The Short Answer
A fake Fifty Fathoms 5050 is a replica of the Blancpain Fifty Fathoms reference 5050, a large steel dive watch with a sapphire bezel insert and an in house automatic movement. Copies of this reference fall into three bands: crude builds with glued inserts and quartz movements, mid grade copies with a decorated automatic movement, and high end copies that copy the case profile and crown guards with some accuracy. Photos cannot settle the question on their own. The bezel ratchet, the caseback engraving, the dial print under magnification, and a timing reading are what separate a decent copy from a poor one.
Prerequisites
- A 10x loupe or a phone macro lens
- Vernier calipers for case and lug measurements
- A timing app or a timegrapher reading
- Reference photos of the genuine 5050 for side by side comparison
How to Inspect a Fifty Fathoms 5050 Replica
- Measure the case across the bezel and across the lugs. Record both numbers before you look at anything else.
- Turn the bezel through a full rotation. Count the clicks and note whether the action feels gritty or even.
- Press the bezel edge at four points to test for vertical play. A wobbling insert means a cheap retaining system.
- Examine the dial print with the loupe. Check letter spacing, the depth of the lume plots, and whether the date window edges are cut clean or show burrs.
- Inspect the crown guards from the side. Genuine guards taper into the case; poor copies leave a visible step.
- Flip the watch and read the caseback engraving. Look at line weight and whether the serial and reference numbers align with the case band.
- Run the movement for 24 hours and log the rate in six positions. A decorated rotor does not mean a regulated movement.
- Compare your photos against the reference images at the same angle and lighting.
What Usually Gives a Copy Away
Bezel feel is the fastest tell. A genuine diving bezel indexes with a firm, repeatable click and no back play. Copies either spin with light resistance or lock up after a few degrees. Lume is the second tell. Charge the dial under a lamp for 30 seconds, then check brightness and color after five minutes. Copies fade fast and often glow green when the original glows blue.
Case finishing is the third tell. Look at the transition between brushed and polished surfaces under raking light. A crisp line stays crisp along its whole length. A soft line wanders. On the 5050 the lug bevels and the crown guard blend are the hardest areas for a copy to get right.
Price Signals
- Prices far below the market band for a given copy tier mean a quartz movement or a plated case.
- Sellers who refuse a movement photo or a live video call are hiding something.
- Listings that reuse catalog photos instead of shots of the actual watch should be skipped.
Before You Commit
Ask for the movement caliber, the case diameter, the lug width, and the water resistance claim in writing. Ask whether the crystal is sapphire or mineral. Ask for a short video of the bezel turning. A seller who answers all four with specifics is worth dealing with. A seller who answers with adjectives is not.