View Full Version : A Lens Testing Question for the Experts

Brian Ellis
2-Apr-2006, 22:39
I recently sold an 80mm Schneider Super Symmar XL lens that I bought from Midwest Photo Exchange a couple years ago. The serial number was well past the numbers of these lenses that supposedly had the infamous "soft focus wide open" problem and the lens always seemed to focus wide open just fine to me. The purchaser wants to return the lens. He says that when he opens it up and focuses it on a street light at night he sees a halo around the light that disappears when he stops down a stop or two. He says this means the lens has the "soft focus wide open" problem.

I'm going to return his money, I never want someone to be unhappy with anything I sell on ebay, so I'm not asking whether I should do that or not, I'm going to do it regardless. I also plan to send the lens to Jim at Midwest and ask him to look at it again. But in the meantime, I'm curious - is the halo that this person says he observes when the lens is wide open and focused on a street light at night a true indication that the focus is in fact soft when the aperture is wide open? In other words, is this a valid test for a "soft focus wide open" problem?

Jack Flesher
2-Apr-2006, 23:41
I think you can be comfortable it is.

However, I've owned two of these lenses, one of which was the soft wide open model, and it was plenty sharp stopped down. I sold it thinking I would rather use my (cheaper) 90 and soon missed it, so I bought another. Truth be told, I wish I had the old one back since I happen to like the ability to get the soft look if and when I want it...

My .02,

Christopher Perez
3-Apr-2006, 09:20
Schneider should be able to replace that lens with a better example.

Anyone have any ideas on how many of the 80SS-XLs were incorrectly built like this?

Joseph O'Neil
3-Apr-2006, 10:30
I've never used this lens, so I am stepping firmly into "foot in mouth" territory, but here goes some comments & questions from the peanut gallery...

- I know expectations on this lens are pretty high, but I personally have never believed that any lens is "perfect" wide open under "all circumstances" - and that includes a Zeiss Biogon I once used. I've never found any lens to be perfect, form 35mm, 120 or 4x5 use in every single situation.

A street light at night? Different situation, IMO, than "regular use". I mean, if we are all going to get super nit-picky, I used to do astro-photo work with a wide open lens, on 4x5 sheet film, and i can almost certianly gurnatee you that no LF lens, wide open, will give you even, pinpoint stars right to the very edge of the image circle. I've seen others do the same, and yes, the Zeiss biogon "fails" the star test. How you get a sharp image is you use a lens that has an image circle for 5x7, and use 4x5 film, so that the optical "failure" at the edge of the image circle stays off your film.
So where do you draw the cut-off? Somebody can always develop some kind of criteria or situation where a lens, no matter how expensive it is, can fail.

- If we use the "streetlight at night" test as standard criteria, then I would have to say, from first hand experience, that many lenses would fail the "soft focus wide open" test, including some "classic lenses" that otherwise get rave reviews. I've done plenty of night shots - land shots - with my 4x5, and I often found I had to stop down one or two because of light sources. At least, for me, and what I peerceive to be acceptable.
I guess perception is part of the issue. For sake of arguement, I wonder if that new, very expensive 229mm lens from Cooke Optics would "fail" the wide open test. Yeah, I know, I'm being silly here - as it's a soft focus lens to begin with.

- last thought. Depending on how "bad" this problem is, and considering Cooke charges a premium for a soft focus lens to begin with, like one of the previous posts said above, isn't a lens that gives you both sharp and soft focus something of an advantage to begin with?
Like I said, perception. Maybe the fault is not always the lens but the marketing surrounding the lens and the overly high expectations of it's performance - notwithsanding the fact there are/were Super Symmar lenses that had real problems, so in no way insulting or downplaying that fact or the people who suffered through them .

Too bad there isn't a buy/sell department on this list, as sometimes i think Ebay isn't all the great to begin with - and yes, I use it often myself. But that's another story.


Brian Ellis
3-Apr-2006, 10:55
Thanks for the comments. I perhaps didn't make one thing clear. The buyer isn't claiming that the lens is unsharp stopped down and he isn't claiming that photographs made with it wide open are soft. Neither he nor any other LF photographer is likely to actually make a photograph with this lens wide open. The sole issue is the ability to focus with it wide open. He says the "light at night" test demonstrates that it's soft wide open and therefore not suitable for focusing when wide open. I used the lens and never had a problem focusing wide open under normal conditions so I was just wondering if the "light at night" test was valid and indicated that I have been missing something. Thanks again for the responses.

3-Apr-2006, 11:39
i just wonder what his frame of reference is. every large format lense i've seen is soft wide open. schneider's data shows that the 110 xl is very soft wide open. softer even than the older design super angulons.

Michael Mutmansky
3-Apr-2006, 11:56

It sounds like he is tryng to equate flare resistance with sharpness, and it's not a good thing to do. It's common that higher speed lenses will often have a bit worse flare, which in most cases results in a lower contrast lens, but when shooting under the conditions that are discussed here, can result is visible flare. In other words, I don't think this is a valid test for sharpness.

The issue isn't whether the lens exhibits flare (as long as the flare isn't overpowering the primary image, which is not my understanding of the problem with the 80 XL as mine doesn't exhibit the problem) but whether the primary image is sharp. Looking at a light source is definately not how I would determine this. I would be focusing on a good strong contrast 'target' that has edges or lines of small enough detail to determine if they are actually rendered on the GG sharp enough to actually focus.

Even in the example cited by the buyer, there may be flare visible, but was the light source sharp or not? If not, the lens may have the problem, but if so, then he is simply seeing flare from a very bright light source on an otherwise very dark background. I think it would be easy to expose a sheet of film at maximum aperture and see the results for real. Looking at the film with a good loupe on a lighttable will make it plainly clear if this is a case of sharpness or flare resistance.

Did you ever hear about the widespread failure in windshield glass that happened in the Pacific Northwest many years ago? It seems that a news report alerted people to a potential problem, and everyone went outside and inspected their windshields very closely, and lo and behold, suddenly there was a preponderance of pockmarked windshields out there. It turns out people just don't look too closely at things until they are alerted to a potential 'problem'. I think much can be said about that with respect to this lens and it's reported maximum aperture sharpness problems. Yes, there was a problem with a batch, but...


Henry Ambrose
3-Apr-2006, 12:49
I don't think its a reasonable test. The lens is made to make photographs -- not to pass a fuzzy test of focusing under artificial conditions.

Chances are he's never seen more than one sample of the lens (I suspect few of us have) so how would he determine that this is the "definitive" test? I think anyone would need lots of experiemce with many same model lenses to be able to determine the "definitive" test for that lens. Even then this is kinda like looking for dust in a lens - if you look hard enough they're all dusty inside.

If he had tested the lens properly at working apertures and found it to be not sharp (perhaps resolving less than an average lens) then he might have a legitimate complaint. Still if he's not tested a large number of this particular lens (or has had tons of experience working with high end stuff) he has no real basis for comparison.

My 80XL is not crispy sharp wide open but I can focus it just fine in any situation I've ever needed to. When stopped down its super sharp - I'd never think of selling it unless I was quitting 4x5. And I've never even considered testing it - there is simpy no need when I can look at the film and scans and prints and see that they are excellently sharp.

You're to be commended for being honorable in taking it back.

Joseph O'Neil
3-Apr-2006, 14:27
Hi Brian;
Another thought reading everyone's comments - I operate a retail business, and sometimes you run into "buyer's remorse" wherein a customer realizes they really don't have the money for the purchase, and for whatever reason, instead of just returning an item, they have to find a flaw in order to save face.

Especailly rampant amoung men who forget to hide the Visa statement from thier wife after claiming they don't have the money for a new refridgerator or carpeting or to fix the A/C on the wife's car, etc, etc. :)

tounge in cheek mode = on

If you are really still at a loss, loan it to me for a few months, I'll be happy to test it out for you - totally free of charge. I think you would find several helpful souls on this list who would be happy to do the same, all free of charge of course.
(big evil grin)

Your story kinda reminds me of one car dealer told me long ago. A customer complains his new sports car wouldn't do 100 mph and wants to return it for refund. When the dealer asks where did he ever try driving at 100 mph to begin with, the customer says on those old gravel roads out in the far end of the country. The dealer says you cannot drive anything, even a tank at 100 mph on those roads they are in such poor shape. The customer responds to the effect that if he drives that fast on the paved roads, the cops always nail him for speeding.



Conrad Hoffman
3-Apr-2006, 15:40
I don't buy it. The eye is non-linear. It's entirely reasonable that you'll see a halo, flare, or spill, with the lens wide open, and this has nothing to do with any soft-wide-open problem. You can't see it stopped down just because it's dimmer and the eye is less sensitive. Not that the problem may not exist, but the test is bogus.

John O'Connell
3-Apr-2006, 16:41
You're a good man for taking it back, but the test is bogus. The bad lenses, as far as I know, were nigh-impossible to focus wide open. Your lens doesn't sound like that.

At working apertures, by the way, the Perez/Thalmann lens tests showed the bad Super Symmars to be just as fine as the good ones:


If the buyer was comparing it under the same conditions with a known bad sample, fine. If not, I don't think the test means anything. Hell, I've got a 105/1.8 Nikkor that does the same thing with light sources.

It's too bad Schneider released those bad lenses.

Michael Gudzinowicz
3-Apr-2006, 20:46
The "test" protocol makes you wonder if Marion Post Walcott used defective lenses...