To clarify a few things...

You first need to ask yourself WHY you think you need to switch to a mirrorless camera. It may not be necessary. It may or may not accomplish what you are hoping to achieve with the change.

Generally speaking, the image quality potential of a mirrorless camera is no different from that of a DSLR. While there are some exceptions, they largely use the same or very similar image sensors.

Also, while there are exceptions, yes Canon lenses tend to be less expensive than the most comparable Nikon (while both tend to be less expensive than Sony lenses). In some cases it's only a few dollars, but in others it's a more dramatic difference. However, it's typically quite costly to change systems, whether it be going from one brand to another or going from DSLRs to mirrorless cameras How much depends upon how deeply invested you are in your current system, the age and condition of that gear which affects how much you can get selling it, and the cost of the new system.

Your current lenses probably won't be "useless". Many existing and vintage DSLR/SLR lenses can be adapted for use on a mirrorless camera. For example, Nikon FTZ Adapter allows many F-mount lenses to be fully used on the Z-series cameras. Check out https://www.nikonusa.com/en/nikon-products/camera-lenses/dslr-lenses/index.page for info about what Nikkor lenses will see full AF and AE usability. If you own third party F-mount lenses (such as Sigma or Tamron or whatever), chances are they can be adapted too, but you should check the manufacturer's website or search online for more info, to be certain.

There also are adapters that allow many Nikon lenses to be used on other brands of mirrorless cameras such as Sony and Canon. Depending upon the adapter, it may result in slower autofocus or no autofocus and/or limited exposure control.

The Canon R-series mirrorless cameras use a new RF lens mount, much like same way the Nikon Z-series mirrorless use a new Z-mount. Just like above, Canon offers adapters that allow their legacy EF/EF-S mount lenses be used on the RF-mount cameras to produce as good or even better image quality. And there are numerous adapters allowing other mounts, such as vintage Nikon F-mount, to be used on the Canon R-series cameras.


Do you want/need full frame? If they are the reason you're considering this change, be aware there is less weight and size savings with full frame mirrorless versus DSLRs, than there is with smaller format mirrorless. Nikon offers a Z50 mirrorless that's APS-C "DX" format (both the Nikon z5 and z7II are full frame "FX" cameras). If you use a DX Nikon now... or use telephotos a lot... or simply are looking for significant reduction in size and weight... one of the crop sensor cameras might be a better choice. Full frame cameras generally require full frame lenses, which like the cameras tend to be bigger, heavier and are generally more expensive. In most cases, APS-C cameras can use full frame lenses OR smaller/lighter, less expensive APS-C lenses.

Sony cameras use e-mount lenses. They've been seriously producing mirrorless cameras a lot longer than Canon or Nikon, so there are more native fit lenses, more adapters and more complete selection of accessories for them right now. Sony offers both full frame and APS-C mirrorless cameras, both using e-mount lenses. Some of those e-mount lenses are crop designs for use on their APS-C cameras, while their full frame e-mount lenses can be used on both.

It's different with Canon. There is no APS-C camera yet, in the R-series mirrorless. Instead Canon has offered a different line of M-series mirrorless cameras for over eight years, almost as long as Sony has been in the mirrorless business. While the latest Canon M-series models are quite good, compact, affordable cameras and there are lots of adapters for them, too, there are relatively few EF-M mount native lenses offered and those lenses are in no way cross-compatible or adaptable for use on either Canon's R-series mirrorless, on EF-mount DSLRs or onto anyone else's mirrorless cameras. There are lots of rumors that Canon will eventually discontinue the M-series, probably after they have introduced an APS-C format R-series camera. Speculation is that this may happen next year or in 2022.

The Canon and Nikon DSLR systems are the most fully developed and comprehensive. They choice of roughly 90 lenses, including many specialized types you simply cannot find in other systems. Both Canon R-series and Nikon Z-series mirrorless systems are relatively new (about 2 years old) and have limited native lenses so far... about 15 each. This will change soon. Canon is predicted to double that number next year, while Nikon has mapped out doubling the number of lenses they offer for Z-mount in the next two years.

For comparison, Sony has roughly 45 lenses for their mirrorless cameras. It's a fairly comprehensive system, but lacks some of the more specialized lenses that can be found in the Canon and Nikon DSLR systems (and that can be adapted for full usefulness on their respective mirrorless systems).

Very generally speaking, comparing similar lenses across the "big three" brands... Sony tend to be the most expensive, Nikon a little less and Canon are usually the most affordable. There are some exceptions, each manufacturer has occasional sales and they offer factory refurbished cameras, lenses and accessories for some savings. (Canon treats their refurbs like new, with the same warranty. Nikon usually treats them as used, with a shorter warranty. I don't know what Sony does.)

Fujifilm is the another maker of APS-C mirrorless cameras. They don't make any full frame models, but do manufacture some of the most affordable medium format mirrorless cameras (though a lot more expensive than even full frame cameras and lenses). There are a lot of fans of Fuji mirrorless cameras and their X-mount lenses. There are about 35 X-mount lenses to choose among, as well as a number of adapters to allow lenses in other mounts to be used upon Fuji cameras.

Panasonic and Olympus offer some of the smallest/lightest mirrorless of all, by using Micro Four/Thirds sensors that are slightly smaller than APS-C used by Nikon, Sony and Canon. Panny and Oly also use the same lens mount, so their lenses are fully interchangeable. There are roughly 30 lenses to choose among for these cameras. Panasonic has recently introduced a full frame mirrorless camera, too. There are limited lenses for it so far. Olympus has sold their camera division to a company (JIP or Japanese Industry Partnership) that says they will continue production, but that remains to be seen. The sale is expected to be completed by the end of the year.

There are advantages and disadvantages to both DSLRs and mirrorless cameras. It's not just differences in size. For example, while DSLRs use an optical viewfinder (OVF), mirrorless cameras mostly use an electronic viewfinder (EVF). Each type of viewfinder have their advantages. EVF's can brighten things up when shooting in low light, simulate exposure and display useful tools such as a histogram or manual focus assist. But during bursts of shots they tend to have some blackout between frames (some systems are worse than others) and EVFs draw a lot of battery power, so most mirrorless cameras get a lot fewer shots per charge than relatively comparable DSLRs. Some mirrorless offer an electronic shutter that can shoot bursts with more frames per second than is possible with any DSLR that has to move a mirror out of the way, then open and close a physical shutter. Electronic shutters also can be completely silent. However, due to the way they read the data captured there are problems using electronic shutters with rapidly moving subjects... distortions that occur in images. So for fast action photography, where a super high frame rate might be most useful, the electronic shutter still may not be usable.

The latest mirrorless are featuring some of the most innovative autofocus systems. Because most mirrorless incorporate AF sensors directly into the imaging sensor, there is no lens calibration needed, the way there can be with DSLRs. By combining AF with the image sensor, it also is possible for mirrorless to have many more AF "points" and to spread those points over more of the image area than is practical with DSLRs. For example, the latest Canon R5 has nearly 6000 AF points covering over 95% of the image area. In comparison, the most advanced Canon 1DX Mark III's AF system has array of 191 points that cover approx. 35% of the central image area. In other words, you can use the R5's AF system to focus almost anywhere in an image, while all DSLRs and even one of the best like the 1DXIII is more limited to just part of the image area (people use "focus and recompose" technique to work around this). Plus, thanks to the large number of AF points they use and the small, precise size of each of those points, the latest mirrorless AF systems are capable of tricks like subject tracking, face detection and even eye detection (both people and animals).

Personally I use two APS-C Canon DSLRs to shoot sporting events (and have two more as backups).

And I have a full frame DSLR that I use for scenic shots, some portraits and macro. It's an older model that I plan to update soon. I haven't decided between mirrorless or another DSLR. Either would work well, but right now I can buy the DSLR for less than half the price of the mirrorless. The mirrorless might be more versatile, mostly thanks to a significantly more advanced AF system. Also I would need to update post-processing software to work with the files from the mirrorless, while the DSLR is newer than what I have but still a slightly older model that produces image files that my current software can handle.

I have 22 lenses from 10mm to 500mm (and two teleconverters) for use on the above DSLRs. The majority are full frame lenses that can be used on both APS-C and full frame cameras, but three of these lenses are "crop only" for use on only the APS-C cameras.

I also have a Canon M5 mirrorless (APS-C) that I use for travel (some day!), street and some portraiture. I have a small system of four compact, manual focus, prime lenses for use on this camera. This entire kit weighs about the same as one of my DSLR bodies or one of the larger telephotos I use on them.

Finally, while there may be good reasons to make a switch... changing from DSLR to mirrorless... or for that matter changing brands... doing so doesn't automatically make for "better images". Skillful use of either type or brand of camera can produce great results. In some ways DSLRs are more "mature" than mirrorless. The latter are still seeing development and significant innovation, while there's less pressure to update to the latest and greatest DSLR because new generation improvements are now less dramatic, more incremental in nature. Also, the prices of DSLRs, their lenses and accessories are dropping now due to softer consumer demand. At the same time, the popularity of mirrorless, the perception that "you gotta upgrade to mirrorless" and stronger consumer demand means they're still commanding premium prices. There's also some scarcity of mirrorless, in particular, due to the pandemic disrupting manufacturing. For example, the new Canon R5 model is often out of stock or only rec'd in small quantity. Canon is struggling to meet demand. Back orders and long waits for them are common. And the Nikon "f/2.8 holy trinity" of pro grade zooms... 14-24mm, 24-70mm and 70-200mm... is largely unavailable. All three were formally announced by Nikon early this year, but only the 24-70mm has arrived and can be found in stores today. The other two lenses have been showing "new item, coming soon" in stores for many months, so no one has been able to actually buy either of them! Plus, since the DSLR systems are based largely upon the film SLRs that preceded them, there are 30+ years worth of used autofocus lenses for both Canon and Nikon.... That's literally millions of used lenses still compatible with today's DSLRs, no adapter req'd, at discount prices. As people move to mirrorless, we can expect the availability of DSLR lenses on the used market to increase, which should in turn mean even lower prices.

Only you can say what's right for you. This isn't intended to tell you "don't buy mirrorless" or to encourage you to make the switch. I'm just trying to clarify some things that you appear to have bad info about and suggest you take some time to look deeper into what your real needs and wants are, before making any switch. I've only scratched the surface with some of the pluses and minuses, as I see them. But those are the considerations I weigh for me and my uses. It may or may not be the right thing for you to do. Again, only you can really say.

I am considering buying a mirrorless camera. I currently shoot Nikon.
The new Nikon mirrorless cameras have a different lens mount. Making all my lenses useless.

so I will look at the Nikon z5 and z7II

I read the new Canon mirrorless cameras use their same lens mount and
Canon lenses are def cheaper in price that a nikon lens.
Now that I am retired money is a lot more important than before.

but if you are using a mirrorless camera, what one are you using and how do you like it
and last but most important how is the picture quality compared to your old DSLR?

I have read reviews, I have talked to salesman . everyone has an agenda , as do some of you but I know i'll get some good answers.
Thanks

To clarify a few things...

You first need to ask yourself WHY you think you need to switch to a mirrorless camera. It may not be necessary. It may or may not accomplish what you are hoping to achieve with the change.

Generally speaking, the image quality potential of a mirrorless camera is no different from that of a DSLR. While there are some exceptions, they largely use the same or very similar image sensors.

Also, while there are exceptions, yes Canon lenses tend to be less expensive than the most comparable Nikon (while both tend to be less expensive than Sony lenses). In some cases it's only a few dollars, but in others it's a more dramatic difference. However, it's typically quite costly to change systems, whether it be going from one brand to another or going from DSLRs to mirrorless cameras How much depends upon how deeply invested you are in your current system, the age and condition of that gear which affects how much you can get selling it, and the cost of the new system.

Your current lenses probably won't be "useless". Many existing and vintage DSLR/SLR lenses can be adapted for use on a mirrorless camera. For example, Nikon FTZ Adapter allows many F-mount lenses to be fully used on the Z-series cameras. Check out https://www.nikonusa.com/en/nikon-products/camera-lenses/dslr-lenses/index.page for info about what Nikkor lenses will see full AF and AE usability. If you own third party F-mount lenses (such as Sigma or Tamron or whatever), chances are they can be adapted too, but you should check the manufacturer's website or search online for more info, to be certain.

There also are adapters that allow many Nikon lenses to be used on other brands of mirrorless cameras such as Sony and Canon. Depending upon the adapter, it may result in slower autofocus or no autofocus and/or limited exposure control.

The Canon R-series mirrorless cameras use a new RF lens mount, much like same way the Nikon Z-series mirrorless use a new Z-mount. Just like above, Canon offers adapters that allow their legacy EF/EF-S mount lenses be used on the RF-mount cameras to produce as good or even better image quality. And there are numerous adapters allowing other mounts, such as vintage Nikon F-mount, to be used on the Canon R-series cameras.


Do you want/need full frame? If they are the reason you're considering this change, be aware there is less weight and size savings with full frame mirrorless versus DSLRs, than there is with smaller format mirrorless. Nikon offers a Z50 mirrorless that's APS-C "DX" format (both the Nikon z5 and z7II are full frame "FX" cameras). If you use a DX Nikon now... or use telephotos a lot... or simply are looking for significant reduction in size and weight... one of the crop sensor cameras might be a better choice. Full frame cameras generally require full frame lenses, which like the cameras tend to be bigger, heavier and are generally more expensive. In most cases, APS-C cameras can use full frame lenses OR smaller/lighter, less expensive APS-C lenses.

Sony cameras use e-mount lenses. They've been seriously producing mirrorless cameras a lot longer than Canon or Nikon, so there are more native fit lenses, more adapters and more complete selection of accessories for them right now. Sony offers both full frame and APS-C mirrorless cameras, both using e-mount lenses. Some of those e-mount lenses are crop designs for use on their APS-C cameras, while their full frame e-mount lenses can be used on both.

It's different with Canon. There is no APS-C camera yet, in the R-series mirrorless. Instead Canon has offered a different line of M-series mirrorless cameras for over eight years, almost as long as Sony has been in the mirrorless business. While the latest Canon M-series models are quite good, compact, affordable cameras and there are lots of adapters for them, too, there are relatively few EF-M mount native lenses offered and those lenses are in no way cross-compatible or adaptable for use on either Canon's R-series mirrorless, on EF-mount DSLRs or onto anyone else's mirrorless cameras. There are lots of rumors that Canon will eventually discontinue the M-series, probably after they have introduced an APS-C format R-series camera. Speculation is that this may happen next year or in 2022.

The Canon and Nikon DSLR systems are the most fully developed and comprehensive. They choice of roughly 90 lenses, including many specialized types you simply cannot find in other systems. Both Canon R-series and Nikon Z-series mirrorless systems are relatively new (about 2 years old) and have limited native lenses so far... about 15 each. This will change soon. Canon is predicted to double that number next year, while Nikon has mapped out doubling the number of lenses they offer for Z-mount in the next two years.

For comparison, Sony has roughly 45 lenses for their mirrorless cameras. It's a fairly comprehensive system, but lacks some of the more specialized lenses that can be found in the Canon and Nikon DSLR systems (and that can be adapted for full usefulness on their respective mirrorless systems).

Very generally speaking, comparing similar lenses across the "big three" brands... Sony tend to be the most expensive, Nikon a little less and Canon are usually the most affordable. There are some exceptions, each manufacturer has occasional sales and they offer factory refurbished cameras, lenses and accessories for some savings. (Canon treats their refurbs like new, with the same warranty. Nikon usually treats them as used, with a shorter warranty. I don't know what Sony does.)

Fujifilm is the another maker of APS-C mirrorless cameras. They don't make any full frame models, but do manufacture some of the most affordable medium format mirrorless cameras (though a lot more expensive than even full frame cameras and lenses). There are a lot of fans of Fuji mirrorless cameras and their X-mount lenses. There are about 35 X-mount lenses to choose among, as well as a number of adapters to allow lenses in other mounts to be used upon Fuji cameras.

Panasonic and Olympus offer some of the smallest/lightest mirrorless of all, by using Micro Four/Thirds sensors that are slightly smaller than APS-C used by Nikon, Sony and Canon. Panny and Oly also use the same lens mount, so their lenses are fully interchangeable. There are roughly 30 lenses to choose among for these cameras. Panasonic has recently introduced a full frame mirrorless camera, too. There are limited lenses for it so far. Olympus has sold their camera division to a company (JIP or Japanese Industry Partnership) that says they will continue production, but that remains to be seen. The sale is expected to be completed by the end of the year.

There are advantages and disadvantages to both DSLRs and mirrorless cameras. It's not just differences in size. For example, while DSLRs use an optical viewfinder (OVF), mirrorless cameras mostly use an electronic viewfinder (EVF). Each type of viewfinder have their advantages. EVF's can brighten things up when shooting in low light, simulate exposure and display useful tools such as a histogram or manual focus assist. But during bursts of shots they tend to have some blackout between frames (some systems are worse than others) and EVFs draw a lot of battery power, so most mirrorless cameras get a lot fewer shots per charge than relatively comparable DSLRs. Some mirrorless offer an electronic shutter that can shoot bursts with more frames per second than is possible with any DSLR that has to move a mirror out of the way, then open and close a physical shutter. Electronic shutters also can be completely silent. However, due to the way they read the data captured there are problems using electronic shutters with rapidly moving subjects... distortions that occur in images. So for fast action photography, where a super high frame rate might be most useful, the electronic shutter still may not be usable.

The latest mirrorless are featuring some of the most innovative autofocus systems. Because most mirrorless incorporate AF sensors directly into the imaging sensor, there is no lens calibration needed, the way there can be with DSLRs. By combining AF with the image sensor, it also is possible for mirrorless to have many more AF "points" and to spread those points over more of the image area than is practical with DSLRs. For example, the latest Canon R5 has nearly 6000 AF points covering over 95% of the image area. In comparison, the most advanced Canon 1DX Mark III's AF system has array of 191 points that cover approx. 35% of the central image area. In other words, you can use the R5's AF system to focus almost anywhere in an image, while all DSLRs and even one of the best like the 1DXIII is more limited to just part of the image area (people use "focus and recompose" technique to work around this). Plus, thanks to the large number of AF points they use and the small, precise size of each of those points, the latest mirrorless AF systems are capable of tricks like subject tracking, face detection and even eye detection (both people and animals).

Personally I use two APS-C Canon DSLRs to shoot sporting events (and have two more as backups).

And I have a full frame DSLR that I use for scenic shots, some portraits and macro. It's an older model that I plan to update soon. I haven't decided between mirrorless or another DSLR. Either would work well, but right now I can buy the DSLR for less than half the price of the mirrorless. The mirrorless might be more versatile, mostly thanks to a significantly more advanced AF system. Also I would need to update post-processing software to work with the files from the mirrorless, while the DSLR is newer than what I have but still a slightly older model that produces image files that my current software can handle.

I have 22 lenses from 10mm to 500mm (and two teleconverters) for use on the above DSLRs. The majority are full frame lenses that can be used on both APS-C and full frame cameras, but three of these lenses are "crop only" for use on only the APS-C cameras.

I also have a Canon M5 mirrorless (APS-C) that I use for travel (some day!), street and some portraiture. I have a small system of four compact, manual focus, prime lenses for use on this camera. This entire kit weighs about the same as one of my DSLR bodies or one of the larger telephotos I use on them.

Finally, while there may be good reasons to make a switch... changing from DSLR to mirrorless... or for that matter changing brands... doing so doesn't automatically make for "better images". Skillful use of either type or brand of camera can produce great results. In some ways DSLRs are more "mature" than mirrorless. The latter are still seeing development and significant innovation, while there's less pressure to update to the latest and greatest DSLR because new generation improvements are now less dramatic, more incremental in nature. Also, the prices of DSLRs, their lenses and accessories are dropping now due to softer consumer demand. At the same time, the popularity of mirrorless, the perception that "you gotta upgrade to mirrorless" and stronger consumer demand means they're still commanding premium prices. There's also some scarcity of mirrorless, in particular, due to the pandemic disrupting manufacturing. For example, the new Canon R5 model is often out of stock or only rec'd in small quantity. Canon is struggling to meet demand. Back orders and long waits for them are common. And the Nikon "f/2.8 holy trinity" of pro grade zooms... 14-24mm, 24-70mm and 70-200mm... is largely unavailable. All three were formally announced by Nikon early this year, but only the 24-70mm has arrived and can be found in stores today. The other two lenses have been showing "new item, coming soon" in stores for many months, so no one has been able to actually buy either of them! Plus, since the DSLR systems are based largely upon the film SLRs that preceded them, there are 30+ years worth of used autofocus lenses for both Canon and Nikon.... That's literally millions of used lenses still compatible with today's DSLRs, no adapter req'd, at discount prices. As people move to mirrorless, we can expect the availability of DSLR lenses on the used market to increase, which should in turn mean even lower prices.

Only you can say what's right for you. This isn't intended to tell you "don't buy mirrorless" or to encourage you to make the switch. I'm just trying to clarify some things that you appear to have bad info about and suggest you take some time to look deeper into what your real needs and wants are, before making any switch. I've only scratched the surface with some of the pluses and minuses, as I see them. But those are the considerations I weigh for me and my uses. It may or may not be the right thing for you to do. Again, only you can really say.