Prime over zoom, much difference.

[thebigsky]

I'm currently using a Canon 5D with a 17-40L for shooting landscapes, however I'm getting a little fed up with the amount of image problems in the corners of the images, fringing etc.

Do you think I may have a particularly poor example or is this to be expected with a zoom, if I buy a prime am I likely to see a jump in quality?

Charlie

[mercphoto]

I'm interested in this as well as I'm about to buy a 17-40, which I have generally heard great things about. Canon wide primes, however, I've heard hit and miss about.

[Glenn NK]

A good part of the problem may be that the 5D uses the full width of the lens where vignetting and distortion are more prominent.

The 1.6 crop models such as the 10/20/30D and the XT's, only utilize the best part of the lens (the centre).

[gluwater]

I think it all depends on how picky you are. From what I've seen all Canon wide angles have issues with corner sharpness, primes and zoomes alike. If you really want a sharp image across the frame you are going to have to go with a Zeiss Distagon or Olympus Zuiko. Those are really some of the only lenses I have seen images from that truely have a sharp image across the entire image. Check out this article (http://theonlinephotographer.blogspot.com/2007/01/canon-5d-wide-angle-night-photography.html)
Personally I find the 17-40 acceptable, but it is definitely not as sharp in the corners as it is in the center.

[wxwax]

You're going to have softness in the corners with the 5D. Same with the 16-35 and the 24. I agree, very frustrating.

The solution is to spend an ungodly amount of money on the glass Andy bought, a Distagon 21mm.

[gluwater]

The solution is to spend an ungodly amount of money on the glass Andy bought, a Distagon 21mm.
Didn't he buy that one twice and sold them both?

[marlinspike]

Take a picture on a full frame with the lens at 17mm and f/7.1, shoot it in RAW and do a little vignetting repair in the raw conversion process. Do some unsharp mask, contrast, the usual things. Print it at 24x36 and tell me if you find the corner sharpness to be an issue. I've found things that don't look so great on the screen look fine in print sometimes.

Or get one of the new Zeiss 25 2.8 for Nikon mount and put a Nikon to Canon adapter on it, though that won't be ultra wide like the 17mm.

[wxwax]

Didn't he buy that one twice and sold them both?
Not sure if he still has one or not.

[wxwax]

Canon's announced (http://www.usa.canon.com/templatedata/pressrelease/20070221_1dmark3.html) a new 16-35.

Sounds like it's meant to adress corner softness on full frame sensors.

EF 16-35mm f/2.8L II USM Lens:
A new EF 16-35mm f/2.8L II USM Lens succeeds the versatile EF16-35mm f/2.8L USM Lens as a high-performance L-series wide-angle zoom lens, specifically designed for improved peripheral image quality. Compatible with all EOS SLRs past and present, it uses three high-precision aspherical lens elements and two Ultra Low Dispersion (UD) lens elements to minimize lateral chromatic aberration and to produce superb image quality with excellent resolution and contrast. New coatings minimize ghosting and flare. It is an internal focus design, so the front element does not rotate during focusing and zooming, a convenience for users of circular polarizer filters. The lens is also fully gasketed and sealed for dust and moisture resistance, and it features an electronic diaphragm with circular blades for natural-looking background blur effects.

[thebigsky]

Thanks everyone for taking time to reply, seems as though I'm stuck with this problem.

I have a 20D as well, I could try that, or I could compose the image I want inside the actual frame with the intention of cropping out the problem areas.

Seems as shame though to lose that resolution and have something else to think about.

Charlie

[Andy]

Not sure if he still has one or not.
:nod I do, I do...

[erich6]

Thanks everyone for taking time to reply, seems as though I'm stuck with this problem.

I have a 20D as well, I could try that, or I could compose the image I want inside the actual frame with the intention of cropping out the problem areas.

Seems as shame though to lose that resolution and have something else to think about.

Charlie

Charlie,

There's another option. Check out www.dxo.com (http://www.dxo.com) . Their software is specially designed to remove the imperfection of lenses. They do this by applying the mathematical inverse of the aberration that cause image problems.

You can download a trial version and see if this corrects your corner issues. I believe they have the 17-40mm lens module for the 5D. I use the software on my 20D and it does wonders (it also has a great lighting and noise reduction module).

This could solve your problem without having to invest in another lens.

Erich

[LiquidAir]

Rectilinear lenses between 14mm and 24mm are problematic for full frame Canon mount. I have been looking for quite some time and there are aren't any really good answers (except for the CZ 21mm if you can stomach the price). The Nikon 17-35 is supposed to be better than either of the Canon offerings in this range and you can adapt it to Canon mount. For landscapes, I am considering getting the 24 TS-E and stitching. Right now I plan to wait and see if Canon finally got it right with the 16-35 II.

BTW, Andy, where did you get your CZ 21mm?

[thebigsky]

Charlie,

There's another option. Check out www.dxo.com (http://www.dxo.com) . Their software is specially designed to remove the imperfection of lenses. They do this by applying the mathematical inverse of the aberration that cause image problems.

You can download a trial version and see if this corrects your corner issues. I believe they have the 17-40mm lens module for the 5D. I use the software on my 20D and it does wonders (it also has a great lighting and noise reduction module).

This could solve your problem without having to invest in another lens.

Erich

Thanks Erich, I'll take a look, I've tried the tools in Photoshop but don't seem to get satisfactory results.

Charlie

[ziggy53]

Thanks Erich, I'll take a look, I've tried the tools in Photoshop but don't seem to get satisfactory results.

Charlie

Also check out "PanoTools", PTLens:

http://www.epaperpress.com/ptlens/index.html
http://wiki.panotools.org/Chromatic_aberration

In some cases, PTLens matched and even surpassed DXO:

http://www.dpreview.com/reviews/dxoopticspro/page3.asp
http://www.dpreview.com/reviews/dxoopticspro/page4.asp

[erich6]

Also check out "PanoTools", PTLens:

http://www.epaperpress.com/ptlens/index.html
http://wiki.panotools.org/Chromatic_aberration

In some cases, PTLens matched and even surpassed DXO:

http://www.dpreview.com/reviews/dxoopticspro/page3.asp
http://www.dpreview.com/reviews/dxoopticspro/page4.asp

Interesting review Ziggy. I wonder how the tools would compare now that DxO is at v4.1 (the review was for DxO v1.1). Either way it's another choice.

Erich

[ziggy53]

Interesting review Ziggy. I wonder how the tools would compare now that DxO is at v4.1 (the review was for DxO v1.1). Either way it's another choice.

Erich

The great thing is that PanoTools and PTLens are "freeware", so you could try it yourself.

I understand too that DxO is so much easier to use, and that should be factored in to a decision to purchase. (If you don't use PTLens because it's too much trouble, it doesn't matter if it's free or not, it's not much value.)

[erich6]

Thanks Erich, I'll take a look, I've tried the tools in Photoshop but don't seem to get satisfactory results.

Charlie

Charlie,

Please do let us know if any of these tools work out for you.

Erich