Opinions of the 21mm Super-Angulon

[Tom A]

Rui, thanks for the heads up on Jean Loup Sieff's 21 SA work. He also used a 28f2.8 Version I which does exhibit similar traits when it comes to edge fall off.
Maddoc, I am one of those SA user who never regrets selling a 21 SA - as I usually had two or three of them - and always kept one - and I still have one. The only time I have sold them is to upgrade for glass condition or switch from chrome to black.
Schneidar and Leica did some manipulation of the coating on the SA and the version with a # 2.600 xxx and over is slightly better when it come to contrast. My current SA is one of the last ones made #2917099. The trick with the SA is to buy hoods whenever you see them. It is made of plastic and they crack if bumped. Also watch that the rear element "pack" is not coming off. It can unseat itself - particularly with air travel or bumpy car trips. Easy fix, but I have had the whole rear pack falling off once!
The miniscule 21f4 VC does exhibit some of the character of the 21f3.4 - but with a more modern look.
Anyway, it is one of the great classic Leica lenses and with black/white it just sings!

 

[Rob-F]

While the 21/3.4 SA does have some limitations, as noted above, its true wide-angle design allows it to be very low in distortion. That makes it a favorite for architectural work, and like Tom, I keep one around (I like to photograph buildings). If you like to take buildings, and don't like straight walls looking curved when they are near the frame edges, this is a lens to have.

OK, you can't meter with it. Just keep it on a non-metered body--M2, M3, M4P, whatever you have. Then the lens and camera were made for each other, you might say.

Light fallof: yes, there is more than you will get with a retrofocus 21mm. But the retrofocus lens has significant distortion. There's no perfect answer there! The amount of falloff has to be kept "in perspective" (no pun intended). With an expanse of blue sky across the width of the frame, the upper corners will be darker than the upper center area. I have found that opening up a 1/4 stop or a 1/3 stop or so helps to minimize this. I believe that the additional elements in the SA make the lens slightly slower than the marked speeds--in other words, I think its transmission is less than the f-numbers would indicate. But do not believe anyone who says that the falloff goes away on stopping down. It is certainly still there at f/8.

Then again, when you photograph something that does not have a large uniform area, but rather the frame is filled with items of varied brightness, then the light falloff is eclipsed by the variation in brightness of the subject matter. Then you don't notice the falloff.

No, it is not as sharp as the 21mm ASPH; nor, as Tom says, is it as sharp as the Zeiss alternative. But give it a break--it's a much older lens, yet still rates a grade of "B+" overall!

 

[oscroft]

I will revise and say falloff rather than vignetting. The two are not synonomous.

What's the difference?

 

[Rob-F]

It is OK to say vignetting to refer to light falloff. It's just that there are three kinds of vignetting: one is mechanical vignetting, causing by a filter or lens hood blocking the view; another is artificial vignetting, caused by the apparent change in the shape of the rear element as "seen" by the film from the extreme viewpoint of the edge or corner. The rear element looks like a cat's-eye from from that angle, and thus has less area, so it effectively passes less light.

The third kind--close vignetting of the third kind--is explained by the fourth power cosine law. So what is that? It means that since the corners of the image are farther from the rear element than the center is, the light travels further and gets dimmer in the process.

The last two causes both decrease the illumination into the corners, contributing to a darkening also called "falloff." The latter term is convenient when trying to avoid an argument about whether any loss of light toward the edges and corners not caused by a mechanical obstruction ought to be called vignetting. But it is vignetting "of the second and third kind" arguments to the contrary notwithstanding.

 

[oscroft]

It is OK to say vignetting to refer to light falloff. It's just that there are three kinds of vignetting...

Very interesting, thanks 🙂