Flare Champion

[joe_pelizza_salusso_di_vol]

In your experience, amongst all Leica lenses, which is the most flare

prone?

Joe

[kaiblanke]

I would vote for my uncoated, dirty and scratched Summar lens. Although it produces nice effects on portraits under very controlled conditions, it is almost unusable if the sun is shining.

[jonathan_reynolds]

At the risk of high-jacking Joe's thread, please may I add another question: at each focal length, which is the LEAST flare-prone M-fit lens, Leica or otherwise?

[brentdlong]

Yes, yes, yes... the 50/2 Summar, uncoated! Absolute champ... and a lovely lens for it... with practice and patience!

[steve_unsworth1]

Same reply as on Leica's forum - most flare prone Leica lens that I own is my Tri-Elmar :-)

 

Least flare prone M lens that I have is the Noctilux.

[mskovacs]

What is the optical design (elements/groups) for the Summar and Summitar? Zeiss lenses at the time (e.g. Tessar 4/3 & Sonnar 7/3 or 6/3) had only 6 air/glass interfaces.

[mskovacs]

Also, its probably a t/stop difference due to the reflections, but I find that I need to develop films from my uncoated 50/1.5 Sonnar longer or I get negs that are thin. I'm guessing its probably about a t/2, resulting in 2/3 stops of underexposure due to the lower light transmission from internal reflections.

[albert_smith]

My first Leica lens was a M mount Summarit. I was expecting magic after reading over and over about the Leica greatness. I should have done my home work better. The Summarit was not bad after you got down to f/4 or so, but wide-open if was very flarey and a bit soft. FWIW, the glass was flawless, crystal clear in this lens, but it was still outclassed by every 50mm lens I had ever used from any company. Getting my first Summicron was such a shock, and the Summarit was sold to a collector (it was pristine).<P>

 

An example of a front-lit subject shot with the Summarit at full aperture can be seen here:<a href="http://d6d2h4gfvy8t8.cloudfront.net/935765-lg.jpg"> LINK </a>

[gaijin]

My vote would go to the pre-asph (1st version) 35mm f/1.4 Summilux. Mine was the flare champion of the world.

[blakley]

Look <a href="http://www.photo.net/bboard/q-and-a-fetch-msg?

msg_id=00A37J">here</a> for an example of flare from my "fat" tele-elmarit 90. It's

pretty bad.

[dan flanders]

I know this sounds like a broken record but I keep preaching that a properly designed rectangular shade can do wonders for a flare prone lens that is badly served by conventional circular shades. Circular shades leave peripheral area nearly the same size as the main image format unprotected from stray light that bounces aroud inside the lens doing no useful work. If they are deep enough to protect the central image, they crowd the corners and produce vignetting. The rectangular shade permits the depth necessary to prevent the flare without cutting the light rays off at the corners. It is simple logic regularly ignored by many who should know better.

[Rob F.]

Adding a rectangular hood to an older lens not originally supplied with one, is a good idea in theory. But then there is an issue of how to maintain proper alignment of a rectangular hood on a lens that has no provision for holding the hood captive in the proper position.

 

As an example, the 12524 hood for the version IV 35mm Summicron, will lock in place on a 50mm collapsible Summicron, as well as on a 35mm version I. But it is free to rotate 360 degrees. The extra flare protection would have to be weighed against the likelihood that it will have drifted unnoticed to a cockeyed angle, spoiling the picture.

 

I'd say that needs to be solved before converting to rectangular hoods. Maybe someone could make a clamp-on hood that stays put.

[dan flanders]

I suppose if you are going to confine yourself to the stuff you can buy in a camera store you will be forever compromised by the limitations of OEM gear. It is easy enough to make a bracket that cilps into the accessory shoe or the tripod socket, projecting forward to hold the shade over the end of the lens but free of its rotation. Most quality lenses today are rectilinear and not subject to that limitation . I sometimes use a Kiev and have rigged a bracket to accommodate its rotating lenses but I also use a similar gadget with my old Elmars and Amotal on my Leicas. A little imagination and ingenuity is all that is needed to ovecome such limitations.

[mskovacs]

Also problematic are lenses that rotate the front when you focus them. I have a rectangular 42mm slip-on shade for my prewar Zeiss 50mm Sonnars which is effective, but requires repositioning after a focus change.

[dan flanders]

MIKE: What would it be worth to you to have a bracket that would solve that alignment problem? <p> Also the issue of the rotating shade on a rectilinear lens is easily solved with a rubber band or a couple of drops of epoxy. It is my experience that most parties who raise the issue seem more concerned with the aesthetics of their rigs than of their results. Perhaps it would be profitable to establish a consulting service for those who are sincerely concerned with the gear's limitations and desire a practical solution.

[jonathan_reynolds]

Harry, on this page (http://www.luminous-landscape.com/columns/sm-03-01-12.shtml) Mike Johnston writes:

 

<<By the way, a common misconception about lenses is that you need the longest possible hood to protect the lens. This isn't necessarily so. With some lenses, acutely-impinging light is the biggest cause of flare, more so than more directly impinging light. A short lens hood which protects the lens from this glancing sidelight will serve well to reduce flare, even though it's relatively useless at protecting the front element of the lens from direct light rays.>>

 

I wish you would convince me that a better hood will really reduce the problem with the current Summicron 50/2. But I'm willing to experiment. How do you arrive at the correct dimensions? Is it just trial and error?

[dan flanders]

It certainly isn't scientific but a pragmatic method is to make a cardboard template of the lens's nominal angle of view and cut off the apex to approximate the image's height. Assuming that the depth of the hood should equal the width of the image (and this is purely an assumption, not necessarily a fact), placing the template in front of the lens should indicate the height of the hood opening. Repeating with the apex folded to the width of the image should give you the width of the opening. It is true than many shades are marked as adequate for a couple of lenses, for instance Leica often specifies the same hood as effective for both 35mm and 50mm lenses. It stands to reason that a hood effective for a 35mm lens will be less effective for a 50mm. However if the shade is rectangular it will certainly be more effective than a circular one that if deep enough to not vignette will admit flare inducing light above, below, and to the sides of the immage area. I use the 12526 shade on my 50mm Summicron and it has prevented flare under conditions that would have been troublesome with the 12585. I am sure that there is a more scientific method of determining the ideal shade but I am satisfied that the pragmatic method is more effective than any of the circular shades usually provided. The circular shade that is part of my Leitz swing-out polarizer is a monster that not only blocks the viewfinder, but is notoriously ineffective when used on my old collapsible Summicron. I fixed it by installing a mask the shape of the image format in front of the filter. It helps, but a proper rectangular shade would provide better shielding and less interference in the viewfinder.

[jonathan_reynolds]

Thanks, Harry. Apologies for my complicated mind, but does your 'angle of view' that defines the slope of the lens hood sides originate at the film plane, or from the optical centre of the lens (wherever that is), or where?

[dan flanders]

An unscientific answer is that I use the front of the bezel as the starting plane and radiate the acceptance angle of the lens from the sides of the scene format. It seems to me that the shade should prevent all light outside of the acceptance angle of the lens from reaching the front element. I am aware that difraction modifies the angle of light entering around a sharp edge, but in the practical sense it can be confined to the amount of falloff tolerated at the corners. I don't pretend that this is a precise method, but it has proven to me that much of the reputation of the old collapsible Summicron for flaring can be negated noticably with the adoption of the 12526 or similar rectangular shade.