Since the introduction of the Canon EOS 1D Mark III way back in 2007, middle to high-end camera owners have been able to adjust the focus system of their camera to work better with each lens.
Reikan FoCal takes the guesswork out of this adjustment by automating the process and using advanced computer analysis to determine the best adjustment for your camera and lens. Over the past 5 years, FoCal users have been uploading their results to our database, and we process this information and feed it back to let them compare how their camera and lens compares with everyone else.
In this post, I wanted to take a look in more detail about the real world need for AF Microadjustment on Canon cameras and specifically Canon EF lenses. In a previous post, we looked at the the results of adjustment across all cameras and lenses (Canon and Nikon) supported by FoCal and saw that on average more than 60% of all cameras and lenses would significantly benefit from calibration.
This might not come as a massive surprise, but we think it’s a really good idea to calibrate every single lens you own!
But don’t just take our word for it. I’ve shown below exactly why it’s a great idea to adjust your lenses with your cameras.
There have been more than 100 different Canon EF lenses produced since 1987, and our database contains high quality information for nearly 90 of these lenses across the 16 different Canon camera bodies supported by FoCal.
For this post, I’m going to use the results to show how likely it is that any particular lens will benefit from calibration. I want to try and answer the question:
“When I take that shiny new lens out of the box, what are the chances that I’m going to get the best from it without any adjustment?”
How likely is is that a lens needs no adjustment at all?
We’ve taken all the data and worked out the percentage of each lens type that required no calibration at all (i.e. the AF Microadjustment result from FoCal was 0). Here’s that data shown for all the Canon EF lenses (ordered from most-likely to least-likely to need no calibration):
(Note: click on the chart to see a large view)
Let’s start at the very left of the chart. The EF 90-300mm lens has a value of just under 25%… so what does that mean? It means that – on average – if you had 4 of these lenses on the bench in front of you, 3 out of 4 would produce sharper photos if you ran them through FoCal. Only 1 of the 4 (25%) would not need any calibration. And that’s for the best on the list!
Move a third of the way along the chart (to the 60mm Macro), and you’re down to less than 10%, i.e. more than 9 out of 10 lenses would benefit from calibration!
And at the far right, the last 2 lens types( the 85/1.2L and 300/2.8L) could do with calibration for every single copy of this lens!
Relax A Little
To be honest, we’ve gone for a pretty stringent requirement above of needing a calibration result of 0. In reality, you’ll usually not notice much of a difference with an adjustment of 2 AF Microadjustment points, so let’s have a look at what happens if you include all the results that need just a tiny amount of calibration:
Again, starting at the far left, this time it’s the EF 11-24 f/4L that’s best, and our number has jumped to almost 75%. So now only 1 in 4 lenses will see a significant improvement (remember, the other 3 will probably still see an improvement, just not huge).
But… (there’s always a but!)… only the top 15 lenses have values above 50%. That means that even with this more relaxed requirement, nearly 80% of the lenses are more likely to be significantly better after running through FoCal.
For the half of the lenses on the right side of the chart, you’ve got a 2 in 3 chance that you’ll see a decent improvement using FoCal.
What does this adjustment look like?
I keep mentioning tiny, small and large calibration differences, but what do these actually look like? The images below show the difference between a well calibrated lens, and an offset of 2 points (barely any noticeable difference), a 10 point error (significantly blurred), and a 20 point error (hugely blurred):
The yellow chart above (Percentage requiring very little calibration) shows the percentage of lenses that fall somewhere between Calibrated and 2 point error. The remaining lenses – that’s more than 1 in 2 lenses for 80% of the different lens types – are somewhere between 2 point error and 20 point error!
The Scary End!
Finally, let’s take a look at the scary end of the figures – the lenses which needed a huge calibration (more than 10 AF Microadjustment units):
This time, the left side of the chart is a bad place to be. If you had 10 copies of the EF 28mm f/1.8 lens on your desk, 4 out of 10 of them would likely get a massive improvement after calibration with FoCal!
Thankfully that number drops quickly, but for around a third of all tested EF lenses you’ve still got a greater than 1 in 10 chance that you’ll need a really big adjustment to get the best from the lens. And to put that in context, all of those lenses will be producing results between the 10 point error and 20 point error images above!
There’s a pretty simple conclusion here (and it’s great for us at Reikan!): you really should run every lens you have through FoCal!
For most lenses there’s a high chance you’ll get a noticeable improvement in image quality after calibration.
FoCal takes all the guesswork out of adjusting your lenses, so for the sake of a few minutes with each lens it really is worth it to get the best from your kit.
Take a more detailed look at FoCal on the website.
In the next post, we’ll look at Nikon lenses so we can see how things compare.
Fire away in the comments section with any questions you might have about all this data, or any suggestions for other things you’d like to see.