Despite reasonable arguments to the contrary, there's still a very strong perception that more megapixels are better, even when comparing on the same size sensor. It means that each individual photo receptor is smaller, and that means less light sensitive but the theory is that this is balanced out by increased detail and sharpness. Canon, as of this article, currently rules the megapixel roost in 35mm full frame with the Canon 5DS and Canon 5DS R cameras. The questions to ask are what does 50.6 megapixels bring you, and what do you give up?
5SD vs 5DS R
Let's get the difference between the 5DS and 5DS R out of the way. The cameras are the same except that on the 5DS R the Low Pass Filter effect is negated. Canon does not say that there is no low pass filter, it says the effect is negated so I'm not exactly sure what that means, but it would be akin to the difference between Nikon's D800 and D800e cameras. A low pass filter helps prevent moire and some colour artifacts but takes away a tiny bit of sharpness in the doing. If you shoot fashion, you want the Low Pass Filter because fabrics such as silk and pretty much anything with nylon or polyester can show moire interference patterns when lit in certain ways. Removing moire in post is such a pain, that you don't want to bother. If you are only shooting landscapes, moire will be less of a problem and you might want the extra sharpness. Now that we are clear on the difference, I will simply refer to the 5DS and you'll know what I say applies to both unless I specifically say not.
Please be aware that this is not a comprehensive review as I only had the body for three days before it had to go back.
General Feel and Usability
Users of the Canon 5D Mark III will know their way around the 5DS. The physical layout is the same. Several peers have said that they find that the body feels more plasticky than the 5D3. It's subjective, but I have to agree. We also all agree that the camera sounds different when the shutter is tripped. I expect that this is due to enhancements in the mirror damping process.
This brings about some confusion for the customer. Canon and others have suggested that the 5DS needs to be more stabilized than other cameras because the high megapixel count and sensitivity will be more likely to experience microshake. I'm not clear on the physics behind this concern, but let's accept it as a what's so. Yes the individual pixels are smaller but the body, shutter and mirror are the same size and it looks like the mirror (but not the mirror box) is the same as on a 5D3, so I am struggling with this. Certainly Canon has toughened up the tripod mount on the 5Ds. Again, I cannot tell if this is to address a real increase in the risk of microshake or just an incremental improvement based on learnings from the 5D Mark III.
As I worked my way through the menu system, it's very familiar if you've seen the 5D Mark III, the 7D Mark II or the 1Dx. While there are some differences, fundamentally it is similar. The camera does have two storage slots, which is a darn good idea considering that full RAW images are averaging 55MB per in my tests. Since an uncompressed RAW in a Nikon D810 is over 80MB, Canon must be doing some compression in their RAW save. Personally I would prefer that I have the choice of compressed or uncompressed RAW as I do with Nikons. Fortunately there are RAW converters already in Lightroom and Photoshop to take the 5DS derivative of Canon's CR2 RAW format so importing was not a problem, so long as one has a USB3 card reader and plenty of patience. The camera does have an internal USB3 bus, like the 7D Mark II, and so can move information through the bus very quickly. Connecting the camera to your computer directly does require USB3 ports. If you only have USB2, connections work but are throttled back to the glacial and irregular performance of USB2, so find a way around that wait forever scenario, or start drinking heavily.
From a card perspective, there are as I mentioned, two slots. Sadly, gross stupidity prevails and the slots are different. One is a CF Type I slot that supports up to UDMA7 while the other is an SDXC slot supporting up to UHS-1 throughput. I don't know if the 5DS has the same performance issue as the 5D Mark III where the camera slows to the performance of the slowest card installed and the presence of an SD card always negatively impacts the performance of the CF slot.
This use of two different cards is not unique to the 5DS or to Canon. Many manufacturers who do dual slot cameras build this level of mental defectiveness into their products. It's not convenient, it's asinine.
Selecting Memory Cards
Ok rant over. Since you are moving very large files and since the bus can handle UDMA 7 and UHS-1 respectively, unless you want to spend a lot of time waiting for the write indicator to go out you will want to buy the fastest cards you can get. An 800x card is slightly slower than the bus capability, so go 1000x or faster, budget allowing. You do not want to be trying to shoot this camera with a 400x or 600x card, unless you are happy to watch grass grow.
Unlike the 5D Mark III that has very good high ISO performance, the 5DS is capped at ISO 6400. How 2012 of Canon that is. Online it says the camera goes to 12,800 so that would be a Hi setting. I understand the rationale, because those very small photo-receptors are not going to fend well in low light and so running this sensor at ISO 25600 where the 5D Mark III is still usable would be a complete splatter fest. But before igniting the torches and grabbing the pitchforks, let's be honest that low light and high speed photography is not what the 5DS is built for. This is a tripod camera for high detail, well metered exposures, or handheld images where you have lots of light that looks great. For landscapes and macro work where you can manage the light, the camera (mostly) turns out terrific images when you do your job. This is not the camera for sports or wildlife, although you might be able to get some nice snail or sloth images with it.
What About Noise?
The slideshow below is the ISO test. All images were shot with the Canon 5DS and Canon 70-200/2.8L IS II mounted on a Really Right Stuff tripod. Camera was in Aperture Preferred mode, RAW, Automatic White Balance and a completely flat Picture Style so as not to skew the JPEG on the LCD. The shutter was tripped using Canon's electro-mechanical release. Mirror lockup was not used, nor was a self timer, because in a headshot scenario they ought not to be. Lighting was provided by a Westcott Skylux continuous LED upper right through a 9" x 36" strip light. A white reflector was placed on the left (model's right).
On the web, all the images look decent but when I zoom in on the right eye, where the focus point was placed, the noise grows linearly to about ISO 1600 then gets pretty nasty by ISO 6400. I would propose that the 5DS is very much like the 7D Mark II with a high usable ISO of 3200 without correction. If this sounds low in today's competitive space, it is. My 1Dx is perfectly usable at 51,200 and I found that I could set the Nikon Df to 25,600 and get great images consistently. Many buyers of the 7D Mark II expected a significant improvement in higher ISO performance over the predecessor and were very disappointed. The 5DS makes no headway here.
I find the images are all warm. I tried both Lightroom and Canon's own Digital Photo Professional software and both rendered very warm using the AWB setting in camera. Colour temperature out of the Skylux is rated at 5500 Kelvin. Switching in camera white balance to Daylight rendered more correctly. Sondra has very pale "skin" so this makes her look a bit more healthy, or as healthy as an inanimate head is going to get. I compared this to other cameras in AWB mode, from Canon and others and in every case the rendering of the AWB on the 5DS is very warm.
I then changed the lighting setup to a Profoto D1 in a 22" beauty dish with a diffusion sock. There was no change in the AWB colour skewing. Switching in camera to the flash preset was better but still not as good as what came out of the 1Dx or 1D Mark IV.
Autofocus is very similar to the 5D Mark III. I do not find it as quick as on the 1Dx but it still has the 61pt AF capability using both contrast and phase detection. Autofocus works between -2 EV and 18 EV so pretty decent range although I found that with high magnification macro work, you are better served to go manual. For this reason I wish the focusing screen was user interchangeable, but sadly like the 5D Mark III, it is not. For a camera designed for this level of precision, that's a mistake on Canon's part.
Metering is Canon's EOS ISA metering system so 252 zones measured across 150,000 pixels. It works like the other Canon metering systems, but only in the range of 0 EV to 20 EV so it doesn't match the AF system. In my testing, I found the metering to be very accurate except when metering full frame purple flowers. In every case then it was underexposing by about one stop.
The 5DS shoots video. At about the same level of sophistication as the old 5D Mark II. So no real advantages for videographers here, and no frame rates past 30fps at Full HD, so if someone where to be shouting "lame" right about now, I'd have to remind that person that the use case for this camera is not video. But it's 2015 and video SHOULD BE a viable use case, especially when you can get a killer still camera that does excellent 4K video for less than half the body price of a 5DS. Canon used to rule still camera video. Now it seems that they've forgotten all about it.
Power and Battery
Canon says the camera is good for about 700 frames on a full charge of the LP-E6n battery when using the viewfinder and about 220 frames shot with Live View. This is very comparable to other full frame DSLRs. The 5DS uses the same optional battery grip as the 5D Mark III. I like battery grips myself and am glad to see this. I did not get anywhere near 700 images in my testing, your mileage may vary. The AC adapter I have for my 7DM2 worked fine in the 5DS, useful for long studio sessions, particularly if like me you are only getting 400 images to a charge.
So What About All Those Megapixels?
I thought it would be interesting to try some 32 bit HDRs with this camera so I set up a 5 shot bracket at 1 ⅓ stop intervals and set the camera to go from under to over. Combining the images using Merge to HDR Pro in Photoshop actually went reasonably quickly on the new Mac Pro but when I tried doing a 3 shot merge on the 2009 Mac Pro, you could smell the GPU working hard. I had to do these shots on multiple tries because I was shooting the Canon 180mm L macro with three extension tubes and depth of field was razor edge even at f/32 and even with the lens mounted on my RRS tripod and macro focusing rig, I think that there was some microshake evident. I made my first sequence using a Westcott Skylux continuous light and this made for some pretty long shutter durations even with the Skylux at full power. Overall, I was not happy. I put the Hasselblad H4D-40 with 120 Macro and extension tubes on EXACTLY the same rig and got substantially sharper shots. The Hassy is rated at 40MP and the mirror slap on it can be heard across the street. If Hasselblad can effectively dampen the slap on a mirror 4x bigger than the 5DS, there should be NO microshake on the Canon. Underwhelmed so far.
I went back and tried some focus stacking, without the extension tubes and got much better results. While there is certainly lots of data in the images, I'm not sure that I can see anything more than I would see with a properly exposed image from my 1Dx and there is definitely a usability edge to the 1Dx. I've not experienced the level of microshake as I did on the 5DS. So anyone buying a 5DS should also buy a copy of Piccure+ through my web site because that software is golden when it comes to addressing microshake. Given the alleged suitability of the 5DS for macro or copy work, the lack of an eyepiece shutter is a glaring omission. This further references that Canon has stuffed a higher MP sensor into the generic 5D frame and in my opinion, did not think through the use cases completely. I do a lot of evaluations and always have strips of gaffer tape on the tripod legs to block the viewfinder for no eye at the viewfinder images. On a body costing over $4000 with this huge MP sensor, one should not have to worry about tape. Canon has added a lag function that injects delay between mirror up and shutter release. This is found on some medium format cameras. It's a nice function, but further emphasizes that the 5DS is not a run and gun camera. I did not have the camera in studio long enough to do comprehensive testing using this function. I have it on my Hasselblad and have only ever used whatever came set up from the factory.
Going Outside At Night
Later that night, I went out with other members of the Newmarket Camera Club where Darren Gahan was demonstrating the functionality of the Pixel Stick. The pixel stick is a kind of interesting toy, although I would never spend the money on one. The 5DS was shot with a Canon L Series 24-105 in bulb mode using a simple mechanical release at apertures between f/5.6 and f/8, all at ISO 100. Because it was literally in the dark, I was not solid on focus in a couple of images, but overall things worked out well. I will give the 5DS' big MP field a gold star for this kind of work where you may need to crop excessively, in a couple of cases up to 75% cropped away and the image quality remains very high.
Canon 5DS with Canon 24-105/4L on tripod, bulb mode, f/5.6, ISO 100. Illumination by Pixel Stick
Since the 5DS is basically a 5D Mark III with a higher MP count sensor, all your expected 5D3 accessories work with it. While I was out shooting the night work, my co-host on Daytripper Television, Bryan Weiss (founder of DayTripper Photo), asked me what camera I was shooting. Even from eight feet away he noted how quiet the mirror box was on the 5DS and said it made other cameras sound like a box of rattles. It certainly is quieter than others.
eTTL flash is consistent and Canon's radio controlled speedlites worked just fine. Some of the menus are a bit different but that is quickly handled with practice. Like the 5D Mark III, there is no built in pop up flash. Canon does a pretty darn good IR controlled flash system like Nikon's better named and better marketed Creative Lighting System. I understand that adding a popup would negatively impact overall durability, but I still would like to see a popup on the 5D lineup to help buyers control off camera flash without having to buy into external triggers. Infrared is line of sight only and not much use outdoors, but it's better than nothing. Fortunately you can get good TTL radio triggers from folks like Phottix at competitive prices, and there is always Canon's own ST-E3-RT for use with the 600 EX RT radio flashes if you need multiple zones and exposures. As I tend to use flash a lot for light supplementation, I would go this route myself (and have done so) but other less demanding clients would probably be happy with infrared.
Better Images Under Fluorescents
One of the new features that Canon has enabled in recent bodies is Anti-Flicker control. I use it on my 7D Mark II when photographing amateur hockey as the fluorescents in these arenas are really bad flicker monsters. This function is built into the 5DS as well. What is not well documented and is a serious gotcha, is that when Anti-Flicker is on, you can not enable Mirror Up mode. I am sure that there is a good reason for this, but I would prefer that the disabling of mirror lockup be more clearly spelled out.
The Importance of Dynamic Range
For many serious photographers, and I include myself in this group, megapixels are not the driving force any more. We have enough to accomplish our work. What we look for instead is dynamic range. In the early days of digital we had between 5.5 and 6.5 stops of dynamic range and that was ok. Times have changed and so has technology. We now look more to dynamic range as an indicator of viability rather than megapixels.
Canon has been lagging in dynamic range versus its competitors for the last few years. With the 5DS, Canon's dynamic range is measure at 12.4EV or nearly 12.5 stops. That sounds quite awesome, especially when their pro 1Dx model is rated at 11.8 EV. When announced, Canon predicted that the 5DS would have the same dynamic range performance as the 5D Mark III which is rated at 11.7EV The 5DS is better by more than ½ a stop. Also important is where that span starts and stops, and the 1Dx fares far better in low light DR than the 5DS. This is expected because the individual photo receptors are larger. But compare the relatively new 5DS against the established Nikon D810 and we see a large disparity. Nikon's D810 has been out for quite some time and it is rated at 14.8EV of dynamic range, In most all aspects, the two cameras are identical except for the megapixel count and the dynamic range. The Nikon body sells in Canada for about $500 less than the Canon 5DS body. So depending on your success criteria, you would have a decision on your hands.
For the last several years in the DSLR space, I have been shooting Canons. Because of the significant investment in lenses, moving to an alternative would be cost prohibitive. If I were to take the 1Dx and the D4s out of the equation completely and compare the top of line non-Pro bodies, for my work, the Nikon family is the current leader. In dynamic range, they rule the roost, and DR is far more impactful on the image than the megapixel count. That's not to say that for a Canon owner a 5DS is a bad buy. It isn't, so long as the customer use cases are satisfied by it. I specialize by not specializing. The only work where the 5DS would really suit me is landscapes on a tripod. Headshots, wildlife, aviation, macro are not strong suits. It is a very specialized piece. Am I disappointed? Yes. I have a substantial investment in Canon and I expect better functionality, better innovation and less incremental update from a company of their scope and capability. If the 5DS is to be the next big thing for Canon, I think that they have missed the boat on it. Apparently there are multiple 5D somethings on the horizon as well as a replacement for the proven 1Dx. I, and photographers like me, don't need nor care about another Rebel, or another XXD family body. We want high dynamic range with higher megapixels and excellent low light, all in the same body. It's doable. Nikon is doing it with the D810. Time to stop resting on your laurels Canon friends and bring the fight.