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Chromatic Aberration with 1785mm EFS


Well-Known Member
I recently bought a 20D with the 17-85mm EFS lens and, though I'm very impressed with the camera, I have had horrible problems with chromatic aberration with this lens.
There are thick magenta or blue bands at the edges of the image (high contrast borders), particularly at the wide angle end.
I have had the lens replaced by the supplier and the same poor quality was evident with the 2nd lens.
I have now opted to change for the 17-40mm f4L as I have no faith in these new EFS lenses.
This is my first experience with Canon as I have used Contax/Zeiss T* for the last 20 years. I was astonished that Canon could put out such c**p at a supposedly high end level (£470 is not a cheap lens).
I assume the EFS lenses do not use low dispersion glass, they obviously need it.
Has anyone else experienced this problem?
P.S. I've also just got a 70-200mm f2.8 IS and that is an absolute beauty, I can highly recommend it (maybe Canon reprieved themselves a bit with that one).


Well-Known Member
Hello Matt

I too switched from 20 years of Contax/Zeiss to Canon earlier this year, starting with the 10D and now the 20D. The 20D is A LOT of camera for $1,500 ... especially when you compare it to the N-Digital.

Yes, unfortunately Canon's "consumer grade" lenses can be very nasty and I would steer clear off those lenses. Most (but not all!) of their L-series and macro lenses are very good though, especially their long lenses. Their wide angle lenses are not as good.

Before you buy more Canon lenses, check the user reviews at the FM Forum to see the ratings and what users have to say about it:

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You may also want to check the ratings on Photodo.com.

Happy shooting!



I'm in the same boat as you guys, but the only thing drawing me out of my ND is the 1Ds Mk II. I'm planning on getting the 24-70L and 200L for serious shooting and the 70-300 OD for more casual snapshooting. I'll see where I go from there. I know I'm going to miss my Zeiss 24-85 and 70-300 lenses at times, but I hope not all the time

Waiting for the 1Ds Mk II (I keep hoping Contax will announce a new ND before then - fat chance)


Well-Known Member
I went Canon digital quite awhile ago, while still plunking around with Zeiss and the ND. Except for the 50/1.4 which is non L, stick with Ls even for goofing off. The 50 is really inexpensive and outperforms the N 50/1.4 in the Bokeh department. Sharp as hell also.

Here's a tip, Canon's discontinued 20-35/2.8L is one of their best zooms ever. The 70-200/2.8 non IS is a better optic than the IS version IF you can hold it steady.

If you shoot RAW with digital, and use PSCS RAW developer, you can correct aberrations pretty well in the advance set of controls under "lens". Magenta edging sometimes happens with digital when a hard light edges an object. Edge vignetting from wide angles can also be corrected in seconds.


Well-Known Member
I believe Canon's 135/2.0L is better than the 200/2.8L. Their 200/1.8L is another matter, but that lens cost an arm and a leg. That and their 300/2.8 IS and 400/2.8 IS are all awesome lenses, and they will all work well with the 1.4x TC.

I have a 50/2.5 macro and I find it incredibly sharp with terrific resolution and color. The focussing is a little slow and the non-USM motor is rather noisey, but if you can live with that, I think the 50/2.5 macro can match the performance of the Zeiss 50/1.4


Well-Known Member
Thanks for all the comments and advice guys, I've read many reviews now and will look into the PSCS RAW developer - sounds useful.
I've checked some shots with the 17-40mm F4L received today and it's definitely better, though there are still slight magenta edges with a strong light source, it is more acceptable and the general build quality inspires more confidence.
FYI I have taken shots with my Zeiss 21mm f2.8 using a CY-EOS adapter and there is absolutely no evidence of the problem under identical conditions (I knew there was some reason I had stuck with Contax for 20 years!). I think I shall probably keep this lens for the meantime until I have more experience with the 17-40mm.
I have also taken shots with my Zeiss 100mm f2.8 Makro Planar on the 20D, the results from these are astounding. Interpolating to 30"x20" the detail is beyond belief and I will definitely be keeping this lens, as there is pretty much no need for autofocus at 1:1 and I really can't see how any lens could possibly improve on these results.
From what I can see Canon are going to be best at the telephoto end, and having read many of the reviews, I think the next purchase is going to have to be a 300mm f2.8 IS (sorry, it's HOW MUCH??!!) I just have to justify the expense now...
Thanks again guys.


Well-Known Member
Matt, your Distagon 21mm and Makro Planar 100mm lenses are definitely keepers and it looks like it will work very well with the high-resolution and low-noise 20D. You must be one happy c&er!

Can you imagine how much better it will be if you shot these lenses with the new 16-megapixel full-frame 1Ds Mk II? I think it will blow any medium format film camera out of the water. Wow ...

It looks like you don't have any focussing issues either. I discovered just this morning that my 20D is back-focussing by 6mm or 1/4" ... what a bummer! I shall have to take it to a Canon Service Center for re-calibration or re-alignment.


Well-Known Member
Hi Bobby,
When you say your 20D is back-focussing do you mean with Canon lenses or with adapted Zeiss lenses?
The reason I ask is that I have noticed (more with the 21mm) that using the adapter, infinity focus is actually not at the infinity setting on the marked scale, I have to set it to about 6ft or 2m to focus correctly at infinity.
I think this is because of the thickness of the adapter moving the lens a couple of millimetres further away from the camera, which of course is a huge amount as far as point of focus is concerned.
It is more difficult to notice on the focussing screen using the 21mm because the detail is so small. Obviously with the makro planar I'm generally moving the camera to get focus at 1:1 so it's not as relevant.
And yes I am soooo pleased with the results with the 100mm. Full frame on the 21mm? - get thee behind me satan!!


Well-Known Member
Matt, the test I did was with Canon lenses on auto-focus. Very oddly, when I did the test in manual-focus mode with the same lenses, the problem was reversed ... it focussed in front of the focust point! Really weird. Didn't do any test with my Zeiss lens.

But I did help a colleague this afternoon with the same test using his 1Ds and Leica manual-focus R lenses with a CameraQuest adaptor ... and they all focus perfectly ... spot on! I would therefore have to assume that the Zeiss lenses would behave the same way i.e. you should not have any focussing issues either.