Canon 17-55, dust and flare question

eoren1

Took a few photos yesterday of Fall foliage including some with the mid-day sun in the frame. Shot at f/16 and f/22 with my EF-S 17-55/2.8 lens. In addition to a sun star, I also found a number of circles around the sun. My sensor is clear as is the front element of the lens and there was no filter on (I did have a Canon hood). I do have dust in the lens itself and wonder if having the lens pointed at the sun would cause these dots to show up because of the dust particles. I'm at work and can't post an image right now but was hoping for some advice. Also, if dust is the cause, anyone have experience sending the lens to Canon to be cleaned? Do they charge for the service (lens bought Feb 2009).
Thanks,
E

ziggy53

With your description of the scene, with the sun included in the frame, I have to wonder if this is lens flare? When we can see the images it should be easy to determine.

eoren1

Ziggy
The more I think about it, the more this does seem like flare.
I almost never include the sun in the frame in portrait orientation and, in landscape, often put it to the side. The hood for the 17-55 is such that the petal is longer on the top and bottom in landscape and shorter in portrait. That likely accounted for increased flare. My concern was the nature of the flare - lots of dots around the sun and the dust particles in the lens that I thought might be the cause.
Still at work but will post pix later.
E

bgarland

I have the same lens and yes it does suck in dust at times. The good thing is it's very easy to clean it out yourself. I have done this twice already. Just remove the stick on decorative ring on the front and use a jewlers philips screw driver to remove the three lens retention screws. The front lens will then fall right out, preferably into your hand.

From there all I had to do was blow out the dust particles and ensure the front lens was perfectly clean before reassembling. It takes me about 15 mins now that I have been through it previously.

Probably no help with your sun flares but at least it will be clean again.

eoren1

Here are the shots:
Portrait with flare/dust-induced?


Landscape version


Brad-
Interesting about the cleaning process. Saw some posts and a Youtube video and it looks deceptively easy. I would only do it if dust really caused this though...
E

bgarland

eoren1 wrote: »

Here are the shots:
Portrait with flare/dust-induced?


Landscape version


Brad-
Interesting about the cleaning process. Saw some posts and a Youtube video and it looks deceptively easy. I would only do it if dust really caused this though...
E

What F stop were these taken? To me the first shot looks like a small aperture and possible dust on the camera sensor not the lens. The second shot I don't see any flare, just the staring of the sun which can be just from a smaller aperture and looks cool to me.

Every time I cleaned my lens it was because I saw the dust looking into the lens. I never actually saw the dust show up in an image.

Seriously if you look into the lens and see dust behind the front lens it really is a piece of cake to remove the front lens and blow it out. You can do it yourself.

eoren1

Both at f/22
Sensor is clean - just cleaned it last week and no other shots at f/22 show these spots
That's what made me thing of the dust in the lens itself
E

bgarland

eoren1 wrote: »

Both at f/22
Sensor is clean - just cleaned it last week and no other shots at f/22 show these spots
That's what made me thing of the dust in the lens itself
E

F/22 would bring out any dust spots if they are there. I guess it's possible it could be in the lens but it sure looks like sensor dust to me. Also all I see in both shots is the star effect and not what I think of as flare. To me a flare is disconnected from the light source and typically shows up as an orange luminescent blob along the path of the light.

If you shine a light into the front of the lens do you see any dust in there?

Edit: after going back and looking closer your right. The spots are not dark like sensor dust would be they are more lit up like they are on the surface or inside the lens.

ThatCanonGuy

My 70-200 can show bad flare with the sun in the frame. I guess even L's are susceptible to flare:cry

bgarland

Correct me if my terminology is off base. To me flare is away from the light source in disconnected areas of the image away from the sun in this case. What I am seeing in my words is nothing more than the star effect of a small aperture.

This image had big time flare (same lens at F/22) that I worked to minimize. It was in the foreground and you can still see the left over orange glow on the ground in the foreground. I wanted the sun star effect, that's why I shot at F/22.

bgarland

Bumping this for other opinions. I would like to hear other thoughts on what E is seeing in his images.

ziggy53

I suggest doing a test for sensor dust. Was there a filter attached to the lens?

eoren1

No filter. No dust - cleaned sensor last week with copperhill and rechecked against blue sky

ziggy53

I am baffled by this problem.

bgarland

Have you closely inspected the lens with a good light? The spots really do look like they are from dust on the outer surface of the lens since they are lit up with reflected light.

Sensor dust shows up as darker shadow type spots.

eoren1

I'll check again tomorrow but just went through a pretty good cleaning.
I've shot other subjects including sunstars at f/22 in the past 2 weeks without this phenomenon. The only difference is I never include the sun in a portrait shot....

bgarland

eoren1 wrote: »

I'll check again tomorrow but just went through a pretty good cleaning.
I've shot other subjects including sunstars at f/22 in the past 2 weeks without this phenomenon. The only difference is I never include the sun in a portrait shot....

This is a good example of what I think of as sun flare. The orange blob off to the left of his knee. Same lens.

eoren1

Update:
Shot a blue sky at f/22 - clean

Shot portrait at f/22


Upside down portrait f/22


With hood on (rotated so long end facing sun)


Landscape version


f/11


f/8


f/5.6


f/4


So, the question is, does anyone else's 17-55/2.8 flare this much/badly in a similar situation?
If so, looks like the 10-22 will be coming out for all shots with the sun in it.
What's strange is that I've had this lens since Feb 09 and never had flare this bad from it before. I have noticed some fairly pronounced CA at times but can't imagine that the two phenomena are related.

E

bgarland

I agree you have something significant going on. I still say it looks like surface dust on the front or back side of the front lens.

I can try the same experiment with mine tomorrow to show you what I see.

Of course I'll be ticked when I end up seeing how much dust I have on my sensor and I'll have go into anal mode to chase them away.

bgarland

Ok I shot several times tonight against the setting sun at different apertures. Obviously these were not composed or exposed for a decent image but they do show the flares.

F/22


F/20


F/16


F/8


F/3.5


F/2.8

bgarland

Just for comparison here are similar direct sun shots with the Canon 10-22 lens.

F/22


F/20



F/18


F/10


F/5.6


F/4.5

billythek

I'm confused, what's the mystery? In the first post he says there is dust in the lens. Is there any reason to believe that isn't the problem (the spots)? Why not just clean it out and retry the experiment?

Cameron

billythek wrote: »

I'm confused, what's the mystery? In the first post he says there is dust in the lens. Is there any reason to believe that isn't the problem (the spots)? Why not just clean it out and retry the experiment?

I agree - under less extreme lighting conditions, a significant amount of lens dust would likely just decrease overall contrast. However, with direct/bright light reflecting off dust on or in the lens I'd bet that's the problem. That lens does tend to collect dust under the front element.

As bgarland said in an earlier post, removing that front element isn't too difficult. I did it with mine and it was easier than I had feared. If it's still under warranty perhaps Canon would clean it out for free, otherwise you can try it yourself or pay Canon to do it.

eoren1

Thanks Brad - appreciate your taking the time to do this. Yours seems to show less of the circular flare than mine which does make me wonder about the role of dust
Bill and CSwinton - that was precisely my question...is that extra amount of flare around the sun directly attributable to dust? The lens was bought in Feb 09 so I'm probably on my own to clean it if that is indeed the culprit.
E

NeilL

Dust, or mould. Or abrasion.

Neil

insanefred

I believe this is a perfectly normal problem with lenses of more complex design. Even my brand new Nikon 24-120 does this, but it really isn't a problem for me.
So, I wouldn't worry too much.

eoren1

Well, I checked last night and my 14 month old lens is still under warranty. Figured I would take advantage and send the thing in to Canon to let them sort it out. At the same time, they can put to rest my concerns over the level of CA I have been getting as well as the mild lens creep that I have had recently. Oh, and a free cleaning without my having to take the thing apart will be nice too...
I'll report 'after' photos when i get it back
E

Stella7d

eoren1 wrote: »

Update:
Shot a blue sky at f/22 - clean

Shot portrait at f/22


Upside down portrait f/22


With hood on (rotated so long end facing sun)


Landscape version


f/11


f/8


f/5.6


f/4


So, the question is, does anyone else's 17-55/2.8 flare this much/badly in a similar situation?
If so, looks like the 10-22 will be coming out for all shots with the sun in it.
What's strange is that I've had this lens since Feb 09 and never had flare this bad from it before. I have noticed some fairly pronounced CA at times but can't imagine that the two phenomena are related.

E

This might be a long shot, but.........is it possible that the small disc shaped objects could be the result of microscopic dust particles in the air, rather than in the lens or sensor itself??

I've wondered if when the sun reflects against pollen or tiny dust particles in the atmosphere if it can cause this anomaly, much like when the sun and moisture refract creating a rainbow.
Or maybe I just too much time on my hands to be thinking this hard.

I've experienced this same disc shaped phenomena on a rare occasion even when using a brand new camera and new L glass. It's usually most visible when using a narrow aperture.

I actually love lens flare! Although it might not be considered technically correct, I adore it from an artistic stand point. :

eoren1

It WAS the dust!!
Just got the 17-55 back from Canon. They cleaned it (under warranty) and also tightened up the zoom as it was starting to creep.
Took same shots as above this morning and there is the normal amount of flare (those blue/green/yellow orbs near the bottom of the frame) but the crap around the sun is gone!!! This makes me both happy and upset as I will now need to clean the lens anytime dust gets behind the front element. What is also interesting is that the lens/camera was hunting a bit under these conditions with the dust; the clean lens locked on quickly...
E

ziggy53

eoren1 wrote: »

Just got the 17-55 back from Canon. They cleaned it (under warranty) and also tightened up the zoom as it was starting to creep.
Took same shots as above this morning and there is the normal amount of flare (those blue/green/yellow orbs near the bottom of the frame) but the crap around the sun is gone!!! This makes me both happy and upset as I will now need to clean the lens anytime dust gets behind the front element. What is also interesting is that the lens/camera was hunting a bit under these conditions with the dust; the clean lens locked on quickly...
E

Excellent news and good information.

bgarland

Sweet! Glad to hear it worked out well for you.

Down the road when it gets dusty again you just need to be brave and remove that front lens for a quick cleaning.