Strange flare with 5dII. Please check.

Started Feb 12, 2009 | Discussions
panikspace Regular Member • Posts: 117
Re: this seems to be a pretty serious problem

So, did I read this thread right - there is something inherent in the design of the mirror and/or mirror box of the 5dmkII that causes these ugly reflections to happen? This seems like a pretty serious issue - even if there is more subtle degradation happening in less extreme lighting situations, it doesn't sound good to me. I'm considering buying one in a few weeks, but...

Andrew.

Graham Meale
Graham Meale Senior Member • Posts: 2,629
This happened on my 5D

I remember one of the very first shots I took on my 5D was some Christmas lights in 2005. There was a strong light source just below the frame and I observed exactly this phenomenon. It was very obvious. I took several more shots and they were fine, so I deleted the faulty one. It never happened again (although admittedly, I didn't make a point of trying), and I assumed that the shutter had been open for a fraction of a second while the mirror was moving up or down.

So I'm interested to read this thread. If it happens in Live View then clearly my theory was incorrect.
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OP elgeorgio Forum Member • Posts: 59
I consider it a fairly annoying issue.

A tight time schedule did not permit me to post any news on the subject, but:

  • I have confirmed that this is due to a very reflective back of the mirror flap.

  • It shows on dark frames with strong lights outside the frame (a lot)

  • It degrades image quality on every shot to a varying degree unless the surrouning of the subject is black (bottom side).

  • It is more obvious if there is backlight (not even strong) behind the main subject and at the bottom of it.

  • At least one other Canon camera that I tried (40D) does not have it.

If you happen to own any other models or brands would like to know how they handle such scenes.

Large prints (exchibition stands for me) reveal this issue.

It is psychologically very annoying (at last to me) because the fix is so cheap and easy (yet impossible to do one by himself) and it degrades performance of high quality expensive gear.

It affects a "landscape camera" like 5DmkII in the worst possible way. Imagine shooting a landscape with sunny snow and a shift lens for stitching three frames. The large image circle of the lens and the high brightness of the snow (outside the frame) degrades contrast and color in the frame.

Go buy the best sharpest glass, close the aperture down to the sweet spot, the loss is still there.

Check the previous posts in this thread for pictures.

I hope to find a solution soon. I would pay for a repaint/replacement of the mirror, if anyone knows a place please post. I consider it the first major improvement in IQ for this camera.

Cheers
George

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ev1 New Member • Posts: 9
It's easy to reproduce this problem with Live View and a flashlight

I reproduced the problem with my 5Dii. It's easy to see with Live View with a light source such as a flashlight just outside the frame. It appears on the bottom of the frame most strongly, and to a reduced extent to the sides of the frame, too. I don't see it at all from the top of the frame. I can't reproduce the problem with my 30D.

bionet Senior Member • Posts: 1,072
Why is it hard to fix?

You can use mirror lock-up and then paint the backside of the mirror. If it's really that reflective, some black marker pen should already improve it a lot.

Victor Engel Forum Pro • Posts: 18,567
Re: This happened on my 5D

Yeah, I looked at my 5D and 5D II and the back of the mirror both are a smoth, grey plastic.
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panikspace Regular Member • Posts: 117
Re: Imagine shooting a landscape with sunny snow

Well, exactly - I can imagine tons of situations - reflections on water at the bottom of the frame... I wonder which lenses are more affected, and which ones less....

elgeorgio wrote:

A tight time schedule did not permit me to post any news on the
subject, but:

  • I have confirmed that this is due to a very reflective back of the

mirror flap.

  • It shows on dark frames with strong lights outside the frame (a lot)

  • It degrades image quality on every shot to a varying degree unless

the surrouning of the subject is black (bottom side).

  • It is more obvious if there is backlight (not even strong) behind

the main subject and at the bottom of it.

  • At least one other Canon camera that I tried (40D) does not have it.

If you happen to own any other models or brands would like to know
how they handle such scenes.

Large prints (exchibition stands for me) reveal this issue.
It is psychologically very annoying (at last to me) because the fix
is so cheap and easy (yet impossible to do one by himself) and it
degrades performance of high quality expensive gear.
It affects a "landscape camera" like 5DmkII in the worst possible
way. Imagine shooting a landscape with sunny snow and a shift lens
for stitching three frames. The large image circle of the lens and
the high brightness of the snow (outside the frame) degrades contrast
and color in the frame.
Go buy the best sharpest glass, close the aperture down to the sweet
spot, the loss is still there.

Check the previous posts in this thread for pictures.

I hope to find a solution soon. I would pay for a repaint/replacement
of the mirror, if anyone knows a place please post. I consider it the
first major improvement in IQ for this camera.

Cheers
George

OP elgeorgio Forum Member • Posts: 59
You HAVE to see this

This is another test I set up to verify that the problem comes from the mirror assembly.

The idea is to light only one area of the mirror box at a time and check the reflection in the sensor. Since we have a different behavior for the top and bottom parts we should be able to see the difference.

I did this test with 5DmkII (which did exhibit the problem) and 40D which did not. This further comparison could verify the whole theory.

I shot one camera with the other. The two pairs of shots were with manual exposure (same settings) and direct sunlight hitting only the mirror backside or the bottom plate with the AF sensor.

The reflection can be easily seen on all 4 but with different brightness on each shot.

The ideal material would have a black hole where the reflection is. In our case the less bright the better.
HWG:

5DmkII

40D:

Note that the lit mirror back on the 5DmkII reflects so much light that almost blows the highlights.

But most important check the reflection in the sensor area. I think the image speaks for itself and explains the whole phenomenon.

Now let's see how we can solve it...

George

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BusyBeingBorn Regular Member • Posts: 491
Are you telling Canon ?

I think you should - and it would be interesting to hear their reply, please.

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OP elgeorgio Forum Member • Posts: 59
Re: Are you telling Canon ?

Hi B.B.B !

Yes I am going to. I have already contacted the local importer (Greece) and they said this should not be happening and I should take the camera in for check/repair. But now it seems that most people have the same mirror assy so I'm not sure they can help at all.
I'll probably e-mail Canon Europe and of course let the forum know.
Cheers
George
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Philip Harle Regular Member • Posts: 245
Another way in which 40D is better than 5D?

This seems quite an important issue (certainly far more so than the black dots nonsense) so I am hopeful that if Canon fixed that they may be persuaded to fix this. It is not dissimilar to the 24-105L flare issue which I suffered from, being an early purchaser of that lens. Canon replaced the entire lens under warranty.

Somewhat off topic, can you, or anyone else with a 40D, please confirm something else I heard which annoys me about such an expensive camera as the 5DII (I don't have a 40D and have never used one). I am told that on the 40D (and I presume 50D) in live view mode the focus/exposure square can move all the way to the edge of the image. On the 5DII it stops short of the edge which is really annoying. It would be even more annoying if this is true and the "lesser" cameras work better in this respect. Can you confirm?
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OP elgeorgio Forum Member • Posts: 59
Re: Another way in which 40D is better than 5D?

Hi Philip

Philip Harle wrote:

This seems quite an important issue (certainly far more so than the
black dots nonsense) so I am hopeful that if Canon fixed that they
may be persuaded to fix this. It is not dissimilar to the 24-105L
flare issue which I suffered from, being an early purchaser of that
lens. Canon replaced the entire lens under warranty.

I certainly hope that they will fix it somehow.

I e-mailed them (Canon Europe) and got the automated confirmation. 2-3 days they say...

Somewhat off topic, can you, or anyone else with a 40D, please
confirm something else I heard which annoys me about such an
expensive camera as the 5DII (I don't have a 40D and have never used
one). I am told that on the 40D (and I presume 50D) in live view
mode the focus/exposure square can move all the way to the edge of
the image. On the 5DII it stops short of the edge which is really
annoying. It would be even more annoying if this is true and the
"lesser" cameras work better in this respect. Can you confirm?

I just checked and both cameras behave the same way.

on 5x live view magnifications you get to see all the way to the edge of the sensor. But on 10x you loose some pixels, not many though.
Cheers
George

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BusyBeingBorn Regular Member • Posts: 491
Good Luck! /NT
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wildlife1212 Senior Member • Posts: 1,109
Great Test !!!!

elgeorgio wrote:

OK, these are from last night and today.

There is no extreme conditions here no black dots hunting at 1000%.

The scene with lights in

And lights out

More pictures. These are daytime with heavy overcast

wildlife1212 Senior Member • Posts: 1,109
What about painting your sensor

bionet wrote:

You can use mirror lock-up and then paint the backside of the mirror.
If it's really that reflective, some black marker pen should already
improve it a lot.

I guarantee: No more flare

paint your sensor black and thick

rrcphoto Veteran Member • Posts: 6,173
Re: Strange flare with 5dII. Please check.

elgeorgio wrote:

Hi Ppl !

I recently got my 5DmkII and been having good fun with it.

I was playing about and got the shot bellow. Notice the strange flare
at the bottom ?
I tried with EF24-105l at 3 different focal lengths, with EF50/1.4,
EF70-300, Zeis Planar T* 50 and all created the same problem.

part of this bugs me .. been pondering this one for a while now - especially considering .. we've never seen this before even on a 5D or before your test on a 5DII in real life scenarios.

all n number of those lenses will have a different angle from the point of light exiting the rear element to displaying the image circle on the sensor plane.

for this reflection off the submirror to occur - the light would have to be bouncing for one .. against the back of the mirror - but that would tend to be too large of an image circle. and the angle of exiting the lens and projecting into the sensor, would change with different lenses.

they are all not going to have the same angle - therefore how are all of them displaying this issue? some of them would bounce at a different angle and show the flare near center .. or moved in .. or moved out .. all depending on the angle in which it was hitting the reflective part.

also - does this also occur stopped down - which would change the angle?

if it happens stopped down or wide open, I'd say we're looking at an effect, but incorrectly deducing the cause.

Andre Affleck Senior Member • Posts: 2,362
Try this...

rrcphoto wrote:

for this reflection off the submirror to occur - the light would have
to be bouncing for one .. against the back of the mirror - but that
would tend to be too large of an image circle. and the angle of
exiting the lens and projecting into the sensor, would change with
different lenses.

Think of it this way. If the light can reach all the way to the corner of the sensor (and beyond to reduce vignetting), it most certainly can reach directly above the sensor. Different lenses will have different angles but they all will have minimum image circles in order to reach all of the way to the corners and beyond. The question is how large is the image circle.

Try this:

Take a typical lens and hold it directly below a ceiling light in order to project the image of that ceiling light onto a surface (white paper on a table underneath lamp for example). Adjust the distance from the rear bayonet mount to the paper so that it is the same as camera bayonet mount to the sensor. Adjust focus and measure the projected image circle. Is it large enough to reach the mirror edge if it was mounted to the camera? If so then that is your answer. Try again with other lenses to see differences. Stop down on the lens (by mounting lens, pressing DOF button and removing lens) and note differences.

xLnT Regular Member • Posts: 164
Can also confirm

70-200 4L, @70 Hood on

Shot straight on a energy-saving electric bulb

Shot just above electric bulb, and same upside down

This is real

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Bastian09 Contributing Member • Posts: 521
Sidelight hitting Microlenses. Use a lens hood.

totally normal. Do you use a lens hood? I guess the answer is no.
So its your error.

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Bastian09 Contributing Member • Posts: 521
Extrem Easy to fix. Use a Lens hood.
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