Haze on lens/ how discernable in final image ?

[greg zinselmeier]

Good morning,

I was hoping you might be able to lend some thoughts on: comparing 2 lens of same manufacturer, same focal length. Let's say this lens covers an 8x10. One lens has slight haze. and one with no flaws. lets say its 8x10 negative shot in the same camera using one negative with one lens, and another negative using the other lens. , etc . . .. b&w, same processing of film, and contact printing, each printed on a seperate sheet for comparison, same type of paper, same developer, same processing. Would any one be able to tell the difference? seeing them side by side? would someone be able to say looking at the one print made from the lens with slight haze and say "there is something wrong with that print! it sucks!!

How does haze from a lens effect the final print? lower contrast, by how much? can't that be corrected with dev. times. or contrast filter?

Has anyone done a comparison side by side or what. . . .?
Can any one scan in image shot with a hazy lens?

My personal opinion, , , , ,I think Its all "Talking points" in selling. "the Confidence gane" bend their arm/ and/or break their knuckles for sub par equipmen ! get it for a lower price!!!

my suspicion is not much, but i do not have alot of experience on this matter to confirm or denie my gut feeling.

In these matters and I am asking you ( PHOTRIO) what is your professional opinion. I thought the severity will effect contrast?T/F?
but what about sharpness?

If I contact print , a POP like a salt print, or using a modern paper by developemnet will i see it ?

Will I feel ashamed because I bought and /or use sub par equipment ( joke)

what about moderate haze and heavy haze? does haze get worse over time? I heard fungus over time spreads, but what about haze? what cause haze? is it from oxidation of . . .. ( something) i.e. grease? or what?


I appreciate a few words of wisdom and guidance? for using a" known lens" that has "haze" . . .. .

 

[shutterfinger]

Flare in side lighting as well as reduced contrast.

 

[Alan Gales]

I've heard that haze can be caused by lubricants in the lens, moisture in the lens, off gassing of cement in the lens and dust in the lens.

Can it get worse? It's possible. I guess it depends upon what is causing it. Will it get worse? Maybe, maybe not.

How bad will it cause flare in side lighting and reduced contrast like shutterfinger says? I guess that depends upon how much haze is in the lens and the lighting in the frame. For example, shoot into the sun and you will get more.

Send it out for a good cleaning. A pro can take it apart and clean out the haze no problem. Get the shutter CLA'd while you are at it.

Or you can shoot it as it is. Maybe the haze won't bother you. Low contrast is nice for portraits. Just shield the lens really well with a lens hood, hat or dark slide to prevent flaring.

 

[bdial]

Much depends on how much haze, in my experience, specifically with a lens I bought last year, the haze reduces contrast by a fair bit and gives a soft look compared to a non-hazy lens. I don't have a ready example at the moment, but I can probably post one tomorrow or so, I still have the hazy lens. I found in testing that lens that a shade helps slightly, but everything still had a "veiled" look. Best to avoid it unless you plan to only use it for soft portraits. Bumping the contrast helped a bit too, but not enough, IMO, to make the lens worth using as-is. Unfortunately it requires a good bit of disassembly to rectify.

On a large format lens, it may be easy to fix if the haze is on the accessible elements in the front or rear cells.

For an extreme example, this photo is made with a Leitz Summacron with a front element that looked to have been cleaned with sandpaper.
It worked out nicely for this particular photo, but was not very useful otherwise. I had a shop polish and re-coat it and it's perfect now.

 

[Sirius Glass]

Lens haze can occur when camera equipment is left in hot cars for many days.

 

[neilt3]

So , are you buying or selling ?!

Haze can be on the surface of an element at any point in the lens , which can be fairly easy to dismantle and clean off .
It can also be in the cement / balsam used two bond to elements together.
The problem there is they need separating , cleaning , and regluing .
Not necessarily a DIY yob , and a more expensive one than that when paying for a repair .

Effects will vary depending on , aperture , severety , subject , lighting and conditions used in .
It's easy to replicate the effects a hazy lens could give you on a good lens for artistic reasons , but if your lens is hazy , you might not get a shot worth bothering with that a lens in good condition would give you easily .

Unless the lens is especially cheap , cheap enough to have it cleaned up , why buy it ?

Don't believe a seller who says it make no difference to image quality .
It can , and what other things are they trying to mislead you on ?

 

[greg zinselmeier]

ya, i'm looking to buy, . . . . . thanks for the advice neilt3- . . . 1. Is there a way to tell on which surface/side of which element it is on? 2. Generally speaking, how much does it cost to have the professionally cleaned ( ball park 100-300 USD?) or this ( 500-1500 USD) ? i suppose it all depends. I was lloking at a Fujinon 250mm F6.7 in Copal for 250 USD, with slight haze! There are other 240's or 250's out there to choose from for 8x10 coverage.

 

[bdial]

Are you able to examine the lens in person? If so, it's pretty straightforward (on most LF lenses) to unscrew the lens groups from the shutter, then you can examine the easy to access surfaces. This, of course, assumes the seller is willing to allow you to do that. A shop likely would, it could be iffy with a private seller. Were I selling the lens, I would, but I'd also, most likely, have already cleaned it.
If the haze looks to be on some internal surface that needs retaining rings to be removed to access, I'd likely pass on that lens unless it's something special, that I really, really wanted/needed. There are a lot of "garden variety" large format lenses around that are in good condition, and great pictures can be made with any of them.

As for cost, if it's a matter of removing a retaining ring or two, it's probably in the < $300 realm for someone who knows the lens and has the tools. But, just the cleaning is probably not cost effective vs servicing the shutter too. Even for both you're probably still in the <300 realm. For separating elements and re-cementing, probably more, nowadays, presuming you can find someone who could do it, and the lens is special enough.

 

[Nodda Duma]

Haze causes two effects: The primary effect is loss of contrast due to forward scatter. In addition, haze obscures i.e. reduces the effective clear aperture, which impacts the MTF of the optical system. As a general rule, obscuration of ~13% of the surface area of an optic will result in a noticeable degradation in image quality to the average observer or viewer. A more experienced observer will notice degradation with less of the clear aperture obscured. This is a significant amount of obscuration, but there is an impact.

For the amount of haze we generally see on used optics we use, the impact of haze is primarily loss of contrast due to forward scatter and for a given amount of haze on a lens is non-deterministic. Another way to say that is that you cannot tell what the effect is until you put it to use. It'll either work for you or it won't, and it's difficult to judge the impact just by observing the amount of haze (if it's slight.. if you can't see through the lens it's going to be pretty obvious that the imagery will be screwed up).

The only real trend is "the more haze, the greater the potential for adverse effects".

I have a recent example of this, with a Cornu Ontoscope that I just acquired and ran some dry plates through.

This is a stereo camera from the WW1 era, and in this pic the lenses appear fine. However, viewing through the open aperture showed the lenses had haze / contaminants on the optics. By visual appearance, they showed about the same amount of contaminants on both the left and right lenses. This provides a unique opportunity to remove all other variables to demonstrate this non-deterministic property of "haze" and other contaminants. Shot at the same time, with same lighting conditions, with optically-matched lenses, so the only real difference is the distribution of haze and contaminants on the lenses. However, scans reveal a significant difference in the image quality between the two lenses. Rest assured this image is fresh off the scanner without modification except to reduce the resolution so it can be uploaded here.

On the left, you can see a loss of contrast due to forward scatter (above and beyond the halation inherent in the dry plate).. there is low contrast in the lower right shadows of the big rock and rock wall on what is in fact a higher contrast emulsion.
On the right, there is significant loss of contrast as well as loss of high spatial frequency information i.e. details.

Again.. the haze / contaminants on the lenses visually appeared very similar. This is why I say it is non-deterministic, and you won't know until you try.

The rest of the story is that after seeing this, I stripped down the optics and cleaned them. Here is the result with the optics restored (ignore my poor focusing .. still tracking that issue down), and the camera taken back to shoot pictures in the same area the following day (so lighting is similar).

This is also a straight scan (same settings) with nothing done to the image except to scale down for posting here. Pretty obvious the contrast has significantly improved and the image quality is consistent on left and right.

So to recap...

1) Haze always degrades contrast and image quality. Below a certain threshold the effects are not noticeable.
2) You cannot determine the impact by visual inspection. It is a non-deterministic effect and varies on a case-by-case basis.
3) The only trend that can be inferred is: the more haze the more likely you'll have a problem.
4) If the degradation is noticeable, clean your optics carefully. You will see improvement.

One more comment:

Haze due to contaminants.. i.e. outgassing mentioned above, can be cleaned off with little more effort than getting to the lens surfaces to be cleaned. (by the way, very little attention is paid to this in the consumer world since cost is everything, but outside that industry optical designers pay very close attention to the problem).

Haze due to surface damage cannot be cleaned. The surface damage has to be polished off. Coated optics are actually easier to address, because the damage is typically limited to the coating. So to fix the coating is stripped off via pitch polishing, and then either left off or recoated.

We've all toyed with the idea of getting a hazy lens at low cost.. sometimes successfully, sometimes not. In the end, it's a crap shoot unless you have a way to address the problems caused by haze when you get the lens into your hands.

-Jason

 

[gone]

It wouldn't be possible to venture a guess w/o seeing how bad the haze is, so a pic would help. I had a Summar that was hazy. It performed just as the urban legend said it would: very soft images w/ lots of flare. I sent it to be cleaned, and afterward it was one of the sharpest lenses I'd ever used. The Summar urban myth is just that, a myth. Get a clean one and you'll be blown away. Probably my favorite M mount lens.

 

[greg zinselmeier]

I very much appreciate everybody's imput, thannk you Nodda Duma for chimming in, . . . I was considering buying a fujinon 250mm f6.7, with some haze from Japan ( i can not inspect), but i am NOT doing that! considering the cost to bring it up to speed. The Fujinon 250mm 6.3 does not have the same coverage, even though there are plenty on the market right now... However I looked on LF photography page on Lens Comparison Chart. It looks like Nikon W 240MM has a nice image circle for that length of lens. I saw a couple on the poplular site that looks reasonable. again, thank again for every ones thoughts and suggestions. they have been very helpful. cheers.

any other suggestions for that length for coverage of 8x10 is welcomed.However, I am looking to spend under 500 USD. I can not afford anything too Awesome!!

 

[ic-racer]

Flare has been studied for decades. Flare is a integral portion of the tone reproduction cycle.
Measurement schematic:

Measurement device:

Results; Aperture vs percent flare:

Results; Aperture, vs light axis vs percent flare:

Representation of flare in the MTF method:

 

[Arthurwg]

It wouldn't be possible to venture a guess w/o seeing how bad the haze is, so a pic would help. I had a Summar that was hazy. It performed just as the urban legend said it would: very soft images w/ lots of flare. I sent it to be cleaned, and afterward it was one of the sharpest lenses I'd ever used. The Summar urban myth is just that, a myth. Get a clean one and you'll be blown away. Probably my favorite M mount lens.

Hoping for the same when my Summar comes back from Youxin.

 

[StepheKoontz]

I will take a lens with surface scratches over haze any day of the week. Light internal dust or scratches aren't likely to even be seen in use but haze just robs a lens from being able to perform. If you are having to jack up contrast grade or change development times because of a len defects, clearly it is having other negative impacts on the image.

 

[craigclu]

Don't underestimate the effects of even a very slight haze. It's bad in camera lenses and even worse in enlarger lenses.

 

[Kodachromeguy]

The Summar urban myth is just that, a myth. Get a clean one and you'll be blown away. Probably my favorite M mount lens.

Are you referring to the 5cm f/2 uncoated thread mount Summar lens? Wasn't this discontinued years before the M era?

 

[John Wiegerink]

Are you referring to the 5cm f/2 uncoated thread mount Summar lens? Wasn't this discontinued years before the M era?

Adapter!!!!!!