Size DOES Matter!
Friday 25 April 2014 — Category: Equipment
Yoda — does that put me on the Dark Side? — but I just can’t agree with him that “size matters not.” Of course, I am taking his statement out of context, because he wasn’t referring to digital cameras. Nevertheless, when it comes to image sensors, size DOES matter!
You might be surprised that I, who am so passionate about Micro Four Thirds (µ4/3) cameras, would make such a statement. After all, isn’t it the proponents of full-frame sensors and APS-C sensors who insist that sensor size matters? Isn’t it the fans of µ4/3 who adamantly insist that size matters not? HAVE I turned to the Dark Side?!
Before you start jumping to conclusions, let me explain and clarify what I mean by saying that sensor size DOES matter.
When it comes to the issue of sensor size and image quality, then I am definitely in agreement with the mainstream µ4/3 view that size does NOT matter all that much. As Olympus and Panasonic bring each new generation of µ4/3 cameras to market, there are more and more rave reviews which proclaim that the image quality of these cameras rivals the image quality of many APS-C cameras, and even some full-frame cameras.
Lindsay Dobson entitled Micro Four Thirds vs Full Frame | The Arguments Continue and Full Frame v Micro Four Thirds II.
Of course there are situations when a larger sensor is going to result in a better image. But I think it is fair to say that in MOST situations, for MOST photographers, sensor size is not really an issue that needs to be wrestled over. It is often pointed out that there are numerous factors which determine image quality besides the sensor size, like the quality of rest of the camera equipment, the experience and skill of the photographer operating the camera, and the lighting and other environmental conditions. Sensor size is just one piece of the puzzle, and not a humongously-large piece at that.
However, when it comes to the bulk and weight of camera equipment, then sensor size DOES matter. In fact, it makes a HUGE difference! I've been wanting to write about this issue for more than a year, but it was a recent comment left by a reader of this blog which motivated me to finally do it. After reading last year’s article Canon S100: A Failed Experiment, Canadian Caspar Davis wrote:
I have just discovered the same problem with an S-100 I bought (fortunately used) last year. Mighty disappointing. I have been looking at the Fuji X series, and also their waterproof cameras. Any thoughts about those?
Some manufacturers have decided to use image sensors which are smaller than the µ4/3 sensor, with correspondingly-small lenses. I have taken a closer look at such systems in my article Are the Nikon 1 and Pentax Q Cameras Pocketable?
Most manufacturers have gone the opposite route by using image sensors which are much larger than the µ4/3 sensor. Generally these cameras have an APS-C sensor, but a handful have gone so far as to stuff a full-frame sensor into a small mirrorless body. Although not an exhaustive list, these systems include:
Despite the nice compact bodies on many of these APS-C-sensor and full-frame-sensor cameras, lens sizes have not seen a corresponding reduction in bulk, because there is a direct correlation between sensor size and lens size. If you have a full-frame sensor in a camera, then you need to have a lens with a large enough diameter to cover the entire sensor. Otherwise you will have major problems with vignetting and even unwanted image cropping.
Some of these DSLM cameras have a good selection of native lenses within their system, like the ones from Sony and Fujifilm. Samsung’s NX series doesn’t have a great selection, but it’s not too bad either. All of the other series — Nikon 1, Canon EOS M, Pentax Q and Leica T — have a pretty pitiful selection of native lenses. It kind of makes you wonder if the manufacturers themselves believe in their own DSLM systems!
Most pathetically, major camera manufacturer Canon doesn’t seem to be taking the DSLM market very seriously, because their ENTIRE mirrorless interchangeable-lens system consists of only two cameras and three lenses! And the newest camera and lens are not even available outside of Asia. All the more reason to go Micro Four Thirds!
Even for those systems with a decent selection of lenses, things are not all rosy. In order to reduce the sizes of their lenses to be in proportion to the smaller camera bodies, many of the lenses on offer have quite slow apertures. For those photographers who are used to the faster, more professional lenses available for cameras with full-frame or APS-C sensors, this trend makes these mirrorless systems less appealing. For fans of the Micro Four Thirds system, its large selection of lenses, and the fact that a good number of them are decently fast, is a major attraction.
With everything else being equal, it is generally the rule that faster lenses will be larger and heavier than slower lenses of the same focal length. This is clearly shown in the photo to the right.
Both are Canon 85mm full-frame lenses, but the smaller one on the left has a maximum aperture of f/1.8 while the larger one has a maximum aperture of f/1.2. That is only one full stop difference, and yet the 85mm f/1.2 lens is 75% larger (by volume) and 2.4 times heavier than the 85mm f/1.8 lens! Both of these Canon lenses have a solid five-star rating by customers on Amazon.com.
Now that we've looked at 85mm lenses on a full-frame-sensor camera, let’s take a look at a similar five-star lens built for a Micro Four Thirds camera. The Olympus 45mm f/1.8 lens — pictured to the right, at the same scale as the two 85mm lenses above — has a full-frame-sensor equivalent focal length of 90mm, due to the µ4/3 focal length multiplier of 2x. Therefore a 45mm lens on a µ4/3 camera has the same angle of view as a 90mm lens on a full-frame-sensor camera — which close enough to 85mm for the sake of our discussion today.
Even though the Canon 85mm f/1.8 lens is much smaller and lighter than the Canon 85mm f/1.2 (as we saw above), it is still 2.8 times larger and 3.7 times heaver than the equivalent Olympus µ4/3 lens — even though they both use plastic for the construction of the barrel! Why the huge difference in size and weight? The most significant factor is that a µ4/3 sensor is around a quarter of the size of a full-frame sensor. The greatly reduced sensor size allows for greatly reduced lens size and weight. Sensor size DOES matter!
Lest you think this is just a fluke, allow me to give you a few more examples. When I was first building my µ4/3 lens kit nearly two years ago, I carefully documented the vast physical differences between my new µ4/3 lenses and the equivalent full-frame Sony lenses I had previously owned.
So, why does lens size matter? The µ4/3 Olympus OM-D E-M5 and the full-frame Sony α7R bodies have a very similar form factor, size and weight, in contrast to a standard full-frame DSLR, as the image below makes clear.
Nevertheless, as we have already seen, the lenses for the Sony α7R are two to four times larger and heavier than the equivalent lenses for a µ4/3 camera. Therefore the advantages of the compact α7R body which Sony boasts about in its marketing material disappear into thin air once you consider the camera system as a whole (that is, with the lenses), and not merely the camera body in isolation.
The weight of these large lenses was painfully real to me when I took my last hike with my Sony APS-C system gear. As I reported back then, when I added up the weight of all the photographic equipment I was carrying — including a camera backpack big enough to hold all that equipment — it came to a staggering (literally!) 25 lbs. Of that, about 8.5 lbs. was the Lowepro backpack itself, 10 lbs. for the camera and lenses, and 2 lbs. for a small tripod. The remaining 4.5 lbs. included a holster case and miscellaneous items like spare batteries and lens-cleaning equipment.
For the sake of our discussion, let’s focus on the 10 lbs. of primary photographic equipment. My previous Sony α77 camera with vertical battery grip came to 2.3 lbs, while the four lenses I had taken came to 7.7 lbs. Here’s the rundown of the lenses:
Because this µ4/3 equipment is so much smaller than its APS-C and/or full-frame counterparts, I am able to take the lenses out hiking in a much lighter shoulder bag rather than that huge and heavy Lowepro backpack. I am also using a smaller and lighter holster case which is the perfect size for my Olympus camera with even the longest lens attached.
Between the equipment and cases, I’m saving perhaps 10 lbs. when I’m out hiking. That might not sound very significant to you, but when you have to carry that on your body all day long, mile after mile, it makes a HUGE difference! And besides, my 52-year-old, somewhat-overweight body just can’t carry that kind of heavy photographic equipment any more, even though I have tried to get in shape for the hiking season. In a very real, physical and visceral way, I've found out the hard way that sensor size DOES matter!
Just for fun, let’s take this relationship between sensor size and lens size to an extreme. How is it that my 1/2 lb. (232g) Fujifilm FinePix F900EXR pocket camera can boast a 25-500mm (35mm-equivalent) f/3.5-5.3 zoom lens, when such a lens — the closest I could find is the Sigma 50-500mm F4.5-6.3 DG OS HSM — with a full-frame-sensor camera would weigh about 12.5 times as much, at approximately 6.5 lbs. (nearly 3kg)? That definitely would NOT fit in my shirt pocket!
By now the answer should be obvious. The tiny size of the F900EXR’s sensor — at 6.4 x 4.8 mm it about 28 times smaller than a full-frame sensor — allows for an analogous reduction in lens size. Of course, I’m not talking about the relationship between sensor size and image quality. Obviously photos from a full-frame sensor (and a good lens) are going to be of much higher quality than from this tiny pocket camera. But when it comes to the correlation between sensor size and lens size, it is indisputable that sensor size DOES matter!
So, to wrap things up and answer Caspar’s questions, when shopping for a pocket camera, the handful of waterproof models can be a good choice IF that waterproofness is the MAIN feature you require. In my own case, I bought an Olympus TG-2 iHS “Tough” camera a while back, and it IS pretty cool to be able to take it in the water and other camera-unfriendly environments without having to worry about it getting ruined.
However, I soon became disenchanted with the TG-2 because, like all of the other pocket waterproof cameras, it cannot shoot RAW images. Another strike against this group of cameras is their paltry zoom ranges, generally no more than 4x. These two major limitations are a deal-killer for me, so after only a few months I chose the above-mentioned Fujifilm FinePix F900EXR to take the place of the TG-2 as the camera which I carry around all the time.
I would say that when shopping for an interchangeable-lens camera smaller than a traditional DSLR, I would not even consider the Fuji X series, nor any other mirrorless interchangeable-lens cameras which use APS-C or full-frame sensors, because those small bodies are still encumbered with large and heavy lenses. That’s the whole reason I got rid of my Sony APS-C system in the first place. Why would I want to go back to APS-C in a smaller camera body, just to be stuck once again with lenses which are too big and too heavy?
On the other end of the scale, the two systems with the smallest bodies and lenses — the Nikon 1 series and Pentax Q series — seem to me to be half-baked solutions with mediocre performance and a dearth of system lenses. I think investing in either of these systems is a dead-end street, which does not make any sense.
That leave Micro Four Thirds as the last man standing. As numerous professional and amateur reviews have pointed out, the latest generation of µ4/3 sensors rival the image quality of APS-C and full-frame sensors in all but the most demanding circumstances.
At the same time, because a µ4/3 sensor is about one quarter the size of a full-frame sensor, µ4/3 lenses are two to four times smaller and lighter than equivalent lenses on APS-C and full-frame cameras.
Well, Yoda, you’re probably getting sick of hearing it, but I just have to say it one last time: when it comes to image sensors, size DOES matter!