Has anyone downsized from Full Frame (35mm size) to micro 4.3? I'm considering this for travel but not sure what I'll miss. Obvious;y resolution changes but the smaller size and increased depth of field is a bonus. I'm currently using a Nikon D800 in a Seacam Housing and thinking about Olympus.

Hi BJS

Not to M4/3 but I “downgraded” from D800 to D500 about 8 years ago and am still using the D500. Haven’t regretted it for a second. I’ve posted many times about the advantages of sub-FF in terms of cost, portability and ergonomics - and no noticeable quality cost unless, maybe, serious commercial use or massive prints involved.

There are a good few M4/3 members who will join in.

I shoot the OM-1 in Nauticam, quite happy with it. I didn't downgrade from full frame UW, though I went from using a Canon 1DIV on land to olympus as well . I still have the 1DIV and Canon lenses including a 500mm f4 and 180mm macro , but I've switched over to using the OM-1 for all of that and the Canon gear only gets used very occasionally as the OM-1 is every bit as good and for land based macro using focus stacking among other features easily surpasses the Canon and other full frame options. There are others here who have gone Full frame to APS-C and never regretted it such my fellow moderator @TimG . My feeling these days is APS-C is a bit of an orphan child with lens range a little limited in some ways. I used to try to shoot everything so that I could print big!! but I've found in reality I almost never do.

Other advantages include you don't need to stop down so much so you can shoot lower ISO as you are at least 1 stop further open compared to FF, this means smaller cheaper flash units will work for you. The lens lineup is very complete with excellent macro, rectilinear wide (14-28, 16-35 equivalent etc.) and fisheye options. The lenses are cheaper than full frame and a lot smaller as are the ports required.

On the full frame question, a lot depends on what you want to use the images for and I can see two main reasons for wanting full frame these days -1. you make your living from the images and clients demand it and 2. You want (and actually do) make large prints - I'm talking A2 size and bigger. The 20 MP sensor in the OM-1 can print A3 natively at 300 dpi and up-ressing to A2 is quite feasible, it's starts to suffer a little beyond that. A third reason might be you can afford it, can put up with size and weight and you want to. Ports and lenses in m43 are quite a bit cheaper as are the housings.

I have the 60mm macro, which is my most used, the 12-40 in a 170mm dome and now use the an adapted Canon 8-15 fisheye in the 140mm dome for wide angle - you can't get this so cheaply in any other system. It combines a full diagonal fisheye with a 14-28 equivalent lens and includes much of the range of a WWL setup in one package. Full frame requires either Sony and the same adapted 8-15 lens with a Sony 2x or using the very expensive Fisheye conversion port. Amazing flexibility and image quality and uniquely micro43 allows you the most flexibility. Only downside is it needs lots of flotation to get near neutral.

Your two main housing options are Nauticam and Isotta. I started with Nauticam and I'm bought into this system, but Isotta for example would allow you to do the Canon 8-15 significantly cheaper. I can pack my setup including housing, ports, camera, lenses and two strobes into a carry on size photo backpack.

Feel free to ask more specific questions about shooting with the OM-1. There's lots of images on my website and most recent ones since about late 2023 are with the OM-1. You can also find my gallery here on Waterpixels.

I'm also considering switching to M4/3 from my aged Sony NEX5 and have been eyeing up the Olympus OMD-EM10 and AOI housing for reasons of cost and weight (especially cf. Nauticam). I'm undecided and lens/port choice though, I guess a fisheye (or wide zoom) and small dome would be lighter than a wet lens?

@Stig Consider one of the bodies supporting PDAF autofocus, OM5 or OM1. I don't know if it is just a different camera generation, but going from an EM-5-II to an OM-1 is a huge improvement in autofocus performance. AOI makes fairly affordable housings for the OM5 and OM1 also. I'm a happy recent adoptee of their OM1 housing. I think @bvanant has the same housing, and he actually knows how to use his 😅.

1 hour ago, Stig said:

I'm also considering switching to M4/3 from my aged Sony NEX5 and have been eyeing up the Olympus OMD-EM10 and AOI housing for reasons of cost and weight (especially cf. Nauticam). I'm undecided and lens/port choice though, I guess a fisheye (or wide zoom) and small dome would be lighter than a wet lens?

Either the Panasonic or Olympus 8mm fisheye is very light and affordable and they work well in a 4"dome.

Agree though the AF in the OM1 and EM5 is way better than the old series like EM-5II - mainly a benefit when using the 60mm macro lens which was relatively sluggish on the EM-5 II. I upgraded to the EM-1 mKII 8 years ago it was way better than the old EM-5 II. If you are concerned about expense a second hand EM-1 MII or III in an aluminium housing would be a great option. The OM-1 and OM-5 are better but not as much of a step up as the EM-5 II to EM-1 II.

9 hours ago, BJS said:

Has anyone downsized from Full Frame (35mm size) to micro 4.3? I'm considering this for travel but not sure what I'll miss. Obvious;y resolution changes but the smaller size and increased depth of field is a bonus. I'm currently using a Nikon D800 in a Seacam Housing and thinking about Olympus.

I used Olympus m4/3 for years then developed Sensor Envy (SE). I moved to Sony full frame with its amazing autofocus, but I have to say that I miss the form factor and great ergonomics of OMS/Olympus every time I shoot the Sony. I think for my needs, which is trying to capture marine life for prints, documentation and social media - that the 1/2 frame-sized OM sensor is quite good. I’ve had no issues making 11x14 prints but haven’t tried going larger, though I’m sure the m4/3 sensor certainly could. And you’ve already figured out everything about full frame is bigger and bulkier. I think m4/3 is great for travel and personal work. If you have a budget and assistants for paid work, then go big. Your clients expect it, though they may have no clue how you really make images.

Edited 2 hours ago2 hr by humu9679
sentence structure correction.

10 hours ago, Chris Ross said:

My feeling these days is APS-C is a bit of an orphan child with lens range a little limited in some ways. I used to try to shoot everything so that I could print big!! but I've found in reality I almost never

My personal feeling is that FF (especially with Sony, but also the other brands) is the real unwanted orphan child what regards lens choice for UW: No native zoom fisheye (and when (now discontinued) adapted is available, just the choice between circular and 180° diagonal - nothing like the (now discontinued) Tokina 10-17mm for APS-C. Meager selection in true macro lenses. Regarding lens selection for UW photography, MFT is clearly the king...👍

This is opposed by 61 Mpixel, 14-bit raw images (and S/N ratio clearly deserves to be digitized at 14-bit resolution) with 4x the maximum light gathering capability (and according dynamic range)...

I went the opposite route, upgrading from Olympus EM1II to Sony A7R5. Regarding IQ, I do not look back, I certainly will not "downgrade" to MFT in the midrange (maybe some (remote) day when I have become old and weak, no longer being able to carry a FF rig) , but I clearly miss the lens choice for UW (I am eagerly awaiting new lenses for UW to come out)...

Wolfgang