50L Lens Question for Owners

I'm considering replacing my Canon 50 1.4 with the Canon 50L lens. Does the 50L's backfocussing problemss only occur at close focus range or is it across the entire distance range? Also is this still a problem or if I purchase a new lens has the problem now been corrected? I called Canon about this and their statement was the 50L never had a focus problem. I would use this lens for its great ability wide open but would also use it throughout the full aperture range. Is the lens pretty sharp at all apertures, not just wide open? Finally is the focus speed closer to the 85L or to other faster Canon lenses? Thanks for any other words of wisdom. Steve

The 50L can have regular back focus or front focus just like any lens. It can be corrected by either finding a good copy, send it to Canon for calibration or micro adjust on a body that has that feature.

Additionally, at around f/2 - f/4 at near MFD (1.5' to 3'), the 50L has a focus shift, where the plane of focus is slightly to the back of where it is at f/1.2. Since AF is done at f/1.2 regardless of the set aperture, the image will be slightly back focused. All 50L has this, some shifts more to be noticeable, some shifts less. A good copy is the one that only shifts within the DOF of a given aperture, so you can't see it.

The focus shift can be worked around by
- Avoid f/2 - f/4
- Shoot from farther away (> 5ft)
- Use AI-Servo instead of One-Shot
- Use off-center focus point

My copy of 50L at f/1.2 gives a dreamy look. It gets sharper at f/1.4 and razor sharp at f/1.8 - f/2. Above f/2, the focus shift kicked in, at f/4 the DOF is large enough to hide any problems.

The 50L is a tough lens to learn, but when you do master it, the result is truly magical beyond what can be described by sharpness alone. The way it renders color, background blur and contrast make it worth the price to me.

My 50L has a slight backfocus which was easily fixed by doing a microadjustment (-6) on the 5D2.

Did I hear right that the 50mm 1.4 II is coming out end of the year? Focus shift isn't fun to be honest. My 85L exhibits some of it and it's a real pain. If you can nail it then brilliant but if it misses at crucial moments then oh boy!

cristphoto wrote in post #9929851
I'm considering replacing my Canon 50 1.4 with the Canon 50L lens. Does the 50L's backfocussing problemss only occur at close focus range or is it across the entire distance range? Also is this still a problem or if I purchase a new lens has the problem now been corrected? I called Canon about this and their statement was the 50L never had a focus problem. I would use this lens for its great ability wide open but would also use it throughout the full aperture range. Is the lens pretty sharp at all apertures, not just wide open? Finally is the focus speed closer to the 85L or to other faster Canon lenses? Thanks for any other words of wisdom. Steve

Yes, typically the lens performs better the further you are from the subject including the focus shift, ghostly look wide open, etc...

Thanks for the replies. If I know how to "work around" any deficiencies that's fine. If the lens has focus troubles at all lengths and apertures then its not worth getting. I hear people complaining about focus at macro lengths used wide open. To me that's a situation I would rarely use. My 50 1.4 works fine but its my only non-L lens and I know I get great results with my other lenses. Do any of the people responding have a fairly new lens or are yours all earlier models? Since Canon is known to make "running changes" to their products (I have a later model 1D3 that works fine) I'm curious if this issue has been fixed without any fanfare from Canon.

Jam.radonc wrote in post #9930731
Did I hear right that the 50mm 1.4 II is coming out end of the year? Focus shift isn't fun to be honest. My 85L exhibits some of it and it's a real pain. If you can nail it then brilliant but if it misses at crucial moments then oh boy!

Typically Canon is VERY secretive about new product releases. They do tend to make updates when they feel the need to respond to a similar Nikon product. For example the response to the new Nikon 70-200 lens forced Canon to release their updated 70-200. Has Nikon come out with a new 50 1.4 lens to push Canon into a similar update?

ahendarman wrote in post #9929923
A good copy is the one that only shifts within the DOF of a given aperture, so you can't see it.

I'm not an expert by any measure, but I read a lot before I purchased my own 50L. According to the consensus I gathered, focus shift is an optical phenomenon caused by an aberration. This aberration is normally corrected by using floating focusing elements. 50L does not have this corrective design and given all 50Ls are manufactured the same way, one would expect the focus shift for all copies to be pretty close. So any given 50L would not shift more or less than any other 50L. However, within the tolerance of the manufacturing process, an individual lens may have different focus characteristics giving rise to back/front focusing. This latter can be adjusted by calibration of the lens or microadjustment.

What we see as the end result is a combination of a few factors including the focus shift, back/front focusing due to optical assembly as well as calibration/sensitivit​y/accuracy of the AF system in the body. While the product of focus shift is constant, the effect of other factors can counter this effect or conversely, make it worse. As a result we may or may not see a discernible effect on the outcome.

To add a caveat to your comment, we might say that a good 50L copy is that which has an inherent calibration issue enough to counter its focus shift at shallow DOFs. Now for a purist, a lens which has calibration issues can be perceived as a bad copy...

My 50L is perfectly reliable on my 1D3. But I need to be careful when I use the same lens on my 5Dc. I tend to believe its because of 1D3's superior AF.

Bought it used and had some focusing issue. Took it to Canon to have it calibrated with the 5Dc. Used it also with my 1DIIN, never had a problem before calibration.

Same thinking as "actprivate" where I tend to believe of 1DIIN AF > 5Dc.

My 50L behaves the same whether it be mounted on a 5DC, 5DMKII, 1DMKIII, 7D, 1DMKIV.
You get the picture. It's the design of the lens, so camera has nothing to do with it.

To the OP, if you are going to buy, just make sure you buy it from a shop with a good return policy. (B&H, Amazon to name a few) This way you can try it out and see if you like it and return it if you don't like it.

BTW, I wouldn't call the 50L's MFD distance macro. Not at all. Danger zone is between MFD and as much as 6 feet. Hardly "macro-ish" distance at 5-6feet out.

I've owned two copies of this lens now and I can say there is some sample variation out there. I also agree that anyone saying their lens doesn't have any focusing problems at all is just not using it in the areas you'd notice the problem the worst.

Every 50L produced will shift focus, it's just a limitation of the design they chose. It's also not an uncommon thing at all with extreme aperture lenses.

I still love my 50L, it does cause me to miss shots some times if I'm not paying attention, which is admittedly frustrating, but all-in-all I really love the lens.

If canon did finally update the 50 f/1.4 to be a more sturdy lens with true Ring-USM perhaps to compete with the Sigma 50 I would probably switch to that and buy myself the 35L again as well (or even the 24L)