Matt, I had the EM5 MKiii and my wife still does, and it is still a very capable camera. I swapped my EM5 MKiii for a used OM-5 and while the OM-5 is incrementally better than the 5.3, it wasn’t a huge difference and had I not found an OM-5 used for a great price, I do not feel it would have been worth it. I sold my OM-5 and my silver Pen-F for the OM-3 but I do plan to keep my black Pen-F. The Pen-F is still a wonder camera.
Regarding the OM-3, IMHO, it is a completely different comparison. The OM-3 is an OM-1.2 in different clothing. I would say it is worth upgrading from an EM5 MKiii because of the sensor (stacked BSI), bigger battery, USB C, the new menu, and of course it is snappier in use. Then there is the front creative dial from the Pen-F that I actually enjoy using. The CP button is a nice addition over any of the previous camera versions, including the OM-1.2. The dedicated dial for stills, video and slow motion is also kind of interesting as well. I briefly played with the slow motion and while I doubt I would use it much (I don’t do a lot of video) I can see occasions where it would be fun.
There are misses for me, namely a threaded shutter release, the missing ISO button, and the missing front FN button but I will survive. I already have the Olympus Bluetooth remote for the OM-1.
Regarding the flat front, I will plan to get a half case when they become available with a slight bump, I do this for nearly every camera I have except for the OM-1.2 which I added an Arca Swiss base plate to. The half cases help a lot with the Leicas in particular. Arca Swiss grips are already available for the OM-3 on eBay.
This is similar to the grip I bought for my Q3 and is the same seller. If I were to buy a grip for the OM-3 (I am planning to wait for a half case), it would probably be
this one since it has a little indentation for your index finger.
There is a thread on FredMiranda where I guy made a very good list to which I mostly agree with. I will quote part of it here or you can click on the embedded link:
“The purpose for buying the OM-3 is to potentially replace my Pen-F for the following benefits - listed in importance to me
* ND
* Live GND
* Weather sealing
* 1053 vs 81 focus points
* anti-flicker
* same battery as OM1M2
* same menu as OM1M2
* Higher LCD resolution
* USB 3.1
I received my OM-3 Friday.
* noticeably larger than the Pen-F
* looks more svelte than the OM1
* substantial thumb rest looks like an aftermarket lick ’n stick
* LCD not integrated to the body as flush as OM1 or Pen
* Control dial damping is inconsistent. Ex. Rear dial turns much easier and faster than front dial. On my OM1, both dials has the same resistance
* Plastic covers on the left for the Mic, Headphone, USB are not as secure as the OM1. Need to deliberately and firmly press them into place.
* FN lever is mushy and does not “snap” into position like the OM1
* Top plate buttons (Movie and FN) are positioned close to other dials requiring me to use the tip of my finger to press
* Handling with the 12-32 and 35-100 is great. With the 12-45, 12-40 and 40-150 I need to support the lens from underneath.
* Easy to one-hand shoot with the 12-32 and 35-100
* CP button is useful
* Menu and Info button are slightly raised while the Trash and Play are flush.
* Arrow Pad has nice feel.
* No plans to use the Create dial at this point since I only shoot raw
* EVF is the same as the Pen-F and since I don’t plan to MF, the EVF is not an issue.
* Expert Shield screen protector enables LCD to fit flush
* Would remove the bulky and unnecessary Strap Eyelets. I plan to use a simple strap vs the Peak One setup with my OM1
At this point, I am undecided if the benefits outweigh the ergonomic and design misses.”
Personally, I think the price is reasonable for a camera that has a stacked BSI sensor and all of the various computational features that most other manufacturers do not have. The weight is a little more than the Pen-F but much less than the Zf. I love the Zf but I found it too heavy for me and then lenses on the whole are going to be larger than my MFT and Leica M mount lenses. My sweet spot for a dual carry is an M body and a MFT body and the OM-3 is a perfect addition. I can have a zoom or an AF prime on it or use one of my M lenses that I am carrying anyway and double the reach, an M mount 75 or 90 is perfect for a small mini telephoto on a MFT body.
Hopefully this helps you and others. I think this camera will sell well, but what do I know? When people complain about the price, where else can you find legendary weather sealing, a stacked BSI sensor, class leading IBIS, features such as in camera focus stacking, live ND and GND, Pro Capture and Live Composite among others. When I talk to other photographers who have only used Canon or Nikon and I begin to explain what an Olympus/OM Systems camera offers, they are amazed at the images I can get in such a small body and small lenses. Shooting with MFT as you know is a different mindset compared to FF which many do not understand until they actually see the benefits in person/use. I am not saying MFT is better than FF because I love FF as well, particularly my Leica bodies. They have benefits that MFT does not have, I see all cameras as tools that meet specific wants and needs, at least for me.
Good luck with your decision 👍🏻
This was immensely useful, thanks a lot for that. It triggered another information gathering spree.
The result is simple: For the time being, the OM-3 offers nothing I need over the E-M5 III. But it is the vastly more desirable camera. So, if the E-M5 III ever fails (me), I know what camera to get. The same goes for the new 17mm and 25mm lenses - they're exactly what I'd choose over the lenses I currently have if I didn't have those. But truth be told, I don't use the E-M5 III for wildlife or event shooting anyway because I want to keep things small and kind of minimalist. However, if I were to get (back) into

in a big way, the OM-3 would be the camera I'd pick up. It's got flagship specs in a small, sturdy body - fantastic. For now, the E-M5 III is sufficent, as are the lenses I love to use with it.
There's another path forward, though: Replace
both my current bodies (and some lenses) with the OM-3 and the two new primes ... But no, at the moment, I don't think so - not after picking up the GX9 again yesterday: There's something intangibly great about that camera.
Interesting observations about the Zf, too - yes, this isn't the "do all" camera its specs might suggest, either, at least not for me: It's bigger and heavier than most people anticipated, me included, and it took me a while to figure out how I have to configure it in order to make it work for me. It's now the camera that the OM-3 could also be, but I've already put together a kit that plays to the Zf's strengths.
Note that I own both the Z6III and Z7II (in that order) for bigger lenses; the Z6III is a marvellous camera for event shooting and everything outdoor in general, the Z7II is a great people camera. So, in that respect, I'm completely covered.
However, the Zf is a camera that I much(!) perfer carrying, especially with suitable lenses, and even though I like my EDC cameras small and light (enter the Zfc ...), I often pick the Zf for that task because it offers so much more. Its mainstay lens is the Z 26mm f/2.8 - I know many people don't like that lens, and I think I understand why, but it's a great performer, even if its AF is kind of rough around the edges. For me, it's ideal because it matches the camera for sturdiness and even offers weather resistance. I don't enjoy using the Zf with most bigger lenses, though - even the Yongnuo 35mm f/2 I specifically bought because it's smaller and lighter than the Z 35mm f/1.8 S feels kind of clunky on the Zf, not least because the body itself is so weighty. Go figure ...
Here's the list of what's in the bag and what I really like to use: Nikon Z 26mm f/2.8; Voigtländer Nokton 40mm f/1.2 (perhaps the most enjoyable lens for the Zf); Voigtländer Nokton 28mm f/1.5 (you know about that one
@BruceRH); Laowa 15mm f/5 Cookie - a little limited, but lots of fun (and chipped, too, like the Voigtländers!). Alternatively, I use the Nikon Z 40mm f/2 (SE) and the Nikon Z 28mm f/2.8 (SE), often as a pair - the latter renders a slightly smoother image than the Z 26mm f/2.8, but is somewhat less impressive optically (IMO); they make an astonishingly flexible and light travel kit, though. Then there's the Viltrox 20mm f/2.8 "Air" - not a lens I'd use for architecture or travel (its distortion pattern is hard to correct), but it's quite a nice walking and hiking companion, fun to use.
I've even decided what's next: After finding the Viltrox 35mm f/1.7 to be such a good companion lens for the Zfc, I'm now waiting for the Viltrox 50mm f/2 to come out to sort of "complete the kit" for the Zf - I don't really need anything, but if that upcoming lens is the equal of its sibling (Viltrox say it'll be even better), it's simply a must-have, especially at the projected price; it may serve as a nice portrait lens on the Zfc as well.
For the record: I don't use straps or external grips for the Zf or the Zfc (or my Leicas). No half-cases, either. I've found a way (a hand position) to carry them for extended periods of time - it's just a matter of habit. I always take a bag with me, though. So, different strokes for different folks in that regard.
M.