About six months ago, I made the big switch to a mirrorless camera body, the brand new Canon EOS R6. My previous camera, the Canon EOS 5D Mark IV was working fine, but mirrorless cameras offered some advantages that I felt would potentially make my work easier and better. Both features are related to the auto-focus system.
The first improvement is that the mirrorless autofocus almost always achieves perfect focus with any lens you put on the body. With the older DSLR bodies, the system had different autofocus errors with different lenses. To get accurate focus, you had to perform a task called "micro-focus adjustment" with each lens you owned.
Even when adjusted, some lenses would exhibit different amounts of focus error at various distances and even at different zoom settings. While it was annoying, it was just part of being a professional photographer. You dialed in the adjustment as well as you could, then shot extra images to allow for deletion of poorly focused shots.
Even if your autofocus system is perfectly adjusted, you still have to make sure you place the viewfinder autofocus point exactly where you want it, which takes attention and practice. It's not always easy to do if you and your model are moving.
The second autofocus feature I really wanted to try was the eye tracking function. The EOS R6 and many other mirrorless cameras will continuously track a particular subject that moves around within your view and it will keep the lens focused on that object. This is obviously a great thing for sports photography or working with moving children, just to name two genres, but I find it very helpful when shooting with models.
Once I switch on the autofocus system with the button on the back of the camera, the powerful computer inside the R6 goes to work analyzing the scene. A focus box appears in the viewfinder and quickly starts moving. It first finds the head of the model, then places a very small focus box on one of her eyes. It does a pretty good job of tracking that eye as long as it is visible and there is enough light in the studio. If it loses the eye, it will default to head tracking. If the model moves so that her head is no longer visible, the camera struggles to find something else to focus on. At that point, I press another button and the autofocus system changes to a small spot that I can place wherever I like.
It is now extremely rare for me to reject an image due to imperfect focus!
Most people assume that you always want to buy a camera that will record the largest possible number of megapixels. In many genres, such as landscape photography with the goal of making large prints, that is surely correct. But when photographing people, I believe that is not the case. Very few people make prints any more, especially when the images are erotic. My photos are generally shared electronically and posted to online sites with limited resolution. Beyond a certain point, additional megapixels are wasted.
My previous camera had a 30 megapixel sensor. When viewing those photos at full resolution, skin and makeup imperfections are very distracting. You can spend a huge amount of time retouching skin and throwing away much of the detail you recorded with your high-megapixel sensor.
The current generation of Canon mirrorless full frame cameras includes the R6 and it's more expensive brother, the R5. The R5 has a 40 megapixel sensor - I knew that was more than I needed so I chose the R6 with a 20 megapixel sensor. This is the first time I've stepped down to a lower resolution body, so I was a bit nervous. But I was pretty happy with that resolution in my old 5D III and even with the 12 Mp sensor in my very old 5D Classic.
After six months of photoshoots, I can say the reduction in sensor resolution was a good decision. I feel the images have a smoother, more flattering skin texture and I've never wished for higher res images. As a big bonus, the smaller RAW files are noticeably faster to process and store. I had been thinking it was time to build a new desktop computer, but it looks like my last build will be adequate for a few more years.
The sharpness of an image is not the same as resolution. It is determined by many things, but in this case I'm only discussing the effect of the lens. I've read articles stating that a mirrorless camera body has a sharpness advantage over an old DSLR body because the back of the lens can be closer to the sensor. Perhaps this is true, since the mid-priced 24-105 lens I bought with the new camera is extremely sharp, on a par with earlier expensive professional lenses. It is so good and so convenient to use that I don't have a lot of experience using other lenses on this new body.
Overall, I am very pleased with the R6. I think it is a great choice for photographers who work with human models and distribute their work for viewing on video screens.