So we have a camera looking through an optical device. And the question is: Is it a lens or an objective? Or anything else?

Ocularlens

We have a long ongoing discussion about weather to use the word "objective" or the word "lens" for the exchangeable package of optics that are in front of the camera.

Objective lensmagnification

Objective lenstelescope

If the predominant aspect of the optics is lenses, you lose nothing by writing 'lens'. If they are a mirrors or a mix of mirrors and lenses, you might say 'optical elements'. Of course, if the buyers are technically savvy, you could say 'objective'.

In microscopes and telecopes, the objective lenses are the elements of the optical system closest to the specimen or viewed thing. In cameras, the whole optical system of lenses used for focusing the image onto a film or sensor, informally called a 'lens', is formally called a 'photographic objective'.

Back in the late 20th century among photographers, at least in the U.S., "objective" tended to refer to the first lens element or group of elements in a compound lens system. For example, with a 70-200mm f/2.8 lens with 23 elements in 19 groups, the first 2 lens elements would be considered the "objective group".

Because your audience is technical, you should use the most precise term -- and include an explanation or definition. For example: "The objective is the part of the device that gathers and focuses light to produce an image. The objective is composed of multiple lenses." (It might include other devices too, such as mirrors)

Types ofobjectivelenses

In the jargon of optics an objective lens is the lens (can be compound) that is the first to receive the image-forming rays from an object being examined or imaged. This lens or lens group is often called the objective lens.

Among "non-photographers" in English speaking countries, I would think that "lens" would be much more understandable than "objective". Pretty much anyone who understands the technical meaning of "objective" used in the context of an optical system would also understand what "lens" means. The obverse would not be the same case, not everyone who understands what a "lens" is would also understand what "objective" means when used in the same context. There are many English speaking photographers who have not a clue where their camera's "objective" is located. They all know what "the lens" is.

What is an objective lensused for

Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

As someone who is an English speaker and has been doing photography for almost 50 years, I'd say that a compound lens system is usually called a "lens" when used in the context of creative photography, which is what Photography.SE is mostly about. We even call catadioptric mirror + lens systems used on cameras "mirror lenses."

What is an objective lensin microscope

As I tech writer, I understand your concern. "Lens" refers to a single optical element. A compound lens is a single optical element with multiple focal properties, such as a bifocal lens. An "objective" is an assembly of multiple lenses.

I'm working at a German company that is building production machines. These machines are using cameras and microscopes to align small structures. Because we sell them worldwide we have to properly name the parts in English.

Though it is true that in the nomenclature of optical physics, lens refers to a single optical element, in the nomenclature of cameras, "lens" can and does often refer to the entire light gathering optical system made up of many lens elements and even mirrors.

Based on one quarter (as opposed to semester - if that doesn't date me as a fossil nothing does) of 'German Language and Culture' back in my college days, I'd say that the way most German speakers use das objektiv is very similar to the way most English speakers use the lens.