Veiling Glare

[TOP publishes on Monday, Wednesday, and Friday.
Comments are added the following day.]

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Saturday I happened to find perfect conditions for illustrating veiling glare. Here the sun is just out of the frame. The air was exceptionally clear and the morning sun almost preternaturally bright. The dew was glinting like myriad diamonds on the grass and I was wondering if the phone could catch it (it didn't, at all. I've always wondered how much camera you need to resolve back-lit dew. I guess it depends how close you are). The above picture is one with no shading of the lens.

Here's very nearly the identical scene, taken just moments later but with my hand shading the lens. Pretty big difference. Enlarge the pictures by clicking on them, set them side by side, and let your eyes go back and forth, noting the differences.

It's worth noting that, as with many properties considered defects in photographs, flare is often present in pictures in amounts too small to consciously register unless you're good at spotting it. The same is true for misfocus, color cast, motion blur, and many other defects. I think it's interesting and instructive every so often to create a picture that has no defects at all, just to "calibrate" your brain and eye. I've done a number of such exercises over the years.

"Flare" is the general name for non-image-forming light reaching the sensor. There are various types. I can actually see three types of flare in the top picture (see if you can spot them), but the predominant one is veiling glare—that overall flare that lightens the scene, cuts contrast, and "washes out" the colors.

Flare is often caused by light sources in the frame or just out of it that are way brighter than the camera is set to record. Lens hoods are useful in controlling it, but only incompletely—you can't shade the lens from a picture that contains the bright light source in the picture, and there are many situations where, even with a shade, direct sunlight can still strike the lens directly. 

Historically, the "Eagle Eye" of Zeiss—the 1902 Tessar designed by German physicist Paul Rudolph and his assistant Ernst Wandersleb—had remarkably little flare for its day because it only had six air-to glass surfaces. (Copied in 1926 by Leitz in the fixed Elmar for the Leica 1A.) Today, modern coatings have made great strides in eliminating flare even in much more complex lenses, however, so it's not something we have to think about too much any more. Not like it used to be, anyway.

Flare was especially undesirable in spotmeters with lenses, because it could throw the readings off.

The most important thing a lens hood can do on a normal or wide lens is shade acutely impinging light (light striking the lens from an angle more toward 90 degrees). So a short hood is often nearly as good as an optimized one, and a recessed front element, like you find on some macro lenses, serves as well. (I've always liked lenses with recessed front elements.)

Bear in mind, though, that the many effects of flare are only properties of lens imaging. Flare is generally considered undesirable, but it isn't necessarily—many pictures have incorporated flare successfully.

For instance:

The Dalai Butta receiving doggie enlightenment. ("Make me One with the tennis ball....") It can be fun to play with flare! Didn't I post an example just the other day? (This was taken with my old iPad.)

And don't forget that our friend Juan Buhler (street photographer extraordinaire) and his colleagues at Pixar actually added CGI lens flare, focus, and bokeh effects to the animation for the 2007 movie Ratatouille....

Mike

Book o' the Week

Photography, The Definitive Visual History by Tom Ang. This is a book that can't exist—it's too much work to put it together, like several others I know of (I'm looking at you, Q.T. Luong). Amazingly, it exists anyway. A brightly-lit shop window for the attractions of photography—a whirlwind tour of people, cameras, and pictures. The author still has time to be an accomplished travel photographer, although I don't know how.

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(To see all the comments, click on the "Comments" link below.)
Featured Comments from:

Ken Bennett: "My Fuji 35mm ƒ/1.4 is very good at showing this sort of veiling flare or glare with a light source that is in or just outside the frame. Most of the time I think it's a feature, but there are times when I need to correct it in post (the Dehaze slider works at minimizing it.) I shot a lot of photos at a late afternoon gala reception inside a fancy tent yesterday (the tent was the size of a couple of football fields, with clear plastic roof and sides. And heat.) Lots of late afternoon backlighting, which looked great, but I got that glare all over the frames from the 35mm. The 16mm ƒ/1.4 and the 56mm ƒ/1.2 had none. "

Ken later adds: "Followup to my original comment, Mike. I just received the new Fujifilm 33mm ƒ/1.4 lens, and shot it side by side with the original 35mm, wide open, with a bright light in one corner. The difference is amazing—the new lens shows none of the veiling glare/flare of the old one."

David L.: "Long ago I had a Leica 90mm Tele-Elmarit, the slim version with 39mm filter size. I shot a roll with it on a cloudy day, and every frame had excess veiling flare. Sunny days were worse. Seemed like every circumstance caused flare. I studied the geometry of the tapered barrel and saw that any light reflected off the inside would bounce toward the film plane. I was very glad to sell it."

Mike replies: Yet if memory serves, that's the lens Alice Springs (a pseudonym of June Newton, Helmut's wife) used for her wonderful book of portraits, long a personal favorite. I could be wrong about that.

Comments

[Albert Smith]

This is interesting timing. Just last night I watched a YouTube review of the new Voightlander 35mm f/1.2 lens chipped for Fujifilm cameras. This reviewer parrots what others have said, that this lens has crazy flare. He talks like it's a feature, designed in to give a vintage look. I gave the lens serious consideration given my positive experience with the brand on my Nikon DSLRs, but it would make me feel pretty stupid to spend $700 for a lens that gives the illusion of being cheap.

If interested, link to video:

https://youtu.be/ZaKNtlivrUY

[Anders Holt]

Dear Mike,
Interesting article about flare!

Also: When tipping us about books, please include bookdepository.com links also (thus I can save the shipping cost), and you get the cut (commission(?))all the same. :-)

All the best,
Anders H.

[Kenneth Tanaka]

Excellent explanations and illustrations, Mike. That’s where a hood can com in handy…or not. Strangely, the worst flaring lenses I own are both Leica M’s! My 90 Apo Summicron f2 is particularly touchy, even with a hood.

But, towards your general guidance to get to know your lenses, I sometimes try to make flare/glare work towards a visual concept. As a publicly-viewable example, my iPhone X had a lovely sweet spot for flare with light source at about 75 degrees. It was a perfect moment to enlist the optical phenomenon for this contemplative scene.

https://www.kentanaka.com/just-a-moment#16

No later models of iPhone cameras have shown such predictable flare effects. They’ve become too “smart”!

[Rob de Loe]

I use a lot of lenses with image circles that are larger than needed to cover the sensor, sometimes a lot larger. Veiling glare can be especially hard to manage with these. I have some where the primary function of the lens hood is to protect the glass from knocks; even a very long hood can't manage flare. For those lenses, only a baffle at the rear is effective.

My wide-brimmed fedora is another essential tool in my photography tool bag. It's not just for fashion ya know!

[Ha! Yes. I used to wear a brimmed hat when using the Mamiya 6 because it helped shade the metering sensor. Sunlight on the meter could mess up the reading. --Mike]

[Stephen Scharf]

Good post, Mike.

These days, I see all of the "problems" you've mentioned, and more.

Submititng your photographty into competition every week for the better part of four years makes you...very discriminating.

Moreover, having shot a lot of commercial photography the last three years, I've become particularly aware of extension distortion and color casts (both of which there is skosh of in the Butters photo).

Cheers.

[John Russell]

Reminded me of the old film production joke:
What's the difference between a flare and a highlight?
$1,000 a week.

[John Krumm]

The updated lens on the Fuji x100v has some of this flare, even with a hood. Otherwise, great contrast.

[Bill Tyler]

Ansel Adams in one of his books (I'm too lazy to look up the exact reference) noted that lens flare can be useful in high-contrast situations by lifting the base exposure of the dark areas, somewhat like might be done with pre-flashing the film, and suggested choosing lenses with that in mind.

[David Dyer-Bennet]

Veiling glare is my least favorite of the flare family; I've spent real money to replace a lens for having that as its besetting sin.

Flare is easier to spot before exposing, so less likely to be a nasty surprise, compared to veiling glare. And I find flare easier to use artistically.

Not that veiling glare can't be used artistically, or for that matter "technically" as in the Ansel Adams suggestion mentioned above. But I find the artistic uses harder to come up with.