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EF 24-105mm f/4L Soft and Hazy


I have the above lens that is very soft and hazy - but i cannot see any dust or mold. I think i want to try to tear it down and see if i can do anything with it.  Like this guy is doing here:

But he says that the "Axis Test" showed poor results early in the video. I gather that some of the elements are misaligned causing the blurriness. I'd like to confirm that it is indeed an axis problem. Any idea what exactly is an axis test? What charts are used? Is it the same as a lens calibration test?



Not applicable

Not exactly a direct answer to your question, but do you get good focus when using live view shooting on the camera? Live view uses a different focus system than viewfinder shooting. If it is focused in live view, then the lens is not at fault.

I have about 5 other lenses including the 70-200 which focuses really good - either live view or normal shooting. The camera can do with some cleaning - its a 5D Mk 3 thats was bought in 2013 i think when it just came out and have never been serviced. But the 24-105 had been my main lens until i sent it to canon to repair and it came back with this problem. See the photo below - not a good photo but it gives shows the problem - the haze tends to be bad as you move away from the center and the focus appears to be somewhat off. And this is an outdoor photo. 


Not applicable

I would send it back to Canon and tell them of your issue after they repaired it. I would think that they would warranty the repair. Don't mess with it yourself.

I think i need to give some backstory. A few years ago i sent my EF 24-105mm f/4L to Canon USA (from Trinidad & Tobago), for canon service because it had an Error when i tried to use it. Canon Charged me 350 in Labor (no parts) and repaired the lens and shipped it back. Because this was outside of the US, I had the camera returned to a family member in Florida where i visit twice per year. When i got the lens back i realized it was not focusing properly - 80% of the time it would refuse to focus, Eventually over time, the focusing improved to where today it focuses fine, but the lens takes horribly soft pictures - hazy especially outwardly. I could see no signs of dust or mold inside the lens. Canon told me because of the delay they wont fix it unless i pay for new service. (about 2 months after they sent it back)

Not applicable

I still think that you don't want to take it apart yourself.

Are you using a filter or lens hood on the lens?

Yes i have a Hoya polarizing filter that remains on - and the hood never comes off. 

Not applicable

Try removing the polarizing filter and make sure the lens hood is not installed crooked. That haze looks like some sort of reflection to me.

@wilmark wrote:

Yes i have a Hoya polarizing filter that remains on - and the hood never comes off. 

Hoya makes some six or seven different qualities of polarizing filters, ranging from very good to utter crap. It is probably the filter is causing the problem you are seeing and I'm guessing it's not one of their better, multi-coated ones (such as their "HD3" or "NXT Plus").

While a quality circular polarizer is one of the most useful filters with digital photography, there is no way one should "remain on". There are many situations where the filter can help... but there are also many where it will be more of a problem.

A C-Pol cuts 1.5 to 2.25 stops of light, forcing you to use higher ISO and/or slower shutter speeds. When shooting in marginal lighting conditions, the filter is just hampering you unnecessarily.

There also are times when a C-Pol is effective and times when it's not. The polarization effect is greatest  at 90 degrees from the light source, tapering off to nothing at 0 or 180 degrees. So shooting a scene midday with the sun right above your  head might give a fairly strong filter effect. But pointed directly at a sunrise or sunset, or pointed directly away from a sunrise or sunset, the filter does nothing but potentially cause flare.Here is an example where the sun was high and a bit behind me, so the effects of the filter deepening the blue of the sky and the green of the water was fairly strong (in fact I dialed it back a bit, so the reflections of the boats in the water wouldn't completely disappear)


In addition, because of the variation in the polarization effect, you can get uneven look in broad, plain expanses, such as the blue sky in the image below:

5734569759_1e1cfd7c90The sun is low and off to the left in this image, so the filter's effect is stronger on the right hand side of the image. It was a plain blue sky, so I didn't mind the difference in this case. But I could have gotten a more even sky without the filter.








Here's an example where clouds in the sky tend to "hide" a similar uneven effect from a C-Pol... this time with the sun low and to the right:


C-Pol filters reduce reflections... but sometimes the reflection IS the image! The last thing I wanted for the shot below was to reduce the reflection of the sunset off the water or the wet sand and rocks (not to mention, directly shooting a sunset would mean no polarizing effect in the middle of the image), so I didn't use any filter at all:


A C-Pol can be helpful for portraits, too... if a subject wears eyeglasses or has "shiney" skin.

But a C-Pol should not be left on all the time. If you try to photograph a rainbow, a C-Pol will make it disappear! As you can tell, I don't hesitate to use a C-Pol... It's by far my most used filter, ever since I switch from film to digital 20 years ago. HOWEVER, I probably only use one 10 or 15% of the time. I would never let one "remain on" my lens all the time!

Try some shots without the filter (and with the lens hood properly installed) to see if you have less flare issues.

There is another possibility... a dirty sensor in your camera. That also can cause problems like you're seeing. And, yes, it can be problems with the lens itself. But both of these are far less likely than the filter.


Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2), EOS M5, some other cameras, various lenses & accessories

Hi - i did some trial shots - with the filter/hood on and off and with the same filter on my 70-200 for reference, both Wide and Zoomed.

First i made a mistake about the filter - its a simple UV filter like this one

The photos were generated using Print from Lightroom because i can figure out no other way to put either the file name or other keywords on the photo - amazing that this cant be done in 2023. I ill appreciate any feedback - the Hooded + no Filter seems just slightly better. (Forgive the quality - trying to make the image small and i suspect that using "Print" also has issues)


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