Seeking Clarification: Professional -- Standard -- Consumer

From searching POTN, I've learned there are 3 basic lens classifications:

Professional ("L")
Standard
Consumer

I have a good understanding of prime vs. zoom. Each has its strengths and weaknesses and photographers might (or might not) prefer one over the other. Fast lens usually refers to a prime lens which generally provide lower f-stops.

Most would agree that while a consumer lens is good, a standard lens is better, and an "L" lens is the best. My question is: what makes this so? Is the glass in an "L" lens ground or manufactured differently from other lens? Are the internals made from better material or made using a better design? I've heard the 50mm f/1.8 II refered to as fantastic plastic (I know the nifty-fifty is classified as a cheaper lens, but I am thoroughly enjoying mine), but it has the same f-stop range as the 85mm f/1.8 USM lens. Thus, what makes the 85mm a better lens? Wikipedia states that the 50mm f/1.8 II lens is constructed with "5 groups / 6 elements" and the 85mm has "7 groups / 9 elements". What does all that mean?

I apologize for a rambling post that is full of questions. I realize I don't have to know everything about a car to drive one. These are a few questions that have surfaced as I read/research and seek to move beyond the novice level. Any info would be greatly appreciated.

R/fiVe

Quality... it's all about the quality... Plenty of pro's use the 85 1.8 in their bag and it does fantastic. Have you used an L lens yet? Rent one for a few days and you'll understand why people pay the difference. If you don't notice it then don't worry about it and save yourself a LOT of $$$$

All of the above. The quality of a lens involves many factors(in no particular order): image quality(which can be broken down further), build quality(including weather sealing), focal length, max aperture, AF performance(speed and accuracy), IS performance, and ergonomics. Lenses which are better at one or more of those various things are better and more expensive.

The groups/elements data just means how many pieces of glass are in the lens and roughly how they area arranged.

The main differences between the 50 1.8 and the 85 1.8 are in the categories of focal length, build quality, ergonomics, and AF performance.
Focal Length: Lenses close to 50mm are easiest to design and manufacture as you get wider or longer lenses get more expensive.
Build Quality: The 85 is a much more robust lens, metal mount etc. It uses better/stronger/more expensive materials.
Ergonomics: The manual focus ring on the 85 is much larger and easier to use.
AF performance: The focus speed and accuracy of the 85 is fantastic. For this reason it is widely used for sports in addition to portraits. The 50 struggles in this area.

As to your first question, you answered it yourself. Quality in every respect (Fluorite glass and weather sealing for instance).

As to the second, I can't answer it because it is unclear. Are you asking what makes the 85 1.8 better from a hardware and design perspective, or why it is subjectively (or objectively) better in use?

As to the groups/elements question, that I can answer. Elements are pieces of glass. Groups are elements that work* together. So if there are 6 elements in 5 groups that means there are four pieces of glass that work on their own and 2 that are literally glued together and then work independently of the other groups. Similarly for 9 elements in 7 groups, there are either 6 individual pieces of glass and 3 that are glued together, or 5 individual and 2 groups of 2 that are glued together.

*By "work" I mean that if they move at all they move together, if they don't move they don't move together.

Also, read this:

http://www.earthboundl​ight.com …-elements-and-groups.html

Another thing.

Lens design is not a straight-forward thing. There is no single formula for making a lens of a certain focal length. Every lens is a little different, and there are multiple and very distinct ways to make a lens of any given kind. However, there are some "standard" designs that certain companies use a lot (modified for every lens of course). This is why lenses from certain manufacturers provide different results under various circumstances.

For instance there is the "planar" design originally developed by Carl Zeiss in 1896 and still used by Zeiss today. Canon doesn't use the planar design and so there are certain things you can do with a Zeiss Planar that you can't do with any Canon. For instance the bokeh in this:

arentol wrote in post #11896976
The 85 1.8 just straight up produces better images when used properly than the 50 1.8 and so it is better.

Not if you need 50mm, lol

Canon's book "Lens Work", downloadable as a PDF from their site, goes into great detail about lens design in general and Canon technologies/designati​ons in particular. There's a link in the stickied thread with that name in the index for this forum.

themadman wrote in post #11897085
Not if you need 50mm, lol

If you need 50mm and you are using an 85mm then you aren't using the 85mm properly.

arentol wrote in post #11897172
If you need 50mm and you are using an 85mm then you aren't using the 85mm properly.

You're welcome to step back into the traffic or over a cliff. This will be my final post in this thread.

Pro quality is partly about the build and weather characteristics. It helps you keep shooting despite the weather and how many clicks. It's like the difference between a household screw gun and the one that the contractors use who attach drywall day in and day out. Other than that, those lenses are bought by pros, wanna be pros, those obsessive about their art, and the rich who like spending money for bragging rights.

If you leave the view of a photographer:
All the Canon EF lenses are called "consumer" lenses in my business - machine vision.
So for industry applications they are not rigid enough, have no lockable iris, distance and zoom. And you have no or nearly no possibility to get them in an OEM version which small adjustments to your needs.

arentol wrote in post #11897172
If you need 50mm and you are using an 85mm then you aren't using the 85mm properly.

Lol, love the look of Zeiss tho, I need the 100 makro bad... lol

fiVe wrote in post #11896713
From searching POTN, I've learned there are 3 basic lens classifications:

Professional ("L")
Standard
Consumer

Well, Canon really does not market their lenses in these categories, and the difference between 'standard' and 'consumer' seems to be undefined anywhere.

According to Canon their lenses are 'L', 'DO' and 'Everything Else'.

I think you are falling into a pretty commong trap in thinking that what makes an 'L' lens better than the others is exclusively that it has better image quality.

In general, 'L' lenses do have very good image quality over other choices that are similar. This comes from use of more expensive lens elements a lot of the time like flourite, ultra-low dispersion glass and aspherical elements.

But really what is more likely to define an 'L' lens is a set of features. Like having a fast maximum aperture for the focal length, or having an especially broad focal length range in a zoom.

'L' lenses often also have the best in other features like ring-USM focus motors and weather sealed and rugged construction.

It's harder to make an 85mm lens as fast as f/1.8 than it is to make a 50mm lens f/1.8 for 35mm format.

Also, the 50/1.8 is not a very sharp lens below f/2.8, while the 85/1.8 is.

Finally - the 85/1.8 has a fast and accurate ring USM focus motor and has pretty nice construction. The 50/1.8 has a slow and inaccurate arc-form drive focus motor and is built cheaply.

JeffreyG: thanks for the info and the education.

themadman wrote in post #11897085
Not if you need 50mm, lol

This.

The thing is, that just because lenses are cheap doesn't mean they are not useful.

The 85mm makes a great low light lens, great portrait lens, etc. Imho the 50mm 1.8 doesn't unless you manual focus, because the AF is so unreliable (at least for me).

However, if you are doing a landscape shot at 50mm, the 50mm might be the best 50mm lens Canon makes for you. It's as good as the 1.4 and 1.2 when stopped down to f/5.6 or f/6.3, so why pay more and carry more weight? At least until someone looks at you funny and the lens body breaks :P