Canon 5DS and 24-70mm f4L IS Lens

[JoeDavid]

I took some additional  test shots with the 5DS and 24-70mm lens on a tripod with IS turned off.  I took essentially the same shot at f8, 11, 16, and 22 in order to evaluate the sharpness of the overall image.  Here is a down-sampled version of the scene:

http://www.throughjoeslens.com/Temp/TheScene.jpg

 and here is a resulting 100% crop from each image:

http://www.throughjoeslens.com/Temp/Crop100.jpg

Make sure to view them at 100%.  Web browsers tend to scale them down to fit the current window size.

The raw files were processed with the exact same settings in Photoshop.  Notice the progressive softening of the 100% crop images with the most noticeable hit to the sharpness happening from f16 to f22.  I believe that I read that the Diffraction Limit Aperture of the 5DS is f6.7 due to the pixel size (similar to the 7DM2).  Plus the lens itself may perform better at specific apertures.  I did the test with several runs and two different scenes to make sure the results were repeatable.  I used Live View to focus in the area of the scene where the 100% crop was taken from and the 2 second timer to trigger the shots.  Basically, I minimized the possibility of camera shake with every trick I know.  Since the shutter speeds got progressively slower, ignore some of the softness in the foliage since there was a slight breeze.  The rocks don't lie though.  They definitely weren't moving.  To be honest, with 50MP, the f8, f11, and f16 images could be printed at 20x30" and you probably wouldn't notice a difference other than the depth-of-field difference and that's only in the extreme foreground.  I think softness of the one taken at f22 would be visible if compared at a very close distance to one of the others.  I plan on repeating a similar test with Canon's 17mm TSE lens to get a better handle on how much of this softening is diffraction and how much was the lens. 

[TCampbell]

Thanks for the post and samples.

I noticed the 100% crop area you selected is located about 10mm away from the center axis of the lens.  Since lenses tend to provide the highest level of detail at the center, I'm wondering how much different is it if you inspect the 100% crop area at the center point of the image.  

[JoeDavid]

The 100%crops are from the area where I had the camera focus so that the DOF would extend through most of the scene at all 4 apertures.

The next test I do now that I know that diffraction is more of an issue will be something like a brick wall so that the plane of focus can be parallel to the wall. That way the whole image can be examined for critical sharpness. It also makes it easier to check wider apertures since DOF wouldn't be a factor in assessing sharpness.

[JoeDavid]

Sorry to be a while getting back to this.  The day job has been pretty demanding lately.  I finally took another shot at multiple apertures for comparison, this time with the 17mm f4L TSE lens.  First the conditions were 5Ds on a tripod, manually focused the lens on the brick in the center of the scene using magnified live view, identified the exposure I wanted in Manual based on the live histogram, and then switched to Av and dialed in +2/3 compensation to get the same exposure.  I took all apertures from f4 through f22, even the 1/3 stops but I'm using full stops for this comparison.  Here is a link to a down-sampled version of the non-award winning scene.

http://www.throughjoeslens.com/temp/TheScene2.jpg

I've highlighted the areas where the 100% crops were taken from with the first crop being from where I focused the lens.  If this was an award winning scene, I'd want good depth of field throughout so the other three crops represent areas of interest to inspect image sharpness in conjunction wtih depth of field.

Crop 1, the focus point.

http://www.throughjoeslens.com/temp/Crop1.jpg

There are several observations that can be made from this crop.  Number 1 is that the lens is as sharp in the center at f4 as it gets!  There's not a whole lot of detail difference between f4 and f5.6 but the image contrast is a little better at f4 which makes it look a little sharper to me.  Similar to the first post about the 24-70mm f4 IS shot taken at 61mm, f22 doesn't fair well at all.  Image quality takes a noticeable hit from f16 to f22.  The other apertures just show a slight degradation of image sharpness as you move from one to the other.  One thing to note is the reduction of image contrast as you move up in apertures, especially f8 and above.  That's a side effect of diffraction.

Crop 2, far DOF.

http://www.throughjoeslens.com/temp/Crop2.jpg

First thing to notice is that vignetting is strong enough with the 17mm lens wide open that the f4 crop is noticeably darker than the other apertures.  When looking at this crop remember that the front roof is almost in-line with the wall where the plane of focus is so I'm judging the DOF using the far roof line of the other house where it meets the trees.  To me it looks like it definitely gets sharper from f4 to f5.6 and maybe slightly more so at f8.  F8 to f11 is pretty close to the same while f16 is softening a little.  Ironically f22 isn't providing any obvious increase in DOF and is in fact the fuzziest of all the crops.

Crop 3, near DOF.

http://www.throughjoeslens.com/temp/Crop3.jpg

Again the f4 crop is a little bit darker due to vignetting and is obviously fuzzy due to lack of DOF.  F8, f11, and f16 are almost a toss-up but I'll give it to f11.  In this crop f22 looks better than f4 due to the lack of DOF in the f4 shot.  Oddly it looks pretty close to the f5.6 crop as far as image softness goes. 

Crop 4, shadows and reflections.

http://www.throughjoeslens.com/temp/Crop4.jpg

Again the f4 crop suffers from lack of DOF and vignetting.  F5.6 is OK but f8, f11, and f16 appear to have the sharpest reflections.  F22 softens up and, in this case, is worst than f5.6.  The one thing I don't like seeing in all of these crops is that, even at ISO 100, the shadows could use a little noise reduction (look at the white window frames). 

Oh well, I promised a follow up and that's it.  If it was a print worthy image, I'd probably apply a mild unsharp mask sharpening and use the f11 shot as the best compromise of image sharpness and DOF.

[ebiggs1]

I don't have the 5Ds but I suspect you are going to notice every possible discrepancy. I don't shoot at f22 on my 1Ds Mk III, unless I believe the defraction is not going to be a factor.

You are probably going to have to go to primes to get the best from the 5Ds.  Although the EF 24-70mm f2.8L II is fantastic, it too has its limits.

You turned off IS ?  

[JoeDavid]

On the original test with the 24-70mm, yes.  Of course the TSE lens doens't have it.  I have a collection of prime lenses and certainly they will be used for specific landscape photography but it is usually impractical for travel photography where I need a wide range of focal lengths and have limited space to carry the equipment.  If I think I'll have the room on the planes (i.e., was able to avoided smaller planes when booking flights), I take a larger backpack with a butterfly design.  The two separate sides allow you to get at the equipment without exposing all of it to the greater likelihood of dropping something out.  I usually carry two camera bodies with a lens attached; one with an all around zoom like the 24-70 2.8L II and one with a telephoto zoom like the 70-200 f2.8L IS II, 70-300L, or the newer 100=400L IS II.  In addition to the two cameras I can pack in an additional 2 to 4 lenses depending on the size of the lens.  Usually the newer 16-35 f4L IS is one of those and maybe a TSE or macro lens.  The 24-70mm f4L IS is especially attractive for travel since it has the 0.7x macro mode and eliminates the need for a separate macro lens.  I do hate that Canon took that route instead of updating the 24-105/4L IS lens.  It is a better range as a walk-around lens on full frame.  I guess with having the 5Ds now the second bodie will be the 5DM3 with the telephoto zoom on it.

I've also picked up one of the new 11-24/4L ultra-wide zooms.  It won't go on many of my future trips though since it is so specialized that it would rarely be used with most travel photography.  It is so large that it would have to replace both the 16-35mm and one other lens.  It would be good inside cathedrals but, if a tripod isn't allowed and with no IS, I'd have to up the ISO quite a bit.  At that point I'd definitely use the 5DM3 for better higher ISO performance. 

[ebiggs1]

"You turned off IS ?"

Sorry, I missed the fact you used the 24-70mm f4L.  I assumed it was the 24-70mm f2.8L II.  I don't really understand why you would use it, if you do have the f2.8 version?  But whatever.

You certainly carry a lot of stuff.  Way more than I would or do.  My unsolisted thoughts;

11-24mm f4L

24-70mm f2.8L II

70-200mm f2.8L II

11-400mm f4.5-5.6L II

IS is of little value on the 11-24mm so, to me, that is no concern.

You have a lot of great gear there! 

[RobertTheFat]

---

@ebiggs1 wrote:

"You turned off IS ?"

Sorry, I missed the fact you used the 24-70mm f4L.  I assumed it was the 24-70mm f2.8L II.  I don't really understand why you would use it, if you do have the f2.8 version?  But whatever.

You certainly carry a lot of stuff.  Way more than I would or do.  My unsolisted thoughts;

11-24mm f4L

24-70mm f2.8L II

70-200mm f2.8L II

11-400mm f4.5-5.6L II

IS is of little value on the 11-24mm so, to me, that is no concern.

You have a lot of great gear there! 

---

Who makes the 11-400?? Without even looking it up, I'm going to bet it isn't Canon.

[JoeDavid]

Realize that you can just about buy all of the lenses mentioned for the price of one of Canon's series II "big white" lenses.  Fortunately I don't do serious wildlife or sports photography any more.  As for the travel photography, when I go it is for photography so, yes, I carry what I can get on the plane with.  Sometimes I'm headed to a country that I'll probably never make it back to.  I'm not a small person so the weight is not generally a big deal to me if I'm using a good backpack.  Where IS is concerned, I shoot a lot with a tripod but there are times and situations where it is impractical or simply not allowed.  IS comes in handy there.  If I don't need to stop action, say in an old European cathedral or castle, the IS of the 24-70mm f4 more than makes up for the 1 stop f2.8 version especially since I may be using f4 or smaller anyway.  IS helps keep the ISO down a couple of stops which equals better image quality most of the time.  Plus I don't buy the line that you have to use a tripod to get a sharp shot; even with a 50MP camera.  I've got too many images that prove you don't.  Technique and taking multiple shots if possible can yield a very sharp image, even without IS.  Obviously it depends on the focal length, the actual shutter speed, and how well you can brace yourself (human tripod of sorts). 

[ebiggs1]

If sharpness is your main concern the f2.8 version without its IS is sharper than the f4 version with it.  If you read the lab tests. You may be fooling yourself with that thinking.  It isn't even close but everyone is different and see things differently.  And you can read the charts as well as I.