After I wrote about the Voigtländer optical viewfinder or OVF on the Panasonic GF1 yesterday, our friend Edward Taylor, who has written several reviews of small cameras for us, wrote a comment to the effect that his Lumix 20mm ƒ/1.7 lens was giving him a lot of trouble with flare. "I have never had a lens that suffers as much from flares or backlighting or even light coming around a corner. Contrast is ruined," Ed wrote. When I emailed him and asked him to clarify, he said, "I love the lens, but if a subject is backlit or if there is a bright light source even outside the frame of the photo, contrast is lost and the photo looks washed out. It almost looks like the lens is fogged and a lot of detail is lost so it can’t be fixed in post. It is not an exposure problem as no amount of bracketing will correct it. I have noticed this since I got the camera, and I use it virtually every day."
That didn't sound right to me at all, and I know Ed knows what he's talking about, so I wandered around this morning and snapped off a few quick "flare and glare" tests to help him troubleshoot. (For the terminologically fastidious, "flare" refers to ghosts and other visible artifacts caused by spurious reflections inside the lens or camera; overall hazing or loss of contrast is technically "veiling glare." Hence "flare and glare.") All these shots except the last one are default JPEGs right out of the camera, resized and converted to sRGB for the web but otherwise untouched.
Nine a.m. sunlight on a dirty window, at ƒ/2.8. Not the worst case for backlighting, maybe, but I'm not seeing any problems.
A "100-watt equivalent" compact fluorescent, shot handheld with –3 stops of exposure compensation, with the lens wide open at ƒ/1.7. The picture looks quite a bit darker than the visual impression. No flare except for very slight haloing around the fluorescent coil, which is to be expected. The contrast in the pull chains is fine.
A picture with the sun in the frame, but placed off-center—it's at the edge of the trees but not obscured by branches. This shot was exposed (maybe even a little overexposed) for the foliage (ƒ/2.8). There's a little flare here, finally, but you can see it better...
...in this shot, the same scene exposed (maybe even a little underexposed) for the sky (ƒ/7.1). This is the only flare I was able to get this morning—that purple blob just to the left of the orb of the sun is a so-called "ghost." But the branches show good detail even very near the sun; that deteriorating contrail wasn't visible to the naked eye, as it was lost in the brightness of the sun. Also, if I goose the contrast and brightness a bit...
...you can even see a little detail in the foliage quite close to the sun.
That all looks like extremely good flare 'n' glare performance from the Lumix 20mm to me. In fact, it's one of the standout qualities of this fine little lens, in my opinion. I never worry about flare when I shoot with it.
When I sent him these test shots, Ed realized immediately that there is something definitely wrong with his copy of the lens. He's going to send his back to Panasonic.
If you're having flare 'n' glare trouble with the Panasonic Lumix 20mm ƒ/1.7, you shouldn't be. And if you read out in the wilds of the internet of people having such trouble, you should clue 'em in that their results are not what they have a right to expect.
Mike
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Original contents copyright 2010 by Michael C. Johnston and/or the bylined author. All Rights Reserved.
Thanks for the tip. BTW, I bought this lens on your recommendation, and I like it a lot. Here's a recent shot, marred a bit by a water bottle in the foreground, but it still shows what I like about the lens.
Posted by: Ben Rosengart | Saturday, 07 August 2010 at 03:08 PM
Ask Ed whether he uses a protective filter on his lens. I bet that you do not. The 20mm panny has a reputation for playing badly with non-professional quality filters.
Posted by: Tim F | Saturday, 07 August 2010 at 03:35 PM
Mike -
Thanks again for helping me out with this problem. My lens is packed up and ready to go back to Panasonic.
As an aside, I found myself returning to your photo of "sunlight on a dirty window" several times. It is haunting me a bit, but I don't know why - maybe something from my childhood. I know it was a quick shot for you, but I think the artist in you was on autopilot at the time. I really like that photo.
T.O.P. is the best.
Ed
Posted by: Edward Taylor | Saturday, 07 August 2010 at 03:56 PM
Mike:
Were these taken with or without the lens hood shown in your previous post on the 20mm?
Posted by: Steve G, Mendocino | Saturday, 07 August 2010 at 04:00 PM
Steve G,
With. But these shots would not bring the lens hood into play. Lens hoods are really to protect against acutely impinging light; with long lenses they are often able to be long enough to act as gobos against light sources outside the frame. Some lenses are remarkably susceptible to radically impinging light, so even a shallow hood can help, and never hurts. but hoods really don't help with the light source is in the picture and thus able to strike the surface of the lens directly.
Mike
Posted by: Mike Johnston | Saturday, 07 August 2010 at 04:15 PM
Thanks for all your hard work Mike. And thanks to be passed on to Ctein for his postings.
I have this lens too and I have not noticed any flare. I will shoot a few pics to see if I get any.
There is a page or two on my wordpress thingy about the GF1. I will try the Voightlander viewfinder too!
Posted by: Chris Wormald | Saturday, 07 August 2010 at 04:22 PM
Tim -
I was not using a lens filter. There just seems to be something wrong with my lens or its coating.
I have ordered a lens hood from ebay, but I agree with Mike that it shouldn't make much difference in these situations.
Ed
Posted by: Edward Taylor | Saturday, 07 August 2010 at 04:28 PM
I'm a bit puzzled here, Mike. If what you suggest is true -- some samples of the 20mm lens are more flare-prone than others -- how do you explain the fact that we came to different conclusions about the same lens used on the same GF1 body (mine being the sample you originally reviewed way back when)?
Mind you, I'm otherwise very happy with the performance of the lens and even the small hood I use helps enough to make this "problem" a non-issue most of the time.
Posted by: Jeffrey Goggin | Saturday, 07 August 2010 at 04:50 PM
Since lens hoods for the Panasonic 20 seem to be something that people want I suggest the lens hood supplied for the Voigtländer 40mm f2 SL lens would be ideal for this lens. It is a very compact. I have requested a stepping ring so I can try it but just holding it in place suggests it does not vignette. I am not sure Voigtländer sells this hood separately though.
Posted by: F. Hall | Saturday, 07 August 2010 at 05:52 PM
Jeffrey,
I apologize, I don't recall the specifics of our discussion about this. Although I do try to pay attention when they're transpiring, in time the thousands of such conversations I've had tend to blur together!
There is certainly room for variance of opinion, though, with something as unpredictable and hard to quantify as flare. Every situation is in a sense unique.
Mike
Posted by: Mike Johnston | Saturday, 07 August 2010 at 07:38 PM
Hi,
I use a B+H protective filter on my 20mm and no big issues with flare so far. But it happens, as with all lenses under the circumstances Mike's just described. A couple of weeks ago I got a big ghost full moon when shooting the moonrise over the sea, the moon's brightness was extraordinary that night. But I can account for maybe 4 or 5 cases of flare and 10-12 of glare in more than 3000 pics so far (mostly outdoors in sunny Spain), so I suppose it's not a bad score after all. And without hood.
H.
Posted by: Henry | Saturday, 07 August 2010 at 07:52 PM
Henry,
And that's the filter that caused that. Was the ghost of the moon just opposite the real moon relative to the optical axis (i.e., center of the picture)?
Mike
Posted by: Mike Johnston | Saturday, 07 August 2010 at 08:52 PM
I tried taking the identical pictures of the 27 watt florescent bulb, and did not find any flare when the bulb was centered in the frame, however even small changes in angle produced some flare. I also took test shots at F2.8, shooting directly into the sun, and found similar results as on Mike's samples. It seems like this lens flares when there is a lot of sideways light. I often notice some veiling glare when shooting outside in daylight, so now I am going to use it with a lens hood and stopped down a little and see if that makes any difference. - Thanks!
Posted by: Mike Meskin | Saturday, 07 August 2010 at 09:31 PM
Being an "old fart in training" myself, Mike, I certainly do understand about your not remembering the sum and substance of every email conversation you've ever had. Besides, for whatever reasons, you've come around to my way of thinking and are using a lenshood on your 20mm, so no apology is necessary! ;-)
Posted by: Jeffrey Goggin | Saturday, 07 August 2010 at 10:55 PM
Here is a link to a "glare test".
GF1 with Lumix 20mm:
http://thepubliceyeblog.blogspot.com/2009/10/datura.html
Posted by: Martin | Sunday, 08 August 2010 at 04:46 AM
Mike, I'd suggest you not make a habit of shooting directly into the sun. I'm not an engineer but according to what I've read, it could burn out your sensor.
Posted by: John Haines | Sunday, 08 August 2010 at 09:49 AM
Sometimes the filtre you're using could be the culprit. I only use original Panasonic filters or Nikon depending on the brand. I had the flare problem on my Lumix 20mm when I purchased a cheap filter ND.
Posted by: Luis Gomez | Sunday, 08 August 2010 at 10:24 AM
My experience says, that for most of the prime lenses at least the lens prone to flare is the dirty lens.
I have and use much Zuiko 100mm f/2.8 lens (for OM sys). It doesn't have multi-coating which was used by olympus only for bright wide-angles at a time. And even this lens is not prone to flare. But it is a clean lens.
Posted by: Bernard | Sunday, 08 August 2010 at 06:00 PM
Perhaps Ed can show us some of the problematic photos he has?
Posted by: WLH | Monday, 09 August 2010 at 07:52 AM
This site has some interesting effects related to flare and filter flare.
http://toothwalker.org/optics/flare.html#filter
Posted by: Bill Lewis | Monday, 09 August 2010 at 10:26 AM
Mike: This is too late to expect anyone to read, but the EP2/Panasonic 20mm combination is my favorite camera experience of all time. I want to thank you for the many posts some time ago on the GF1/EP2 and their respective lenses. The shooting experience, for me, is just so much better using this smaller camera. I had a D200, but our home was burglarized and they got it and tons of other stuff. Insurance to the rescue, I was able to get my beloved Oly and 3 lenses, and I'm so happy with it as an intermediate amateur. The Pani 20 is just so beautiful and easy to work with. Anyway, thanks again for mentioning these cameras every once in awhile.
Posted by: Bill Coleman | Monday, 09 August 2010 at 12:48 PM