Sensor cleaning

What's up guys, best way to clean the sensor (A7R3) ?

Get yourself a pair of +3.50 reading glasses (or stronger). Together with a high intensity spotlight (preferably LED) you will be able to see those particles that are most important to remove. Of course a small aperture image of an out of focus non-detailed object (like the sky) will also show the dirt that affects images, but upside-down.

A rocket blower is always a good start, but some dust may remain. A pointed, medium stiff artists paint brush and condensation from your breath works well for removing a few small fibers and dry dust. Move the particles towards the edge of the sensor and try to "catch" them. You may wrap a sheet of lens cleaning paper on the brush to make some sort of disposable brush tip. (Minimal cost with this method, and if may work well with dry dust.)

Oily, greasy or sticky spots may need some sort of solvent. Heptane is probably the most effective of all "usable" (not too harmful or damaging) solvents for oil or grease. Alcohol is a milder and generally less effective alternative - it also evaporates slower. Gel sticks (used by some professionals like Lensrentals) and wet cleaning might be a fast and working catch-all/standard procedure, but it's often overkill and adds cost.

In the field I will resort to the quick and less controlled action of a rocket blower and even careful wiping with a clean/new lens pen if needed to get some important shots.

BTW, the voice-coil type imager stabilizer in Sony cameras are not a mechanism that is particularly easy to damage, but you may want the sensor to not move when cleaning. (The old piezo type in Sony DSLR and SLT cameras is different and prone to break on camera impact, but not sensor cleaning.)

Heptane does not affect glass surfaces with the coatings typically used on lens elements and on sensors (or uncoated glass). Remember that sensors have a "cover glass" that is meant be tough (unless you intentionally have removed it for modifying to a full spectrum camera). I have used heptane many times on lens elements when they have oil or grease on the surface and it works very well. From what I have heard, some service shops use it regularly to clean sensors. I don't clean sensors very often, so I have not used it many times on sensors.

Heptane is a of course a last resort when you know the dirt is some kind of oil, grease or glue that cannot be removed by normal blowing or wiping. You should never drip solvent directly on the sensor, add it to the cleaning device sparingly (and if heptane, use it immediately before the heptane evaporates). This eliminates the risk for excess solvent to drip into other parts of the camera.

Heptane has for decades been used for removing stains from clothes. Nowadays it's used by stamp collectors to remove self adhesive. A stamp is much more fragile than a sensor "cover glass".

Would be great if Dyxum site had a "tech note" or article as an instruction how-to for all members to use. Must be a big bunch of knowledgeable people here

The Knowledge Base Index page is not so easy to find if you don't know it exists. There is room on the main page to mention it and put a link in the Welcome to Dyxum section.