Dpreview member Semor made what I consider to be an acurate dafe bet on how the A7rV could be:

Sony A7R V AKA nail in the coffin of Canon.

Seeing many YT influencers (I agree they are not all real working pros) talk about how they are considering switching from Canon to Sony after using A7SIII, I can see Sony going for the jugular of Canon and make a canon 5R without overheating.

It safe to say, it’ll take Canon 2 years to resign their body to deal with the heat issue. Canon’s best bet is to take the 5R and put it inside their cinema camera with ample fan and cooling and call it Cinema R 500. Or keep the EF mount and call it EOS C400 and offer it at a reasonable price to keep their base from jumping ship to Sony. They still have the dual gain system in their new C500 that is designed close the gap with Alexa. So they can differentiate pricing and products but at the same time save face a bit with their 8K PR nightmare.

61 MP. Same sensor as A7R IV.

We have seen Sony alternate between image sensor update and processing update. With A7RIV we saw a new sensor, with A7R V will get a new processor.

Bionz XR Same processor(s) as A7SIII

This update cycle of the A7Rx is with the image processor. Sony’s new image processor is designed to handle high volume data processing (4K @ 120 fps) and probably room for more.

It’s safe to assume outside of the upcoming A5/A6 which probably will be a crippled A7III (Sony’s answer to Nikon Z5) the future full frame Sony systems will use the new Bionz XR.

8K Video at 30 FPS

It’s safe to assume if the new processor can churn through 120 FPS @4k it can handle 8K at 30 FPS.
We also know the A7R IV sensor is probably able to have a readout of 1/30 if not more, https://blog.kasson.com/a7riv/how-fast-is-the-sony-a7riv-silent-shutter/

The new CFExpress A can handle that kind of bandwidth. Taking 4k 30 All-I H.264 at 300 Mbs. We can assume a 1200 Mbs for 8K All-I. Remember the new Sony Tough Cards are claiming 5600 Mbs (700 MBs). So potentially the could even handle 8K at 120FPS one day.

Sony has figured out how to dissipate heat and will basically release a competitive “halo” product to Canon’s 5R without the heating PR nightmare.

1.1-1.3x crop.

We can assume there will be a slight crop (1.1 ~ 1.3) for 8K (for D and U). This crop will probably allow for a better stabilization by combining IBIS and electronic.

4K HQ at 30 FPS (possibly 60 FPS)

This is the 8K image downsized to 4K. 30 Is probably do able, 60 probably is and to match Canon with specs Sony might just include it.

120FPS (4k pixel binned, APSC or HD)

Just like the Sony A7RIV we’ll have a 120FPS option. With a new processor Sony should be able to have a better 120FPS video but we shall see. Minimum will be HD it’s possible they can do a crop 4K 120 FPS.

5.5 ~ 6 Stops IBIS

It’s possible Sony might need to have a crop option (1.1 ~ 1.2) for even stronger IBIS to match Canon’s or they could just keep what they have.

Dual CFExpress A

So long as other manufactures are late to the game, you can view CFExpress card as a bit like the printer cartridge business. For a pro who need to buy 4-5 cards (maybe even more) it grantees additional revenue stream to Sony.

Copied from A7SIII – View finder (for a large pixel camera they’ll keep a high resolution viewfinder), LCD screen, AF system, menu system (this is obviously the menu going forward), color science (we might assume Sony has reached the peak of their color science).

Full size HDMI ?

Unclear if Sony wants to differentiate between S and the R model and not include a full HDMI cable. I have a feeling Sony is going to go for the jugular of Canon and probably offer full HDMI.

16bit linear RAW ?

Sony/Atomos might be working on some kind of a recorder to keep all the 16 bit linear for external recording. Atomos Ninja has been upgrading well, but I’m wondering if an upgrade is in the works. I think the A7RV is going to be a canon 5R killer and Sony will probably won’t hold back.

What about Sony A7IV?

This is going to be even a more of an anticipated wait. A7IV is coming (October/November?). It must be based on the Bionz XR so very possible it’ll be the camera that will dominate the full frame market in 2021. We could expect a 6K raw camera that will go head to head with Panasonic S1H. It might not have all the video functions like S1H but image quality will be similar with a really good and functioning AF.

What are your thoughts?

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— Kazuto Yamaki (@KazutoYamaki) January 1, 2021

I do indeed expect a ton of new FF E-mount lenses including the 70-200mm f/2.8 and new f/1.2 FE primes!