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Canon Illumination Correction and Third-Party Lenses

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I while back I put out a notice that the Sigma 150mm and 180mm OS Macros had an issue if you shot JPGs on a Canon 5D Mk III and left peripheral illumination correction on. The camera auto-corrected for vignetting that wasn't there, leaving an interesting pattern with a dark center and lightened edges and corners.

 

Sigma 180 f/2.8 OS jpg shot on Canon 5D MkIII

 

Several people emailed me about different combinations of cameras and lenses that did similar things. The interesting thing was some people clearly had the problem with a certain lens, but other people clearly didn't have the problem with that same lens. Some people saw the same lens act up on one Canon camera but not a different one. Some people assumed it was because the third-party lenses identify themselves to the camera as this or that Canon lens. Several claimed only bad photographers noticed it; while others felt it was a rumor started by Canon to keep people from buying third-party lenses.

It was all very confusing. So I thought I'd spend a couple of hours trying to figure out what was actually going on.

That didn't turn out like I expected. Instead of a couple of hours, it was over a week. In the end, though, we ended up with some useful information about what does cause the issue and debunked at least one myth. Like so many things we look into in our lab, it ended up creating some new questions, too. Plus it gave a few hints about how cameras and lenses talk to each other.

I'll warn you, though, if you don't use third-party lenses on Canon cameras, or you aren't into how camera electronics work, you'll find this very boring. If you just use third-party lenses, but don't care about why this happens, just drop down to the last table and at least we'll show you exactly when it will happen.

Other than that, this does provide yet another piece of evidence in the message I keep trying to deliver: When you ask about this Sigma lens or that Tamron lens only ask people who shoot the same camera that you shoot. Because third-party lenses do NOT behave the same on different cameras.

The Lens Identification Myth

A number of people felt this problem (and some others) resulted from third-party lenses identifying themselves to the camera, at least partially, as being a Canon lens. Rolando Ruzic linked me to Phil Harvey's excellent ExifTool software, and I started doing some investigation into this. ExifTool (in the majority of cases) correctly identifies the third-party lens that is attached to the camera and also tells us what the lens tells the camera that it is.

We shot images with every third-party lens we stock on various Canon cameras and noted which Lens ID the lens was using. To make a very, very long story short - the lenses identify themselves the same way to every camera. So, the Tokina 12-24 f/4 PRO tells every Canon camera that it actually is a Canon 20-35mm f/2.8 L lens.

But the Tokina 12-24 (and a number of other third-party lenses) don't have the peripheral illumination problem on every camera.  It doesn't matter what Canon camera the lens is mounted to (and we repeated it with every lens on every body), the third-party lens is always identified as the same Canon lens. So obviously Lens ID does NOT have anything to do with how peripheral illumination is controlled.

Because some will be interested, and because we went to the trouble to get the data, here are the various third-party lenses and what lens they actually identify themselves as to the camera, according to ExifTool.

LensCanon Lens ID
Sigma 4.5mmCanon 180 f/3.5 macro
Sigma 12-24 IICanon 85 f/1.2 L
Sigma 20mm f/1.8Canon 14mm f/2.8 L
Sigma 30mm f/1.4Canon 14mm f/2.8 L
Sigma 50mm f/1.4Canon 17-35 f/2.8
Sigma 70mm f/2.8 macroCanon 17-35 f/2.8
Sigma 85mm f/1.4Canon 17-35 f/2.8
Sigma 105 f/2.8 macroCanon 17-35 f/2.8
Sigma 150 f/2.8 OS macroCanon 100-400 L
Sigma 180 f/2.8 OS macroCanon 100-400 L
Sigma 8-16Canon 85 f/1.2 L
Sigma 10-20 f/3.5Canon 85 f/1.2 L
Sigma 17-50 f/2.8 OSCanon 85 f/1.2 L
Sigma 24-70 f/2.8 HSMCanon 85 f/1.2 L
Sigma 70-200 f/2.8 HSMCanon 135 f/2
Sigma 70-200 f/2.8 HSM OSCanon 135 f/2
Sigma 50-150 f/2.8 OSCanon 135 f/2
Sigma 50-500 OSCanon 135 f/2
Sigma 120-300 f/2.8 OSCanon 135 f/2
Tamron 10-24mmCanon 85 f/1.2 L
Tamron 17-50 f/2.8 VCCanon 28-70 f/2.8 L
Tamron 17-50 f/2.8Canon 85 f/1.2 L
Tamron 24-70 f/2.8 VCCanon 28-70 f/2.8 L
Tamron 28-75 f/2.8Canon 35-80 f/4-5.6
Tamron 28-300Canon 85 f/1.2 L
Tamron 18-270 VC PZDCanon 28-105 f/3.5-4.5
Tamron 70-300 Di VCCanon 28-70 f/2.8 L
Tamron 90 f/2.8 MacroCanon 70-200 f/2.8 L
Tamron 200-500mm
Canon 20-35mm f/3.5-4.5
Tokina 10-17Canon 85 f/1.2 L
Tokina 12-24 F/4 PROCanon 20-35mm f/3.5-4.5
Tokina 11-16 f/2.8Canon 20-35mm f/3.5-4.5
Tokina 16-28 f/2.8Canon 28-70 f/2.8 L
All Voigt Zeiss as Voigt / ZeissZeiss/Voigt

 

Please note that all Zeiss and Voigtlander manual focus lenses identify themselves only as Zeiss/Voigtlander MF lens, even if they have AF confirmation. This suggests that the lens identification may have something to do with telling the camera what AF signals to send to the lens motor. All completely manual lenses (Rokinon, Schneider, etc.) do not identify themselves at all.

Have I Mentioned I Really Started to Hate This Study?

In looking at all of the data ExifTool provides, we noticed there was a section regarding peripheral illumination. It told us if Peripheral Illumination Correction was on or off, and gave a numeric value associated with the correction. We spent a lot of hours looking at the numeric values. At first, we incorrectly assumed the numeric value was the issue. Since it changes from one lens to another we thought the Lens ID might be assigning an incorrect numeric value to the third-party lenses.

So we literally took several hundred images with a dozen different lenses. We varied focal length, ISO, illumination, zoom range, cameras, and lenses. We plotted that peripheral illumination number with every possible combination and variable. The data filled up 12 pages on a legal pad and we painstakingly put it all in an Excel spreadsheet. We analyzed it. We charted it. We cussed at it. When we were finished, we just cussed.

Because that number varies with all kinds of things: lens, ISO, focal length sometimes, but not others. Most importantly, it's not the same for a third-party lens and for the Canon lens the third-party lens identifies itself as. For example, the Sigma 180 f/2.8 OS is identified as the Canon 100-400, but the numerical value they show in the peripheral illumination section are different.

Testing Some Canon Lenses

We did notice one other thing of interest, though. When we tested Canon lenses with the Peripheral Illumination function turned off, the Exif data showed peripheral illumination was off for every lens. If we tested Canon lenses with Peripheral Illumination turned on, the Exif data showed Peripheral Illumination was on, unless the camera didn't have data for the lens.

In other words, if you look at the Peripheral Illumination menu on the LCD with the lens mounted, the camera either tells you that it has data for that lens, or that the data is unavailable. The newest lenses and tilt-shifts lenses don't have peripheral illumination data. We tested every camera, including the 5D III, 1Dx, and 7D with new firmware. When no data is available, peripheral illumination is automatically turned "Off" according to the Exif data even though you have it turned on in the menu.

Canon LensLCD readingEXIF state
14 f/2.8 L IIOnon
17 TS-Eno dataoff
24 f/1.4 LOnon
24 TS-Eno dataoff
24 f/2.8Onon
24 f/2.8 ISno dataoff
28 f/1.8Onon
28 f/2.8 ISno dataoff
35 f/2Onon
35 f/1.4Onon
40 f/2.8 STMno dataoff
50 f/1.4Onon
50 f/1.2 LOnon
50 f/2.5 macroOnon
85 f/1.8Onon
85 f/1.2 LOnon

So we went back to our 6-page spreadsheet and checked two camera-lens combinations we knew had the problem. Sure enough, when either a Sigma 180mm f/2.8 OS Macro or a 150mm f/2.8 OS Macro was mounted to a Canon 5D Mk III Exif data showed peripheral illumination was ON. The other Sigma lenses we'd tested showed peripheral illumination was OFF in the Exif data when mounted to a 5D Mk III.

I'd gotten an email and some pictures that morning from someone who complained their Tamron 70-300 VR did something quite similar so I mounted it to a 5D Mk III and took some shots. I hadn't seen any problems when shooting that lens on a 5D Mk III, and the Exif data said, as it should, that peripheral illumination was OFF. Just for grins, though, we mounted the same lens to a 5D II and 'Eureka!' there was clearly some abnormal peripheral illumination in the jpg, and the Exif data on the 5D II screamed that Peripheral Illumination was ON in the Exif data.

And Then There was Grunt Work

After that it was a simple, if very time consuming, task to test every third-party lens on every camera. If Peripheral illumination showed ON in the Exif data we compared JPGs and RAW images to confirm that there was some peripheral illumination correction being applied. We could generally tell the difference easily, although sometimes it was pretty subtle. And some of the "ON" combinations involved crop-sensor lenses mounted to full-frame cameras, so they aren't really important.

We tested most of the third-party lenses we carry on several different Canon bodies we stock. I've presented the results in the table below. If a lens-camera combination says ON in the table, then according to Exif data it was turned on even though the camera's LCD menu said it had no data for that lens. When that lens is mounted to that camera, the camera is applying Peripheral Illumination Correction even though it has no data for that lens.

Lens5DIII5DIIT4i7D/2.07D/1.2.5
Sigma 4.5mmoffoffoffoffoff
Sigma 12-24 IIoffoffoffoffoff
Sigma 20mm f/1.8offoffoffoffoff
Sigma 30mm f/1.4offoffoffoffoff
Sigma 50mm f/1.4offoffoffoffoff
Sigma 70mm f/2.8 macrooffoffoffoffoff
Sigma 85mm f/1.4offoffoffoffoff
Sigma 105 f/2.8 macrooffoffoffoffoff
Sigma 150 f/2.8 OS macroONoffoffoffoff
Sigma 180 f/2.8 OS macroONoffoffoffoff
Sigma 8-16ONoffoffoffoff
Sigma 10-20 f/3.5ONoffoffoffoff
Sigma 17-50 f/2.8 OSoffoffoffoffoff
Sigma 24-70 f/2.8 HSMoffoffoffoffoff
Sigma 70-200 f/2.8 HSMoffoffoffoffoff
Sigma 70-200 f/2.8 HSM OSoffoffoffoffoff
Sigma 50-150 f/2.8 OSoffoffoffoffoff
Sigma 50-500 OSoffoffoffoffoff
Sigma 120-300 f/2.8 OSoffoffoffoffoff
Tamron 10-24mmoffoffoffoffoff
Tamron 17-50 f/2.8 VCoffoffoffoffoff
Tamron 17-50 f/2.8offoffoffoffoff
Tamron 24-70 f/2.8 VCoffoffoffoffoff
Tamron 28-75 f/2.8offoffoffoffoff
Tamron 28-300offoffoffoffoff
Tamron 18-270 VC PZDoffoffoffoffoff
Tamron 70-300 Di VCoffONoffONON
Tamron 90 f/2.8 MacroONoffoffoffoff
Tamron 200-500mmONoffoffoffoff
Tokina 10-17offONoffoffoff
Tokina 12-24 F/4 PROoffONoffONON
Tokina 11-16 f/2.8offONoffONON
Tokina 16-28 f/2.8offoffoffoffoff

We confirmed that each of the lenses showing an inappropriate "ON" signal in the Exif data does have some odd illumination correction applied to in-camera JPGs, but not RAW images. It wasn't usually as apparent as the Sigma 180 on Canon 5D III we'd seen originally. In several cases you really had to compare the RAW and JPG images to be certain it was there.

The image below, for example, is the Tokina 11-16 f/2.8 shot on a Canon 5D Mk II. It does show an odd illumination with the upper and lower center being lightened (the test chart in the picture is evenly lit to within a lumen across it's entire surface). If this picture was a landscape you might not really notice it, or might just notice the darker edges and consider it vignetting. But if you shoot the same image in RAW and then convert it to JPG, or shoot it with peripheral illumination turned off, the chart appears evenly lit.

 

 

With all of the "ON" lenses in the table above, if you turn the Peripheral Illumination Correction off in the camera's menu, the Exif data shows it is, indeed, off.

I only have gathered data for 4 of the Canon cameras, taking the opportunity of a recent firmware upgrade to compare the 7D with versions 1.2.5 and 2.0 firmware. If you don't see a lens-camera combination you are interested in, please email me. Not as in 'email me and ask me to check it.' Instead, download Exiftool and email me the results after you've done the test yourself and I'll post it.

I am completely and totally done with this. I've removed Exiftool from every computer I own. I will never check this stuff again. Ever. Probably.

More Questions, of Course

If you've been following the blog lately, you probably realize I have an amazing inability to stick to one subject for very long. But much of my interest lately has revolved around how cameras and lenses communicate during autofocus. This ended up being yet another camera-lens communication issue, and it's a bit puzzling.

Canon cameras know if a Canon lens is mounted, but there is no peripheral illumination data available, don't try to correct peripheral illumination. When a third-party lens is mounted, they usually know to not correct peripheral illumination, but not always. It varies from camera to camera and lens to lens. There's no obvious pattern to it that I can see.

It doesn't appear to have anything to do with the Lens ID the third-party lens uses. It changes from camera to camera. While we only have one example of a firmware upgrade tested, that didn't change any of the 30 something lenses we tested on that camera.

I don't even understand what the "OFF" signal is. If it was a simple code from the firmware of the lens, then I would expect one lens to have problems on all cameras. But not one lens has the issue on every camera tested.

So if some of you understand what's going on better than I do, help me out and post a comment. I've found out what is going on. I would love to understand why.

 

 

Roger Cicala

Lensrentals.com

August 2012

17 Responses to “Canon Illumination Correction and Third-Party Lenses”

Dave Dugdale said:

Wow thanks for all the hard work on this one Roger. I have the Tamron 24-70 VC on my 5D3, so that is good info to know.

john edwards said:

Roger you are the man. With the long weekend coming up I suppose you are going to do this test with Nikon cameras for Tuesday's Blog.

Me, I'll be in Finland on Tuesday so excuse me if I don't comment.
John

LensRentals Employee

Roger Cicala said:

John,

I don't think Nikons have the peripheral illumination issue with third-party lenses like this. But regardless, I'm going back to testing Nikon AF systems for the other article I promised to have ready two weeks ago.

Roger

Charles Lanteigne said:

(I apologize if this has already been assessed, I just didn't see it mentioned in the article.)

Using Canon's "EOS Utility", you can manually register/unregister lens correction data in cameras that support Peripheral Illumination Correction. Have you checked that the lens profiles of the Canon-lenses-the-third-party-identify-themselves-as had been equally registered in all the cameras?

For example, for my 5D Mark II, I registered only the profile for the lenses I own, which excludes the EF 20-35mm (since there is no way I'd ever use that lens), so I would imagine, on my 5D Mark II, the Tokina 12-24mm would NOT present the issue.

Makes sense?

Joe said:

Geek, we all appreciate the extensive work you do. I can see how 'liar lenses' can be a huge issue if in the wrong hands. Knowing 3rd party folks won't update their lenses, can we ask Canon to include a 'lens is a liar' in the MFA menu?

Siegfried said:

Dear Roger,

As a geek I can only explain it the following way: that different cameras (by a camera I mean a certain model running under a certain firmware) go with different lens databases inside. Or with different versions of the same database. This is the theory - more or less probable, though slightly absurd - which fits your results, although it doesn't make any sense to me from IT-engineering perspective.

And by the way, you've done a great work, sir!

Alles gut,
Zig

mshafik said:

Exactly what Charles said, I came here to tell you this, but he explained it very good.

LensRentals Employee

Roger Cicala said:

Charles and Mohamed,

That makes perfect sense. As a rental house, though, we aren't able to do that so having the data available will help our renters who get a camera and third-party lens know what to expect. Or really, at least know they need to check before shooting 1,000 jpgs and finding out their all not quite right.

Thanks for the input -- I think every third-party lens owner should be doing exactly what you describe.

Roger

Roger Knight said:

Roger -
Now that you've shot so many extra exposures for this test and your Leica MM review would it be possible to get a deal on a "well used" 5D MK3? I don't shoot Canon, but with the right incentive I might be tempted.
Aloha.

StefanMc said:

For each camera model was the same body used for all the tests? If so, then it doesn't seem likely the illumination correction database in the camera is the cause of the problem.
For instance both the Tamron 70-300 Di VC and 17-50 VC use the 28-70L ID code, but only the 70-300 showed the issue here. Same with the lenses using the 85 f/1.2 ID code, the Tokina lens and some of the Sigma lenses using that code showed problems, but the Tamron one didn't... If several bodies of the same model were used to get the data for the charts this doesn't really mean anything though, which I am hoping is the case.

LensRentals Employee

Roger Cicala said:

Stefan,

I'm not sure I understand the question, but in each case we tried several copies of each lens on a couple of copies of the camera. Every Tamron 70-300 or 17-50 identify themselves as 28-70s. On some bodies they get automatic peripheral illumination correction (every copy of the 70-300 placed on any copy of the 5D II, for example). Which is why we don't think lens ID has anything to do with peripheral illumination correction.

Roger

Caleb Luke said:

Unfortunately I am experiencing this with the Sigma 180mm 2.8 OS on both my 5D MKIII and 1DX, both JPEG and RAW.

Rohan Gupte said:

Roger,

Thanks for all the hard work. I rarely use third party lenses with my Canon body so this may not pertain much to me. But there was one other thing on the PIC that I had encountered when I did some testing a few weekends ago. I upgraded by 5D Classic to a MKII and found some odd behavior with PIC, focusing and the self-timer function combined together. I did this testing on a 5D and then the Mk II. In case you find yourself without a thing to explore or look into, I would welcome if you wanted to look into the issue that I extensively blogged about here: http://www.rohangupte.com/blog/files/upgrading-canon-5d-to-canon-5d-mark-ii.php

Thanks for all that you do - I don't say this often to you...

Regards,
Rohan

jn said:

Two discontinued lens + older version of Sigma 70-200mm.

Lens 3rd. party ...

With Canon 5DIII Peripheral illumination turned on.

Sigma 24-60mm f2.8 EX DG
exifTool reports ...
Lens Type ... Canon 28-70mm f2.8L or Sigma or Tamron lens
Lens ID ........ Sigma 24-70mm f2.8 EX
Peripheral illumination state off, value 0.

Sigma 17-35mm f2.8-4.0 EX DG HSM (later of these models)
exifTool reports ...
Lens type ... Canon EF 28-80mm f2.8-4L or Sigma lens
Lens ID ....... 100% correct ID of this lens
Peripheral illumination state off, value 0.

Sigma 70-200mm f2.8 APO EX HSM (film era version)
exifTool reports ...
Lens type ... Canon 28-80mm f2.8-4L or Sigma lens
Lens ID ....... Sigma APO 50-150 f2.8 [II] EX DG HSM + 1.4x
Peripheral illumination state off, value 0.

ruevs said:

Hi Roger,

Here is a theory:

Apart from the lens type the lens reports to the camera its focal length range, the currently set focal length and the maximal aperture.

While using IDs of existing Canon lenses (simply because Canon would not allocate their own) third party lenses may report their actual focal length range and aperture.

Using the above data the camera firmware can distinguish the third party lens from the Canon lens it "mimics"(this is what ExifTool does I believe). Once it has done this it is logical to not apply illumination correction in order to avoid the described problem.

The discrepancies may be due to the database in the firmware of different cameras being different (more or less complete, more or less wrong). I can not imagine Canon putting too much effort into this - it is a great opportunity to say "Use only Canon lenses, we do not guarantee results with anything else".

Here is an example of the camera firmware logic that I am suggesting (built from your data above):

"A lens that identifies itself as Canon 85 f/1.2 L but reports a focal range 17-50 and f/2.8 must be a "Sigma 17-50 f/2.8 OS"

Brent March said:

I have experienced this problem with the Sigma 85 1.4 lens on my Canon 5D mark iii. I ordered replacement lenses as my camera store was puzzled as well and finally contacted Sigma who advised me of the peripheral illumination issue. I have used a wide variety of Canon lenses without issue on this camera but this venture left me in a conundrum. Love the lens but have a large headache.

Thanks for letting me know I wasn't alone in this experience. You do good work.

Martin Helthuis said:

I have the new sigma 35mm 1.4 dg hsm. Could you tel me please with specific cannon lens it corresponds in the eos utility software? Thanks for doing this.

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