Strange Lens defect on Olympus 35 SP. What is it?

<p><img src="http://www.photo.net/photo/15344392" alt="" />Hi!<br>

I recently got an Olympus 35 SP RF on ebay. Sadly, despite being described as "clean", the lens had this strange blemish in it (I should say somewhere under the second element?) which unfortunately comes up in the lower center of the picture as an irregular blotch. I got a 60% refund, it is true that the defect can be missed when looking head on, it is more clearly visible when viewed at an angle. Could it be a balsam of Canada problem? The rest of the camera is in great shape (incl. the meter) but how easy is it to find a junker SP with a clear lens to use as spare? Go figure... Any ideas as to what this might be? (www.photo.net/photo/15344392). I somehow can't upload the actual image here...</p><div></div>

<p>It looks like a lens coating blemish on the top surface of the front element. Have you looked closely at it with a high powered loop? I have this type of blemish on a couple of my lenses and have detected no effect at all on the negatives. I'm very surprised this is showing up in your photos. Can you post a sample photo showing the blob on a photo?</p>

That could be fungus. If so, then as-is it shouldn't affect your photos; the problem is that it's difficult to kill off completely (even if you kill this growth, further spores can lie dormant within the lens assembly) and it can permanently etch the lens coating if left unchecked.

The SP doesn't have the front elements glued together so it isn't a problem with balsam separation. It looks like a flaw

in the coating. If it is shaped something like a snowflake, and has a silverry appearance, it is a flaw. If it is dirt or

debris, it is not hard to open the lens to remove it. The glass and coating of the SP lenses is very good, and fungus

can usually be removed with a bit of toothpaste without damage. If the problem is a coating flaw, it won't polish out,

but, on the other hand, these flaws usually have no effect on the images. I have an old Rplleiflex 2.8C which has

several of these marks, yet still takes stunning photos.

<p>First, I agree with others that such a surface defect will show up in the image, except for extreme backlighting situations where it might cause flare. <br>

Second, if it is fungus, I would not try to remove it with toothpaste. I removed fungus successfully several times with vinegar, or concentrated vinegar if it does not work the first time. Moisten a q-tip and the fungus probably will be gone in a few seconds. To avoid further grow, keep the camera in a dry environment and avoid storage in organic materials such as cotton, leather or wood.<br>

If it is a coating defect or a blemish on the surface there is no way to fix that, except for swapping the front lens element. But in this case you would have to re-adjust the lens and the rangefinder. </p>

 

<p>A 60% refund for a minor problem is a pretty good deal. I wouldn't worry about it unless it really is fungus. Imperfect front elements have very little impact on images under most conditions. An online rental site has a demonstration of a lens with a badly cracked front element, with surprisingly little effect on most images.</p>

 

<blockquote>

<p>"I have an old Rolleiflex 2.8C which has several of these marks, yet still takes stunning photos."</p>

</blockquote>

<p>I had a Rollei 2.8C with the original owner's thumbprint etched into the front taking element. It had no effect at all on photos, even in daylight shots with the sun in the frame. The seller (not the original owner) clearly pointed out the flaw to me and offered an irresistible price.</p>

<p>oops... should read "will NOT show up" in my posting. So the rest of the phrase will make sense, too.</p>

<p>Just a missing piece of coating I'd say, no biggie, shouldn't cause any problems to your photos. This certainly doesn't look like fungus, so a strip down won't be required. I have found that the SP benefits from a lens hood as the front element is quite forward.</p>

<p>I understand you can kill lens fungus by heating the lens to around 115F for a few hours. That sounds plausible to me.</p>

<p>If you want to polish a flaw in the lens surface, Zeiss recommends rubbing with cigarette ash.</p>

<p> </p>

<p>Yes, camera repair can be very easy... I would never try the heating procedure to kill fungus. Heat will make any grease in the lens more liquid. Maybe the fungus is gone, but maybe the shutter and/or aperture blades are oily and will not work any more. </p>

<p>Never heard about any re-polishing hints recommending cigarette ashes from Zeiss. The coating layer is very thin and very probably will be more damaged by any abrasive process. </p>

<p>Thanks a million. I have medical training and this is too sharp and acutely defined to be a fungus colony. Usually they are like multiple branching strands in the periphery of the lens and I have never seen them in isolation. This is silvery when observed at an angle but very faint when looked at straight on and it has a sharp contour. All this is supportive of it being some coating defect i think. I seem to have misplaced the test photos and the negatives I took, but there was definitely a small blotch showing on both the prints and the negatives very low in the image, the defect on the lens being relatively central. I will take some more photos and see what they come up like. What would be the situation most likely to reproduce the blotch if it really is a coating defect? </p>

<p>Winfred, it's safe to heat any lens to 115. I once had my entire lens collection (and their copiously dripping owner) in that sort of heat every single day for two entire weeks. No harm came of them, and their owner managed to live at least another few decades. Trust me that lenses are designed to withstand the hostile environments where we use them.</p>

<p>As for the cigarette ash, I've never tried it. However, that's what CZ does recommend somewhere on their website. They also say not to expose lenses to less than 40% relative humidity, but I apparently missed that advisory. (My gear survived many years of those conditions, too.)</p>

<p>Fungus has to be cleaned, killing it should be the first step in the process. That being said, since it simply sounds like it is likely to be a coating defect, I'd just watch it for changes. The only time it should show up in the frame are in situations you want to avoid anyways; with a strong light source in the image, it may cause odd flare. </p>

<p>Er... correction... That 40% should have been 30%. Sorry for the typo.</p>

<p>Again, I have severe doubts that such a coating defect will show up in your image, let alone causing any blob-like structure in the image. <br>

"Blobs" (circular or rounded spots brighter than the background) can be caused by internal reflections of the lens assembly. They will rather show up in backlighting situtations, but sometimes just with certain postions of the light source and certain aperture settings, so it will hard to reproduce them. Even coated lenses will show this effect. Sometimes you can even see a series of blobs on a line pointing to the light source, sometimes these spots have a shape similar to the iris of the lens. </p>

 

<p>Definitely, not fungus. More like impact?<br>

These defects do not show in pictures at all unless extreme backlighting, and then, it might even help.<br>

I have an Olympus Pen D3 with a similar defect in the lens, that's why I got it for half price. Pictures are perfect. <br>

In any case you should use a hood with the 35SP, that lens is excellent, but tends to flare easily. </p>

 

I have repaired a couple dozen Olympus SP cameras, and I have found regular toothpaste carefully applied with a

damp Q-tip to be the best way to remove fungus without damaging the coating. The only difficult part of the operation

is that to remove the lens you need to pry off the name plate on the front of the lens, as it is glued in place. About 1 in

10 SP cameras have a name plate which threads in. If the plate has only one hole it is the glued in type. If it has two

holes, it is the thread on type, and can be removed with a lens spanner. The front element group can be removed with

a pointed spanner, and the front element can be removed by removing it's lock ring. If the spots are on the inside of

the rear element, it is often easier to remove the rear lens group from the back of the camera. The rear lens group can

also be separated for cleaning if necessary. The hardest part of the operation is keeping the dust out when the lens is

opened up.

<p>A dark blob on the negatives is more likely to be dust inside the camera body than anything on the surface of the lens.</p>