Pages

Monday, April 18, 2016

Aurora HDR - The New Champ?

Aurora HDR was released in 2015 for $99 direct from Aurora or $25 for a standard version on the Apple App Store. It is currently Mac-only, but Aurora alluded to a Windows version later in 2016. It competes directly with my three long-standing favorites: Nik’s HDR Efex Pro 2,  Photomatix Pro 5, and Lightroom's HDR Merge. But is it better? 

Aurora Standard vs. Aurora Pro
Though Aurora’s website says the standard version is $39.99, I paid only $24.99 on the Apple App Store, so go figure. You can later credit the standard's cost to a Pro upgrade. Below are the major items lacking in the standard version and my opinion as to the impact.

No raw support
You can’t import raw files and instead need to convert them to TIFF. In my opinion, this isn’t much of a loss since any previous raw edits are not carried over. I always, as a minimum, adjust white balance, apply noise reduction, and enable lens profile before transitioning to the HDR software. With Aurora, just as in Photomatix, you have to do those edits after the fact if you import raw files. If you want any previous raw edits to carry over, you have to convert to TIFF first. That is what I routinely do for Photomatix anyway (HDR Efex Pro automatically does the TIFF conversion for you), hence this isn’t an issue for me.

What, no raw support is no big deal!? 
Those who have read my ebooks or previous posts know that I’m a rabid raw advocate. It’s not that I wouldn’t like raw support (even if prior raw edits aren't supported), it’s just that in the real-world, it’s unlikely you’ll see any difference. Difficult highlights in improperly bracketed exposures may possibly render better using raw files, but that depends on how Aurora performs the conversion. As long as you exercise proper HDR bracketing techniques, you shouldn’t have a problem with TIFF files. 

[Update: Aurora just introduced a $4.99 app that adds raw file support to the standard version.

No deghosting
Given my general distain for this feature, I’m incline to say good riddance. If you really need deghosting, it’s better to use Photomatix Pro because it allows selective deghosting. You don’t need to tone in Photomatix if you don’t want to, just save the 32-bit file after it deghosts the image. Then, you can tone the file on a different HDR program instead.

No luminosity and gradient masks. 
This pertains to the biggest “wow” feature in Aurora: it supports layers and masks! A luminosity mask allows you to easily select either highlights, mid-tones, or shadows and perform separate HDR editing. That’s a terrific feature because sometimes it tough perfecting all the major tonal areas without compromising. HDR Efex Pro has its Selective Adjustment tool that helps in this regard, but that is trumped by Aurora’s layers feature. In lieu of gradient masks, the standard version provides brush tools to customize a layer mask; so though not anywhere as convenient, you do have a workaround. 

The rest

There are other minor differences that you can view on Aurora’s website, none that I judged important.

Tool Set Overview
To keep this review brief, I only address the task of producing a realistic landscape image. If you’re into the grunge or pseudo-realistic look, you’ll need to explore that on your own; though I’ll say briefly that Aurora won’t disappoint in that regard. I also hit only the highlights of the major tools and how they compare to the other HDR programs.

First impressions
I don’t think Aurora ever heard the old saying: less is more. You are initially overwhelmed with an array of tools, some of them obvious as to function, and others with odd titles like Spectrum and Final Touches. Don’t expect Aurora’s numerous video tutorials to help. They’ll worth viewing just to get the overall flavor, but they do a poor job of explaining exactly what each slider does. You’ll need to download the pdf user manual to get a better description, though it can still be wanting.

Presets
Aurora includes several presets that cover the usual spectrum of HDR applications. However, I never use presets because most times I find them useless. Even if one is close, I find fine-tuning a preset is more work than just starting from scratch where I can follow a familiar workflow. You should still play with them just to get a feel for the scope of Aurora's capability.  I was, however, a bit amused by their  landscape "realistic" preset, which I felt deviated considerably from the dictionary's definition of the word.

Tone Mapping (Spectrum, Spot Lighting, and Final Touches)
Only Camera Raw and Lightroom’s HDR Merge make tone mapping a straightforward task. Everyone else seems to think it should be mysterious. Fundamentally, tone mapping is adjusting the dynamic range, which is what Photomatix and HDR Efex Pro do (albeit in their own peculiar style). Aurora’s Spectrum slider instead acts as an exposure adjustment that tapers at the endpoints to prevent completely white or black areas. In other words, it behaves somewhat like Camera Raw and Lightroom’s Exposure adjustment. 

The Spot Lighting slider is a puzzling tool that backlights detail to highlight it. Increasing it can cause halo problems, so you’ll probably want to leave it alone and wonder why it’s even there. Aurora doesn’t give the Final Touches slider a very quantitative description other than right is more realistic and left is more “detailed.”

At the end of the day, you usually don’t need to worry about these sliders. Even Aurora says to leave them at default unless you’re dealing with a unique problem. I suggest you collapse the menu and, as Tony would say, fuhgeddaboudit!


Tone
With the exception of an added Midtone slider, this panel is essentially a one-for-one equivalent to Camera Raw and Lightroom's Basic panel (Smart Tone being similar to Exposure). HDR Efex Pro is also similar in this respect, which is why both programs have a superior advantage over Photomatix’s more arcane adjustment process.


Structure
Aurora's detail enhancement adjustments are superior to HDR Efex Pro and Photomatix. For one, it doesn’t suffer from the noise emphasis that plagues HDR Efex Pro’s Structure adjustment. You also have more adjustment options, though I think they’re a bit overkill. 

For starters, you have the familiar Clarity adjustment found in Camera Raw and Lightroom. Next is the HDR Look, which the grunge lovers will certainly want to crank up. But for traditional landscape work, you’ll likely reduce the effect by moving the Amount slider to the left. Sometimes when trying to maintain a perfectly natural appearance, you still pickup a tinge of that pseudo-realistic HDR look. This adjustment allows you to back that off a bit. Also, this slider may help eliminate minor haloing. But in most cases, you probably want to leave the HDR Look sliders alone and adjust only Clarity.

The Softness and Boost sliders are active only when the Amount slider is adjusted off its zero setting. Softness performs as the name implies and Boost is essentially a gain control. Also, the polarity of these two sliders reverse depending if the Amount slider is positive or negative. For example, for a positive Amount value, a positive Softness value softens the image. For a negative Amount value, a positive Softness value has the reverse effect.

HDR Detail takes the HDR Look down to a finer detail and, as such, can mimic sharpening and induce noise. It’s best to avoid this adjustment unless you’re desperate to spike up your image.


Color
This panel is similar to the one in HDR Efex Pro except it adds a Vibrance slider, which is similar to the same slider in Camera Raw and Lightroom. There is also a Color Contrast slider that is mostly a play-around-with toy and likely not to see much use. Nik has a similar feature in its HDR Color Efex Pro (which comes with HDR Efex Pro). 


Detail
This is a sharpening utility exclusive to Aurora. All the controls are conventional and self-explanatory. Instead of a usual single-radius adjustment, you can choose individually or collectively between small, medium, and large details. However, unless you're trying to accomplish all the image editing within Aurora, I recommend waiting till Photoshop or Lightroom. In my case, I use Nik’s Sharpener Pro, which automatically factors in all output-specific parameters. (Click here to see my review on Sharpener Pro.)


Color Filter
This is another feature exclusive to Aurora that mimics a subset of Camera Raw and Lightroom’s HSL/Grayscale panel, but lacks a hue adjustment. Normally, I would defer these type adjustments to either Photoshop or Lightroom. However, you'll need this tool as well as the Color tool to battle the one major flaw in Aurora (which I'll get to shortly).


Some of the Rest
There are Glow and Image Radiance tools that Aurora delights in demonstrating on nighttime cityscapes. There is also a built-in noise reduction filter, which so far I haven’t needed. The Tone Curve tool is identical to HDR Efex Pro’s except it lacks a luminosity channel. However, adjusting the tone curve in Aurora is easier than in HDR Efex Pro, which is very coarse and hard to make fine adjustments. Finally, there is an ND gradient tool, called Top & Bottom Lighting, that is identical to HDR Efex Pro’s Graduated Neutral Density tool. Aurora’s gradient tool is easier to use since it displays reference lines showing the gradient’s position and blend-width while HDR Efex Pro doesn't. 

Image Comparisons
Extra bells and whistles mean nothing if the resulting image is no better than the competition. I compared several images rendered in Aurora against HDR Efex Pro, Photomatix (using Contrast Optimizer tonning), and Lightroom's HDR Merge. At first, Aurora seemed to take over the dance floor, but then it suddenly tripped and knocked itself out.  Turns out there is a serious problem when Aurora renders sunrise and sunset images.

Aurora's Problem
As a landscape photographer, I'm sure you like to take sunrise and sunset images where you have a background lit by a warm, low-setting sun. If so, Aurora isn't for you. The problem is excessive over-saturation, mostly with the warm colors. In some cases, I couldn't control it using Aurora's Color and Color Filter panels and needed to address the problem in Photoshop or Lightroom (if I could). Below is an example of the problem. The image is Cathedral Rock in Sedona, Arizona near sunset. The top photo is Aurora and the bottom is HDR Efex Pro. In both cases, raw files were unedited in Camera Raw before being converted to TIFF. Both images are as they initially appeared after rendering and with all sliders at null (i.e., no presets applied).  

HDR Efex Pro starts out in typical style, an open and somewhat flat image—which is exactly what you want for maximum editing latitude with the HDR tools. The Aurora image was marred by the  over-saturated and garish red-illuminated rocks, with much of it out of gamut. You eventually can correct the problem either with Aurora's color tools or later in Photoshop or Lightroom, but that's not an acceptable solution in my opinion.

Aurora: Image starts out with over-saturated and out-of-gamut warm colors.
Adjusting Color and Color Filter only reduces the problem, not eliminate it.
HDR Efex Pro: Prior to any adjustments, the images starts out
well-rendered with natural color.

2nd Example
Here I show results from all four HDR applications after editing within the applications. In this case, I could control the saturation problem of the backlit autumn tree in Aurora with the Color and Color Filter sliders. I still preferred HDR Efex Pro's rendering of the backlit tree, but on the other hand, the sky was noisy to the point of being noticeable in an 8x10 print. Photomatix and HDR Merge lacked the higher contrast in shadow detail and were less saturated overall. Basically, Aurora and HDR Efex Pro tilted slightly to an HDR "dramatic" look while HDR Merge and Photomatix tended towards a more traditional photo appearance. Which style is best is obviously subjective, but I'm guessing most HDR enthusiasts prefer the added drama. Keep in mind that any of these examples can be further improved in Photoshop and Lightroom.

Aurora: I was able to control the warm backlit autumn-tree
saturation within Aurora.
HDR Efex Pro: Beter rendering of backlit tree, but sky
has noticeable noise.
Photomatix: Good photorealistic results. 
HDR Merge: Good photorealistic results that I preferred over
Photomatix in this particular example.
3rd Example
This image isn't dominated by any sunlit areas (other than the clouds) and I felt Aurora was the best of the bunch. HDR Efex Pro emphasized the detail a bit too much. HDR Merge was good except it had the most problems with the highlights. Photomatix, at first, appears more "plain vanilla" compared to the others. But as I previously stated, due to its open tones it easily lends itself for further enhancement in Photoshop or Lightroom.


Aurora: Best sky rendering and a bit more realistic than HDR Efex Pro 
due to softer texture.
HDR Efex Pro: Very good overall, but a little to much detail
emphasis compared to Aurora.
Photomatix: A more open image that provides good editing latitude in
Photoshop or Lightroom. 
HDR Merge: Good except it struggles with the highlights in the sky.
Conclusion
As I have cautioned in the past, you can’t make a sweeping judgment based on a few images. This is especially true with HDR software that can have a Jekyll and Hyde personality depending on an image’s content and structure. Except in this case, Aurora's over-saturation, especially of warm colors, is a consistent problem. There are a few other quirks too. The screen update to a slider adjustment is sometimes erratic, making it difficult to settle on a final value. Finally, their terminology is a bit unconventional and their documentation leaves a lot to be desired. 

But there is a lot to like about Aurora. Aurora isn’t anywhere the noise maker that HDR Efex Pro is notorious for. Also, Aurora didn’t seem prone to high-contrast edge halos that is also another HDR Efex Pro nuisance. And their Layers feature is dynamite, and along with a rich set of tools and an otherwise excellent tone-mapping engine, Aurora would clearly be the leader of the pack if it weren't for the maddening saturation problem. As it stands now, I can't recommend Aurora for general landscape photography. I have contacted Aurora's technical support and supplied them with sample images. They acknowledged there was "minor" over-saturation and will fix it in the next update. It concerns me they described it as "minor", but if the next update corrects the problem, then I'm ready to declare Aurora the new champ.

[Update: Aurora released a new update (version 1.2.3) in June, 2016. The saturation problem still persists.}

Thursday, March 24, 2016

Nik Collection Now Free

This short blog is to help broadcast the news that the entire Google Nik Collection is now free starting March 24, 2016. If you purchased it in 2016, you will be refunded (automatically, I believe). I have posted many articles on the Nik Collection and you can peruse through the Blog Archive to find them. My favorites are HDR Efex Pro, Sharpener Pro, and Color Efex Pro, all that are now permanent tools in my workflow. Beside those, there is Silver Efex Pro, which is considered by many as one of the best black-and-white conversion programs available. The remaining programs are Dfine (an excellent one-click noise filter); and Viveza and Analog Efex Pro, neither which I use but you may find Analog Efex Pro entertaining.

Click here to download the Nik Collection.

Friday, March 11, 2016

Lightroom's Latest Panorama Feature

In a previous post, I wrote that Lightroom and Camera Raw have replaced Photoshop for stitching panoramas in my workflow. The main reason was the stitched panorama remained a raw file, which is the best format for heavy-duty editing before transitioning to Photoshop. (Click here to view that post.) Lightroom and Camera Raw have now added a new feature that ups the ante even more. 

How Big is Greenland?
One of the rather arcane aspects of stitching panoramas is mapping the multiple frames—which represent the "spherical" view of the photographed vista—into a flat medium. It's the same old problem of creating a map of the earth. When you project the round earth on a flat map, suddenly Greenland, for example, doubles in size. Adobe offers many ways to project panoramas, but for most run-of-the-mill panoramas (two to four horizontally shot frames) Cylindrical is the most relevant. Basically, Cylindrical mathematically projects each frame on to a virtual curved screen that is then unrolled flat into a panorama. That projection process is what creates the curvature along the boarder of each frame after stitching. The problem is the misshapen image creates some image loss when cropped. 

In the past, to work around the crop loss you either accepted the loss or stitched the frames using Photoshop's Reposition option that didn't distort the boarders. The latter option could be painful, however, because Reposition was notorious for creating stitching artifacts (example to follow). When Photoshop introduced the Content Aware Fill feature, you could instead simply lasso around the vacant (transparent) areas and perform a Content Aware Fill. But that only worked when the surrounding area was mostly sky, water, or any nondescript subject matter. In the latest version of Photoshop CC, they added to the Photomerge dialog box a new ‘Content Aware Fill Transparent Areas’ check box. This automatically performs the same boarder recovery method. The operation can’t be previewed, so it’s a gamble how well it works. Fortunately, all the fill areas are presented as a selection that you simply delete if you don’t like the results.

Boundary Warp
Now there is a better option unique to Lightroom and Camera Raw called  Boundary Warp that is  located in the Panorama Merge Preview screen (see screenshot below). With this tool, the image boarders are stretched to fill in the transparency gaps. You control the amount of fill-in from none to 100% as you move the slider to the right. There's a reason you may want to control the amount of fill. Remember, when you stretch a portion of an image, you're scaling up and that sacrifices resolution. But in practice, the stretching shouldn't be enough to where, with today's high-megapixel cameras and the scaling confined to the edges, you'll ever notice any image degradation.
Boundary Warp slider located at bottom of Options box.
Examples
Below are three examples of a two-frame panorama stitched in Camera Raw using Cylindrical. The first image shows the rounded edges and the potential crop loss. The second image is after cropping and you can see the amount of loss. The third image is after applying 100% Boundary Warp and the image is completely intact.

Camera Raw Cylindrical Panorama: A good chunk of the top 
and bottom would be lost when cropped as seen the next image.
After cropping: All the trees and their reflections take a haircut.
With Boundary Warp: The image is fully intact. 
Bent out of Shape?
This new feature does pose the question if the panorama’s natural perspective and scale are corrupted. However note that on their own, all projection modes already cause some degree of distortion. Assuming most “occasional” landscape panoramas are two to four horizontal frames with a total field-of-view less than 120-degrees (and exclude any significant architectural features) most distortion isn’t significant enough to be noticeable. Applying Boundary Warp essentially restores the image to nearly the same results you would obtain with Photoshop’s Reposition. Reposition is not really a projection, but is more-or-less equivalent to manually aligning the frames together. It works well if you shot the panorama using the shift function in a tilt-shift lens; otherwise as mentioned before, it is notorious at generating artifacts. The same image below is stitched in Photoshop using Reposition and is essentially identical to the Cylindrical image above after Boundary Warp, except for the artifacts (circled in red).

Photoshop’s Reposition: Essentially the same as Cylindrical
after applying Boundary Warp, but riddled with artifacts.
Example of ‘Content Aware Fill Transparent Areas’ 
I've added to the comparisons an example of the same image stitched in Photoshop using Cylindrical and ‘Content Aware Fill Transparent Areas’ enabled. A couple of noticeable artifacts are the extra palm tree in the upper-right corner and the orphan tree-head reflection in the bottom-left corner.
Content Aware Fill: Without the original frames to compare
against, you may actually get away with this image with most observers.
But astute eyes will catch the artifacts, especially the floating palm tree top.

Saturday, August 15, 2015

Pixel Mania: Canon’s New 5DS and 5DSr


Remember the old joke: “if a little is good, more is better, and too much is just right!” In June, Canon released two new cameras that address the “just right” category. The question is, from the perspective of a landscape photographer, do I need 50 megapixels and, if so, what do I sacrifice in return? Here's my take on that subject after having played with my recently acquired 5DS over the last few weeks.

Megapixel Perspective
You’ll read that this camera is the ticket for landscape photographers who want to produce “large prints”. It’s never clear to me just how large “large” is, but regardless, there is one fundamental fact that may make it a moot point for many photographers. The human eyesight has limited resolving power and, beyond that, more resolution simply isn’t perceived. Convention is when you view any print, from a 5 x 7 to a billboard, the appropriate viewing distance is no closer than the diagonal length of the print. You can try that out yourself and see that's a reasonable assumption. Given that premise, then you’re not likely to see much, if any, improvement in resolution beyond a very good 12-megapixel camera (or there about) no matter how large the print is. 

Human Nature
Unfortunately, many of us love to scrutinize up close at the fine details of a print, even if it has nothing to do with its proper presentation. Then there are photographers (myself included) that find security in all that extra detail in the same way a squirrel feels secure with its stash of acorns: you never know when you might need it. Maybe someday you’ll make a wall mural or you just want the extra cropping space. 

So if your “big print” is 16 x 24 inches and, instead of viewing it at 29-inches, you view it at 12-inches away (and you have excellent eyesight), you'll need the 5DS's pixels along with good optics. But that’s if you want the confidence your prints can withstand scrutiny at any distance. Otherwise, if you are content with a controlled “gallery” viewing environment, then the more common (and affordable) 20-something megapixel cameras will do just fine.

Are Inkjet Printers Up to the Task?
Can a good inkjet printer do justice to a 50-megapixel image? I'm not talking about wide-format printers used by professionals, which obviously benefit from higher resolution. Instead, I'm addressing what the vast majority of amateurs likely use, either a 13 or 17-inch wide printer.  Will that extra detail get lost within the printer's finite resolution at smaller print sizes? The Canon 5DS can generate a 360 dpi print at 16 x 24 inches. That is probably the very-upper limit of an inkjet's resolution. So in theory, at least a 16 x 24 print should benefit from the extra resolution. Keep in mind that things like Bayer patterns, noise, and other parameters affect the true resolution of a camera. In any case, to find out if there was any practical benefit, I ran the following test. 

I downloaded DP Review's test images for the Canon 5DSr (version without antialiasing), the Canon 5D MK3, and the Nikon D810. Without any raw or Photoshop manipulation, I sized each as a 16 x 24 inch print. I did apply output sharpening using Nik’s Sharpening Pro. I then configured my trusty Epson 3800 for the highest-quality print output and focused on the extremely fine scrollwork of a foreign bank note.

And by golly, all that 50-megapixel detail does shine through! Below are scanned portions of each highly-magnified banknote (shot at ISO 800) that give a fair idea of the printed differences. (Note: scan resolution was 1800 dpi and the print paper was Epson Ultra Premium Photo Paper Luster.) The 5DSr was as expected the standout, but Nikon was a respectable second, while the MK3 blurred all the fine detail. However, it took a magnifying glass to see all that! I have corrected vision but aged eyes, and without the magnifier I couldn’t see the difference. But, younger eyes that can focus closer may spot it. 

The results indicate that print sizes down to 11 x 14 should benefit from either the Canon 5DS or Nikon 810 higher resolution. Beyond that, a good 21-megapixel camera will perform just as well. Bottom line: if you don't print larger than 11 x 14, it would be hard to justify purposely upgrading. And as for viewing on a computer monitor, a 50-megapixel camera has no advantage over any 20+ megapixel camera, even on my 5K iMac (unless, of course, you’re zooming in).

Canon MK3: Blurry, but still sharp at a proper distance.
Nikon D810: Pretty good!
Canon 5DS: Momma mia !!
“Buddy, can you spare $3,700?”
All those megapixels do come at a price—literally. The 5DS is $3,700 and the 5DSr is $200 more—not cheap! As a note for comparison, you can buy the Nikon D810 along with a 24-120mm zoom for the same price as the 5DS. Surprisingly, Canon offered a tax-free incentive sale on the 5DS less than a month after its introduction (in the Los Angeles area), which is very unusual for a new model. That made me speculate that either everyone wants the 5DSr (which didn’t have the incentive and is harder to find), or Canon misjudged the demand for ultra-high megapixel cameras.

Teeny Weeny Pixels
50 megapixels obviously bring up the concern over noise and dynamic range. I have analyzed so many raw files from the Canon 5D MK2 (my previous camera), 5D MK3, 7D MK2, 5DS, and the Nikon D810, that my head spun. Canon is often criticized for its poorer performance in noise and dynamic range compared to Sony-based sensor cameras (including the Nikon D810)—and it’s all true to some extent. I’ll admit before buying the 5DS, I seriously considered the Nikon D810. But further analyses (including the costs of buying new lenses) convinced me the 5DS was the right choice. The convincing factor was putting noise and dynamic range into proper perspective. 

Noise
For starters, I always felt my older Canon 5D MK2 was (at the time) a low-noise camera. Though I always shot at ISO 100, I hardly ever applied any noise filtering. Even when I shot at ISO 800, I only needed a little noise filtering. It wasn’t until I started doing HDR that noise became a bit problematic. But that was solved when I stopped pre-sharpening the raw file if destined for HDR (I follow the Bruce Fraser sharpening process). Furthermore, after adding just a touch of noise filtering to a 5DS test image (shot at ISO 100) it evened the noise difference with the Nikon D810 for the same image. This had to be observed at a very-high zoom level since the noise was extremely low anyway; and in this case, normally you wouldn't have bother to apply noise filtering in the first place. But the point is, afterwards I couldn’t detect any reduction in the 5DS’s resolution. Bottom line: if you always shoot your landscapes at low ISO levels (as you should), noise is simply not an issue with the 5DS—period!

Dynamic Range
As a previous large-format Velvia film user, I felt my 5D MK2 had amazing dynamic range—roughly 5-stops better! Now with my 5DS, I have verified that it has a little less noise and a bit more dynamic range in the deep blacks than the MK2, which is amazing considering it has over double the pixels. (Note, I did verify that it was ever-slightly more noisy than the MK3, which all falls in line with what Canon has stated.) In any case, from my perspective, I went from already satisfying performance to even better dynamic range and lower noise (albeit slightly), but now with tons of detail. 

Nikon D810
The Nikon D810 is a popular camera, and for good reason. Anecdotally, when viewing published photos, the Nikon D810 (and the previous D800) and the Canon 5D MK2 and MK3 seem most popular with landscape photographers. All my image analyzes did prove that the D810 does have a little less noise, even compared to the 5D MK3 at low ISOs. However, I wasn’t able to judge dynamic range to any degree. DxOMark says the Nikon D810 has 2.4-stops more dynamic range than the 5DS. However, I’m not sure what to make of DxOMark. For one, they measured a 14.8-stop dynamic range for the Nikon D810—and that was achieved with a 14-bit converter??! Given that and other considerations, I personally have a hard time swallowing DxOMark's measurements. Nevertheless, given the D810’s lower noise, and that noise and dynamic range are interrelated, it’s reasonable to assume that the D810 has an edge in dynamic range. However, I’m skeptical that the difference is that apparent in general usage (see next topic).

Dynamic Range Illusion?
It's possible that many of the anecdotal or off-handed comments made about the dynamic range differences between the Canon and Nikon are more illusional that real. I’ve discovered a noticeable difference between the way Adobe Camera Raw, and Nikon and Canon’s software render raw files. A case in point is the Nikon D810 histogram below of a somewhat wide-dynamic range image. The Camera Raw histogram shows lighter dark-tones and suppressed highlights that may lead one to think there’s a lot of headroom beyond those tonal areas. But Nikon’s raw converter instead pops the histogram to the point of clipping at both ends (see below). The Canon 5D MK3, between ACR and Canon's raw converter, showed a similar but much smaller tendency while the 5DS’s histogram was in better agreement between the two raw converters. (Note that in all cases the raw converters' tonal adjustments were zeroed out.)

Nikon D810 Histogram in Camera Raw
Nikon 810 Histogram in Nikon's Capture NX-D
So which one is right? It doesn’t matter since there isn’t any data loss, it’s just how the raw converters chooses to mess around with the image. Changing the camera profile will alter the histogram somewhat, but since part of the editing procedure is to properly distribute the histogram, it should all even out in the end.

Hands-on Experience
Image Detail
Compared to my MK2, the deep, dark-tones in the 5DS have less noise and slightly more detail. Overall, the increase in resolution is mind-boggling. I can increase the zoom level into the “electron microscope” level that goes well past the pixelated image of the MK2. But there’s good news and bad news. The good news is regardless your lenses quality (unless they're really lousy), you will see substantially more detail; but it's likely many of your lenses (especially zooms) won’t come close to doing full justice to 50 megapixels. Canon has listed L-Series lenses they recommend for the 5DS that were introduced over the last few years (none of which I have). But if you have the “cheaper” L-Series, like the popular 24-105mm and 17-40mm zooms, you will still see definite improvement. It’s the extreme edges that will benefit the least. On the other hand, if you have L-Series prime lenses, then you’ll be in hog heaven.

Image Appearance
Because of the histogram variances mentioned above, your first impression in the raw converter may be that the 5DS images are more contrasty. That may be good or bad, but it won’t matter anyway after you properly edit the image. Though I’m sticking with the Adobe Standard profile, if you want to tone down the highlights initially, try the Camera Neutral profile. I also noticed that the Auto White Balance on the 5DS produced a warmer image than the MK2. Of course that won’t matter since you can change the white balance in the raw converter to whatever suits you.  

Best New Feature
I’m fanatical about keeping the horizon level and always had used an external level. The MK3 had introduced an electronic level that was visible in the viewfinder. Now Canon made it even better on the 5DS by providing a dedicated and less obtrusive scale (at the top of the viewfinder) instead of using the focusing points. I checked it against my Kaiser shoe-mount level and they agreed as accurately as I could eyeball it.

One Annoyance
This may matter only to MK2 users since I’m not sure what the MK3 did in this regard. I always shot bracketed frames (for either exposure insurance or HDR) using the 2-second self-timer and mirror lockup option. That allowed me to avoid, in most cases, a cable release with the added insurance of no mirror shake. Plus, all three frames fired automatically. The 5DS introduced a new feature that allows you to select various shutter delays after the mirror locks up. You can still use the self-timer and mirror lockup, but in all cases the camera no longer fires the bracketed shots automatically. Instead, you have to fire them individually. However, if you skip the mirror lockup and just use the self-timer, then it fires all the frames automatically (go figure). That's a problem when I shoot around 200mm because, even with their touted low-vibration mirror, I still see some blurring. The only solution I've found so far is to engage Live View. Then that locks up the mirror and all frames fire automatically. 

BTW, I compared mirror-slap vibration between the 5DS and MK2, and the 5DS was ever-so slightly better. The 5DS's new motor-driven mirror sounds quieter, but it's no substitute for mirror lockup.

Battery Life
Based on anecdotal usage (and supported from what I’ve read in a few user reviews), the 5DS definitely burns more battery power than my MK2. My experience may be skewed somewhat since I’m doing a lot of menu surfing as I go through all the camera's features. Regardless, you’ll want backup batteries when out in the field. I have shorten my LCD display time and time-to-sleep settings. I also recommend you avoid, or at least minimize, using Live View.

Write Speed
I’ve seen a few reviewers complain about this. I use the super-fast Extreme Pro CF and SD memory cards from SanDisk. My 5DS is configured to record redundantly to both cards. From shutter click to LCD display, it takes almost 2-seconds versus 1.5 seconds compared to my old MK2 (using admittedly slower SanDisk Extreme III cards). Unless you’re hyper Type-A, I don’t think you'll notice much difference. The real issue is with post-processing, and of course that depends on your computer configuration. I recommend you download some 5DS raw image files and run benchmarks to make sure you're not blind sighted by agonizing process times.

Here are a few “relative’ comparisons based on my 5K iMac with 16GB memory and an i5 (4-core) Intel chip. These are based on my MK2's 20-megapixel files. The first time is the MK2 and the 5DS is the second time. All times are approximate.
  • Launch raw file from Bridge to Camera Raw: both were too short to measure
  • Transfer from Camera Raw to Photoshop: 5 sec vs. 9 sec
  • Launch three raw images from Bridge to Nik’s HDR Efex Pro (to the edit page): 42 sec vs 92 sec
  • Time to transfer from HDR Efex Pro to Photoshop: 12 sec vs. 28 sec
  • Time to perform a Tonal Contrast midtone change in Nik’s Color Efex Pro: 8 sec vs. 10 sec.
Buy, Don’t Buy, or Wait?
Buy?
This may depend on which direction you’re coming from. Most likely, anyone buying a high-end camera is already committed to that brand. But if your are starting from scratch or have little invested in legacy lenses, then let me state up front that it’s hard to argue that the Nikon D810 isn’t the top choice just based on value alone. One caveat: that opinion may change after more is learned about Sony’s new A7rII. But if you’re a dedicated Canon user and have legitimate need for more resolution that doesn't compromise noise or dynamic range, then the 5DS or 5DSr is just the ticket. 

Don’t Buy?
If you have either the 5D MK3 or older MK2 (or any APS models) and are satisfied with your 8 x 10 and occasional 11 x 14 prints, then save your money. The same applies if you do a lot of video or rely on high ISOs. The argument changes only if you do a lot of 11 x 14 or 16 x 20 prints and occasional custom poster-size prints, then it boils down to mainly if you want to spend the extra cash.

Wait?
There are two good reasons to wait. First, I have noticed with Canon, Nikon, and even Sony, that their new model cameras often have teething problems. Remember the light leak issue with the 5D MK3? Sometimes it’s just a firmware upgrade. Other times you have to send it back for repair, which is a bummer for a brand new camera! So far, I haven’t experienced any problems and nothing has popped up in any reviews; but these problems can be subtle and take some time to surface. If you’re not in a rush, wait 6-months and then check user reviews for any signs of trouble.

The other reason concerns the next generation 5D MK4. Before the 5DS popped out of nowhere, I expected the successor to the MK3 would rival the Nikon D810. That now doesn’t seem likely, so based on the Canon Rumor website and my own crystal-balling, this is what I predict. The big market discriminator between the 5DS and 5D MK4 will probably be 4K video. Assuming that, pixel count may go up slightly (probably not above 28-megapixels) and actually may drop to 18-megapixels. Dynamic range and noise are likely to be better than both the 5DS and MK3. I don’t think you’ll see this camera until early 2016 at the soonest. Now take all this with a grain of salt, but if 4K video is high on your wish list, I’d wait for the MK4. 

5DS or 5DSr?
The 5DSr cancels out the antialiasing filter and I can detect a very slight increase in sharpness. But it’s so subtle, I feel the difference is insignificant. Plus, since I use zoom instead of prime lenses, I doubt I’d realize any benefit (assuming there was any real benefit to be gained). As for moirĂ© patterns with the 5DSr, judging from what B&H and Amazon reviews have said so far, that seems to be a rare problem, especially with landscape photography. To me, the decision boils down to the $200 difference. If you want the warm fuzzy of microscopically better resolution, then get it; otherwise, save your money.