Is this Haze or something else?

[kb244]

Hard to capture and I only really see it if I look at it from an angle against light rather than straight thru (also there appears to be a tiny pin prick size of a bubble inside the element)

Seems like it's in the middle of the rear element.

Youtube Video :

On the Canon 50mm f/1.8 Type-6 I just got.

Still frame from about 4 seconds.

 

[tedr1]

What I see I would put under the heading "blemishes" rather than haze. Haze usually refers to something even and diffuse with no structure and usually quite faint.

This kind of thing is not uncommon with older lenses. Most of the time it is not too serious, the blemishes are located at a place that is out of focus.

 

[John Koehrer]

Bubbles in lenses were considered a sign of quality once upon a time.

 

[jimjm]

I agree with ted. That looks pretty insignificant and won't have any visible effect on your photos. Haze shows up as a overall cloudiness on the glass and can reduce contrast or increase flare in your images.

Yours looks like a few dust specks or small air bubbles. Air bubbles are not uncommon in some older lenses, and have no effect at all.

 

[kb244]

A link to the thread over on RFF, which for the most part has reached the same conclusion.

http://www.rangefinderforum.com/forums/showthread.php?t=159229

Also when adapted to my digital, I could see nothing that would suggest an optical issue.



At ~ 3 feet / 1 meter (using a Fotasy LTM to Micro-4/3rd adapter)

Fotasy Adapter + short Extension tube (since that would usually exaggerate any anomalies)

Thru the back window, going from f/1.8 to f/16

I have a lens spanner on order, so once I get that I can unscrew the rear element so that I can clean in between the rear and middle. What I see there is a "light" version of what was in between the middle and front element that I already cleaned. I just figured this might be something different just because there was a sort of patterning.

I went ahead and tuned the rangefinder on my Canon 7 with the 50/1.8 since it's a lot easier to see the split/microprism on the ground glass at 1.8 than with a wider 2.8 lens. So it should be much more pinpoint (it was slightly off based on my calibration with a 35/2.8)

 

[Sirius Glass]

I an very afraid that you will just have to enjoy your lens.

 

[zanxion72]

They look like minor flaws of the coating. Not big deal unless you like shooting straight into the sun.

 

[guangong]

Bubbles or even a single scratch on an exterior surface will not influence an image but haze certainly will. Unfortunately, early Canon lenses seem to be prone to haze. Some commentators have noted that this haze is a deterioration of the glass and not the coating and so is irreparable. Seems this was only a problem with early ltm lenses.

 

[kb244]

The spanner came today, so got that section cleaned, very easy lens to disassemble. When I was getting the inner ring off (the one that holds the rear element up next to the center element) I noticed that a lot of that shellac was crusting around the edges and it seems to be the stuff that may have left small deposits to the glass, so I blew that out real good so there wasn't any of that leftover "dust". I had the front portion set aside covered just in case (as not to let anything fall into the rear of the aperture assembly).

Got that all cleaned up, dried, and re-assembled, there's still a very very very very slight film that can only be seen at extreme angle now which is to be expected probably whatever the deposit took with it coating wise if there was any coating. But now it's so extremely negligible that I wouldn't have to worry about it and least know I know if there was anything in there, it's not there now.

I suspect since this was shipped to me from San Francisco, up to here in Michigan that any humidity that was trapped in there from a previous disassembly could have manifested itself when the temperature hit the dew point. And probably why the initial state of it went unnoticed until I got it.

For anyone curious for future reference, this version of the 50/1.8 disassembles exactly like the 50mm f/1.2 shown here.



Same as shown here



For just cleaning behind the front element and front of the center element (ie: around the aperture blades) you need only unscrew the little screw up front by the lip (not completely just enough to unlock the front) and that unscrews giving you access to the aperture blades. For between the rear and center element. You have to use a spanner to get the main black ring undone (with lens in infinity lock), which allows you to lift the back casing off the lens (don't lose the brass focusing washer), then you can take the rear assembly off the back by unscrewing it, and then taking the little ring off the back of that for the loose rear element to come out of. You can try to unscrew that without removing it from the whole assembly, but then the spanner might unscrew the thicker portion instead of just the little ring. Just remember which side is front/rear on that rear element.

Reassembly as shown in the video is just the little ring, the rear assembly back in, then placing the casing back on matching the notch up to the lock inside, then the black spanner collar to tighten it back down. That one black spanner is all you would need if you wanted to just get at the shim or the aperture 'clicks' (such as for video conversion to go clickless).

 

[kb244]

Over on RFF someone mentioned the possibility of lens element separation. I suppose it could be, but seems to be only at the outer circumfrence right now (not even sure how one would slow or prevent it let alone 'fix' it).

"I noticed that a lot of that shellac was crusting around the edges"

Make sure it is not lens element separation.

To the novice eye lens element separation looks like yellowish crusty shellac particles around the circumference edge of the glass.

I got some phone pics in case someone is curious as to it's appearance.

Not sure if that's going to cause an issue a couple years down the road or what, but for now I'm using it (just seems kind of up there in price if that's what it is).

 

[darinwc]

I dont think it is separation.. I think it is either some dust that has accumulated or likely the lens has been cleaned.. This lens in particular often gets a hazy inner element. This is really easy to clean, but difficult to get perfectly clean. Bits of dust land on the surface, discolorations, and wipe marks inevitably remain.
These can add a bit of flare to the image depending on the severity. But according to your tests, I dont think you have anything to worry about.
Now get to shootin!