I received a 5D4 yesterday and as always, my first task was to calibrate it with all of the lenses I might use with it. Since my collection is pretty large, one might assume that this would be a daunting task. However, I just happen to know the most amazing method of lens calibration using this one insane trick. Oh wait, that's for nail fungus. Here is the real super-easy method:
The first thing you need is a large cardboard mat that is sold in sewing stores for cutting out fabric. Ignore all the markings except the grid lines.
Lay the mat out flat in bright sunlight or in your studio under your lights and put your camera on your tripod like this:
Stick some black tape on the mat like you see in the photos. Your autofocus sensors will pick it up perfectly.
If you are calibrating a wide angle lens, you will want to set up your gear closer to the mat than you would if calibrating a longer lens. I recommend using the same distance at which you would most often use that lens. You might also consider what lighting conditions you will most often use and try to duplicate that, but I'm probably being obsessive about that.
Get your center focus point somewhere on the black tape and snap an image with enough light to show the grid lines well. Your aperture should be wide open.
Bring the photo up on your rear LCD screen and hit the magnify button/wheel a few times so that you can easily see the sharp zone. If it isn't centered on the black tape, go into your menu and use the MFA system to change it. Shoot again and magnify. Once you get it right, you can quit. I've not seen any advantage in repeating the process.
The photo above was shot with the EF 85mm F/1.8. The shallow depth of field makes it very easy to calibrate. It's also fun to note the chromatic abberration that you get with this lens wide open.
The photo above was shot with the EF 100 F/2.8 L IS macro. It's a lot sharper lens than the little 85 and you will notice only very slight CA
The final image was taken with the amazing EF 24-70 F/2.8 L II.
This is a very fast process. I was able to calibrate 9 lenses in less than an hour and I have complete confidence that they are now properly calibrated with my 5D4 body. FYI, the calibration settings for this body varied from zero to about +8, so it has a minor tendency to front focus.
You will find that longer lenses are easier to calibrate than wide angle lenses and large aperture lenses are easier than those with small apertures. Some lenses are almost impossible to calibrate this way, the best example would be the 18-55 kit lenses. Their poor image quality combined with small max aperture prevents you from seeing a clear zone.
You can also learn interesting things about a lens doing this. It's easy to get an overall impression of how sharp it is. I've detected decentered elements and loose zoom assemblies. (Well, I knew they needed to go to Canon service, and they told me exactly what was wrong.)
On lenses like the EF 50mm F/1.2 L, you can test at different apertures to see if the infamous focus shift is enough for you to worry about. (It wasn't for me.)
If you happen to have an Art lens, you can test it many times and see how inconsistent the focus is. You can also do the test with peripheral focus points in addition to the center point to see if you have issues of that sort. It's a really good way to diagnose possible autofocus problems when you aren't really sure if you have one or not.
I've been using this process for several years and I love it. One thing I don't like is that when I use a body without MFA capability, I really miss it!
The first thing you need is a large cardboard mat that is sold in sewing stores for cutting out fabric. Ignore all the markings except the grid lines.
Lay the mat out flat in bright sunlight or in your studio under your lights and put your camera on your tripod like this:
Stick some black tape on the mat like you see in the photos. Your autofocus sensors will pick it up perfectly.
If you are calibrating a wide angle lens, you will want to set up your gear closer to the mat than you would if calibrating a longer lens. I recommend using the same distance at which you would most often use that lens. You might also consider what lighting conditions you will most often use and try to duplicate that, but I'm probably being obsessive about that.
Get your center focus point somewhere on the black tape and snap an image with enough light to show the grid lines well. Your aperture should be wide open.
Bring the photo up on your rear LCD screen and hit the magnify button/wheel a few times so that you can easily see the sharp zone. If it isn't centered on the black tape, go into your menu and use the MFA system to change it. Shoot again and magnify. Once you get it right, you can quit. I've not seen any advantage in repeating the process.
The photo above was shot with the EF 85mm F/1.8. The shallow depth of field makes it very easy to calibrate. It's also fun to note the chromatic abberration that you get with this lens wide open.
The photo above was shot with the EF 100 F/2.8 L IS macro. It's a lot sharper lens than the little 85 and you will notice only very slight CA
The final image was taken with the amazing EF 24-70 F/2.8 L II.
This is a very fast process. I was able to calibrate 9 lenses in less than an hour and I have complete confidence that they are now properly calibrated with my 5D4 body. FYI, the calibration settings for this body varied from zero to about +8, so it has a minor tendency to front focus.
You will find that longer lenses are easier to calibrate than wide angle lenses and large aperture lenses are easier than those with small apertures. Some lenses are almost impossible to calibrate this way, the best example would be the 18-55 kit lenses. Their poor image quality combined with small max aperture prevents you from seeing a clear zone.
You can also learn interesting things about a lens doing this. It's easy to get an overall impression of how sharp it is. I've detected decentered elements and loose zoom assemblies. (Well, I knew they needed to go to Canon service, and they told me exactly what was wrong.)
On lenses like the EF 50mm F/1.2 L, you can test at different apertures to see if the infamous focus shift is enough for you to worry about. (It wasn't for me.)
If you happen to have an Art lens, you can test it many times and see how inconsistent the focus is. You can also do the test with peripheral focus points in addition to the center point to see if you have issues of that sort. It's a really good way to diagnose possible autofocus problems when you aren't really sure if you have one or not.
I've been using this process for several years and I love it. One thing I don't like is that when I use a body without MFA capability, I really miss it!