About a year ago a question was posted to the Fujifilm X System / SLR Talk forum of the now-defunct DP Review (which is to the shock and amusement of the camera world is still kicking). I’m not much of a forum posting/responding kind of guy, but this question was right in my wheelhouse and so I gave my $.02. Since DP Review is apparently going to cease existence some day, I decided to save the post and reply for posterity, in case it helps other aspiring photographers figure their stuff out. Here is the question and my response:
Has anyone used an xt-4 vs the om-1 or x-hs2 or indeed vs a second-hand full-frame system?
I have been a Fuji shooter since 2015 and since March  have switched my kit almost entirely over to Olympus/OM System. I have owned both the X-T4 and the OM-1 and I also shoot travel, so some of our experience overlap.
I’ve loved my Fuji gear, but there are two reasons why Oly makes more and more sense to me.
First is size and weight. Fuji is getting larger and heavier. My first “real” Fuji (I started with the X-T10) was the X-T2, which weighed 507g. I traded it in on the X-T4, which weighed 20% more. That 20% was noticeable, but the X-T4 was also chunkier. Blockier. Ergonomically, less enjoyable to use. With the intro of the X-H1 and now the X-H2S Fuji has been getting away from svelte and small and as a stills shooter I feel I’m losing the reason I moved from full-frame DSLR to mirrorless.
My OM-1 weighs the same as the X-T4, but feels better ergonomically. One can look at the dimensions all day and declare them equal, but the OM-1 just fits better, both in my hand and sliding in and out of a bag. The X-H2S is even chunkier and heavier: 9% heavier than the X-T4.
My biggest reason turned out to be image stabilization. I come from the Canon world and owned the excellent 24-105 L f/4 IS and the 70-200 L f/4 IS. Even 10 years ago that IS worked wonders. NOT so with the X-T4. The X-T4’s stabilization was so poor that I thought that the system wasn’t on or broken, until I read this comparison. I’ve also rented the X-S10 and owned the 18-55 f/2.8-4 IS and the performance of both was also “meh.”
Four months ago on a whim I bought a used E-M1.2 and a 12-40mm f.2.8 PRO for a trip I was taking. The IS is astounding and a week after I got back I traded the E-M1.2 in on an OM-1 and soon after started downsizing my Fuji kit.
How astounding? Here’s how Amateur Photographer describes the X-H2S:
Fujifilm’s in-body stabilisation works well, and I was able to get sharp images hand-held at shutter speeds as slow as 0.6sec when using the 16-55mm f/2.8 zoom at wideangle. This is on a par with cameras like the Sony Alpha 7 IV, although it’s some way off class-leading Micro Four Thirds models such as the Panasonic GH6 and OM System OM-1.
[Management: I didn’t call it out at the time, but “some way off” is doing a lot of heaving lifting in that pull quote, as you’ll see below. I respect and admire Amateur Photographer as a magazine, but I wish camera journalists would report objectively in a way that would allow readers to make informed decisions instead of using language designed not to piss off camera manufacturers. Let’s continue, shall we?]
By comparison, here is a shot from the E-M1.2 at five seconds, handheld:
Here’s another at 4 seconds, handheld:
Both images have plenty of detail, even if they’re lacking in artistry. I was pushing the envelope, not trying to be artistic
In real-world use I just posted three fireworks images on my Flickr feed taken from 1.3 to 2.5 seconds, handheld, all at ISO 200 to keep the shutter speed as slow as possible. When I’m out and about I’ll routinely shoot >1 second shots, just to prove to myself that it is possible.
I’m over 50 and my hands are not as stable as they once were, so IS has turned out to be incredibly important to me, though your mileage may vary. If it’s a priority for you, you’re looking at a system that boasts .6 seconds vs. one that performs at 4+ seconds [Management: “some way off” indeed].
This is an old, though recently active, thread, so if you’re still on the fence see if you can get a long-term test with the E-M1.3. It’ll perform much the same as the OM-1, but it’s easier to get ahold of. I’m still keeping my X-T3 and most of my Fuji glass; my X-T2 was the proverbial one-that-got-away and I’m not making the same mistake twice.