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Archive 2009Explain the 50mm L problem
p.1 #1Explain the 50mm L problem
I have a 50mm 1.4 even though I really like it, you need to use an aperture of F2 or higher to get nice sharp pictures. I would like the use a 50mm lens that will take pictures wide open and from what I read the 50mm 1.2 will do the job. Now I have read about the shift focus problem. What does it mean exactly
When does this problem exactly ocurr How do I avoid it??
I would like to use the lens to shoot portraits, and the subject will be anywhere from 5 to 10 feet from me. Head shots, 1/2 body shots and full shots.
When does this problem exactly ocurr
How do I avoid it??I would like to use the lens to shoot portraits, and the subject will be anywhere from 5 to 10 feet from me. Head shots, 1/2 body shots and full shots.
Mar 18, 2009 at 11:20 AM
p.1 #2Explain the 50mm L problem
I just got one yesterday and I am so stoked on it. You should upgrade.
Mar 18, 2009 at 11:25 AM
p.1 #3Explain the 50mm L problem
Probably means because the depth of field at f1.2 is so shallow that the even the slightest movement back and forth will put what you initially wanted in focus slightly out of focus.
Mar 18, 2009 at 11:25 AM
p.1 #4Explain the 50mm L problem
If you shoot at close distances, between the apertures of F2 and F4, and use center point AF, the plane of focus will shift slightly upon taking the picture.
This is not an issue when:
1. Shooting with a faster aperture than F2-F2.8
2. Using anything besides center AF point
3. Shooting a subject more than about 8 feet away.
Quite honestly, this "issue" has been blown so far out of proportion that is has become a running joke in the forums. If you are buying the 50L for serious fast aperture work, then this "issue" isn't an issue at all. Even when it is a "problem", it is only very slight.
I've been using the lens in a wedding/portrait situation for the past 8 months or so and it has *never* been an issue for me. Not once.
This is not an issue when:
1. Shooting with a faster aperture than F2-F2.8
2. Using anything besides center AF point
3. Shooting a subject more than about 8 feet away.
Quite honestly, this "issue" has been blown so far out of proportion that is has become a running joke in the forums. If you are buying the 50L for serious fast aperture work, then this "issue" isn't an issue at all. Even when it is a "problem", it is only very slight.
I've been using the lens in a wedding/portrait situation for the past 8 months or so and it has *never* been an issue for me. Not once.
Mar 18, 2009 at 11:33 AM
p.1 #5Explain the 50mm L problem
I could not live with the soft pics, 1.2-1.8, taken close from 50 cm untill 2 meters.
I loved him but I also hate that lens
its a very nice top lens, but I was every time so disapointed when the object was close.
absolutly no sharpness greater than 1.8
so I said goodbey to him and I sold it.
I wait for the markII
I loved him but I also hate that lens
its a very nice top lens, but I was every time so disapointed when the object was close.
absolutly no sharpness greater than 1.8
so I said goodbey to him and I sold it.
I wait for the markII
Mar 18, 2009 at 11:35 AM
p.1 #6Explain the 50mm L problem
deepbluejh wrote:
If you shoot at close distances, between the apertures of F2 and F4, and use center point AF, the plane of focus will shift slightly upon taking the picture.
Why is it so? Is it because you focus-recompose?
I thought the center point was the most acurate.
If you shoot at close distances, between the apertures of F2 and F4, and use center point AF, the plane of focus will shift slightly upon taking the picture.
Why is it so? Is it because you focus-recompose?
I thought the center point was the most acurate.
Mar 18, 2009 at 11:39 AM
p.1 #7Explain the 50mm L problem
The camera focuses correctly, the problem is that the actual plane of focus shift slightly when the lens stops down. This really has been beaten to death ad nauseum in the past.
Mar 18, 2009 at 11:48 AM
p.1 #8Explain the 50mm L problem
Sorry, I have never heard about this before. But why should the center point be worse than the rest og the focuspoints, if you dont focus-recompose.
Mar 18, 2009 at 11:52 AM
p.1 #9Explain the 50mm L problem
Ad absurdum if I may add. It's an excellent lens with an underserved bad rep.
Mar 18, 2009 at 11:53 AM
p.1 #10Explain the 50mm L problem
Gust wrote:
I could not live with the soft pics, 1.2-1.8, taken close from 50 cm untill 2 meters.
I loved him but I also hate that lens
its a very nice top lens, but I was every time so disapointed when the object was close.
absolutly no sharpness greater than 1.8
so I said goodbey to him and I sold it.
I wait for the markII
Near minimum focusing distance the lens is slightly soft. Past about 4 feet, the image quality is quite similar to the 85L, which is to say exceptional.
Wait all you want to on a "Mark II", but your expectations are unrealistic I suspect. I would tell you to go buy a better fast autofocus 50mm, but there are none better.
I could not live with the soft pics, 1.2-1.8, taken close from 50 cm untill 2 meters.
I loved him but I also hate that lens
its a very nice top lens, but I was every time so disapointed when the object was close.
absolutly no sharpness greater than 1.8
so I said goodbey to him and I sold it.
I wait for the markII
Near minimum focusing distance the lens is slightly soft. Past about 4 feet, the image quality is quite similar to the 85L, which is to say exceptional.
Wait all you want to on a "Mark II", but your expectations are unrealistic I suspect. I would tell you to go buy a better fast autofocus 50mm, but there are none better.
Mar 18, 2009 at 11:55 AM
p.1 #12Explain the 50mm L problem
any wide aperture lens will have a very narrow depth of field and thus focus becomes even more critical than on lenses without such wide apertures. the 85L has a very precise focus ring for that reason... the 50L isn't as demanding but is still requires attention to your focusing more than most other lenses do.
Mar 18, 2009 at 11:59 AM
p.1 #13Explain the 50mm L problem
deepbluejh wrote:
I loved him but I also hate that lens
its a very nice top lens, but I was every time so disapointed when the object was close.
absolutly no sharpness greater than 1.8
so I said goodbey to him and I sold it.
I wait for the markIINear minimum focusing distance the lens is slightly soft. Past about 4 feet, the image quality is quite similar to the 85L, which is to say exceptional.
Wait all you want to on a "Mark II", but your expectations are unrealistic I suspect. I would tell you to go buy a better fast autofocus 50mm, but there are none better.
your'e right. working with a lot of primes from 14 till 500mm, but I don't owne a 50mm.
and that will last untill there is a good version
Gust wrote
I could not live with the soft pics, 1.2-1.8, taken close from 50 cm untill 2 meters.I loved him but I also hate that lens
its a very nice top lens, but I was every time so disapointed when the object was close.
absolutly no sharpness greater than 1.8
so I said goodbey to him and I sold it.
I wait for the markII
Wait all you want to on a "Mark II", but your expectations are unrealistic I suspect. I would tell you to go buy a better fast autofocus 50mm, but there are none better.
your'e right. working with a lot of primes from 14 till 500mm, but I don't owne a 50mm.
and that will last untill there is a good version
Mar 18, 2009 at 12:00 PM
p.1 #14Explain the 50mm L problem
The "problem" with the 50/1.2 is focus shift. Focus shift occurs because the lens focuses wide open, but when the lens stops down for exposure, the point of sharpest focus shifts rearward. This is inherent in the design of the lens. My 50/1.2 exhibits focus shift at apertures f/2 through f/5.6 combined with short subject distances. Wider than f/2 there is no appreciable focus shift. Narrower than f/5.6 the depth of field expands sufficiently to obscure the focus shift. At subject distances greater than a few feet, the focus shift is not detectable even with testing. In fact, I can only detect focus shift at the problem apertures and range when I test for it. In "real world" shooting, I have never noticed focus shift. Rather, many other factors not related to the lens itself affect the quality of focus, such as subject or camera movement, poor light, high contrast backgrounds, AF point size, etc.
I also use the 85/1.2 Mark II. It does not exhibit focus shift, but it also does not focus as closely as the 50/1.2. If I were to never focus my 50/1.2 closer than the 85/1.2 minimum focusing distance, my 50/1.2 also may not exhibit focus shift.
Many fast (wide aperture) primes exhibit focus shift, according to what I have read. I am not a lens designer, but my understanding is that focus shift is a design trade-off to gain other lens qualities. While the 50/1.2 is berated for suffering from focus shift, the most commonly recommended alternative to the 50/1.2, the Sigma 50/1.4, also exhibits focus shift almost identical to that of the 50/1.2, accrding to tests available for a fee at the diglloyd site.
Some users of the 50/1.2 claim you can work around the focus shift by using only peripheral AF points. This may be true, but when I tested that workaround, it had no effect on my 50/1.2's focus shift. Therefore, I use no AF workarounds -- or any workaround at all -- with my 50/1.2, and focus shift has never been discernible in my real-world shooting.
Manual focus does not prevent focus shift, but presumably one could manually focus slightly in front of the intended point of focus to counter the focus shift. I cannot manually focus that accurately to even attempt such a feat. One could also sway backwards slightly after locking focus, or focus on the tip of a nose instead of an eye, when shooting in the danger zone (f/2-f/5.6, close focus). Again, I do none of this.
Sean Reid on the pay portion of his site has a fine review of fast 50mm lenses for Canon, including the 50/1.2, the Canon 50/1.4, the Sigma 50/1.4, and the Zeiss ZE 50/1.4. His conclusion is that the 50/1.2 is the superior lens. I haven't used any of those other lenses, but I can say that the 50/1.2 is my favorite lens on my 1DsII.
I also use the 85/1.2 Mark II. It does not exhibit focus shift, but it also does not focus as closely as the 50/1.2. If I were to never focus my 50/1.2 closer than the 85/1.2 minimum focusing distance, my 50/1.2 also may not exhibit focus shift.
Many fast (wide aperture) primes exhibit focus shift, according to what I have read. I am not a lens designer, but my understanding is that focus shift is a design trade-off to gain other lens qualities. While the 50/1.2 is berated for suffering from focus shift, the most commonly recommended alternative to the 50/1.2, the Sigma 50/1.4, also exhibits focus shift almost identical to that of the 50/1.2, accrding to tests available for a fee at the diglloyd site.
Some users of the 50/1.2 claim you can work around the focus shift by using only peripheral AF points. This may be true, but when I tested that workaround, it had no effect on my 50/1.2's focus shift. Therefore, I use no AF workarounds -- or any workaround at all -- with my 50/1.2, and focus shift has never been discernible in my real-world shooting.
Manual focus does not prevent focus shift, but presumably one could manually focus slightly in front of the intended point of focus to counter the focus shift. I cannot manually focus that accurately to even attempt such a feat. One could also sway backwards slightly after locking focus, or focus on the tip of a nose instead of an eye, when shooting in the danger zone (f/2-f/5.6, close focus). Again, I do none of this.
Sean Reid on the pay portion of his site has a fine review of fast 50mm lenses for Canon, including the 50/1.2, the Canon 50/1.4, the Sigma 50/1.4, and the Zeiss ZE 50/1.4. His conclusion is that the 50/1.2 is the superior lens. I haven't used any of those other lenses, but I can say that the 50/1.2 is my favorite lens on my 1DsII.
Mar 18, 2009 at 12:02 PM
p.1 #15Explain the 50mm L problem
Galibier wrote:
The "problem" with the 50/1.2 is focus shift. Focus shift occurs because the lens focuses wide open, but when the lens stops down for exposure, the point of sharpest focus shifts rearward. This is inherent in the design of the lens. My 50/1.2 exhibits focus shift at apertures f/2 through f/5.6 combined with short subject distances. Wider than f/2 there is no appreciable focus shift. Narrower than f/5.6 the depth of field expands sufficiently to obscure the focus shift. At subject distances greater than a few feet, the focus shift is not detectable even with testing. In fact, I can...Show more →
Well said
The "problem" with the 50/1.2 is focus shift. Focus shift occurs because the lens focuses wide open, but when the lens stops down for exposure, the point of sharpest focus shifts rearward. This is inherent in the design of the lens. My 50/1.2 exhibits focus shift at apertures f/2 through f/5.6 combined with short subject distances. Wider than f/2 there is no appreciable focus shift. Narrower than f/5.6 the depth of field expands sufficiently to obscure the focus shift. At subject distances greater than a few feet, the focus shift is not detectable even with testing. In fact, I can...Show more →
Well said
Mar 18, 2009 at 12:09 PM
p.1 #16Explain the 50mm L problem
The AF problem aside there's a really good argument that the 50L is the best superspeed 50mm you can get (including "alternatives" which, of course, only focus manually on the EOS). Remember that the vary rare F.95 and F1.0s are really mediocre wide open and nowhere as good as slower lenses, open or closed down.
Consider that, when using F1.2 and the center sensor, the DOF is so thin that it's likely the OOF is due to focusing on some thing other then a pupil or face (for full figure). If the subject is animate and/or you are handholding then focus and recompose can allow time for the subject or photographer to move and-OOF! Many people use only use MF with these big apertures (and special VF screens and bursts of captures. etc).
The 50L is a special purpose lens for use in the F1.2-F1.8 range. Otherwise you can do very well/better with cheaper alternatives. It's best not to think of the 50L as a general purpose 50mm lens which has a few more clicks on the F stop.
I am not a fan of the 50mm FL but I do have one (because the F1.4 is sadly lacking in contrast-read ""sharpness-below F2). My 50L works fine for me but I keep both the 85L (Mk I) and 85 F1.8 in inventory.
The 85L is very reliable although the DOF @ F1.2 is even smaller and it's AF is slow. The 85 F1.8 is compact, light and fast focusing. The combination of both of these 2 lenses (bought used) seems to me to be the best utility/performance/value in this FL range.
Consider that, when using F1.2 and the center sensor, the DOF is so thin that it's likely the OOF is due to focusing on some thing other then a pupil or face (for full figure). If the subject is animate and/or you are handholding then focus and recompose can allow time for the subject or photographer to move and-OOF! Many people use only use MF with these big apertures (and special VF screens and bursts of captures. etc).
The 50L is a special purpose lens for use in the F1.2-F1.8 range. Otherwise you can do very well/better with cheaper alternatives. It's best not to think of the 50L as a general purpose 50mm lens which has a few more clicks on the F stop.
I am not a fan of the 50mm FL but I do have one (because the F1.4 is sadly lacking in contrast-read ""sharpness-below F2). My 50L works fine for me but I keep both the 85L (Mk I) and 85 F1.8 in inventory.
The 85L is very reliable although the DOF @ F1.2 is even smaller and it's AF is slow. The 85 F1.8 is compact, light and fast focusing. The combination of both of these 2 lenses (bought used) seems to me to be the best utility/performance/value in this FL range.
Mar 18, 2009 at 12:10 PM
p.1 #17Explain the 50mm L problem
So it's safe to say I shouldn't have any focus shift if using the lens between 1.2 -- 1.8 at any distance.
And might have focus shift if using the lens at 2.8 - 5.6 if the subject is less then 4ft from the camera What is the minimum focus distance on the 50mm L
And might have focus shift if using the lens at 2.8 - 5.6 if the subject is less then 4ft from the camera
What is the minimum focus distance on the 50mm LMar 18, 2009 at 12:26 PM
p.1 #18Explain the 50mm L problem
One thing I want to add about fast lenses...
Granted it is known the 50mm 1.2 has focus shift, but, like others have stated it is blown completely out of proportion.
A lot of users who get their fast primes arent used to dealing with the super shallow depth of field. They use autofocus (manual is better at those aperatures for most people), and the autofocus picks whatever but since the dof is so thin its not exactly what the user wants in focus and they think that the lens is soft and has problems.
Get the lens, you wont regret it
Granted it is known the 50mm 1.2 has focus shift, but, like others have stated it is blown completely out of proportion.
A lot of users who get their fast primes arent used to dealing with the super shallow depth of field. They use autofocus (manual is better at those aperatures for most people), and the autofocus picks whatever but since the dof is so thin its not exactly what the user wants in focus and they think that the lens is soft and has problems.
Get the lens, you wont regret it
Mar 18, 2009 at 12:35 PM
p.1 #19Explain the 50mm L problem
For a $1k+ L lens, focus-shift is IMO unacceptable, regardless of how minor some people like to think it is. For that price you could easily have 3 of the best MF 50/1.2s, all of which have no appreciable focus shift, and IQ that is IMO equal to the EF 50/1.2L. And still have change left over.
Mar 18, 2009 at 12:50 PM
p.1 #20Explain the 50mm L problem
Overblown or not, the problem exists. To some it's a "problem" but to others it's a Problem. It's good that there's so much info on the issue out there. As a potential buyer you can read about it and make up your mind to whether the issue would be significant or not for your use. As always, take what info is out there with a grain of salt, and filter it for your needs.
Personally, I like equipment to stay out of the way. If I have to think about what optimum apertures to use a lens with and avoid others because of technical concerns, I'd rather stay away and I have. I test a lens up front to see if its performance is up to snuff, and once I'm satisfied that it is when I use the lens I set aperture based on creative factors (how much do I want in focus, do I want some motion blur shooting Av mode, etc.), not technical ones (what aperture gives me max sharpness, will I experience focus shift at this aperture, etc.). I'm perfectly happy with my 35L, 85L, and 135L--all similarly large-aperture lenses--and probably would've owned a 50L a long time ago if not for the focus shift. I knew it would be a problem for me so I avoided it. Others decided differently, and more power to them.
Personally, I like equipment to stay out of the way. If I have to think about what optimum apertures to use a lens with and avoid others because of technical concerns, I'd rather stay away and I have. I test a lens up front to see if its performance is up to snuff, and once I'm satisfied that it is when I use the lens I set aperture based on creative factors (how much do I want in focus, do I want some motion blur shooting Av mode, etc.), not technical ones (what aperture gives me max sharpness, will I experience focus shift at this aperture, etc.). I'm perfectly happy with my 35L, 85L, and 135L--all similarly large-aperture lenses--and probably would've owned a 50L a long time ago if not for the focus shift. I knew it would be a problem for me so I avoided it. Others decided differently, and more power to them.
Mar 18, 2009 at 12:59 PM