According to DPreview, they were making similar comparisons.
The GH3 body only is about US$100 more than the D7100. Given the great video abilities, the GH3 is likely the better choice for someone who wants to do stills and video, but the D7100 is undoubtedly a better stills camera.
I decided against the D7100 because I didn't want to spend US$4000 on the D7100 and 70-200mm f/2.8 lens, and possibly be underwhelmed. The GH3 and 35-100mm f/2.8 came close enough to US$3000 but I could use an adapter to make use of my high end Olympus glass.
The D7100 uses the sophisticated auto focus unit from the D300/D300s as an upgrade from the adequate auto focus unit in the D7000. However, when I use auto focus, I use 1 point in the centre and while I have it locked, I move the frame however I like. I really don't want to think about which of the 51 points work with which lenses at which aperture and I definitely don't want the focus on something other than what I intend.
Maybe obviously, I'm not a fan of auto focus. With earlier camera bodies, I didn't even use auto focus. The Olympus E-5 is pretty quick in good light with the lenses I have. The Panasonic GH3 is quick with the 35-100mm lens although neither body always puts focus where I want it during sports.
On build quality, I think the GH3 is better than the D7100, from my physical inspection. That said, compared to the E-5, neither one feels that strong. Of course, the E-5 still retails for US$500 more than the D7100 and US$400 more than the GH3, including the much older sensor and smaller resolution.
After all the complaints about Electronic Viewfinders (EVFs), I expected to hate using one. The EVF in the Panasonic GH3 may not be the most sophisticated, but it works well enough for me to get the shots. I've noticed problems while wearing sunglasses, but I'll become acclimated to pairing them, as I would with any other viewfinder and sunglasses. (Update: the Olympus E-M1 is better than the GH3 and seemed as good as an optical viewfinder, but I only used it for a couple of hours.) The rear display of the D7100 is in a fixed position while the GH3's display is fully articulated.
I'm amused every time I hear some micro Four-Thirds user complain about the size of the GH3. It's really not huge but the typical micro Four-Thirds camera body is tiny. The GH3 is smaller than the Olympus E-1 and much smaller than the E-5 or D7100. Of course, the balance of the body/lens combination should not be a problem.
|The Olympus E-5 and Nikon D7100 are similar in size but the Panasonic GH3 is not.|
The D7100 and 70-200mm are a little off-balance because the 70-200mm f/2.8 is rather massive. I see the same problem with the E-5 and the 35-100mm f/2.0. It's not horrible but it makes you pay attention. On the other hand, the GH3 and 35-100mm f/2.8 feel like a pocket camera to me--too small and almost too light. I've finally put the strap on the GH3 so I can wear it while using the E-5.
The Panasonic 35-100mm f/2.8 is so small that I have trouble using it manually. Here is where the combination is too electronic for my taste. The body helps me focus manually by giving me a magnified view. The E-5 works similarly in Live View mode. It takes acclimation. However, the 35-100mm is so small that my fingers are often past the end of the lens, trying to find the focus ring. I plan to take a few hours and practice nothing but manual focus with the lens, so that I'm ready for anything. It's so easy to push the lens aside and pull out an Olympus lens that I haven't done enough to acclimate myself.
As far as image quality goes, I think there isn't that much difference between them, but the best lenses have much between them. Can the Panasonic 35-100mm f/2.8 compete with the Nikon 70-200mm f/2.8? Yes, more-or-less. The 35-100mm isn't a great lens and US$1499.99 seems expensive, except that it's about US$1000.00 cheaper than the Nikon lens, and the Nikon lens is more in line with the Olympus 35-100mm f/2.0--beastly. I don't think that the Panasonic 35-100mm would stand much abuse but the 70-200mm could be used as a hammer. Still, from all the photos I've seen comparing the GH3 and D7100, there isn't enough difference in image quality to call it decisive. The extra telephoto reach is important though, as the 70-200mm becomes 105-350mm effective focal length in 135 format terms and the 35-100mm becomes 70-200mm.
In the end, D7100 or GH3, I think I'd be having regrets. However, the D7100 is holding on to the past while the GH3 is headed toward the future. It's better to be prepared for change that to meet it kicking and screaming, don't you think?
• High resolution sensor
• Availability of lenses
• 1.5x zoom factor--i.e., 70-200mm becomes effective 105-350mm
• Optical viewfinder and continuous auto focus for sports but small raw buffer lessens the advantage
• Video formats and bits rates extremely flexible
• Articulated rear display
• Light and small lenses
• Direct sensor feed to viewfinder
• Buffer size for continuous shooting
Update 2014.02.18: Is anyone surprised that the Nikon D7100 is not being replaced while the newer GH3 is? I am.
We've seen the D600, the D3200, the D5200 replaced and the Df added but not the D7100. Even Canon has replaced the D7100's main dSLR competition, the 60D, but not the ~4 year old 7D.
The problems with the D7100 are small--the frame buffer and the image noise. They should be able to handle those two things cheaply by adding to the frame buffer and substituting a newer image processing unit.
Considering the price of the Sony A7, and the viability of the GH4, E-M1, and X-T1, I don't understand why they're not moving more quickly, except that the profit in US$1000-$2000 isn't huge. Slap a "MkII" on the name and increase the price by US$100 for now. We get that the D400 isn't coming, but the need still exists.
Update 2014.04.10: Earlier, I was reading a review on the Pentax K-3 on DPReview. They've been known to throw non-Canikon equipment under the bus from time to time. In this review, it was no exception:
The Nikon D7100 is a safer bet in this respect, too, though it is somewhat hobbled by its small Raw buffer - 7 images, rather than the K-3's 23-or-so.
Now, to me, a 3.x to 1 ratio is hardly "somewhat". "Extremely" is a better choice of words, unless you're worried about offending Nikon D7100 users. In the comments, a person or two mentioned the problem, and they were smacked hard. I understood the bit about the Pentax lenses not all focusing at the same speed, which I'm sure goes for all brands, including Nikon.
In any case, the D7100 is looking like less of a contender these days with opponents from all sides. Yes, it's good for casual photography and for slow sports, where you have time to wait for the buffer to be written and cleared. I've almost bought one, once or twice, but in my case, the GH4 is on my list now. Oh, and if I was to buy another dSLR--it would likely be a K-3 since it's in that same price range as the D7100 and the GH4.
Update 2014.10.28: Given recent price drops for the D7100, it looks a good deal for someone willing to pay for the highest quality Nikon lenses. The D7100 and 70-200mm f/2.8 always looked a good match for me. Now that the D750 is available at roughly double the price of the D7100, I'm thinking that the D750 would serve me better and longer into the future, since it's not a two year old body. Even Canon finally revised the 7D into a new version, along with the 70D.
I traded my GH3, which I used for indoor sports, for an Olympus E-M1, merely because the trade-in value would decrease as the GH4 would become available. I'm looking to buy the GH4 because of the enhanced video functionality. However, it's received a number of negative comments about sports photography, mainly that the auto focus is not as good as it should be. It doesn't surprise me--e.g., I was photographing a track & field meet one day and the auto focus selected the fence behind the runners instead of the runners. I worked around it by using single point AF and moving it, but I would have rather used manual focusing to be precise.
I still feel that the GH3 and GH4 are the best hybrid bodies anywhere. If you want to shoot video without more equipment, you need one of them.
Update 2015.01.10: I got the GH4 around Thanksgiving Day, when the deals were good. It really is great for video, further distancing itself from the D7100 for video, but not quite matching the image quality. However, the D7100 was notable for the image noise. I suspect that having a pixel density around the same as micro Four-Thirds 16 MP sensors showed that physics can be bent, not broken. That's why the bigger sensor in the D750 is likely how Nikon meant to divert attention from the D7100's age. They both are important bodies.
The Pentax/Ricoh K-3 has turned out to be really amazing but with a boatload of idiosyncrasies that only Pentax could do. If any other camera maker were to re-program the hardware, I suspect it would be 100% amazing and Nikon would be replacing the D7100 NOW.
Update 2015.03.15: The D7200 looks as good as it should be. Sadly, I think it's the camera body I believe it should have been over a year ago. Even though the D7200 is a mid-range model, it takes an important place with more serious photographers. Since there is no D400, it takes on Canon's 70D and 7D Mk II. I believe it's up to the job.
However, this blog entry was about the GH3 and how it compared to the D7100. While the D7200 is very capable, the GH4 seems quite a bit more. Would I trade my GH4 for a D7200 for stills? It would be a difficult decision. The GH4 is quite capable but the auto focus, for still photos, isn't amazing, though I almost always get my photos. Video tips the scales in a big way, and since I have the Olympus E-M1 for stills, I don't have to worry.
The only real reason for me to buy the D7200 is for certain lenses related to sports, and I could buy Metabones SpeedBooster adapter in order to use those photos--with manual focus, of course.
Update 2015.04.27: I chose to buy a Pentax K-50 to see if the Pentax way of doing things would be possible to handle. Since they've been making digital bodies, I've found their thinking to be quirky. I considered the *ist body and I just couldn't handle it.
However, the K-50 is an inexpensive, weather-sealed body that appealed to me. If I can live with the quirks, I can put money into the system, rather than buying the D7200, which would be the safe alternative. However, in investing the D7100 and the D7200, suddenly, I was looking at the D750, and for just a little more, the D810. Suddenly, a US$2300 camera body and lens pair became more like US$4200.
In any case, seeing how the GH3 has been dropped in price, is the D7100 or D7200 enough? Overall, can the D7200 compete with the K-3 Mk II that's been recently introduced or, for that matter, the Canon 7D Mk II? The market from US$1000 to US$2000 has become crowded, especially when you include mirror-less camera models.
Update 2015.09.15: I have both the Panasonic GH4 and the Nikon D7200 now. While the D7200 is arguably a better stills shooter, I have not seen it surpass the GH4 so greatly. It can be a pain to use at times, while the GH4 seems well organized.
In low light, the ability to capture photos belongs to the GH4. If you have better image quality in low light with the D7200 and it cannot take the photo, how good is the image quality of the photo you didn't get?
Yes, the depth of field is larger with the smaller sensor, but I have struggled to get more depth of field with Four-Thirds and micro Four-Thirds, not less. The D7200 and Sigma 18-35mm f/1.8 are good but when it comes to getting a lot of work done, I'm using Panasonic and Olympus equipment.
Update 2016.10.05: I expanded my Nikon-related lens set from just the Sigma 18-35mm f/1.8 to include Tokina 11-16mm f/2.8, Nikkor 10.5mm f/2.8 fisheye, and Tamron 18-200mm f/3.5-5.6. It made the D7200 more capable with a variety of lenses but I never saw the incredible increase in image quality that I was told was so certain. I'm not even sure there was a credible increase in real-life image quality but I limit my usable micro Four-Thirds photos to ISO 3200 and the Nikon D7200 went to ISO 4000 with similar quality. Nowhere else was anything truly noticeable.