I have been trying to understand why I get so many fuzzy shots sometimes, and I have a question to pose to those with more experience than I.
Using a 500 and 1.4 on a 1DIV, I noticed that when I was shooting a subject that was motionless, while in AI Servo, I was more likely to get less than clear results. Occasionally I would get very good results but often when the subject was not moving I seemed to have erratic results. When I switched to One Shot on a motionless subject the results were usually better.
1. As a rule, should I be using One Shot on any subject that is not in motion, even a flying bird that alights?
2. Is it possible that using AI-Servo, the camera's algorithm is anticipating where it believes the subject will be, and therefore when viewed in DPP, the clear focus is not where the af point is? That is, in AI-Servo, when results are checked in DPP, even though the af point is exactly on the eye, the clear focus is often behind or in front of the af point because the camera adjusted for anticipated movement as the shutter was fired.
I hope I have explained this properly, and would very much appreciate some input from those who might know.
Frank, I have had better luck using oneshot on static subjects like you mentioned. That holds true for any of the Canon line I have used up to and including the mark4. Ron
PS set it up so your 500 will use the button near the front of the lens to switch from AI servo to oneshot when pressed and held.
The AI settings are trying to make guesses about the direction and speed of moving subjects - so there is no reason to use that mode for a static subject. I don't know whether or not doing so creates a problem or not, but there is no reason to use it. Of course, in your "flying bird" example you might like to use AI for the BIF and not have to switch out for the static bird...
Depending upon the size and placement of the subject in the frame (and on how much time you have to fiddle around before the subject departs) you might even want to try a single activated AF point to avoid having the AF pick up some element in the scene that is not in the same plane as you primary subject.
Dan
Frank Kearney wrote:
I have been trying to understand why I get so many fuzzy shots sometimes, and I have a question to pose to those with more experience than I.
Using a 500 and 1.4 on a 1DIV, I noticed that when I was shooting a subject that was motionless, while in AI Servo, I was more likely to get less than clear results. Occasionally I would get very good results but often when the subject was not moving I seemed to have erratic results. When I switched to One Shot on a motionless subject the results were usually better.
1. As a rule, should I be using One Shot on any subject that is not in motion, even a flying bird that alights?
2. Is it possible that using AI-Servo, the camera's algorithm is anticipating where it believes the subject will be, and therefore when viewed in DPP, the clear focus is not where the af point is? That is, in AI-Servo, when results are checked in DPP, even though the af point is exactly on the eye, the clear focus is often behind or in front of the af point because the camera adjusted for anticipated movement as the shutter was fired.
I hope I have explained this properly, and would very much appreciate some input from those who might know.
Unless you are motionless, there is no such thing is static subject if you shoot handheld & shallow dof. I always have AI servo with appropriately adjusting on board AF operating parameters to better accommodate unpredictable camera/subject movement. All these AF parameters can be programed w/ 1 series.
mttran wrote:
Unless you are motionless, there is no such thing is static subject if you shoot handheld & shallow dof. I always have AI servo with appropriately adjusting on board AF operating parameters to better accommodate unpredictable camera/subject movement. All these AF parameters can be programed w/ 1 series.
Yes, but that is not the type of motion that AI is designed to correct if I'm not mistaken.
gdanmitchell wrote:
Yes, but that is not the type of motion that AI is designed to correct if I'm not mistaken.
The camera doesn't know if you are moving or the subject, if you lean forward or backward after half-pressing the shutter, and the depth of field is shallow, the focus will be affected.
Many just leave AI Servo turned on. That is why it is also turned on in the full auto mode, its generally the best setting to use unless your camera is on a tripod, and taking scenery or something that really does not move.
scalesusa wrote:
The camera doesn't know if you are moving or the subject, if you lean forward or backward after half-pressing the shutter, and the depth of field is shallow, the focus will be affected.
Many just leave AI Servo turned on. That is why it is also turned on in the full auto mode, its generally the best setting to use unless your camera is on a tripod, and taking scenery or something that really does not move.
+1, I believe only 1 series offering the AI servo tracking sensitivity so user can fine tune for motion or static subject. This is why fast prime work better with 1 series AF. Hands, fingers and mind will be AF free to compose your subject.
scalesusa wrote:
The camera doesn't know if you are moving or the subject, if you lean forward or backward after half-pressing the shutter, and the depth of field is shallow, the focus will be affected.
Many just leave AI Servo turned on. That is why it is also turned on in the full auto mode, its generally the best setting to use unless your camera is on a tripod, and taking scenery or something that really does not move.
Unless I misunderstand how AI mode works, it is a "predictive" focusing system that attempts to apply some "intelligence" to predicting the future focus point of a moving subject. This would typically be something that is moving toward or possibly away from you at a more or less constant rate. In contrast to this, the slight forward/backward motion of a handheld camera is not going to be predictable in the same way as it will be a roughly random sort of motion.
Is there anyone who is more of an expert on this that either of us who would care to confirm or correct?
mttran wrote:
Unless you are motionless, there is no such thing is static subject if you shoot handheld & shallow dof. I always have AI servo with appropriately adjusting on board AF operating parameters to better accommodate unpredictable camera/subject movement. All these AF parameters can be programed w/ 1 series.
gdanmitchell wrote:
Yes, but that is not the type of motion that AI is designed to correct if I'm not mistaken.
scalesusa wrote:
The camera doesn't know if you are moving or the subject, if you lean forward or backward after half-pressing the shutter, and the depth of field is shallow, the focus will be affected.
Many just leave AI Servo turned on. That is why it is also turned on in the full auto mode, its generally the best setting to use unless your camera is on a tripod, and taking scenery or something that really does not move.
The problem with using AI Servo to focus on a static subject is not so much about whether or not the AF knows the difference between subject motion and camera motion, but rather, that by design, the AI Servo algorithm never actually locks focus. This can cause misfocus when the subject distance is not changing since the AF system may interpret change in phase in the selected AF point(s) as subject motion, and incorrectly anticipate the need to change focus when no such adjustment is actually necessary.
The fact that One Shot AF exists at all (as well as AI Focus AF) should tell you that there is a good reason to choose the appropriate mode for the appropriate shooting condition. Otherwise, Canon would simply have implemented a single AF mode and not cared to make the distinction.
I would say, both are in closed loop - one stop loop to be disabled after 1 or 2 passed, AI servo to be continously tracked until push/release of shutter button. I did test this with camera on tripod and my special LCD AF screen saver.
wickerprints wrote:
The problem with using AI Servo to focus on a static subject is not so much about whether or not the AF knows the difference between subject motion and camera motion, but rather, that by design, the AI Servo algorithm never actually locks focus. This can cause misfocus when the subject distance is not changing since the AF system may interpret change in phase in the selected AF point(s) as subject motion, and incorrectly anticipate the need to change focus when no such adjustment is actually necessary.
The fact that One Shot AF exists at all (as well as AI Focus AF) should tell you that there is a good reason to choose the appropriate mode for the appropriate shooting condition. Otherwise, Canon would simply have implemented a single AF mode and not cared to make the distinction....Show more →
The problem arises when the subject is not necessarily in predictable motion (like a runner coming towards you), but isn't stationary, either. Say you're photographing someone on stage, who is walking around a bit, or leaning forward while speaking or playing an instrument. If you use one-shot, and lock focus, your subject might move before you trigger the shutter. The question is, how well does AI Servo "settle down" if your subject stops moving? Clearly we can't be switching back and forth between servo and one-shot every few seconds. This is similar to the OP question about photographing a bird in flight (obviously a servo situation), but the bird then alights in a tree for a few seconds.
Jim Levitt wrote:
The question is, how well does AI Servo "settle down" if your subject stops moving?
This is a $4K question between 1 series and other model. Second dedicated CPU/Power/support ICs/etc.. and number line of AF code (RAM) does cost that much. This is why we don't have a high hope for 5D3. cos 5d series are their best defense / offense cam in the current dslr market in term of $
I don't beleive what I am reading with these responses to the most basic of questions. You people make things so much more complicated than things need be, thenyou'll post questions on front focus back focus side focus because you don't understand how a focus method works. Knowing how to choose a focus method is photography skill 1
One shot is for still subjects
Ai Servo is for moving subjects.
period
No debate no negotiation no exceptions.
Go read the manual then re read and then read it again.
It is not that hard to understand.
i seriously can't beleive someone who buys 10 grand worth of gear hasn't taken the time to read the manual as if you had of you would know what focus method works in what way.
darryn patch wrote:
I don't beleive what I am reading with these responses to the most basic of questions. You people make things so much more complicated than things need be, thenyou'll post questions on front focus back focus side focus because you don't understand how a focus method works. Knowing how to choose a focus method is photography skill 1
One shot is for still subjects
Ai Servo is for moving subjects.
period
No debate no negotiation no exceptions.
Go read the manual then re read and then read it again.
It is not that hard to understand.
i seriously can't beleive someone who buys 10 grand worth of gear hasn't taken the time to read the manual as if you had of you would know what focus method works in what way.
Stop shaking your snarky head and answer the question that lots of real people, photographing in the real world, face on a regular basis: what do you do with a subject, like the bird in the example of the original poster, that is sometimes moving, sometimes still? If you're photographing a potted plant, OF COURSE you will use one shot. If you're photographing a track race, odds are you'll use servo. There's a whole lot of ground in between.
Or do you see the world in high contrast black and white?
OK if I am shooting a BIF or any other subject prone to movenment then stationary, I'll switch between1 shot and Ai, can be done in a split second, Just hold down the AF button scroll the dial near the shutter button and wholla you've swapped to the most appropriate mode of AF for that situation. No Grey areas. If you shoot that bird in AI then it rests Ai will fail as it is not moving. You need to know what shot your after to determine what AF mode you need.
To me photography is black and white, Its all the grey areas people throw in because they lack the skills to read a manual or understand a manual that creates grey areas then they post on a world wide forum their uniformed and quite often wrong opinions so then others follow the wrong path and we end up with hundreds of people who complain about unsharp lenses front focus back focus is my lens sharp is my sensor crooked etc. It aint that difficult.
Once again I say read the **** manual.
Here is my understanding, and I have been shooting high end bodies for 20 years shooting weddings motor sports football surfing cricket you name it I've shot most sports professionally.
AI servo is designed to predict movement and is calculated on the motion sensed prior to exposure to adjust the AF to be where the camera predicts the subject will be upon shutter opening. That is the camera is assuming where the subject will be based on prior motion.
So that being the case, how does Ai work if the subject is still, a picture on a wall a building or heaven forbid a bird that has decided to take 5 on a branch for example, If it aint moving Ai sevo will give less than satisfactory results as the subject IS NOT MOVING.
A stationary subject will need to be shot in 1 shot mode as focus is acheived and LOCKED on that point and will not change, if the subject, a bird on a branch for example moves an inch or 2 refocusing will need to be done before you take the shot.
That is about as simple as I can make it.
Give it a try you might just see that what I am saying just may be correct.
Many words to explain a "black and white" concept.
darryn patch wrote:
OK if I am shooting a BIF or any other subject prone to movenment then stationary, I'll switch between1 shot and Ai, can be done in a split second, Just hold down the AF button scroll the dial near the shutter button and wholla you've swapped to the most appropriate mode of AF for that situation. No Grey areas. If you shoot that bird in AI then it rests Ai will fail as it is not moving. You need to know what shot your after to determine what AF mode you need.
To me photography is black and white, Its all the grey areas people throw in because they lack the skills to read a manual or understand a manual that creates grey areas then they post on a world wide forum their uniformed and quite often wrong opinions so then others follow the wrong path and we end up with hundreds of people who complain about unsharp lenses front focus back focus is my lens sharp is my sensor crooked etc. It aint that difficult.
Once again I say read the **** manual.
Here is my understanding, and I have been shooting high end bodies for 20 years shooting weddings motor sports football surfing cricket you name it I've shot most sports professionally.
AI servo is designed to predict movement and is calculated on the motion sensed prior to exposure to adjust the AF to be where the camera predicts the subject will be upon shutter opening. That is the camera is assuming where the subject will be based on prior motion.
So that being the case, how does Ai work if the subject is still, a picture on a wall a building or heaven forbid a bird that has decided to take 5 on a branch for example, If it aint moving Ai sevo will give less than satisfactory results as the subject IS NOT MOVING.
A stationary subject will need to be shot in 1 shot mode as focus is acheived and LOCKED on that point and will not change, if the subject, a bird on a branch for example moves an inch or 2 refocusing will need to be done before you take the shot.
That is about as simple as I can make it.
Give it a try you might just see that what I am saying just may be correct....Show more →
