Help!!! Lens damage on Canonet QL17 GIII?

Isaiah Dominguez

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Just purchased a canonet ql17 giii and I looked at the lens with a flash light and noticed what looks like fungus or a scratch and on the rear glass a white hazy circle hard to show but it is not a reflection. Will this affect the picture?
 

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Stan160

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I've got a Nikkor 105/2.5 - a highly regarded lens - bought cheaply on approval with very noticeable coating damage and scratching on the rear element. The glass looks awful.

I set up my DSLR on a tripod, took some comparison shots of a variety of subjects in different lighting conditions with the 80-200/2.8 I owned at the time (another highly regarded lens) set to 105mm.
Viewed on a good monitor at 100% there was no visible difference in quality and I happily kept the lens. No issues on film or digital since.

I've heard front element damage is more likely to be visible, but no experience of that.
 

Don_ih

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Rear element damage more easily shows up in a photo. Front element damage more easily flares a photo. If you can see through the lens fine, it'll take an ok photo.

Take the rear element out and clean it. Make sure you have it facing the right way when you put it back.
 

gone

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Fungus, coating deterioration, that needs to be cleaned off if possible. If the glass has been etched you'll probably still be OK, the main thing is to get the lens cleaned as well as possible. It still might turn out to be a great lens. I've had lenses that had all sorts of nicks, scratches, gouges, etc and they made nice photos, it's that hazy stuff that needs to be cleaned off. Be sure to wipe everything down internally w/ something to kill fungus spores that are probably in there in other places or it may come back, eventually. Hydrogen peroxide and ammonia, vinegar, etc will usually clean the fungus off.

They went w/ a total tear down on this lens, but it's seldom required.

https://petapixel.com/2016/09/29/remove-fungus-lens/
 
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AgX

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I see in those photos neither fungus nor coatingg damage, though I cannot exclude the latter (though it won't matter anyway). But what I see would trickle me to clean the lens. On the other hand getting to those lens elements would not be an easy job for me, thus I would have to weigh hassle and risc against clean optics.
 

BrianShaw

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People need to stop looking through lenses with flashlights; all that does is activate their neurosis!
 

MattKing

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Thread title updated for specificity
 

KinoGrafx

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Good luck trying to find ANY used lens that doesn’t look like a horror show when backlit with a flashlight….
 
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Isaiah Dominguez

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BrianShaw said:
People need to stop looking through lenses with flashlights; all that does is activate their neurosis!
Click to expand...
I'm asking if it's fungus, I have no idea. New to photography and cameras thats why I joined this forum. Thx tho, YouTube told me different several recommend to check the lens with a flashlight when inspecting a camera.
 

Don_ih

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Shining a flashlight through a lens always makes it look bad. A better idea is to open the shutter (I assume that has a bulb setting) and look through the lens at a lamp. If you can see through it clearly, so can the film. The reason scratches don't show up on pictures is because the lens is not in focus. Things on the rear element can cast shadows on the film, though, so that's more of an issue. The rear element is removed by uncscrewing the retaining ring behind it (it has two little notches in it for a spanner) - it might turn off easily.
 

BrianShaw

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Isaiah Dominguez said:
I'm asking if it's fungus, I have no idea. New to photography and cameras thats why I joined this forum. Thx tho, YouTube told me different several recommend to check the lens with a flashlight when inspecting a camera.
Click to expand...
I understand…

Suggest you put some film in that Canonet and shoot some pictures. It’s a fun little camera!
 

NB23

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Just shoot away. Print. Become this great artist. Become an influencer. Create a NON FUNGIBLE TOKEN, then die like a legend.

Yes, all this is possible with a spot on your lens.
 

KinoGrafx

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Isaiah Dominguez said:
Glad it amused you tho... and thx for wasting my time and yours with that reply.
Click to expand...
Sorry didn’t mean to offend- do load it up and shoot a roll, then you can see if the lens issues affect picture quality at all. I have an ancient brass barrel lens that has a chunk of glass actually broken out from an interior element, and I still get great photos from it!
 

MattKing

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Isaiah Dominguez said:
Glad it amused you tho... and thx for wasting my time and yours with that reply.
Click to expand...
You will find that if you post here showing a test of something, you will often get a response about the test itself. It is one of the challenges inherent in communicating over the internet.
The "flashlight through the lens" type of examination is always challenging - it reveals a mixture of useful and not so useful results, and tends to make everything look worse than it should. Most of us who have been around a while have seen a lot of "false negative" results from it.
I too recommend you have some fun with that camera - by using it.
 

AgX

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BrianShaw said:
People need to stop looking through lenses with flashlights; all that does is activate their neurosis!
Click to expand...

Well, you made a point.

KinoGrafx said:
Good luck trying to find ANY used lens that doesn’t look like a horror show when backlit with a flashlight….
Click to expand...

I got practically all my lenses from rummage boxes amd fleamarkets. And nearly all my lenses passed this test as pristine after cleaning the front and rear surface. Few got etched-in fingerprints or buffing scratches on the front surface. Very few a bit of fungus inside and even less got a haze issue, here typically integrated Super-8 lenses. One got a dead beast inside.
 
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Don_ih

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All my RB67 lenses looked like a spider had gone in and made a nest inside (it was fungus). I cleaned it out of all of them. They're great - except for the shutters.....
 

__Brian

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It's probably a bit of condensation that dried. Shoot a test roll. Will most likely have no effect. Not worth risk of damaging the glass or misaligning when reassembling to attempt to clean. The front element of this camera is very thin, and prone to cracking if you overtighten. Always be careful of working on any lens, but especially the front element of this one.
 
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