First off I have owned tons of M4/3 cameras (G1, GF1, GH1, GH2, G3, E-M5). M4/3 are great cameras which are, in my opinion, the best choice for probably 95% of households looking for a large sensor camera. Now let me start off by saying, if you are a fine arts photographer looking to print big or a commercial photographer looking to impress customers and print big then look elsewhere because these are not the cameras for you. For just about everyone else who is looking for the best all around tool to capture their special moments then m4/3 is it.I am going to digress quite a bit here to discuss the sensor "envy" issue I have seen so much on the web from both individuals and so called "professional" review sites. The discussion actually turned in to a master's thesis so I will be presenting the condensed version before the review. The detailed version will be at the end of the review for anyone interested. And if sensor envy is not an issue for you or don't want to read about relative merits of sensors then skip down to the asterisk box for the start of the review.Is a FX sensor better than a m4/3? Is a m4/3 sensor better than a FX? The answer to both those questions is "It depends." Anyone who tries to give you a one size fits all answer either has no clue what they are talking about or are trying to sell you something. I will attempt to try and explain the relative merits of each so you can make an informed decision. I am really only going to discuss FX (AKA 35mm or mislabeled as full-frame. Whatever that even really means as there are medium format cameras and large format cameras with much larger imaging circles.) as what I say about it will apply to DX to a lessor extent.The 4 major components of IQ are Resolution, Color Depth, Dynamic Range, and High ISO. The best FX and DX cameras DxOMark scores exceed the best m43 yet tested (GX7 and EM1 have not been tested). However, the m4/3 scores of 2012 are about equal to the 2006 35mm Canon 1Ds MkII. This was top-of-the-line pro-camera that cost $8000 and at 16.7mp was the first 35mm digital DSLR considered capable of shooting double-truck ads for national magazines. (A comment I want to make concerning High the ISO numbers. I am not sure how these are computed or relate to each other. I shot with the 1Ds MkII extensively and I can without a doubt say the files from the EM5 look better than the 1Ds Mk II at 6400 ISO. Also, you can go to DPReview and see 100% magnified files shot at various ISOs and various cameras. The files from the D800 look to me about 1 to 1.5 stops better than the EM5. That is the D800 files at 6400 look the same with regard to noise as EM5 shot at 3200.) The m43 or 2012 also easily outclasses the DX sensor Nikon D300 a $1600 prosumer camera from 2008. If all you care about is IQ and you need all that IQ, then by all means the D800 is even better than the best medium format except in color depth (used for portraits) so get the D800.However, the IQ of sensors, long ago exceeded what we need for home use. So the fact of the matter is, most people don't need the IQ of the D800 and there are, to me, more relevant reasons why the D800 is not something most people would even like. The first is 36mp files. Shot in 14bit RAW, you are looking at around a 65MB image file. Roughly, 15 of those images make 1GB. Even the JPEGs are huge around 15MB each. That is a pain to store and a pain to process. What do most people do with their images? I would say the number one thing people do is is to put them on the web or their phones. The biggest monitors are around 2.5mp. To print a 300dpi 8x10 requires around 7mp. That means if you view the picture on a 2.5mp monitor you giving up 33.5mp. (This is not entirely accurate as the image is interpolated down and you do clean up noise when you do that.) And that is for a full screen image not the little happy snaps you text or put on facebook which are more likely to be around 1mp or less. Do you really think you need 36mp? If so, then m4/3 is not the right format for you. I mentioned earlier, that when you downsize an image it is interpolated down and this helps clean up the image. Well that applies to the m4/3 images as well. So even though the D800 is 1 to 1.5 stops better for noise, when you interpolate the images down, you are very unlikely to be able to see that on your screen or even on a print except at ISOs greater than 6400. So the FX sensor has better IQ than m4/3 but for most people it just doesn't matter because the m4/3 sensors are more than good enough for tasks most people use cameras for. As a fun test, I have posted 3 images from the GX7 under the customer images. One was shot at ISO200, one ISO6400 and one was shot at ISO25,600 (That is a whopping 7 stops of ISO difference. So if 1 or 2 stops really mattered you should see a huge difference in 7 stops.). See if you can tell which is which. I will say at full screen on my 27 inch monitor I can tell the difference between them. However, the 25,600 still looks really really good and is very usable for web images. The difference between ISO 200 and 6400 is not really noticeable. If they weren't side-by-side you wouldn't even be able to tell one was shot at 6400.So what are the downsides of FX sensors. The first and most obvious is price. However, the other costs associated with the FX sensor are the lenses. The best lenses are very expensive. Also, the imaging circle of a FX is roughly 2x the size of the imaging circle of m4/3. That means, the lenses are going to be bigger and heavier and the difference is not trivial. A D800 with a 70-200mm f.28 is going to set you back about $5300 and around 6-7lbs. A GX7 with a 35-100mm f/2.8 will set you back about $2300 and around 3lbs. If you are traveling somewhere and carrying your camera all day, can you see how the smaller sensor might be better for you? Something to think about.Next, the contrast autofocus use by m4/3 is on the sensor and it is exceedingly fast. What this means, is you have focusing points throughout your frame. The phase detect systems used on FX DSLRs only has points clustered around the middle; the corners are excluded. Also, the phase detect systems are separate from the sensor. Therefore, with FX you have back focusing and front focusing issues. The so called live view systems on the DSLRs are really the only accurate way to auto or manual focus and are terribly slow. That means the only way to quickly frame and focus a FX DSLR is through the viewfinder. Forget holding the camera over your head or down at your feet.The next issue is with dust on the sensor. With all my DX and FX sensors DSLRs, dust has always been an issue (Talk about a way to ruin IQ). However, in almost 5 years shooting m4/3, I have never had one single problem with dust on the sensor. Another "benefit" of FX is the shallower Depth of Field that can be achieved for the same aperture. The reason I put that in quotes is that in a lot of cases the DOF on a FX is too shallow and you need to stop down the lens to f4 or f5.6 to get the DOF you are looking for. In these cases, a m4/3 is clearly superior as you can stay at f2 or f2.8 to get the same DOF. That means you can turn your ISO down 2 stops (From my perspective on the high ISO images I viewed on DPReview, a 100% EM5 image at 1600 looks better than a 100% D800 6400 image). Also, for flash or lighting for video filming, a 2 stop ISO difference means 4 times less light power is required for the m4/3 sensor. That means your flash batteries will last longer and your flash will recycle that much quicker.Another drawback of the FX sensor is it is stuck in the archaic 2:3 ratio which is not as friendly for printing as a 4:3 ration is. To print a 4:5 ration 8x10 from a 2:3 ratio there is quite a bit of cropping to be done and often a picture won't fit.Finally, the pixel densities on m4/3 are the highest of any large sensor camera. A DX sensor with the same pixel density as a 16mp m4/3 sensor would be roughly 32mp and a FX sensor would be 64mp. This is both good and bad for m4/3 cameras. Currently, there are no DX or FX sensors with pixel densities of the m4/3. So you are currently getting more reach on your m4/3 lenses than any other lenses. What this means is, given the same focal length, you are getting approximately 1.5x the data on a subject for the same area than an FX and 1.25 vs a DX sensor. This is not to be confused with crop factor which based on the sensor size is 2x compared to FX sensor and 1.5x compared to a DX sensor. This does come with a downside to the m4/3 in that it works your lenses harder (exposes optical flaws in the lenses) and you hit diffraction limits on IQ at around F8 vice F11.Buy 35mm FX if:- You need the best image quality available to print big. At 200 dpi (good enough for most people) you can print a 16mp image up to 23x17. If you need bigger than that, get a FX.- You absolutely have to have the shallowest DOF available in a DSLR body. I've owned FX camera bodies and I will admit sometimes I do miss the razor shallow DOF images I was occasionally able to capture. With that, however, the DOF was so small I often missed the focus especially on wiggly subjects such as kids. Also, with 2 or more people, DOF at 1.4 was way too shallow so forget about it. With my 75mm 1.8, I don't miss FX as much as my pictures from that lens have a very similar feel as the FX pictures. I liked the D700 a lot but the fact of the matter is, I used my GH1 far more.- You have to have the biggest sensor to feel good about yourself. (And, really, you will still need MF)*********************************************************************************** Start Review Here**********************************************************************************Ok I am off my sensor soapbox and will now get back to the GX7. One of the big deals about the GX7 is it is the first and only ranger-finder style camera (note: it is not a range-finder camera). What this means is you shoot with your right eye one the EVF, the camera is not resting on your face. (It reminds me a lot of the X100 but only much faster and easier to use). The big benefit of this, however, is it leaves your left eye well clear of the camera and able to scan the scene for the right moment to shoot. I am left eye dominant and at first blush that would appear to be a drawback. However, having your dominant eye be the one scanning the scene is a major benefit in my opinion. This setup is one reason I like the rangefinder style cameras such as the GX7. This is the camera either Panasonic or Olympus should have built well before there even was and X100 or NEX 7. To me it felt instantly comfortable and fun to use like an old friend.The single autofocus on this camera is blazing fast. It is the fastest single shot autofocus I have ever used. With the 25mm f/1.4 it is near instantaneous in good light. However, it is the low light performance which really blows me away. In a dark room at night with the only light bleeding in through an open door, the GX7 was as fast as many autofocus systems in bright light. Here is the amazing thing, there was no hunting or searching. It is very noticeably faster than any other autofocus system I have ever used in low-light by a wide margin! I have to say using the EM1 was disappointing as it hunted, searched, and took about 3-4 times as long. Not that the EM1 was bad it is about standard for what I have used. The GX7 is just plain faster. For night shooting, or low-light event photography I don't think you will find a better auto focus system out there for single shot. Tracking focus does not live up to single shot but I don't really use tracking focus. Another nice feature dealing with autofocus is you can have the camera start to focus when it senses your eye at the EVF. If you have this turned on in the menu, and you get used to it by making sure you are pointing at your subject as you raise the camera to your eye, the subject can be in focus when your eye reaches the EVF.Wow what a nice camera. M4/3 have been a little hobbled in my opinion in the past with a crappy 1/160 flash sync and a lame 1/4000 fastest shutter speed. Well that is past with the GX7. It has a flash sync speed of 1/320 which is I believe faster than any DSLR which top out at 1/250. Not really fast enough to get really excited about but fast enough to be useful. The camera also has a built in little fill flash which is handy for daylight shooting. The 1/8000 max shutter speed is also welcome as I like to shoot wide open primes in bright light and don't like toting around ND filters. Additionally, this is Panasonic's first m4/3 camera with In-body Stabilization (IBIS). I don't feel it is a good as the one on the E-M5 but it does work with any lenses which don't have stabilization such as Leica, Nikon, Voigtlander, etc. Shooting the 75mm f/1.8 handheld at 1/10, I got around 50% non-blurry images. Which is pretty decent since the minimum I should be shooting that is 1/160. That is about a 4 stop advantage. Shooing with the EM1, however, all the images were good.It is unfortunate that neither Panasonic nor Olympus are building bodies with 2 card slots in them. Two cards are really nice for paid events for redundancy incase one card dies on you. This camera also, has built in wifi and NFC. One reviewer mentioned it was exceedingly difficult to set up. My experience was completely different. I downloaded the app from Goggle Play store and then followed the instructions in the manual. I was up and running with both wifi and NFC in about 5 min. Now with that said, I don't think wifi is going to be that useful for me. If you need to remotely control a camera then it would be ok. I could see a portrait studio having the camera set up on a tripod and using the phone to trigger the camera. The reason I say this is ok is that the focus seemed really slow. Also, it can transfer photos to your phone to upload to the web, so if that is something you have been waiting for then this will be useful for you. For me, I doubt I will use it. As an aside, the EM1 was even easier to set up and includes an additional feature of geo-tagging you photos with your phones GPS coordinates. This is something I might actually use.M4/3 cameras are so small and light that I use them with a wrist strap instead of a neck strap. It is kind of a shame that neither Panasonic nor Olympus have figured this out yet either. I saw one reviewer commenting on how you need two hands to shoo this camera. I don't think that is true. While the grip is not as steady as the EM1, I can shoot the 75 f/1.8 comfortably one handed all day. With, the wrist grip on you don't worry about it. Just keep it in your hand.The build quality of this camera is top notch. Panasonic's best so far. It has a quality fell and weight to it and is a real pleasure to hold. The grip is nice enough but I prefer a bigger grip when using the bigger lenses such as the 100-300. The EM1 grip is a lot better in my opinion. The switches all feel really nice. As far as handling goes, I feel Panasonic's handling is far superior to DSLRs. To me DSLRs are like dinosaurs compared to the Panasonic's. I always liked the push to click adjustment wheel on previous Panasonic so I am sad to now see a 2 wheel system. With the one wheel, I always knew what I needed to do and could make it happen with out looking. Changing exposure value was so easy. With 2, I always forget which one does shutter and which one does aperture. Panasonic always got bashed, by so called people in the know, for only having 1 wheel so now we get 2. Too bad in my opinion as the new system is far inferior to the G1, GH1, GF1, GH2, G3, etc. The setup used to be everything was viewed at once in terms of exposure data (Shutter speed, aperture, and EV). Now when you press on the wheel, shutter speed and aperture go away and all you have is EV. Boo to Panasonic for listening to so called experts who don't recognize an improvement when they see one because it is different. The quick menu system works great and the touchscreen is useful. Panasonic used to have the best handling going but I am now going to have to say the Olympus EM1 handles better than the GX7.One thing I have found is if you are using the back screen and you are holding the camera on the left, it is easy to trip the eye sensor and have the back screen shut off. The solution for this is either to make sure to flip the EVF up when using the back screen or adjust the sensitivity down to low in the menus.Speaking of EVF, this 2.4 million dot EVF is beautiful. Many pros sites say they prefer the view from a large FX prism. In most cases I actually prefer EVF. For one thing it covers the full frame. For another it actually magnifies the picture better. But for me the big thing is it is somewhat What You See Is What You Get. That means if you set a manual WB and then forgot to change it when you changed settings, you will see that in the EVF as the picture will look either to yellow or blue. I use it as a very fast method of setting exposure. Move the light sources around in the frame until you see the exposure you want and then lock it in. Recompose and shoot. This is an exceedingly fast way to play with your exposure. Tired of taking pictures with people too dark because of a bright background. You will see that in the EVF. If you want a Silhouette then you can see that before you shoot. This is actually less likely to happen with the GX7 because the facial recognition and facial exposure works exceedingly well.I do need to mention an occurrence I just had happen on AWB with the GX7. I was shooting low light sunlight through a gold curtain which makes the light orange. In the EVF the image looked great, however, the JPEGs were way too orange. I reset the WB to incandescent and the images looked fine. The EM1 images looked great even in the strange light. Also, I remember seeing some test images that looked too yellow on a review web site. No one has reported any AWB issues with this camera, but I would make sure to check your photos in weird light. You might need to use a manual WB. This is an issue that Panasonic can and should be able to fix with a firmware update.All in all this is a fantastic little camera, that handles beautifully, takes great pictures, and is, in my opinion, the best all around camera for most people. Since the E-M1 is about to come out I will comment about that also. In most cases, this camera being $500 cheaper is the better way to go. IQ is the same, features that are important to most people are the same and you save a ton of cash. There are a few situations where the E-M1 might be better for you than the GX7. 1) If you have 4/3 lenses, the E-M1 is a no brainer. If you don't know what I am talking about you don't have any. 2) If you need the extra battery life of the grip or you take tons of portrait orientation pictures, the E-M1 is the way to go. If you want the best IBIS in any camera system, that will be in the EM1 (I nailed 100% 75mm shots at 1/10 of a second. I've seen talk of being able to shoot at 1sec hand held. I will update when I test that). If you want the most weather sealed m4/3 camera that will also be the EM1.Pros:Very Fast Auto Focus (Best low light I have every shot.)Range-finder Style CameraBuild QualityImage QualityIBISSmallHandlingLen SystemCons:AWB needs a Firmware Fix. In some rare instances it gets confused and is too orange.Only one SD slotMore expensive than NEX6 and cheaper DSLRsBelow is a buying guide recommendation.Panasonic GX7 - Panasonic's best still camera to date - Great construction, 1/320 flash sync, 1/8000 shutter speed, blazing fast focus, WIFI, IBS, focus peeking, great handling, etc. This camera does cost $150 more than the NEX-6, which is similarly specked (Sony must be giving them away). However, m4/3 lenses are always going to be quite a bit smaller and lighter than NEX lenses. Additionally, the m4/3 lens system is the most complete outside of legacy 35mm systems from Nikon and Canon.Panasonic G6 - Great little camera for a nice price ($740 with lens). IQ not quite as good as the GX7, build quality not as good as GX7, and has slower flash sync and shutter speed. It has a tilt and swivel screen which in my opinion is actually nicer than the tilt only screen on the GX7, EM5, and EM1. If you want to get into the system, this is a good way to start. Save money on the camera and spend it on a nice lens.Panasonic G5 - Right now if you look for the clearance sales you can get them for $300-400. Not as good as any of the other cameras here but still a great camera which takes nice pictures.Olympus E-M1 - Looks to be an absolutely brilliant camera. If you have 4/3 lenses (not to be confused with m4/3) this camera is a no brainer as it is a huge upgrade over the E-5. The camera has the best in-body stabilization (IBIS) of any camera period. Also, for event photographers, the additional battery grip is a must for better battery life. However, at $1400 if you don't have legacy 4/3 lenses and have no plans to get any, and you don't need the battery grip, then the GX-7 is $500 cheaper and almost as good. (Although, the GX7 doesn't have as good IBIS).Olympus E-M5 - this camera has now been outclassed by the GX-7 and costs the same. So while this is still a brilliant camera, the GX-7 is better for the same money.Olympus E-P5 - Has no built in view finder which for me is an absolute no go. If you add the external viewfinder, you have now paid $1500 which is more than the EM-1. And add on accessories always get lost. (I can never find my E-M5 flash) So this camera is way overpriced (as all of the EP cameras have been) and I don't recommend it. Get either the GX-7 or EM-1NEX-6 - Really nice camera - Focus is not as fast a m4/3. Sensor is bigger so for higher ISO and large sizes, it will have better IQ. Price is great. However, this camera does not handle as well as the Panasonic. While the camera is small, the lenses are not so this system is not as small and light as the m4/3. The lens system is nowhere near complete as the m4/3 system. If price is your only consideration, then the NEX-6 is probably the way to go. If size and weight are the primary consideration, the GX-7 is the way to go.Any DSLR - Bigger and heaver - DSLRs are dinosaurs when compared to mirrorless cameras. I really hate going back from shooting my E-M5 and shooting my Nikons. They are big, the focus system is obsolete (not phase focus, but the focus points and how they are arranged). Their, live view is terrible, most of the viewfinders are smaller then the newest EVFs, and are lacking some of the features of the mirrorless. Tons of people buy Nikon and Canon because that is what is around, however, my opinion is the vast majority of families would be much better served by a m4/3 system. If you know why some of the DSLR features are better than m4/3 then a DSLR may be for you. However, if you are looking to step up from your phone and get a camera to take pictures of your family and daily life, then m4/3 is the system for you. If you really need, shallow DOF, then full-frame may be the way to go. As far as event photographers go, we often shoot at f/4 or f.5/6 to get the DOF we need. With m4/3, you can shoot f/2 or f/2.8 to get the same DOF so you can shoot 2 stops lower ISO. The DSLRs have 2 card slots which is very nice, however, with WIFI, you can shoot with your GX7 or E-M1 and upload to your phone while taking pictures. DSLRs also have a better battery life.*********************************************************************************** Start thesis on Sensor Size**********************************************************************************Is a FX sensor better than a m4/3? Is a m4/3 sensor better than a FX? The answer to both those questions is "It depends." Anyone who tries to give you a one size fits all answer either has no clue what they are talking about or are trying to sell you something. I will attempt to try and explain the relative merits of each so you can make an informed decision. I am really only going to discuss FX (AKA 35mm or mislabeled as full-frame. Whatever that even really means as there are medium format cameras and large format cameras with much larger imaging circles.) as what I say about it will apply to DX to a lessor extent.The 4 major components of IQ are Resolution, Color Depth, Dynamic Range, and High ISO. You can if you want go to DXOMark and look at all the sensor data. I will give you numbers for the best of breed of each size. D800 36mp, 25.3 bit color depth, 14.4 Stop Dynamic Range and 2853 ISO. For D7100 it is 24mp, 24.2, 13.7 and 1256. For EP5, 16mp, 22.8, 12.4, 895. Higher is "better" and so by numbers the IQ of the FX D800 is best. (I am using the EP5 because there is not DxOMark Score for the GX7. Before, we move on to some other items concerning sensor, let me show you the numbers for the 2006 35mm Canon 1Ds MkII. Before I show them to you, you need to know this was a pro-camera that cost $8000 when it came out and at 16.7mp was the first 35mm digital considered capable of shooting double-truck ads for national magazines. Here are the numbers for this camera 16mp, 23.3, 11.3, 1480. So, based on objective numbers, the m43 sensor of today is about equivalent of the camera used for pro work in 2006 to 2008. It actually has a better dynamic range than the 35mm camera does. (A comment I want to make concerning the ISO numbers. I am not sure how these are computed or relate to each other. I shot with the 1Ds MkII extensively and I can without a doubt say the files from the EM5 look better than the 1Ds Mk II at 6400 ISO. Also, you can go to DPReview and see 100% magnified files shot at various ISOs and various cameras. The files from the D800 look to me about 1 to 1.5 stops better than the EM5. That is the D800 files at 6400 look the same with regard to noise as EM5 shot at 3200.) Just for info purposes here are some of numbers from some other older cameras I shot with. Canon 30D 10mp, 21.5, 10.8, 736 and Nikon D300, 12mp, 22.1, 12, 679. As you can see the EP5 outclasses both of those cameras based on the numbers and yet I got really nice pictures with both those cameras. (Going back to that ISO number again, I shot extensively with both of those cameras and their files at ISO 800 were about the same as the EM5 at 6400. The EM5 is about 3 stops better yet the DxOMark ISO values are about the same. Also, the EM5 6400 JPEGs are sharp and clean. Very nice.) If all you care about is IQ and you need all that IQ, then by all means the D800 is even better than the best medium format except in color depth used for portraits so get the D800.However, as I showed you with the 1Ds MkII, the IQ of sensors, long ago exceeded what we need for home use. So the fact of the matter is, most people don't need the IQ of the D800 and there are, to me, more relevant reasons why the D800 is not something most people would even like. The first is 36mp files. Shot in 14bit RAW, you are looking at around a 65MB image file. Roughly, 15 of those images make 1GB. Even the JPEGs are huge around 15MB each. That is a pain to store and a pain to process. What do most people do with their images? I would say the number 1 thing people do is is to put them on the web or their phones. The biggest monitors are around 2.5mp. To print a 300dpi 8x10 requires around 7mp. Requires. That means if you view the picture on a 2.5mp monitor you giving up 33.5mp. (This is not entirely accurate as the image is interpolated down and you do clean up noise when you do that.) That is for a full screen image not the little happy snaps you text or put on facebook which are more likely to be around 1mp or less. Do you really think you need 36mp? If so, then m4/3 is not the right format for me. I personally, like the 10-12mp range (and wish they would make a 12mp m43) but 16mp is more than enough for me. I mentioned earlier, that when you downsize an image it is interpolated down and this helps clean up the image. Well that applies to the m4/3 images as well. So even though the D800 is 1 to 1.5 stops better for noise, when you interpolate the images down, you are very unlikely to be able to see that on your screen or even on a print except at ISOs greater than 6400 or maybe 3200. So I think we have established the FX sensor has better IQ than m4/3 but I hope I have established for most people it just doesn't matter because the m4/3 sensors are more than good enough for tasks most people use cameras for.As a fun test, I have posted 3 images from the GX7 under the customer images. One was shot at ISO200, one ISO6400 and one was shot at ISO25,600. See if you can tell which is which. I will say at full screen on my 27 inch monitor I can tell the difference between them. However, the 25,600 still looks really really good and is very usable for web images. The difference between ISO 200 and 6400 is not really noticeable. If they weren't side-by-side you wouldn't even be able to tell on was shot at 6400.So what are the downsides of FX sensors. The first and most obvious is price, although with Nikon's D600 fiasco, you can get a FX sensor for around $1500. However, the other costs associated with the FX sensor are the lenses. The best lenses are very expensive. Also, the imaging circle of a FX is roughly 2x the size of the imaging circle of m4/3. That means, the lenses are going to be bigger and heavier and the difference is not trivial. A D800 with a 70-200mm f.28 is going to set you back about $5300 and around 6-7lbs. A GX7 with a 35-100mm f/2.8 will set you back about $2300 and around 3lbs. I can and have carried 4 m4/3 bodies with 2 fast zooms and 2 fast primes in the same bag I can only carry 2 DSLR bodies and lenses. I also carried several extra lenses in that bag. The weight of that bag, bodies, lenses, and iPad was 10lbs. Two FX bodies and fast zooms alone are going to weigh more than that. If you really feel like you want to lug all that around, then by all means get the FX. All that weight also means you will be carrying around a heavier tripod if you use one. Do you think if maybe you had to hike your camera in somewhere that maybe the smaller sensor might be better? If you are traveling somewhere and carrying your camera all day, can you see how the smaller sensor would be better? Something to think about.Next, the contrast autofocus use by m4/3 is on the sensor and it is exceedingly fast. What this means, is you have focusing points throughout your frame. The phase detect systems used on FX DSLRs only has points clustered around the middle. The corners are excluded. Also, the phase detect systems are separate from the sensor. Therefore, with FX you have back focusing and front focusing issues. The so called live view systems on the DSLRs are really the only accurate way to auto or manual focus and is terribly slow (What you see thought the prism is not what the sensor is seeing it is what the autofocus is seeing.) That means the only way to quickly frame and focus a FX DSLR is through the viewfinder. Forget holding the camera over your head or down at your feet.The next issue is with dust on the sensor. With all my DX and FX sensors DSLRs, dust has always been an issue (Talk about a way to ruin image quality). It was so bad on the D600 they have had to significantly drop the price on that camera. In almost 5 years shooting m4/3, I have never had 1 single problem with dust on the sensor.Another "benefit" of FX is the shallower Depth of Field that can be achieved for the same aperture. The reason I put that in quotes is that in a lot of cases the DOF on a FX is too shallow and you need to stop down the lens to f4 or f5.6 to get the DOF you are looking for. In these cases, a m4/3 is clearly superior as you can stay at f2 or f2.8 to get the same DOF. This means you are collecting 4 times the light and, therefore, you can turn your ISO down 2 stops (According to the images on DPReview, a 100% EM5 image at 1600 looks better than a D800 6400 image). Also, for flash or lighting for video filming, a 2 stop ISO difference means 4 times less light power is required for the m4/3 senso