little below the dial, and that the crystal has an o-ring that keeps it a little above what we judged by measuring the bezels, we have some fractions of mm more than expected between the datewheel and the crystal. And to an extreme lens like the one we designed, some fractions of mm is A LOT of space. RBJ, try to cancel your order with Edmund's. I already did the test. In conclusion: It seems than we can achieve better results with a longer focal length. I.e., with a less thick lens. Not so flat as the one from Anchor that RBJ already tested, but flatter than what we thought so far. This should also make it easier for the companies to manufacture it. I have to perform some new calculations, but weekend is family time. I hope to have some news for tomorrow.

No problem at all, drizznay. Rather, I am flattered from your appreciation. Just, re-reading it after all these months spent on English language, I now realize that 'picking' a dealer is mostly used in order to say 'selecting' a dealer, rather than 'finding' a dealer... You are fully entitled to edit, if you like.

I too have been tempted to sign for a dozen of new accounts using a dozen of other members' name and see what happen...

Hi kruzer, welcome! Flint glass exactly like the last proposal that archibald received -- but actually that lens that I got from Edmund's some days ago. Same as lenses proposed to archibald, just with a thicker edge.

Hi bigshooter, welcome!

It is thinner than one of them, and thicker than the other one. But main differences are: 1) quality: this is impeccable 2) expecially, its useful thickness is much lower than in the other two lenses, while its unuseful thickness (edge thickness) is higher. So, you have to grind more thickness out from it, but when you will be done, then you will have full 2x magnification. 3) And you have 0.2 mm tolerance in your grind work -- quite high, compared with that of all other lenses we tried. Here I copy-and-paste what I said about this lens in our 'old' thread: Numbers already done: that 6x6 lens is already perfect as it is, it will give 2x magnification whatever ET we are going to leave on it. And if we are able to grind out all its ET, then we are going to get 2x magnification with a cyclops less than 1.1 mm thick -- i.e. a cyclops that will surely fit on any reps. And I also wish to stress that, differently from glass, on these lenses we don't need such a high precision in our grinding work. Considering a cyclops 1.3 mm thick (as we did so far), we have a 0.22 mm tolerance. In other words, we are only required to be able to grind out the edge down to CT = 1.3 mm. If we want to go even lower, we are allowed to, but not obliged to. Should we go lower by mistake, no problem as long as we don't go below CT = 1.08 mm. Briefly: grind it how much you like, until it is between 1.1 and 1.3 mm thick. Then polish.

So it seems as you admin and mods had great fun here while we all were away, huh?

Someone put much cleverness in this thing and its details... Did you notice that most used smilies are in the first window? And I really appreciate to be able to have a big smile without having to put on my head a christmas cap

RBJ, that lens is 2.5 mm thick, so you will have to grind 1.2 mm off from it. But as you already grinded and polished the previous glass lens, you should be skilled in the matter. Your best option is to get it directly from Edmund Optics America, where it is cheaper than in EU and you will not pay scandalous expedition fees as I did from UK (you figure, more than $62 from lens + shipping + taxes!). There in USA it is $22.5 + shipping. At that cost it's not worth that I send you mine: on what I paid for it, I simply can't think of getting the risk that it get lost in transit... And I still want to play with it a little, as well as to try grinding and polishing on it. Here is the link: http://www.edmundoptics.com/onlinecatalog/...?productID=1747 and the lens is: LENS PCX 6 x 6 UNCTD TS Stock Number NT45-077

Sorry Faber, thanks for your interest, but right now that was just a call to arms for the people who were involved in the project on the 'old' RWG: archibald, kruzer00, finepics, rbj, ...and me, obviously We hope we'll have some good news for the board soon.

Hi ryyannon, what a pleasure for me to be welcomed from you. Let's make this place even better than ever!

Hello all! Amazing work, admin/moderators/webdesigner/etc.

Ok guys, let's go on? I was saying that SF11 seems no problem about color, transparency, clearness, reflections, and so. But the lens I tried, at magnification max, showed a twisted date window. I think this is not due to SF11. And that test was quite unreliable, as the only case I had at hand to try was from a low-cost 028 rep, whose bezel is about 4 mm high (instead of the usual 2.5-3 mm). Still, that sounds like a warning to me, so I would highly prefer that we could try a prototype lens before placing the big order. Perhaps it could be possible with SF11. Archibald? If that is not possible, still I vote for SF11, expecially because its (very) lower cost is leaving us less exposed in case something goes wrong.