Vignetting problem on EF 24-105/f4L IS

[peter_white2]

Giampi,

 

What's teh point of posting all those images taken with a 1.6 crop sensor? Of course there's no fall-off. It's a cropped sensor.

 

The issue here is fall-off with a full frame sensor. What am I missing?

 

My full frame sensor should be here in a few hours. ;-)

[affen_kot]

so i invented those quotes, then? you guys have fun with this thread. ta.

[lawtmyew]

I have not followed this thread for a few days and surprised to see such big reactions from Canon fans esp Prof Giampi. If this problem has been tested and proved then just send the 'shit' back to Canon. Canon produced lousy lens before .. but this time on an expensive "L" Zoom 24-105mm /F4. Light fall off on many zoom lens are common no matter what kind of sensor or body used. When we buy Canon compatible lens from "S" or "T" we knew the problems exisit from day one.

Julius, thank you for your bravery of bringing this problem up to the forum and standing to so many attacks. I don't agree someone is spreading the rumors and this is just "consumer" and "user" feedback and if Canon is serious about development new zoom lens for FFDLSR, they should look into it seriously and find ways to fix them by software.

 

cheers

[EricM]

yuck. glad i have D70's and D2x with a 17-55.

[the photo addict]

Thanks Lawrence for the support and encouragement. Recent test reports of this lens on several well known web sites have confirmed my original findings. Being the first bad news messenger, I was bound to be shot by die hard Canon loyalists. But I never expected such vicious personal attacks, twisted words, and verbal terrorism.

 

I now fully sympathize Michael Reichmann and the abuse he has been subject to. There are indeed net surfers who hides in studios day and night firing up thousands of irresponsible posts. Being photographers, perhaps their time would be better spent shooting more pictures rather than being embroiled in endless gear talk.

 

Eric, not every Canon user is a bully here. Had Nikon produced full frame DSLRs, I bet its lenses would show vignetting when fully open. With Canon gear, we at least have a choice of sensor size. I now await rigorous test reports on the 5D from impartial reviewers.

[daniel_taylor]

I cannot believe there is a thread this large over a "problem" that has been known since the earliest days of photography. Didn't any of you people ever shoot 35mm? Or is this a thread of green newbies with too much money to spend on, and too much time to worry about, expensive digital equipment?

 

Yes, wide angle and fast lenses have vignetting on "full frame" (i.e. on the format their image circle was designed to cover). This is not light rays striking microlenses at a shallow angle or any other "digital artifact", nor is it a "flaw" in the design of the 5D. It is the reality of designing a wide and/or very fast lens.

 

What's funny is that Reichmann did this test years ago with a 16-35L and a 1Ds and found *gasp* vignetting. Only it was the exact same vignetting he had found with the same lens on 35mm. He subsequently declared the "light ray angle" theory bunk and went out and made beautiful pictures with his 16-35L on his 1Ds just like he had done on 35mm. You know what? The vignetting didn't ruin the lens or the shots. It's rarely as pronounced in "real world" shooting as it is in test shots, especially test shots which are underexposed and which have their levels set in Photoshop to maximize the effect.

 

Julius Wong - there are a lot of photographers who would have little trouble making beautiful photographs with the equipment you've purchased (Reichmann being one who is already on record praising the 24-105L). But hey, if you have a problem with it, by all means, return it and get your money back.

[EricM]

"I cannot believe there is a thread this large over a "problem" that has been known since the earliest days of photography. Didn't any of you people ever shoot 35mm? Or is this a thread of green newbies with too much money to spend on, and too much time to worry about, expensive digital equipment?"

 

dude, you can not show me anything, film or digital, that Nikon has done that is anywhere near as pathetic as this. these images belong in the toy camera/holga forum. Have fun.

[sonny_jet]

Hi Julius,

 

Great Portfolio!

Do you mind if I use your 'Wind Power' image in one of my Wind power vs nuclear power essays for college?

 

I would really like too :)

 

Thanks

 

 

ps. Maybe you could try out another 24-105L and see if it's any better?

[pbizarro]

To Eric above,

 

The famous Nikkor 35mm f/1.4 lens shows appreciable light fall off and softness at f/1.4. I know, I used one with my FM3A.

[eduardphoto]

Did anyone see such a strong light fall-off on EF-S lenses? For example, how is the combo 20D + 10-22 behaving?

[joshua daniels]

I am betting that the Contax N digital camera and its lenses will not produce the kinds of fall off exhibited here from some of the Canon lenses. Why? Because (I'm given to understand) Contax opted for a thorough redesign of the lens mount and optics to go with their FF digital. It would be very interesting to see some comparisons, esp. with the wides.

[the photo addict]

Thanks Daniel for enlightening me on Reichmann's old findings. Yes, I am relatively new to photography and also rather naive. I guess I expected too much on a new "L" lens. I have since realized the design limitations of zoom lenses and came to accept this lens. Sorry to have caused a stir in this community. But I am glad that truth comes out at last after much discussions. Now can we close this thread?

 

Eric and Joshua, please, let's not morph this thread into yet another ugly "Canon vs Nikon (or Contax or any other) brand loyalty" thread.

 

Sonny Jet, you are welcomed to use my wind power photo for your college essay. BTW, thanks for the praise.

 

To everybody else: Happy Shooting! Hope to view more of your wonderful images on photo.net.

[bruce_spear]

My understanding of vignetting is that the problem of reducing light from a large field

onto a postage-stamp sized piece of film or digital sensor is considerable: the world is big

and chips are small, and middle and large-format systems have a much easier task.

 

You can literally see this when moving the front standard on large format lenses up and

down and how, as you move the cone of light towards its margins, distortion and light

fall-off increase.

 

Second, lenses may be designed to reduce optical distortion and light fall-off at the cost

of other qualities. I've worked with lenses in graphic arts darkrooms that created 1:1

negatives that could almost be matched up to their originals -- though the cost was a

huge piece of glass and the need for massive lighting and long exposures. I simply would

not expect a small format camera to produce the flat field and evenness asked for here,

and I assume that lens designers for small cameras are not assuming that either.

 

To make that lovely image of the figures by the bay -- it is a gem! -- even better, I would

use a larger format camera, and since the details in the front and off in the distance and

exquisite colors of that light are such an important part of it, I'd put it on a tripod, too. I

actually don't see the advantage of small format here -- a place the photographer could

go back to and find all the essential elements in place with differences in light and

passersby that might be seized with each visit to even greater effect.

 

It seems to me that small camera work wins up close and social, where you can pull it out

in the middle of a conversation or walking down a street, and where the distortions of that

fancy zoom are worth the cost of being able to select the focal length quickly.

 

Not long ago I fiddled with one of them while having coffee in a cafe, and which my

companion put in my hands, and without leaving my chair I made a dozen images of the

scene across from me that each had their own virtues and interest. I then did what I would

normally do with my own 35mm rangefinder with a 35mm lens on it: I had to get up, walk

forward and back, left and right, and tilt and turn -- a very different experience and very

different kind of image -- not bettor or worse, but different. I left the experience thinking

that I'd love to have such a digital camera and zoom: it would help me work in tight places

(or when I am too old to move! Ha!)

 

Writing this leads me to think about how I was trained to respect the materials: to

experiment and see what kinds of pictures this or that film, lens, format, etc., was

happiest doing and then exploit the advantages and avoid the disadvantages. I think I

have also learned to choose to follow my nose and shift to equipment that would do the

trick. As detail became more and more important to me I shifted to middle format, but

when I thought even more detail would be better and started working with large format I

realized I was losing the mobility that I had gotten used to; middle format on a tripod you

can pick up and carry in an instant, and your small cameras with zooms are, of course,

even faster, lend themselves to even quicker snaps, and might even be more fun, too!

 

Enjoy!

 

Bruce Spear

 

ps: Now that I see photo.net inviting me to attach images I'll attach a snap of

one of my American students being given instructed in the limitations of American foreign

policy and where I think the small digital camera (Canon s50) wins: nobody noticed or

even cared that I was snapping away, I had plenty of time to play with the composition,

and the optical distortions and light fall-off seem part of the compostion. I've tried

photographing such cafe scenes with middle-format, and as you can imagine, pulling out

and firing a Hasselbad is more or less equivalent to firing a cannon in the middle of a

church gathering -- an interesting idea, but not that here, where I was fascinated with the

interaction and humor of the people, and especially my student: he was listening and

learning without giving up too much of his ground, and I think he won a moment of

friendship, too. B

[ilkka_nissila]

Daniel, the well obstruction theory is not bunk, however, it may or may not contribute in a specific sensor and lens design combination. It is obvious that it would contribute disasterously with Leica rangefinder wide angles, and we know that Kodak applied lens-specific correction in the FF DSLRs due to this. How do we know that Canon isn't doing the same with the 5D? It should be easy enough to test. Namely, shoot an evenly illuminated flat and homogeneous surface with an intermediate or high ISO setting. Now, if you calculate the noise from the center of the frame and compare it with the edges, if there is more noise at the edges (pumped up by vignetting correction), you have a corrected image. If the noise is exactly the same, then you probably have the natural effects of the sensor and lens in the image.

 

I would not trust Michael Reichmann's comment about the vignetting being the same on film and digital. I don't even think he'd know how to measure the effects correctly. In order to compare images across media, you need a contrast reference (gray patch scale) which is then used to adjust the curves so that the gray patches match and then you can start comparing vignetting between scan and digital image.

[g_2]

First of all let me make myself's background clear.

 

I am a Canon user for film some 14 years ago, I used to use Canon EOS630 film back with the standard zoom EF28-70mm f3.5-4.

I quit Canon system due to its bad performance for wide angle lens not due to dark angles but the bad distoration.

I took mostly landscape so AUTOfocus is not critical for me and I have found Contax a more suitable system for myself.

I purchased Contax 167MT and subsequently a few Contax Carl Zeiss Lens a 18mm f/4, 45mm f/2.8, 60mm f/2.8 macro, 200mm f/4 and no more till now.

I am taking slide and film but was also interested in digital as this is gonna be the future (before DSLR I got G2 and Pentax Optio S).

Since Contax stop production for all its product, I have no choice but to goto DSLR of other brands, I buy mounts for my Carl Zeiss lens and use it on Canon 20D, because I am used to Canon system in my photography history.

I begin my Contax Film experience since 1999 until now.

 

Now if FF sensor causing the dark angles, I will say MOST LIKELY.

 

Forgive me for being such subjective...but let us forget which brand (Nikon, Canon, Olympus or whatsoever)....let us see the reason why film back is better than sensor.

 

Olympus website did say the answer (please forgive me if I extract anything wrong).

 

Extract from Olympus website:-

 

http://www.olympus-esystem.com/dea/products/e300/feature/index.html

 

Because the CCD image sensors used in digital cameras are flat, they are only able to accurately receive light that hits them straight on. For this reason, when a 35mm film camera lens is used with a digital camera, colour reproduction tends to be inaccurate and brightness insufficient at the image periphery, where light is apt to strike the CCD obliquely, making it impossible to realise the full potential of the CCD. Olympus's Zuiko Digital lenses, on the other hand, are designed exclusively for digital SLRs. By ensuring the same level of imaging quality at the periphery as in the center, these lenses are able to maximise the full potential of the E-300's 8-megapixel CCD. Also, since the Four Thirds System specifications result in a lens mount diameter that is much larger than the image circle, the combination of camera body and lens ensures that the light continues to travel in a straight line to the image sensor.

 

SO STRAIGHT LIGHT is the problem....with wide angle, straight lights is becoming more difficult.....I THINK.....

 

Any sensor no matter CMOS or CCD will have the same situation, if it is a 1.6x crop the problem won't appear, I think I don't need to explain, but FF will not escape with the problem unless there is new technology.

 

Here is a picture I took with my Contax Carl Zeiss Lens on Canon 20D body. I am only interested in Canon's sensor....unless I got a lot of $$$ I won't change to expensive Canon lens. But for doing fast job Canon lens is for sure. I am talking about the situation of myself (I only took landscape and slow objects). I do not mind using manual focus, even for cats. I only buy the sensor....which Contax cannot provide forever (I am not interested in digital N, those are Japanese design Carl Zeiss).<div></div>

[digitmstr]

>>What's teh point of posting all those images taken with a 1.6 crop sensor? Of course there's no fall-off. It's a cropped sensor.<<

 

Did you read the thread?

 

A contention was made about the 10D vignetting. My pictures directly address (and disprove) the contention made.

 

One thing is to theorize, another is to prove it under normal shooting conditions (i.e. NOT in a lab).

[the photo addict]

"A contention was made about the 10D vignetting."

 

Giampi, please DO NOT put words in my mouth. I have never alleged anything about the 10D. I don't know what is your problem, but you have a tendancy to mud sling people. Please leave me out of that.

 

Frankly, I am getting very tired of you and your TWISTED arguments. Case closed!

[jon_bower]

Geez, guys, lighten up! All wide angles and zooms vignette and demonstrate curvilinear distortion wide open. That's a given. Yes, my 24-105 vignettes more than my 24-70 F2.8 on a 5D. Can't say I was that surprised, really.

 

Now get the PTLens freeware plugin for Photoshop (or the standalone app) and just fix both issues...

 

Simple.

 

DxO optics does something similar, so does Photoshop's standard lens correction module. But PTL seems to work well, plus it's simple and free.

 

You won't notice these problems on well captured real-world images most of the time but, if you do, there really are several straightforward fixes in post-processing.

 

So why not go out there and take some pictures...?

 

Hope this helps.

 

Jon Bower (www.apexphotos.com)

[guido_luzzatto]

Hi guys! I've been delighted in reading your posts about EF 24-105 L IS.I recently bought such a lens for use on a 5D FF and I've been imemdiately struck by a relevant degree of underexposure at f 4. Any other conditions being equal, pictures appear darker at f 4, as compared to exactly the same shot got at 5.6 with doubling time exposure.This is not just vignetting, the full picture is affetcted until down to the center, although the effect is more relevant at the borders and corners. A beige wall at f8 becomes light brown at f 4, where an azure sky becomes blue.

This is particularly appreciable at extreme focal lenghts and in subdued light, but still evident in several different light conditions. Such a peculiarity becomes much less evident - if at all -going from 5.6 to 8. Although I was not expecting prime lenses performances from a 4.3x zoom, I think this the major drawback of a lens with more than honest walk around features, far however from what one could expect from L.

I've been wondering whether such features were typical of the lens project and meet production standards, or affected just my own sample.

I applied to my country's Canon assistance, having no satisfactory answer on the phone. I then wrote to the customers care office in Italy and at Canon Europe, getting no answer at all!

I felt rather alone with my problem and I'm happy so many persons have have been dealing with it. I think that 28-70 is by far too heavy and I will keep the combo until I get tired of it and the way Canon deals with me...

[david_thompson9]

Our use for the Canon 5D + 24-105 is professional in respect of the university where I work. With experience going back to a brownie box we can determine the working range of equipment and adapt for any given shooting situation. However, the degree of 'light fall-off' and distortion of the Canon 24-105mm FF is not an acceptable limitation for our use, given the quantity of photographs we take and tight post processing margins. Our own tests show that the lens even with post processing is not useable with impunity below 35mm focal length at about f5.6. We concur with all the pictures shown on this board so far. Separate smaller range lens would provide the necessary quality and range and it is unfortunate that Canon and many reviewers imply that those qualities carry through to the 24-105 lens with little impairment.

 

Commenting on angle of light to photcells. Wide angle lens for reflex cameras are in fact retrofocus lens, which means that their back focal length appears to be closer to a standard 50mm, thus enabling them to fit normally in front of the mirror! Optical design magic does the rest to achieve the wide angle. Telephoto lens also use the same magic in the opposite way. This means that the angle of light rays subtended from the lens back element to the sensor is similar for most front focal lengths and is therefore NOT an issue affecting digital photocells.

 

You may have noticed that if you observe a stopped down iris from the front of a wide angle lens, it appears a slightly larger size and also 'follows you' round when viewed from the edges cf. the middle. This is clever lens design compensating for natural light cone diameter reduction towards the corners. The design question is 'how much will the market let us get away with?' My reply is that the professional market (as well as keen amateurs) want to know the real design spec before buying - Hate Hype, Feed Facts.

 

Fall-off v. exposure. The worst apparant case will be at the correct average exposure as this is the most linear and eye-sensitive part of the light-to-digital-to-light conversion process. Greater compression, hence apparant brightness flattening will occur away from the centre exposure range.

[jason_winshell]

I have a 24-105L that had showed significant at 24mm f/4-f7 (almost gone at 28mm) on my

5D (where you would see it) but not as severe as the images posted above. I sent the lens to

Canon for adjustment and now the vignetting is minimal. This lens was pretty awesome to

begin with -- now it's superb.