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Monday, 16 July 2012

Comments

"...old film days..."??

That would be like Charlie Chaplin, right?
But an interesting article; thanks!

Regarding using filters for protection.
I once advised a friend who was buying a camera to use in photographing his children, to buy a filter to protect the front of the lens. He bought the camera, and put on the filter. His first photograph with that camera turned out to be of his young son flinging a small toy right at the camera. The toy cracked the filter but not the lens. The father's only comment was that I should have advised him to buy a second filter when he bought the camera. While I rely on lens hoods as protection now, a lens hood would not have stopped that small thrown toy, the child was that accurate.

Note, a cracked filter causes a lot of haze.

I always hated seeing flare in my images even though it seems to add something to the images made by other people. Sometimes when the sun is fully in the frame you get some interesting effects.
Sun fully in the frame with lots of flare on a foggy morning in the West Texas oil patch.
http://www.pbase.com/kwhite/image/122111451

Excellent article! Unfortunately, at least on my computer, the "Animation showing scanned Tri-X negatives from the 50mm f/1.4 lens" is frozen on "Lens Hood." The prior animation works fine. Again, an excellent article.

Daniel,
Unfortunately I don't know enough about it to help you. It tests fine on Safari and Firefox for me.

Sorry...

Mike

By using a filter for protection, you are simply altering the design of the lens such that the front element is field replaceable, industry standardized, and low cost.

I think that particular assemblage of words takes a lot of wind out of the anti-arguments.

M'sieur, does your lens flare?

No, my lens does not flare.

Mon Dieu! I thought you said your lens does not flare!

M'sieur, zat is not my lens.

Yes, yes, "use a hood all the time," even if makes your otherwise inconspicuous lens look like a howitzer!

Filters are for filtering (removing some part of) light for a desirable effect, not as a resale shield. I'll only give quarter to those who shoot in sandstorms and on helipads, though.

Uncharacteristically, this post contains some glaring errors.

Mike,

Thanks. Not sure what happened as it's working now in Chrome too, but was definitely stuck earlier. Computers can be rather annoying at times.

Dan

Put it down to my perverse need to get weewee'd up about things over which I have no control; lately it's been DSLR users walking in the sunshine with UV filters on their lenses and hoods fitted on backwards that gets my gorge rising.

Photography gods, I silently scream, please take pity on these poor souls. They've already spent good money on nice equipment and suffered the indignity of being upsold a piece of glass they don't need. Don't condemn them to a lifetime of filter flare and flat contrast; help them find an online article that points out the error of their ways.

Very informative, thanks. My primary lens has a UV filter that is basically glued on. I am really rough on my equipment and the UV filter gives me piece of mind. However, I absulutely hate veiling flare. Maybe it's time to ditch the protection. I'm going to read Mike's take now and then make up my mind. It's funny how much anxiety that little piece of glass causes.

As the owner of a late-1950s era Yashica TLR, I'm intimately familiar with veiling glare. A lens hood helps, but what really makes a difference on those old cameras is using matte black flocking in the interior to cut down on the amount of light bouncing around between lens and film. I haven't done that yet but I've seen examples of the difference it makes. I've seen improvements just by applying black permanent marker to some silver-colored areas which would be exposed to incoming light.

Daniel,
Try copying the problem GIF file to your computer's desktop, then drag it into the browser window. That will display it by itself.
Perhaps a memory issue on your machine permits only one animated GIF file to display at once. The second file WAS fairly big.
Animated GIF files are an ancient technology (well, in computer years at least), and normally shouldn't require anything more than a browser to run.

Ken,
The photo linked shows atmospheric haze more than flare. That's part of the scene itself and not caused primarily by the camera optical system. Having taken advantage of fog and haze myself, I agree that these conditions can make a picture more appealing.

Bill Schneider

Good article.

But also, when using full frame (film) lenses on smaller (APS) sized sensors it’s a good idea to use a deeper hood. My old 35mm film lens gives a 50mm equivalent angle of view on APS-C. So, I use a hood sized for a film 50mm.

And/or, just shoot some test frames to find the deepest hood that does not darken the corners of the frame. Don’t forget to test with filters added, too.

I own polarizing filters for times when the light needs to be polarized but I would never, ever put a "protection" filter on the front of my camera. That's as dumb as wearing your bicycle helmut in your house or office just in case something out of the ordinary should happen.

You probably paid good money for your lens so it would be sharp and contrasty. Adding two more air/glass interfaces messes up the optical formula those poor lens designers worked so hard on....

Can you see people with really nice watches putting protection glass over the crystals, just in case? Grow a pair and shoot with your lenses the way God and the optical designers intended.

This column only addresses the UV filter possibilities to control different flares. In your previous column I did bring up the idea of using a polarizing filter over the lens to reduce the unwanted lightwaves. I seems to me the best test would be to shoot the same scene without a UV filter, with a UV filter, and with a rotating polarize at different settings.

The illustrations for the two lenses show the chart at such different magnifications, cropped fairly tight in one case and showing the whole scene in the other, that's VERY hard to make any kind of comparison between them. This is such a blatant violation of the rule of varying one thing when trying to illustrate something that it almost has to be intentional, but I'm missing the point, and find that it makes the whole article nearly useless.

I'm completely filter free with one exception - harsh environments. I believe that with Canon lenses anyway full weather-proofing requires use of a filter. Besides, I would rather hastily wipe salt away salt spray with a T shirt from a filter than the front element!

One exception I do make is the use of a polarizer for creative effects - its the only filter effect I can't replicate (or possibly improve on) in Photoshop.

As to lens hoods - absolute must for me, both for glare and protection - the scratches and nicks evident on my hoods very clearly illustrates their value!

I'm always surprised by the number of people I see with the hood in the stored position - I wonder if some people buy the lens like this and don't realise it's reversible. If you didn't know much about photography, perhaps it's not obvious.

Cheers,

Colin

Dear DDB,

I think maybe you're looking for the wrong information? This isn't a comparison between the two lenses directly, it's a comparison between how their flare changes when they have filters or lens hoods attached -- both lenses show a lot more flare when the filter is attached, but the low-flare lens is little-affected by attaching a lens hood. That comes across clearly in the animated GIF regardless of image size.

pax / Ctein

David,
I think each set was meant to be self-contained, but Bill can speak up if he wants to....

Mike

Good demo. I make this argument all the time. Most flare comes from the subject itself. I always use a lens hood and only use protective filters when there is an obvious hazard.

It's also important to realize that a) all optical systems suffer from flare to at least a small degree. Nature of the beast; b) most pictures don't suffer from it enough to notice (or to worry about); c) a lens hood makes a difference some of the time but not always. So if flare is not a problem in 80% of your shots, a lens hood will make it so it's not a problem in 85% or 90% of your shots. It's just going to improve your odds--it's not a panacea.

Also, I should have mentioned in my "never use a filter" article that for 20 years I always used a filter, because I liked the look of Plus-X and Tri-X with a yellow filter on the lens. The change in spectral response was worth the very slight downside in optical quality.

Mike

David,

I hadn't intended to compare the two lenses against each other, but I can see how the different magnifications are distracting.

I'll attach the cropped 50mm 1.4 lens example to this comment.

Note that because the lens focal length between the lenses is different, the 50mm example will be a little larger using the same crop dimensions.

Also, I did not attempt to retouch the scratch visible in one frame in the animation.

It's interesting that suddenly everyone's talking about flare. The new Canon 40mm f2.8 is very exciting me because the simple, low element/group design, combined with modern coatings, means it's a very flare resistant design. As someone who shoots at night, with lights in scene, that matters to me. A lot. If only I had a buck to my name...

"By using a filter for protection, you are simply altering the design of the lens such that the front element is field replaceable, industry standardized, and low cost.

I think that particular assemblage of words takes a lot of wind out of the anti-arguments."

No, it doesn't, because you didn't anywhere in there address the fact that you are making the lens performance worse; Especially if you think it's low-cost.

A filter on the front does not alter the optical formula. Middle or back, yes, but not the front.

Ed

Many years ago a big time pro stated that it was ridiculous to put a ten dollar piece of glass (going price for a filter back when) in front of a premium piece of glass costing hundreds. Naturally, I followed the pro's advice, took the UV filter off and a couple of weeks later had a nice gash on my front element to show for it. Ever since I've had a multi-coated filter on front of my lens- along with the lens hood.

Count me among the filter-less crowd in much the same spirit as Colin's remarks.

The old UV Haze filters made sense in the color film era where (a) excessive ultraviolet light could fog a film, and (b) there was little that you could do about it after the shutter closed. Those days are past.

If I frequently photographed in blowing sand or nasty environments I'd consider using a protective filter during daytime. But filters, even coated filters, bring their own issues especially at night. If you want to shoot plenty of UFOs just screw a filter on any lens and shoot near point sources at night.

Today's lens coatings are 10x tougher than those of 20 years ago; they can take a bit of a beating.

The eternal quest for perfection has produced some of history's most dreadfully dull imagery.

Dear Ed,

Actually, yes, it does. The effect may be ignorable, but it does alter the optical design. This is not the place for long technical arguments, so if you want to discuss this, email me: ctein@pobox.com

pax / Ctein

I don't use filters to protect my lenses and have never had a lens damaged from not using one. (I suppose I will now, since I wrote that.)

If I were to worry about a freak accident damaging a vital, irreplaceable lens, I'd wear safety googles everywhere.

If anybody is still following this thread, PDN Photo of the Day happens to have several images up by a photographer who is deliberately, massively using flare in her images:

http://pdnphotooftheday.com/2012/07/15714

I don't particularly like these images, but you want flare... she's got flare for you.

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