Why you should calibrate Canon EF Lenses

[privatebydesign]

AF is a critical factor in a photo, no matter how good is a subject, light and composition if the focus is not there, so it's kind of important.

I'd change that to AF is a critical factor in most photos. I was shocked the first time I went to a Steve McCurry print exhibition, it wasn't so much the focus as the fact that nothing seemed to be sharp in any of his older pictures, and the truth is the older ones were far more compelling than his more recent and 'technically better' work.

There is no doubt that if the subject and composition is compelling enough it can overcome many technical limitations, but I grew up with film so 'accept' some limitations/faults people more used to digital images won't. Indeed on occasions I find ultimate sharpness to be a distraction.

Here is an example where I believe ultimate sharpness would not have improved the image, indeed I believe it would have been a distraction, maybe I am wrong, obviously all these things are subjective, but to me this represents a style of image that is very recognizably Steve McCurry/Nat Geo in the 70's/90's which I like.

 

[SPKoko]

I don't understand why people moan and groan about AFMA, really. I can do any lens right from the camera's display screen within 10 minutes. Includes zooms with long and wide settings. All I need is a reliable target and a pair of reading glasses. Back patio has more than enough light in daytime.

I have lost countless hours trying to AFMA my lenses, first with manual methods like Dot-Tune and others and then with FoCal. But I have never really got accurate AF. I focus on the eye and sometimes the focus plane is slightly moved towards the nose and some other times, towards the ears. AF is more frequently off than spot-on. Perhaps the problem is with the 70D, as there have been many forum threads about its lack of accuracy. In any case, I am totally fed up of AFMA and I will only upgrade to mirroless FF now.

 

[AlanF]

I don't understand why people moan and groan about AFMA, really. I can do any lens right from the camera's display screen within 10 minutes. Includes zooms with long and wide settings. All I need is a reliable target and a pair of reading glasses. Back patio has more than enough light in daytime.

I have lost countless hours trying to AFMA my lenses, first with manual methods like Dot-Tune and others and then with FoCal. But I have never really got accurate AF. I focus on the eye and sometimes the focus plane is slightly moved towards the nose and some other times, towards the ears. AF is more frequently off than spot-on. Perhaps the problem is with the 70D, as there have been many forum threads about its lack of accuracy. In any case, I am totally fed up of AFMA and I will only upgrade to mirroless FF now.

I am sorry you are unhappy with AFMA. It's probably your 70D. My 5DIV and 5DSR give spot on AF most of the time after I have AFMAd the lenses using FoCal. That wasn't the case with my 7D.

 

[SPKoko]

I don't understand why people moan and groan about AFMA, really. I can do any lens right from the camera's display screen within 10 minutes. Includes zooms with long and wide settings. All I need is a reliable target and a pair of reading glasses. Back patio has more than enough light in daytime.

I have lost countless hours trying to AFMA my lenses, first with manual methods like Dot-Tune and others and then with FoCal. But I have never really got accurate AF. I focus on the eye and sometimes the focus plane is slightly moved towards the nose and some other times, towards the ears. AF is more frequently off than spot-on. Perhaps the problem is with the 70D, as there have been many forum threads about its lack of accuracy. In any case, I am totally fed up of AFMA and I will only upgrade to mirroless FF now.

I am sorry you are unhappy with AFMA. It's probably your 70D. My 5DIV and 5DSR give spot on AF most of the time after I have AFMAd the lenses using FoCal. That wasn't the case with my 7D.

Thanks for the feedback. Your comment is very important to me, since it kind of confirms my suspicions. It must be a problem with the 7D and the 70D AF system. In:

Why isn't my Canon 70D autofocus accurate

jrista said:

It should be noted that the 7D AF system is known to have precision problems. I have used the 7D for a couple of years now, and because of the actual design of it's AF sensor, small differences in the actual focal plane for a selected point or zone (i.e. 4.8ft vs. 5ft) are pretty much to be expected. You also get a slight amount of jitter when focusing with the same AF point at the same spot on the same subject over and over. AF won't remain "locked"...it shifts forwards and back by a very slight amount each frame. Using AI Servo, I tend to take bursts of 3-5 shots every time

Still, even with other DSLR models, people frequently complain about not very accurate AF. That's over for me. These days I am very happy with the AF of my Olympus that has totally displaced the Canon and I am only looking forward to a future Canon FF mirrorles with Dual Pixel AF.

 

[captainkanji]

I no longer AFMA my primes since I installed the precision focusing screen in my 6D. I can focus manually better than the camera can. It's a 6D so that's not saying much

 

[YuengLinger]

AFMA is much less of a PITA than doing dishes, and, umm, ahem, somebody in the house does those every single day. :

That's why humanity invented automated dishwashers And also semi-automated AFMA system as well I guess..

Good analogy...But, we cook for a family of four, lots of Asian style cooking. We can't put our cast iron in the dishwasher, nor our good knives, nor bamboo chopsticks. That said, the dishwasher helps a lot! Especially with bottles and sippy-cups for two babies!

When I said "ten minutes" for a lens, I meant from the time I set up the target until finished with AFMA. If I do several lenses, less time per lens.

I understand the idea of automating something tedious that needs to be done often, but, honestly, it seems so simple to dial in accurate AF with the in-camera tool alone, and so rarely that I get a new body or see "drift" of AFMA, that learning to use the software and connect to a laptop seems more complicated and time consuming. You might technically be achieving better results, +/-1 unit, but my results seem "spot" on doing AFMA the simple way.

 

[neuroanatomist]

In:

Why isn't my Canon 70D autofocus accurate

jrista said:

It should be noted that the 7D AF system is known to have precision problems. I have used the 7D for a couple of years now, and because of the actual design of it's AF sensor, small differences in the actual focal plane for a selected point or zone (i.e. 4.8ft vs. 5ft) are pretty much to be expected. You also get a slight amount of jitter when focusing with the same AF point at the same spot on the same subject over and over. AF won't remain "locked"...it shifts forwards and back by a very slight amount each frame. Using AI Servo, I tend to take bursts of 3-5 shots every time

While I respect jrista, and he's someone who takes amazing astro shots, I will also point out that he once stated that the 5DIII has, "Poor, sub-par, unacceptable IQ." After that, I have tended to take his criticisms of Canon dSLR performance with a rather large grain of salt.

Having said that, AF system performance for the f/5.6 lines is specified as 'precise within one depth of focus', and with the f/2.8 lines (and an appropriate lens), as 'precise to within one-third the depth of focus', in both cases at the maximum aperture of the lens. Depth of focus is the sensor-side equivalent of depth of field, but the former has very little dependence on subject distance/magnification. Basically, no phase AF system is going to be perfectly accurate or precise, but AFMA at least allows you to properly calibrate the accuracy.

The other relevant point (mentioned in the post you linked) is that the actual AF point on the AF sensor is larger (i.e. covers a larger area of the field) than the representation of that AF point in the viewfinder. So, while you may be placing the AF point directly on a subject's eye, the eyebrow may have higher contrast (or with a more distant subject, the hairline), and the AF system will lock onto that higher-contrast feature that you only thought was outside the AF point (the Eye AF feature on some newer ILCs is helpful for that). With the more densely packed AF arrays like the 5DIII and later, the actual AF points extend less far from the VF representation, giving the impression of more accurate focus with some subjects.

 

[unfocused]

I haven't really been following this thread, but since the 6DII hysteria seems to be dying down a bit, I thought I'd take a look.

I'm afraid I fall into that category of people who know they should do this, but just never seem to find the time or want to invest in an elaborate setup. Candidly, I also find that most of my focusing errors are related to a subject moving rather than the lens. Still, I'm kind of interested in this, especially when people say they can do it easily in the backyard with no special equipment.

I'd be curious what setup people use and how long they spend doing this.

 

[AlanF]

I am pretty anal about AFMA as I crop bird photos heavily and want to see the detail on their feathers etc. I Use FoCal. I suppose it takes about 20 minutes, and I usually do repeat runs, each extra one about another 10 minutes. I like seeing the other output about the lens that FoCal gives (astigmatism) and how the lens compares with other peoples measurements.

 

[takesome1]

While I use focal and think it is a good product.

This article appears to just be sales propaganda.

 

[takesome1]

AF is a critical factor in a photo, no matter how good is a subject, light and composition if the focus is not there, so it's kind of important.

Some of the finest, sharpest lenses made for Canon can not AF at all. Yet many people take wonderful pictures with them.

 

[YuengLinger]

AF is a critical factor in a photo, no matter how good is a subject, light and composition if the focus is not there, so it's kind of important.

Some of the finest, sharpest lenses made for Canon can not AF worth at all. Yet many people take wonderful pictures with them.

Which FAST lenses are you talking about? And would that be on today's sensors? By today's standards?

Surgeons used to save lives before X-rays, even before anti-biotics. How is that relevant to good practices today?

 

[takesome1]

AF is a critical factor in a photo, no matter how good is a subject, light and composition if the focus is not there, so it's kind of important.

Some of the finest, sharpest lenses made for Canon can not AF worth at all. Yet many people take wonderful pictures with them.

Which FAST lenses are you talking about? And would that be on today's sensors? By today's standards?

Surgeons used to save lives before X-rays, even before anti-biotics. How is that relevant to good practices today?

https://www.bhphotovideo.com/c/product/1077281-REG/zeiss_2040_292_otus_apo_planar_85mm.html

I heard this one is nice, and it will not AF at all.

 

[AlanF]

Made to fit Canon but not by Canon.

 

[takesome1]

Made to fit Canon but not by Canon.

"made for Canon" yes made to fit not by, probably not even for Canon the company.

Maybe this would have been a better example?

https://www.bhphotovideo.com/c/product/606804-USA/Canon_3552B002_TS_E_24mm_f_3_5L_II.html

 

[unfocused]

I am pretty anal about AFMA as I crop bird photos heavily and want to see the detail on their feathers etc. I Use FoCal. I suppose it takes about 20 minutes, and I usually do repeat runs, each extra one about another 10 minutes. I like seeing the other output about the lens that FoCal gives (astigmatism) and how the lens compares with other peoples measurements.

See, this is what I don't understand. Let's say I'm shooting a relatively slow moving bird like a gull. To really nail the eyes I would have to be shooting single point, but that's nearly impossible (for me) to keep focus nailed as the bird soars around and with single-point, as soon as it moves, you completely lose focus. So, I usually use one of the multipoint options, which gives the camera enough information to hopefully at least find the bird and autofocus on it. But realistically, I have yet to find a camera (including the 1DX II) that will consistently nail the eyes at that distance and speed, especially with a long lens. Lucky if it can keep focus anywhere on the head.

Now I always ask myself, what is the point of AFMA since we are talking about differences of a fraction of an inch in focus; and subject movement, slight shifts in the position of the camera and lens, etc., are going to negate any tiny differences in fine tuning the lens.

Maybe others have better technique than I do or have faster reflexes. I'm curious what your secrets are. I'd love to be so close in focus that AFMA would make a difference. It just seldom seems to be the case.

 

[Pookie]

Made to fit Canon but not by Canon.

Never said MADE BY CANON...

Reading comprehension isn't your strong suit...

 

[AlanF]

Made to fit Canon but not by Canon.

Never said MADE BY CANON...

Reading comprehension isn't your strong suit...

I read your comment perfectly and was pointing it out to YuengLinger who missed it, so don't be so damned rude - I will take you on any day when it comes to comprehension.

 

[AlanF]

I am pretty anal about AFMA as I crop bird photos heavily and want to see the detail on their feathers etc. I Use FoCal. I suppose it takes about 20 minutes, and I usually do repeat runs, each extra one about another 10 minutes. I like seeing the other output about the lens that FoCal gives (astigmatism) and how the lens compares with other peoples measurements.

See, this is what I don't understand. Let's say I'm shooting a relatively slow moving bird like a gull. To really nail the eyes I would have to be shooting single point, but that's nearly impossible (for me) to keep focus nailed as the bird soars around and with single-point, as soon as it moves, you completely lose focus. So, I usually use one of the multipoint options, which gives the camera enough information to hopefully at least find the bird and autofocus on it. But realistically, I have yet to find a camera (including the 1DX II) that will consistently nail the eyes at that distance and speed, especially with a long lens. Lucky if it can keep focus anywhere on the head.

Now I always ask myself, what is the point of AFMA since we are talking about differences of a fraction of an inch in focus; and subject movement, slight shifts in the position of the camera and lens, etc., are going to negate any tiny differences in fine tuning the lens.

Maybe others have better technique than I do or have faster reflexes. I'm curious what your secrets are. I'd love to be so close in focus that AFMA would make a difference. It just seldom seems to be the case.

90% of my bird photos are for for them perched, and I use single centre point to focus on the eye if they are close enough or on the body if they are small and far away.
For the 10% of birds in flight, they tend to be about 30m or more away and I still use single centre point because it gives the best AF, and I focus on the body or head, depending on how big they are and how fast they are flying. The depth of field at that distance is usually enough so that most of the bird is in focus, unless the wings are long and the bird is sideways on. By AFMAing the lens, more of the shots have the bird at the centre of the focus for a lens that would have front or back focus without AFMA.

My first really good lens was a 300mm f/2.8 II. It required +7 AFMA on the 7D, and according to the Focal comparative data is typical for this combination, with serious front focus. Without AFMA, it was terrible at f/2.8.

 

[rfdesigner]

I no longer AFMA my primes since I installed the precision focusing screen in my 6D. I can focus manually better than the camera can. It's a 6D so that's not saying much

I dot tuned my lenses to my 6D (plus Eg-S) when I got the camera (on center point AF) and it's been fine ever since..

It took me less than hour and I've never had any problem since, or at least I'm as likely to miss focus short as long.

and the lenses are all quite different, IIRC, +8, +5, -3. Well worth doing certainly.