Mirrorless vs DSLR

When one gets serious about their photography, they must answer the question: Mirrorless or DSLR (Digital Single Lens Reflex)?

In the beginning, I started with a Sony HX30V Point and Shoot. After a couple years, I switched to a Sony a6000. Having been satisfied with these two cameras, it was only logical I'd adopt Sony's Full Frame Mirrorless, the a7 Mark 2 for my wedding photography. I adopted 4 Sony items as follows.

      Sony a7 Mark 2

      Sony FE 70-200 F/4 G OSS Lens

      Sony FE 55mm F/1.8 Lens

      Sony FE 16-35mm F/4 OSS Lens

After two years with the a7ii and a6000, I have consolidated my thoughts regarding the Sony Full Frame Mirrorless system into this review, and will be comparing it to the Nikon DSLR system, and why I have now fully switched over. This review is biased towards Nikon, simply because it is my preference for my wedding, landscape and sports photography. In making a decision on what system you pick, it is important to read articles biased towards Sony as well, to get a holistic picture. From this article, you can pick what is important to you, and pick a system to invest into. Finally, I want to say, gear isn’t everything. Get out there and shoot. Don’t dither around choosing your cameras and lenses. The time should be spent on lighting, business, networking and practice.

My time with the Sony Mirrorless System and the Nikon System can be compared under the metrics of Lenses and Camera Bodies

Lenses

The following table illustrates the price of somewhat comparable Sony and Nikon lenses regarding weight, area (length multiplied by width), price as of the 22nd of December 2015 ($AUD) and sharpness as sourced by DxoMark measurements based on a 36-megapixel sensor without an anti aliasing filter. 
I’d like to note that all Nikon lenses are one stop faster than there Sony counterparts in the table bellow. This is simply down to the fact that Sony has yet to release any F2.8 zoom lenses, or F1.4 prime lenses with the exception of within the 35mm focal range. Click on all tables herein to enlarge.

 

Green indicates that the lens is superior in that category. Orange indicates the lens is inferior to its equivalent lens in its focal length category. Grey indicates the lenses are equally matched.

NOTE: I have used all the above lenses for an extended period of time with the exception of the 35mm lenses. 

As shown, Nikon has the advantage when it comes to pricing. This is mainly down to the fact Tamron, Sigma and other third party manufacturers make lenses for Nikon, but not yet for the Sony Full Frame E-Mount. Additionally, there are simply far more lenses to choose from!

In terms of sharpness, Nikon gets the crown again. Not a single Sony lens from this selection was superior in sharpness to the Nikon "equivalent."

Where Sony wins is in the weight and size department. It seems the increase in price and decrease in lens optical quality is traded for size and weight on the Sony Mirrorless system, compared to the Nikon dSLR system.

This is where you have to make a judgment, and choose what is important to you. Based off the above discussion and opinions of other Sony mirrorless and DSLR users, the system's strong points can be summarised:

*size and weight reduction is at the expense of a one stop aperture reduction between F4 and F2.8 (zoom lenses) or F1.8 and F1.4 (prime lenses).

The lack of F2.8 zoom lenses for me has proven to be a deal breaker. Often, I’d be forced to shoot between 12800 and 25600 ISO, whereas the photographers around me were shooting at 6400-12600 ISO on their 2.8 zoom lenses. 

Camera Bodies

Ergonomics

Ergonomically, these cameras could not be more different. With the original a7 series, the camera was significantly smaller than their dSLR counterparts. Sadly, the ergonomics of the first generation a7 cameras left much to be desired. With the mark 2 versions of the a7 series, the grip has been increased in size. Although I agree with the change ergonomically, it regresses the size and weight benefits of a mirrorless camera. Despite the improvement in ergonomics, it still pains me to say they have a ways to go. On long days of shooting, my hand would start to cramp, as my pinky finger couldn’t physically fit on the a7ii’s still seemingly too small grip. It isn’t the depth of the grip, as that has been improved since the last generation, but the height. This can be fixed with the Sony vertical battery grip. However, this again defeats the purpose of the small size and weight of a mirrorless camera and costs a whopping $396!

Notable Features

The Nikon D750 also offers a handful of notable features that the Sony Mirrorless system is yet to incorporate.

  • Metal Hotshoe – Yes, I have broken a Sony flash hotshoe before.
  • Highlight weighted metering – attempts to preserve highlight detail.
  • Face detect metering – meters off the face to determine the correct exposure.
  • Face Detection Playback - In playback view, you can also rotate a dial to cycle between all faces detected when zoomed into 100% to check critical focus.
  • Warm biased Auto White Balance (AWB) – biases AWB towards the warmer side of the kelvin scale.
  • Minimum shutter speed setting when using Auto ISO and Aperture Priority – There have been times when the shutter speed on my Sony has dropped to 1/10sec when it originally was around 1/100sec (Aperture Priority and Auto ISO). For moving subjects, this is a costly error. I set a custom button on the D750 to adjust this setting on the fly. Now, I don't have to be so cognisant of my shutter speed decreasing, as I know it will always be sufficiently quick.
  • Once you half press the shutter, the D750 shows you the amount of photos left until the buffer fills.
  • Two SD cards. For important events, I write to both cards. For most applications though, I set the second card to be used once the first one is filled. This is handy as you won't be caught with your pants down shooting a family, when your SD Card suddenly fills.

NOTE: Mirrorless cameras have features that aren't available on DSLR's. Consider these features in making your decision.

User Notes

On my a7ii, I set my right rotating dial to adjust ISO. This works fine, although everyone else I have ever given the camera to has bumped this button. For a group photo, I gave the camera to another photographer, who bumped the ISO dial. This resulted in the ISO jumping from AUTO (metered at ISO 6400) to ISO 50. The image was completely obliterated:

Not even the a7ii's great dynamic range could save this one!

A few months into my use, I realised my a6000’s E-Mount was allowing the lenses attached to it to slightly rotate within the mount. Put simply, the lens mount wasn’t fully secure. I read up on this when I realised it was also happening on my a7ii. Turns out, it is decently common occurrence. You can buy third party mounts to replace the stock mount. This apparently remedies the problem. It also voids the warranty.

Back Button Focus

When I begun photography, I experimented with back button focus. Really, it just didn’t feel right on my mirrorless cameras, so I gave up on it altogether. On the d750, I have tried it again, and interestingly, I actually love to use it now. Ergonomically and functionally, back button focus just seems to make sense on a DSLR.

Charging

I wanted to mention a bit of a niggle I have with the D750. Why oh why can’t I charge the camera through a cable. Why do I need to physically take the battery out, and charge using a dedicated charging accessory that gives me no indication to the amount of change on the battery unless its full? Sony allows you to plug a micro USB cable into the side of the camera to charge. Micro USB is the same port used by most android phones and bluetooth accessories, making it great for travel. Very convenient.

Another thing that Nikon has yet to catch up on is the mobile app. The Sony Playmemories app allows you to change settings, focus etc your camera from your mobile phone. The Nikon version is absolutely terrible by comparison, averaging 1.5 stars right now on Google Play. Additionally, live view focusing (used by mobile app) on the D750 is sad.

RAW File Output

The Nikon D750 incorporate lossless compressed RAW files. The Sony a7ii with the recent software update 2.00 now allows for lossy compressed RAW, and a new uncompressed RAW format. Sadly, there is no lossless compressed RAW format like there is on the Nikon. For those unfamiliar with lossless vs. lossy file compression, lossy basically means some information is lost, similar to a JPEG file. Lossless means no information is lost during compression. In terms of practical difference, the Nikon lossless compressed RAW files are around 25 MB, whereas the Sony lossy compressed RAW files are also 25 MB. Sony's uncompressed RAW files however jump to around 50 MB. This fills the buffer of the camera quicker than I can sneeze.

Bit Depth refers to the amount of colours stored within an image file. The higher the bit depth, the more colour information stored within the file. The Nikon offers 12-Bit and 14-Bit RAW files. Conversely, the Sony offers only 14-Bit RAW. This increase in flexibility allows the Nikon camera to shoot longer before the buffer is filled if long bursts are needed, (useful for sports and wildlife). With 12-bit RAW files, the Nikon files drop to around 20 MB. Regarding image quality, the lossy compression can make highlight areas appear grainy as shown bellow:

Shot on a6000, PZ 16-50mm f3.5-5.6 OSS Kit lens at f36

I know all this file format fluff may seem a bit picky, but when I started my photography and discovered that shutting down the aperture on my lens yields the “starburst” effect as pictured above, I noticed the grain immediately, and it has long frustrated me. Happily, for Sony mirrorless users, the issue is now fixed with uncompressed 14-Bit RAW.

 

Battery Life & Battery Grips

For a single wedding, I require 6-8 batteries on my a7ii to get through a day of shooting. For my D750, that number has been reduced to 1-2. This is due to the electronic viewfinder of the mirrorless a7. Viewfinder preference is totally subjective. For me, I like them both. I miss the live view histograms on the a7, but definitely prefer the absence of viewfinder lag in the D750 dSLR. Additionally, Nikon EN-El 15 batteries are almost double the size in terms of capacity to the Sony NP-FW50 mirrorless camera batteries, yet for some reason they are around the same price. Of course, you could extend the battery life by adding the aforementioned Sony a7ii battery grip. However, I have a problem with the engineering of the Sony battery grip. With the Nikon battery grip, the battery stays in the camera, and the battery grip locks onto the camera, where another battery is located. In the Sony battery grip, you have to take out the battery out of the camera, and place it and another battery into the battery grip. Not only is this a waste of space, but with the grips installed, both systems have two batteries, yet the Sony batteries are half as large. That means an Sony a7ii with a vertical battery grip that has similar battery life to a D750 without a battery grip, is heavier, larger, more expensive and slower focusing (see focusing section later). The Nikon D750 is 750 grams, the a7ii is 556 grams (body only). Honestly, I don't see this as a big deal. I don't use battery grips for the aforementioned reasons. However, it is a important point of comparison for many professionals and addresses many who have suggested it. Battery grips are also great if you do a lot of vertically oriented shots. Nevertheless, the absurd amount of batteries you chew through in a day should not be underestimated. Especially, if you can only charge one at a time overnight on a holiday.

 

Dynamic Range

Dynamic Range is a measure of how much information is kept within a RAW file in the highlights and shadows. The Sony a7ii has 0.9 stops less dynamic range compared to the Nikon D750 at the base ISO of 100. The graph bellow illustrates the dynamic range of the two cameras as the ISO is increased. As ISO increases, dynamic range decreases as less light is captured by the sensor. Hence, hess highlight and shadow detail.

I also decided to compare the best Nikon, Canon and Sony have to offer regarding dynamic range in the graph bellow, comparing the Nikon D810, Canon 5DSR and the Sony a7Rii.

Here, we can see the Nikon at ISO 100-400 has more dynamic range than the Sony a7Rii. This is unexpected, as the Sony RAW files are physically larger in size than the Nikon’s, despite the Sony’s lossy RAW compression. However, due to the Sony’s new Back-Side Illuminated (BSI) sensor, it has more dynamic range than the Nikon and Canon at all other ISOs.

Once again, this is where you have to pick what’s important to you. If you’re for example a landscape shooter, likely you’ll be shooting at the base ISOs. Hence, the Nikon would be the better choice. This would also yield sharper images due to Nikon’s aforementioned lens variety. If your shooting high ISO’s and need the extra dynamic range, the Sony is the best camera on the market. It is also important to note that there is more to a good landscape camera than dynamic range. Size and weight may also become a factor.

 

Video

Here, the Sony’s win all day long with one exception: focus by wire lenses. Focus by wire is a technology that replaces the direct mechanical connection between the focus ring and the focus motors with a electronic connection. The focus by wire used in Sony lenses changes focus logarithmically. That is, at differing speeds depending on the speed in which the focus ring is rotated.  This of course leads to apocalyptically inconsistent focus pulls using native Sony lenses. It is for this reason why the professional cinematographers who use the Sony a7S/A7Sii/a7Rii use adapted Canon or sometimes Nikon lenses. 

Do keep in mind adapted lenses on Sony mirrorless bodies are also completely inadequate for professional photography applications due to the outright terrible or even complete absence of autofocus. A very possible exception to this is on the arRii or a6300 and a specific adapter (Metabones with Canon Lenses). This will disable Eye AF amongst other AF features though. The a7Sii and a7Rii both now incorporate internally recorded 4k video. This is reason enough to switch to mirrorless if you’re a videographer. Quite simply, the video coming out of these cameras is outstanding.

 

Focusing

This was the main reason I switched. Mirrorless cameras may have more focus points, but DSLR’s have better focus points. DSLR's also allow you to easily manually select the focus point.

The Nikon D750 adapts the focusing system from the Nikon D810 and Nikon’s flagship, the D4s. Even on overcast sunny days, the Sony a7ii misses focus, even with face detect on for a full body portrait with native lenses. There have been times the camera focused on my knee, leaving my face out of focus. It’s almost a good thing Sony has decided to only manufacture F4 zoom lenses, for the extra depth of field! Using prime lenses definitely helps, but it's still completely unreliable and unusable for professional photography. The camera just hunts back and forth using Contrast Based AF, then gives up. I cannot tell you the amount of missed moments due to failed focusing I have experienced with the a7ii. The a6000 really wasn’t that bad, further adding to my disappointment. That is not to say, for less strenuous photographic conditions, the a7ii won't be sufficient. Just, for professional wedding photography, sports and wildlife, it is just too inconsistent and unreliable. 
Many just tell me to use focus peaking. But just refer back to my statement on focus by wire lenses, and the fact that focus peaking isn’t accurate bellow F2.8, especially at high ISO, where it somewhat detects noise as being stuff in focus. PUBLIC SERVICE ANNOUNCEMENT: Do not under ANY circumstance use a Sony a7ii, a7R, A7S, a7Sii or a7 for indoor sports photography. Happily, the A7Rii has improved on sensor phase detect AF, although I have been informed it is more on the level of a crop sensor Nikon or Canon DSLR. Still, it’s a huge improvement over the course of only a couple years. Sadly, the a7Rii is a whopping $4000 Australian dollars.

 

Price ($AUD December 2015)

Sony a7Rii - $3998

Sony a7ii - $1918

Nikon D750 - $2273

Nikon D810 - $3349

 

 

Conclusion

When I first started switching to Nikon, I got a few general reactions. Professional wedding photographers around me fully encouraged it, as they mostly shared my sentiments. Camera store employees seemed shocked, as the employees pointed out usually people are switching from Nikon to Sony and not the other way around. This got me thinking. The Sony mirrorless system may be worse for my professional use, but it is still ideal for many people. If your livelihood doesn't depend on it, the Sony is still an overall brilliant camera. The lenses will hopefully develop, and third party manufacturers Sigma and Tamron will hopefully soon hop on board, yielding sharper and cheaper less options. The ergonomics and focusing will hopefully improve as well.

I am not about brand loyalty. I just want to pick the camera that works best for me. Just because I ended up choosing Nikon over Sony doesn’t mean you should. After all, we aren’t all event photographers. Sony has offered huge incentives to switch over, such as 4k video, in-body image stabilisation, Zeiss AF optics, Electronic Viewfinders, Focus Peeking, Highlight Alert and more that Nikon and Canon have yet to offer. I am excited to see what Sony and other mirrorless manufacturers bring to the table, and I hope Nikon and Canon catch up on the pleather of features mirrorless has been introduced in recent years.

Update: As of the 3rd of February 2016, Sony has announced a 24-70mm, 70-200mm F2.8 and 85mm F1.4 lenses. Unfortunately, the pricing of these lenses align with the a7Rii. That is so say, they are the most expensive lenses of their type on the market. However, it is certainly an exciting announcement.

Further Reading

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