Honestly, I struggled with the Sony for months until I finally tried the Sigma. For ur a7R V, I would suggest the Sigma 105mm f/2.8 DG DN Macro Art over the Sony FE 90mm f/2.8 Macro G OSS. * Sigma is way sharper for stacking.
* Be careful, the Laowa 90mm f/2.8 2x Ultra Macro APO is fully manual. Lesson learned: 61MP demands the sharpest glass. Basically, Sigma wins for clarity!! gl!

In my experience, the 2:1 magnification on the Venus Optics Laowa 90mm f/2.8 2x Macro is the real game changer for 61MP jewelry shots. It’s a steal at $499. For handheld bugs tho, I’d still stick with the Sony FE 90mm f/2.8 Macro G OSS. Native AF and OSS basically save my shots in the field. Sharpness is cool, but actually hitting focus is everything, right?

Hmm, I've had a different experience with these high-end macros on the a7R series. Honestly, I spent a fortune on the Sony FE 90mm f/2.8 Macro G OSS and was kinda disappointed. Dont get me wrong, its a solid lens, but for 61MP? The AF hunts way too much in the field when you're chasing insects, and the price tag is just painful... especially when you realize that diffraction kicks in so early on these high-res sensors. Instead of dropping $1k+, I'd actually suggest a more practical approach. Look at the Tokina FiRIN 100mm f/2.8 FE Macro. Its significantly cheaper and highkey just as sharp as the others for jewelry shots. I used it on my a7R IV and it held up surprisingly well. Plus, save that extra cash for a dedicated flash setup like the Godox MF12 Macro Flash—cuz honestly, on a 61MP sensor, lighting and stability are gonna be your biggest bottlenecks, not the glass itself. Also, i think the 2:1 magnification on the Laowa mentioned earlier is cool, but it's super frustrating to use handheld. At that level, the depth of field is basically paper-thin. If youre just diving into macro, sticking to 1:1 is way more realistic. You dont wanna waste money on gear that's too difficult to handle in the field. Just my two cents, but focus on the lighting first and get a solid, mid-range lens... youll thank me when youre not struggling with blurry shots at f/11 anyway. gl!

Tbh, looking at the market landscape for E-mount glass right now, you've gotta be careful not to fall into the 'sharpness trap.' With 61MP, you're basically hitting the diffraction-limited aperture (DLA) way sooner than on lower-res bodies—usually around f/6.3 or f/7.1. If you're stopping down to f/11 or f/16 for depth of field on those jewelry shots, the sheer resolving power of the lens starts to matter way less than the physics of light hitting those tiny pixels. I'd also warn you about the communication protocols between brands. A major caution for a7R V users is that the internal focus bracketing feature is somewhat picky. Some third-party brands don't always sync perfectly with the body-driven AF steps, which can lead to inconsistent gaps in your stacks. Before I give a full steer, I'm curious: what's your lighting rig like for the field work? Are you using a dedicated macro flash or just natural light? I ask because the working distance varies quite a bit across the different manufacturers, and some designs have significant barrel extension that can shadow your subject or physically bump into your diffusers when you're at 1:1. That 'wow' factor you're after often comes down to lighting geometry more than the glass itself.

Ok so, have you looked into the DIY route before dropping $1k on a dedicated lens? Tbh, I've had a ton of luck using Kenko Auto Extension Tube Set DG for Sony E-mount with my existing sharp primes. Sometimes these specialized macro lenses have so much internal glass that you lose a bit of that raw clarity youre looking for!!! If youre really chasing that wow factor, here are my quick tips:

• Try high-quality extension tubes on a sharp 35mm or 50mm prime. It is a great self-service way to get into macro without the bulk of a new lens.
• If you want the absolute best optics and dont mind a manual DIY feel, look at the Voigtlander 65mm f/2 Macro APO-Lanthar. Honestly, I am not 100% sure if the tubes will beat the Sigma for jewelry, but for an enthusiast, its way more fun to experiment. Their is a lot of potential in the gear you already have if you just tweak it a bit. Using your own DIY setup for focus stacking often yields better results than any automated professional service anyway!!!

Commenting to find later

^ This. Johnnysib is totally right about the diffraction stuff. Honestly, the 61MP sensor is a double-edged sword. It's awesome for detail, but it makes every tiny mistake look huge. I'd add a word of caution about your support gear tho. People spend all their budget on the glass and then use a flimsy tripod. If you're doing jewelry stacking, you really need a dedicated macro rail. Without one, getting those precise increments for stacking is a nightmare, and that high-res sensor will show every little shift. Also, watch out for effective aperture. When you're at 1:1 magnification, your f/2.8 is actually closer to f/5.6 or f/8 in terms of light hitting the sensor. You're gonna need way more light than you think to keep that ISO down and maintain that clarity you're after. High ISO noise on the a7R series can really muddy up those fine details you bought the camera for in the first place... just something to watch out for. Maybe look into using a bellows system or reversing rings if you want to experiment with extreme magnification without just buying another lens.

Saved for later, ty!