# Strange Lens Flare (Sigma 35mm + MRC filter)



## mrsfotografie (Jan 2, 2014)

FWIW I noticed the Sigma (with a B+W MRC filter on it) is sometimes prone to flare from off-scene light sources, as shown in these pictures. The fact that the flares are all on the right hand side is a coincidence, but all the flares are confirmed to be from bright street lights just outside the frame. I haven't seen any occurrence of the lens flare in horizontal position. 

These shots were all taken hand held, with (near) open aperture (<f/2.5) and the lens hood is on. The camera is gripped but obviously the lens extends beyond the grip. I'm not sure that I like this effect, and it is something I may want to avoid in the future but on the positive side it does have something reminiscent of the anamorphic lens(flare) effect as seen in some movies. 
Does anyone recognize this flare, is it something to do with the MRC filter? All of my UV/clear filters are B+W but this is probably the ony one I have with a multi reflective coating (MRC). Cheers.


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## dgatwood (Jan 2, 2014)

It kind of looks like it might be dust somewhere. Otherwise, no idea.


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## mrsfotografie (Jan 2, 2014)

dgatwood said:


> It kind of looks like it might be dust somewhere. Otherwise, no idea.



I'm sure it's not dust


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## slclick (Jan 2, 2014)

Have you used that particular filter on a different lens to narrow it down?


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## mrsfotografie (Jan 2, 2014)

slclick said:


> Have you used that particular filter on a different lens to narrow it down?



No... I was hoping someone here might recognize the phenomenon.


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## slclick (Jan 2, 2014)

I have the Sigma 35 and use it with a B/W XS Pro Clear MRC with no issues.


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## tolusina (Jan 2, 2014)

Have you tried these type scenes both with and without the filter?


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## mrsfotografie (Jan 2, 2014)

tolusina said:


> Have you tried these type scenes both with and without the filter?



No... this was the first time I used the lens in a situation like this. It may be a complete coincidence but I do have about 1 in 15 shots from this session that show this lens flare.


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## dgatwood (Jan 2, 2014)

mrsfotografie said:


> dgatwood said:
> 
> 
> > It kind of looks like it might be dust somewhere. Otherwise, no idea.
> ...



Never mind. I thought you were talking about the sparkles, which I now realize are, in fact, Christmas lights.  This is the danger of looking at the photos on a cell phone.

The horizontal line at the right edge looks almost like a light leak to me.


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## mrsfotografie (Jan 2, 2014)

dgatwood said:


> The horizontal line at the right edge looks almost like a light leak to me.



You're right, I had thought about this but the flare is not always in the same place, and I cross checked with other photo's from this series that give a better idea of the street layout- it is almost definitely from light sources (bright street lights) just outside the frame. I had thought about light leaking into the viewfinder, but I had my eye in front of it so that may rule it out. The thought had occurred to me that the light may hit the filter and then be bent by the convex front element to produce the flare. 

I just did some tests in my living room with the Sigma mounted on my 5D Mark III, and I was able to reproduce the effect but not quite to the same extent as it was on the street with my 5D Mark II. Again, holding the camera by the grip (with the top of the camera facing left) and with a bright light just on the right edge of the frame, the flare occurs. Turning the camera 180 degrees and taking the same shot eliminates the flare! I shot a f/1.4 and 1/30 sec to simulate the street photo's. I can clearly see a bright sliver in the viewfinder when taking the shot. Depending on the orientation the shape of this sliver changes ( it is much wider when shooting a vertical frame with the top of the camera facing right).


Now this got me thinking... it may be stray light hitting the mirror? This would explain why the flare occurs only in one orientation, and differences in the MkII and III construction may explain why the effect is greater on the Mk II. Hmmm.... :


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## slclick (Jan 2, 2014)

Maybe you did and I missed it but did you perform the same indoor test without the filter?


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## mrsfotografie (Jan 2, 2014)

slclick said:


> Maybe you did and I missed it but did you perform the same indoor test without the filter?



Sorry, but no. I was looking to do a test in the same conditions just to rule out the body. I always shoot with filters and prefer to leave them on to protect the front element. The effect is markedly less on the 5D MkIII (almost unnoticeable and difficult to reproduce). I'm fairly confident now that it is something to do with the mirror, not the filter because the orientation of the body is important (and I checked the filter- it's clean and in perfect condition).


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## slclick (Jan 2, 2014)

So it's the lens. has it taken a hit? Are there any noticeable dings or mars along the mount side? Run your finger along the EF mount.


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## mrsfotografie (Jan 3, 2014)

slclick said:


> So it's the lens. has it taken a hit? Are there any noticeable dings or mars along the mount side? Run your finger along the EF mount.



The lens is pristine, brand new. Nothing wrong with it


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## endiendo (Jan 3, 2014)

That's why I always use the lens hood, even there is no sun....


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## neuroanatomist (Jan 3, 2014)

endiendo said:


> That's why I always use the lens hood, even there is no sun....



So did the OP, if you read his post...


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## slclick (Jan 3, 2014)

neuroanatomist said:


> endiendo said:
> 
> 
> > That's why I always use the lens hood, even there is no sun....
> ...



Yep, she did


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## neuroanatomist (Jan 3, 2014)

slclick said:


> neuroanatomist said:
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> > endiendo said:
> ...



He, not she. MRS are his initials, not the contraction 'Mrs.'


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## slclick (Jan 3, 2014)

neuroanatomist said:


> slclick said:
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> > neuroanatomist said:
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## mrsfotografie (Jan 3, 2014)

neuroanatomist said:


> slclick said:
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> 
> > neuroanatomist said:
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Ha ha thanks Neuro, I know I'm sometimes at risk of being seen as the other sex with those initials 

I have great plane tickets though, they always state 'MR MR Smit', ie 'mister mister'


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## jebrady03 (Jan 3, 2014)

To avoid taking the filter off, indoors, in your own home, because you're fearful of damaging the front element is a bit paranoid, don't you think? Just take it off and retest. This will determine if your (mostly useless and possibly problematic) UV filter (you're using at night) is the problem.


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## mrsfotografie (Jan 3, 2014)

jebrady03 said:


> To avoid taking the filter off, indoors, in your own home, because you're fearful of damaging the front element is a bit paranoid, don't you think? Just take it off and retest. This will determine if your (mostly useless and possibly problematic) UV filter (you're using at night) is the problem.



I'm not fearful of damaging the front element in my home. Just lazy enough not to want the hassle of reassembing it all dust-free. In any case, I'm satisfied. There's no way I'm going to use this lens without a filter, so my current test results are good enough. I challenge you to test your copy and see if you can come up with the same results.


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## slclick (Jan 3, 2014)

mrsfotografie said:


> jebrady03 said:
> 
> 
> > To avoid taking the filter off, indoors, in your own home, because you're fearful of damaging the front element is a bit paranoid, don't you think? Just take it off and retest. This will determine if your (mostly useless and possibly problematic) UV filter (you're using at night) is the problem.
> ...



Since I have the same setup, 5D3, Sigma 35 1.4 and B&W MRC clear filter , I tried with a bright light coming from the side in a few different scenes last night. 

I had no flare or anything that resembles a light leak. I am familiar with light leaks as I shoot Holgas and older film bodies. Sorry I was no help. 

You did rule out the filter so the dust/removal/carefulness issue is moot. Since it's on two bodies it's not a leak imho.

The first course I would take is to update the lens firmware via the USB Sigma dock. If that does nothing send it in.


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## hksfrank (Jan 3, 2014)

slclick said:


> mrsfotografie said:
> 
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> > jebrady03 said:
> ...



i have a 5D3,sigma 35 1.4 art with BW nano XS (forgot full name , only one was coming with nano and XS)

no problem at all (i always use hood too~)


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## mrsfotografie (Jan 3, 2014)

hksfrank said:


> slclick said:
> 
> 
> > mrsfotografie said:
> ...



Well, with the 5D3 I was only able to get a tiny sliver in one or two frames. Not something that would be a problem. That was with the lens fully open and at 1/30 sec. I'm sure it has something to do with the 5D2 but I don't believe it is a light leak. I thought I had an opportunity to do some shooting with the 5D3+35 mm Sigma today but the event (ice sculptures) was so overcrowded, I decided to postpone that one.


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## Mt Spokane Photography (Jan 3, 2014)

The filter seems the obvious candidate, I never use one, even though I have a bunch of them around. I used to use them all the time until I discovered that even the best filters can cause issues.
You can't easily see filter issues by looking at them, but if you can try a different one, that might help to rule it out.

The fact that the lens is new is also a hint, Lenses do have assembly errors and other issues. Still, I'd try a different filter first. Even a cheap $10 one should be able to help rule out or point to a problem with the filter.


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## mrsfotografie (Jan 3, 2014)

Mt Spokane Photography said:


> The filter seems the obvious candidate, I never use one, even though I have a bunch of them around. I used to use them all the time until I discovered that even the best filters can cause issues.
> You can't easily see filter issues by looking at them, but if you can try a different one, that might help to rule it out.
> 
> The fact that the lens is new is also a hint, Lenses do have assembly errors and other issues. Still, I'd try a different filter first. Even a cheap $10 one should be able to help rule out or point to a problem with the filter.



You're right, the filter looks to be the thing that catches the light first (and draws it in) so it is suspect. I think this is my only MRC filter, but I can change it out for a normal filter to see if it helps. I'm not in the mood to test this now, but will most definitely give it a go if the flare remains a problem.


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## fish_shooter (Jan 3, 2014)

This reminds me of light leaks I got with faulty Hasselblad dark slide light traps. The closet thing that has happened to me in Canonland is a faulty shutter (but turned 90 degrees, different shape to the leak). Try shooting verticals with the body oriented the other way as well - two shots per set-up - and see what happens. 
Tom


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## mrsfotografie (Jan 3, 2014)

fish_shooter said:


> This reminds me of light leaks I got with faulty Hasselblad dark slide light traps. The closet thing that has happened to me in Canonland is a faulty shutter (but turned 90 degrees, different shape to the leak). Try shooting verticals with the body oriented the other way as well - two shots per set-up - and see what happens.
> Tom



Hi Tom,

Thanks for your advice, but I tested this already and the phenomenon occurs only with the top of the (5D Mk II) camera facing right


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## photonius (Jan 3, 2014)

mrsfotografie said:


> fish_shooter said:
> 
> 
> > This reminds me of light leaks I got with faulty Hasselblad dark slide light traps. The closet thing that has happened to me in Canonland is a faulty shutter (but turned 90 degrees, different shape to the leak). Try shooting verticals with the body oriented the other way as well - two shots per set-up - and see what happens.
> ...



well, then cover the whole camera and lens (except the front of course) with a black cloth and try again, to see if there is any leak. I recall the 5d III? had a manufacturing defect that leaked the self-timer light (?) into the body. 
So, light leaks are not totally impossible, perhaps if an internal seal fails. At least with this test you know if it is the through the lens, or somewhere else it comes from.


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## mrsfotografie (Jan 3, 2014)

Guess what, it's not the lens that causes the effect. Here's some test shots I just took with my 5D Mark II and *Sigma 50 mm f/1.4* all at 1/30 sec and f/1.4-f/1.6:

The flare occurs with the top of the body facing left (first 2 shots), and is gone when the body is turned 180 degrees (second 2 shots). I covered parts of the body with my hands while I was taking the test shots and there's no difference to the flare produced. Increasing the shutter speed to 1/125 sec made no difference. Anyone want to try this out with their 5D Mk II?


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## Sporgon (Jan 3, 2014)

Strange. You've now changed to a different lens but get the same result on the same body.

Long shot; you haven't done a wet clean on the 5DII sensor yourself and inadvertently left a fluid smear ?


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## mrsfotografie (Jan 3, 2014)

Sporgon said:


> Strange. You've now changed to a different lens but get the same result on the same body.
> 
> Long shot; you haven't done a wet clean on the 5DII sensor yourself and inadvertently left a fluid smear ?



I have wet cleaned the sensor about three times since I have this body, but cleaning involves swiping the sensor lengthwise. These flares are at 90 degrees to that direction  The sensor really is clean by the way. No fuss


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## Cinto (Jan 3, 2014)

Sigma 35mm on Canon5D2. I've noticed this effect a few times with this lens. With the Canon 35mmL never saw it. I have used the Sigma 30 1.4, sigma 10-20 4.5-5.6, and the 150 macro as well and all seemed to have disturbing flare. the 10-20 being the worst the 150 being the best. No filter, with hood camera turned top left.


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## mrsfotografie (Jan 3, 2014)

Cinto said:


> Sigma 35mm on Canon5D2. I've noticed this effect a few times with this lens. With the Canon 35mmL never saw it. I have used the Sigma 30 1.4, sigma 10-20 4.5-5.6, and the 150 macro as well and all seemed to have disturbing flare. the 10-20 being the worst the 150 being the best. No filter, with hood camera turned top left.



Wow, thanks for posting! There you go, there must be a real technical reason behind this flare, and it's related to the 5D MkII and a few Sigma lenses as we know so far. Holding the camera by the grip (with the top of the camera facing left) can produce the flare with light sources just outside the right hand side of the frame.

I'm pretty sure there is an internal reflection occurring in the camera body. Not sure what causes it though (underside of the mirror assembly??), and whether the same can occur with Canon lenses (perhaps the Sigma's rear lens elements protrude further and scatter more light in the body)?


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## neuroanatomist (Jan 3, 2014)

The presence/absence with 180° rotation is a puzzler, though. Could there be asymmetry in the lenses?


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## mrsfotografie (Jan 3, 2014)

Solved!!!, check out this link:

*Canon 5D mark II - Mirror Box Reflections Issue*

http://www.terajunk.com/5d2/


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## mrsfotografie (Jan 3, 2014)

neuroanatomist said:


> The presence/absence with 180° rotation is a puzzler, though. Could there be asymmetry in the lenses?



It could happen the other way 'round but the light source would then have to be on the left; it's because of a reflective back side of the mirror flap.

At least the issue seems to be resolved/mitigated in the 5D Mark III as I found by testing the 35mm on that body.


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## Sporgon (Jan 3, 2014)

How strange. I have never seen anything like that with my 5DII and mine is a very early one from 2009 _ serial member begins with 0.


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## mrsfotografie (Jan 3, 2014)

Sporgon said:


> How strange. I have never seen anything like that with my 5DII and mine is a very early one from 2009 _ serial member begins with 0.



It took me 32000 shutter actuations on the 5D MkII before I took notice of the issue. It also took 32000 shutter actuations before my MkII met the Sigma 35 f/1.4 and gave me the impulse to do more handheld night shooting and the issue became apparent with this fantastic night-street photography lens. I bought my 5D2 new in january 2010. 

Now that I look back in my photo collection I can find some older pictures that do actually display the flare, but I have always overlooked it or thought it was just lens flare.

Apparently the 5D classic is also affected.


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## Cinto (Jan 3, 2014)

Canon 5dmark2 with 40mm 2.8. Maybe related to focal length too? Different, but close.


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## mrsfotografie (Jan 4, 2014)

Cinto said:


> Canon 5dmark2 with 40mm 2.8. Maybe related to focal length too? Different, but close.



You're correct, I can see a blotch in the shy to the right...


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## Cinto (Jan 7, 2014)

I think it might just be flare, check this two pics. Flare both in and out of the frame, unless the mirror is reflecting in the middle as well as the edges.


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## Cinto (Jan 7, 2014)

One more cause I found it. It may be the mirror but it's a combination of mirror and lens I'm pretty sure, I never really saw it on the 35L. Maybe the curvature of the back element make s a difference?


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## mrsfotografie (Jan 7, 2014)

Cinto said:


> One more cause I found it. It may be the mirror but it's a combination of mirror and lens I'm pretty sure, I never really saw it on the 35L. Maybe the curvature of the back element make s a difference?



I think the Sigma 35 does make the camera more prone to showing this effect. Fortunately now that we know why this occurs we can at least take it into account and turn the body 180 degrees if necessary.


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## R1-7D (Jan 7, 2014)

Just want to add that I was shooting with the 5D2 late last night with my 24-70 f/2.8 II and experienced this same sort of flare in one or two of my photos. I put it down to the filter at the time, but after reading this thread regarding the phenomenon occurring with only the 5D2, it makes sense as I've never seen this lens have that flare on my 5D3. 

Looks like its nothing to worry about. I'll post my flare picture tomorrow from the 5D2 and 24-70 II.


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## Nishi Drew (Jan 7, 2014)

Wow, I was blaming my Siggy 35mm, although I liked the "anamorphic lens flare" feel, it would only occur shooting vertically so I couldn't understand the issue. Consequently I haven't gotten any of this since moving up to the MarkIII...


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## mrsfotografie (Jan 7, 2014)

R1-7D said:


> Just want to add that I was shooting with the 5D2 late last night with my 24-70 f/2.8 II and experienced this same sort of flare in one or two of my photos. I put it down to the filter at the time, but after reading this thread regarding the phenomenon occurring with only the 5D2, it makes sense as I've never seen this lens have that flare on my 5D3.
> 
> Looks like its nothing to worry about. I'll post my flare picture tomorrow from the 5D2 and 24-70 II.



That would be interesting, please post the pictures  

I also decided it's not something to worry about, rather just be aware of. in 32000 images I took with the 5D Mk II only a few pictures show this effect which, depending on ones preferences, may be disturbing (or not). In any event, I'll try to avoid its occurrence in the future when I use this camera body.


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## R1-7D (Jan 7, 2014)

Here's my snapshot from the other night. 

ISO 3200
35mm
f/2.8
1/125

Like I said previously, I thought the flare my just be caused by my filter. After reading this thread I'm 95% sure it's just the mirror box in the camera now. Not a big deal... I've never had this type of flare before in any image that really counted.


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## mrsfotografie (Jan 8, 2014)

R1-7D said:


> Here's my snapshot from the other night.
> 
> ISO 3200
> 35mm
> ...



Thanks for posting, it's the familiar flare alright. It looks like there is a small spike in the snow on the road as well... At least it's confirmed it does not only occur with Sigma lenses, and given the right conditions, almost any lens can produce the effect on the 5D Mark II, at least those with a wide aperture.


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