Lens serial numbers - Tamron 17-50mm f/2.8 XR Di-II LD [IF] SP AF for Nikon Digital SLR

all of my Tamron lenses have the serial number on the barrel of the lens right next to the "Made in Japan" label. When the lens is in the camera the MIJ label is on the bottom side. I hope that helps with your lens

You cannot find the age of Minolta lenses by the serial number, Minolta didn't use serial numbers like that. Some lenses have (c) xxxx for the year the type were first manufactured but that means the range, not that lens.
This site has the different versions of the range.

Minolta Konica Minolta Sony Alpha lens data

Remove the rear lens cap and you should find the serial no. round the back element of the lens.

According to the first 2numbers It was made in August 2012. The rest of the numbers are just the serial #

Model 1919.

The serial number is on the bottom of the lens, near the lens mount.

On the Leica X1, unlike other Leica M's and digitals where the serial is on the hotshoe, the serial is actually on the front of the lens, alongside the lens label.
Elmarit 1:2.8 is on the right hand side of the lens and on the left is the serial number.

My Tamron 18-270 has number at bottom side toward tripod hole(when lens is mounted on body)

ivitar Entries

• 100/3.5 Macro, serial number 218434
• 135 mm f2.3 Series 1, serial number 2826606
• 19mm/38 lens for Contax/Yashica, serial number 94061957
• 28/2.8 lens, serial number 282 404 68
• 283, serial number 0032418 (PACK BATTERY)
• 283, no serial number provided
• 283, flash, no serial number provided
• 5600 Autothryistor TTL flash w/ Minolta module & standard head, serial number unknown
• 60 -300 AF zoom, serial number 77900979
• 70-210mm f3.5 series 1 f/Pentax, serial number 22002890
• 90-180 f:4.5 Series 1 Flat Field Zoom, serial number 3517730
• FD fit 19mm f3.8 lens, serial number 93110044
• FD fit 70-210 macro zoom Series II, serial number 09811287
• Series 1 28-90 for Canon FD, serial number 28612541

You don't need the serial number, you need the model number. Look for numbers inscribed on the ring around the lens opening or on the body of the lens somewhere.