Newbie question about the crystal. Listings always say “scratch-resistant sapphire crystal with anti-reflective coating”, sometimes “deep crystal”, and in the QC threads half the questions are about the cyclops that “doesn’t magnify enough”. What difference do these things really make, and what can you judge from a photo?
Let’s start with the basics, which are three different things:
- Sapphire: the crystal material. It’s very hard, so it scratches with difficulty, but it can chip from a sharp knock on the edge.
- Anti-reflective (AR): a thin coating on top of or under the crystal. It cuts reflections and gives that bluish tint when you look at the crystal at an angle.
- Cyclops: the lens over the date. On Rolex the reference magnification is 2.5x.
They’re three separate questions, and it pays to keep them separate in QC too.
There’s a confusing detail about AR. A coating on the inside is protected, while one on the outside wears off over time and with the wrong products, even though the sapphire underneath stays intact. That’s why someone asked whether isopropyl alcohol wipes are fine on the crystal: on sapphire, yes, but an outer AR is the delicate part. Microfibre cloth and water, and for the rest there’s the thread on cleaning the bracelet and crystal.
And the cyclops? How can you tell from photos whether the magnification is right?
Let’s be honest here: you can tell less from photos than it seems. In one thread, two Submariners, same factory, same photographer and the same claimed 2.5x, seemed to magnify differently. One had a black dial, the other a blue one. Dial colour, angle and camera distance change the perception. The same goes for the “it looks weak to me” questions on Datejusts and Day-Dates.
What you can check with reasonable certainty:
- the date fills most of the lens, seen perfectly straight on;
- the cyclops is centred over the date;
- there are no bubbles or glue residue under the lens.
On the question “does the magnification change between models?”: the reference stays the same, even if the cases are different. But a cyclops that’s too weak is a flaw you can see on the wrist, not just in photos. If the date looks almost the same size as without a lens, that’s a real signal. If it looks “a bit less” than the genuine, it’s often the photo.
And “deep crystal”? It’s a taller, domed crystal, usually a mod or an option. The person who fitted one to a GMT finds it much more faithful, but then found that the height of the crystal relative to the bezel changed, and at that point the cyclops looked different. Another user’s question was whether it was worth moving to a deep crystal from a standard AR crystal: for newcomers, no. It’s a cosmetic upgrade, not a problem to fix.
A trick for seeing the AR in QC photos: ask for a shot of the crystal tilted towards a light. The bluish, or purplish, reflection shows the coating. If the seller says “AR” and the reflection is plain white, ask.
Summary for newcomers, with the level of certainty:
- Sapphire: almost always there. Hard to scratch, but watch out for knocks on the edge. High certainty.
- Anti-reflective: visible with a shot tilted towards the light (bluish reflection). An outer AR should only be cleaned with microfibre and water. Medium certainty.
- Cyclops, centring: easy to judge from a straight-on photo. High certainty.
- Cyclops, magnification: hard to judge in photos, because dial colour and angle deceive. Only worry if the date looks barely magnified. Low certainty.
- Bubbles or glue under the lens: close-up macro. High certainty.
- Deep crystal: a cosmetic upgrade, not a requirement for a first watch.
For the difference between “real problem” and “it’s the camera”, the same method as in the Submariner QC thread applies; for the technical terms there’s the movements and parts glossary.
Crystal clear. I’ll ask for the tilted shot and a photo of the date perfectly straight on.