So if you want to compare lenses made for cameras with different sensors, you need to know the crop factor, i.e.

Things are complicated a bit by the fact that angle of view depends both on focal length and sensor size. Often they are supplemented in people’s gear by a 70–300 lens, which on the other hand is a pure telephoto. So an ordinary, basic 18-55 DSLR lens can “zoom” from medium-wide views out to the beginning of telephoto range. From this you can tell what angles of view the particular lens can handle. The first number or pair of numbers indicates the range of available focal lengths in millimeters. The first number gives the range of focal lengths in millimeters, while the second gives the lens speed (for the 1.4/50 designation it’s vice-versa). Very often you’ll see a shortened notation with no units, of the sort “50/1.4.” In exceptional cases, generally on older lenses, you can also find the numbers reversed: “1.4/50.” Everything can also be expressed as “50 mm 1:1.4” or “50 mm F1.4.” But in all cases this is nothing more than a way of writing the numbers their meaning is always the same.ĥ0 mm f/1.4 // 50/1.4 // 1.4/50 // 50 mm 1:1.4 // 50 mm F1.4 Other methods for expressing this information also exist. No matter how the lens is designated, somewhere in the middle of it you’ll find a series of numbers, typically in one of the following formats: And it teaches you that some of them can be very treacherous-one good example is “Tamron SP AF 17-50mm f/2.8 XR Di-II VC LD Aspherical (IF) for Canon.” The Numbers are the Foundation For one thing, this lets you determine how good your lens is, and for another, it lets you quickly search among the dozens of items in shop catalogs when you’re buying a new lens. It’s absolutely essential that get a grip on manufacturers’ lens designations. Take a look at which pieces of information are important for you and what it all means. See current trademark processing wait times for more information.Lens names are full of abbreviations, number ranges, and useless advertising. Processing Wait Times: Please note that due to an extraordinary surge in applications, processing times are longer than usual. For assistance with TSDR, email and include your serial number, the document you are looking for, and a screenshot of any error messages you have received. See current trademark processing wait times for more information.

Trademark Law: Rules of Practice & Federal Statutesįor assistance with TSDR, email and include your serial number, the document you are looking for, and a screenshot of any error messages you have received.

Sigma lens serial number lookup