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Anyone having trouble focusing?
May 23, 2013 08:29:50 #
It may pay to turn off your image stabilisation:
Concerning VR/IS (According to Thom Hogan)
1. The first and most important rule of VR/IS is this: never turn VR/IS on unless it's actually needed.
YES, THIS RULE FLIES IN THE FACE OF WHAT MOST EVERYONE IN THE WORLD SEEMS TO DO AND WHAT NIKON IMPLIES WITH THEIR ADVERTISING AND MARKETING. THE SIMPLE FACT IS THAT VR/IS IS A SOLUTION TO A PROBLEM, AND IF YOU DON'T HAVE THAT PROBLEM USING VR/IS CAN BECOME A PROBLEM OF ITS OWN.
To understand that, you have to understand how VR/IS works. In the Nikon system, VR is essentially a element group in the lens that is moved to compensate for any detected camera motion. Because this element group is usually deep in the middle of the lens, usually near the aperture opening but not exactly at the opening, you have to think about what is happening to the optical path when VR is active. Are there times when it shifts where it imparts a change to the image quality other than pure stabilization? I believe there are, though the impact is visually subtle. Some of the mid-range distance bokeh of certain VR/IS lenses appears to be impacted by VR being on. Put another way, the background in the scene is slightly moving differently than the focus point in the optical path. This results in what I call "busy bokeh," or bokeh that doesn't have that simple shape and regularity we expect out of the highest quality glass.
Most people using VR/IS don't question the mechanics of the system. They simply believe it's some special form of magic. It's not. Physics are involved, not magic. And one of the physics issues is the sampling frequency. The sampling frequency of the motion detection mechanism determines what kind and how much movement can be removed. Care to guess what the sampling frequency might be? 1000Hz according to Nikon. That sounds pretty good, doesn't it? Nope. 1000Hz is 1/1000 of a second. Nyquist tells us that we can only really resolve data accurately below half the sampling frequency, thus it can accurately only take out movements as small as 500Hz (1/500 second). While this sampling frequency is of the camera motion, it is not completely uncorrelated with shutter speed. For example, the shutter curtains only travel across the sensor at speeds above 1/250, exposing only a portion of the image at a time. Another aspect of the VR system is that it "recenters" the moving element(s) just prior to the shutter opening. Simply put, there's a lot that has to be right at very short shutter speeds in order for there not to be a small visual impact, especially with long lenses.
BUT THAT'S NOT ALL: WHEN YOU HAVE VR/IS TURNED ON, YOUR COMPOSITION ISN'T GOING TO BE EXACTLY WHAT YOU FRAMED. YES, THE VIEWFINDER SHOWS THE VR/IS IMPACT, BUT NIKON'S VR SYSTEM RE-CENTERS THE VR ELEMENTS JUST PRIOR TO THE SHUTTER OPENING. THIS MEANS THAT YOU CAN GET SLIGHTLY DIFFERENT FRAMING THAN YOU SAW.
2. VR/IS SHOULD NORMALLY BE OFF IF YOUR SHUTTER SPEED IS OVER 1/500.
Indeed, if you go down to the sidelines of a football game and check all those photographers to see how their lens is set, you can tell the ones that are really pros: VR is usually off (unless they're on a portion of the stadium that is vibrating from fan action). Those pros have all encountered the same thing you will some day: if you have a shutter speed faster than the sampling frequency, sometimes the system is running a correction that's not in sync with the shutter speed. The results look a bit like the lens being run with the wrong AF Fine Tune: slightly off.
THE INTERESTING THING IS THAT PROS DEMANDED VR (IS IN THE CASE OF CANON) IN THE LONG LENSES, THEN IT TURNS OUT THAT THEY VERY RARELY USE IT! I'D SAY THAT LESS THAN 10% OF THE SHOOTING I DO WITH MY 400MM F/2.8 HAS VR TURNED ON (AND BY THE WAY, I HATE THE ROTATING VR SWITCH ON SOME OF THESE LENSES--IT'S SO EASY TO NOT NOTICE WHAT POSITION IT IS IN). A WORD OF ADVICE: SOME OF THOSE PREVIOUS GENERATION NON-VR EXOTICS ARE RELATIVE BARGAINS NOW. CONSIDER IT THE VR BUBBLE. SOME DAY PEOPLE WILL STOP PAYING SUCH SILLY PREMIUMS FOR VR OVER NON-VR. AT LEAST THEY SHOULD. I KNOW OF SEVERAL PHOTOGRAPHERS WHO BLEW US$3000+ MAKING THE SWITCH FROM NON-VR TO VR VERSIONS OF LENSES. THAT'S TOO MUCH OF A PREMIUM, I THINK.
ANECDOTAL EVIDENCE CONTINUES TO PILE UP ABOUT VR AND HIGH SHUTTER SPEEDS. IN HUNDREDS OF CASES I'VE EXAMINED NOW THE RESULTS ARE THE SAME: THE LENS SEEMS TO HAVE MORE ACUITY WITH VR OFF ABOVE 1/500. THAT'S MY OWN EXPERIENCE, AS WELL. A SMALL HANDFUL OF PEOPLE HAVE PRESENTED WITH ME WITH EVIDENCE OF THE OPPOSITE (VR IMPROVES THEIR RESULTS ABOVE 1/500). IN MOST OF THOSE CASES I'VE BEEN ABLE TO FIND THAT IT'S NOT VR ITSELF THAT'S HELPING REMOVE CAMERA MOTION, BUT THAT THEIR HANDHOLDING OR TRIPOD TECHNIQUE IS SUCH THAT THEY'RE NOT GETTING CONSISTENT AUTOFOCUS WITHOUT VR, BUT THEY ARE WITH IT. MY CONTENTION IS THAT THEY'D SEE EVEN MORE IMPROVEMENT BY DEALING WITH THE HANDLING AND FOCUS CONSISTENCY ISSUE AND TURNING VR BACK OFF ABOVE 1/500
However, as with virtually everything in photography, there's a caveat to the above. For instance, what if you're sitting in a helicopter shooting at 1/1000, should you use VR/IS? One of the things that Nikon just doesn't explain well enough is the concept of "moving camera" versus "camera on moving platform." If the source of motion is your holding the camera steady, then what I wrote above about turning VR off above 1/500 is absolutely true. Ditto for semi-steady situations, such as shooting off a monopod. However, if there's a platform underneath you causing vibrations (car, boat, train, plane, helicopter, etc.), things are a bit different. This is what Active VR versus Normal VR is all about, by the way. Active VR/IS should be used when you're on one of those moving platforms. Normal VR/IS should be used when you're on solid ground and it's just you that's shaking. Basically, if you're vibrating due to outside source, Active VR/IS should be On. If you're the only source of camera movement, then use Normal.
3.IF SOMETHING IS MOVING YOU, USE ACTIVE. IF IT'S JUST YOU MOVING THE CAMERA, USE NORMAL.
4, If your subject is moving, you still need a shutter speed that will stop that movement.
THIS IS A TOUGH THING TO LEARN, AND IT'S USUALLY LEARNED THE HARD WAY. BECAUSE CAMERA MAKERS ESSENTIALLY TOUT VR/IS BY MAKING ASSERTIONS LIKE "ALLOWS A FOUR-STOP IMPROVEMENT OVER HAND HOLDING," USERS START THINKING LIKE THIS: "IF I CAN HANDHOLD MY 100MM LENS AT 1/100, THEN VR/IS WOULD ALLOW ME TO HAND HOLD IT AT 1/6." WELL, MAYBE. BUT THE ONLY MOTION BEING REMOVED IS CAMERA MOTION. IF YOUR SUBJECT MOVES DURING THAT 1/6, IT'S STILL GOING TO PRODUCE SUBJECT BLUR. LOOKING BACK AT MY NIKON FIELD GUIDE (PAGE 51 FOR THOSE OF YOU FOLLOWING ALONG), WE GET 1/125 FOR THE MINIMUM SHUTTER SPEED NECESSARY TO FREEZE A PERSON WALKING ACROSS THE FRAME (1/30 IF THEY'RE WALKING TOWARDS YOU). THIS IS, OF COURSE, A GENERALIZATION. THERE'S A MORE DETAILED TABLE BELOW THE ONE I JUST REFERENCED THAT SHOWS HOW DISTANCE IMPACTS THE SHUTTER SPEED, TOO. PLUS THE SIZE OF THE SUBJECT IN THE OVERALL FRAME MAKES A DIFFERENCE. EXPECTING VR/IS TO REMOVE ALL MOTION IS SOMETHING EVERYONE HAS TO GET OVER:
5, VR doesn't remove all motion, it only removes camera motion.
ANOTHER TYPE OF MOTION COMES WITH PANNING THE CAMERA, AND VR/IS HAS IMPACTS THERE, TOO. I'VE SEEN PEOPLE SAY THAT THEY THINK YOU SHOULD TURN VR/IS OFF WHEN YOU PAN WITH A SUBJECT. THERE MAY BE TIMES WHEN THAT'S TRUE, BUT MY EXPERIENCE IS THAT VR SHOULD BE ON WHILE PANNING. THAT'S BECAUSE THE NIKON VR SYSTEM IS VERY GOOD ABOUT DETECTING A CONSTANT CAMERA MOVEMENT. IF YOU'RE DOING A SMOOTH PAN IN ONE DIRECTION, THE VR/IS SYSTEM WILL FOCUS ON REMOVING ONLY MOTION ON THE OPPOSITE AXIS. THAT'S THE WAY IT'S DESIGNED TO OPERATE. THE TRICK IS TO MAKE SURE THAT YOUR PAN IS RELATIVELY SMOOTH, AND NOT JERKY. MOST PEOPLE START TO JERK WHEN THEY PRESS THE SHUTTER RELEASE DURING PANS. YOU NEED TO PRACTICE NOT DOING THAT AND TO CONTINUE THE PAN WHILE THE SHUTTER IS OPEN, NOT STOPPING. INDEED, TRY PRACTICING THIS AT YOUR LOCAL TRACK (OR OTHER PLACE WITH SOME RUNNERS PRESENT). PAN WITH THE RUNNER AND TAKE A PICTURE. WHEN THE MIRROR RETURNED AND THE VIEWFINDER VIEW IS RESTORED AFTER THE SHOT IS THE RUNNER STILL IN THE SAME SPOT IN THE FRAME? NO? THEN YOU DIDN'T CONTINUE PANNING THROUGH THE SHOT. TSK TSK. TRY AGAIN. PRACTICE UNTIL YOU CAN TAKE A SERIES OF SHOTS AND THE RUNNER STAYS IN THE SAME SPOT THROUGH THE ENTIRE SEQUENCE, BOTH IN THE SHOTS AND WHILE YOU'RE PANNING BETWEEN SHOTS. YOU SHOULDN'T BE HAVING TO CATCH UP TO THE RUNNER.
ASIDE: BACK IN HIGH SCHOOL MY PHOTOGRAPHY MENTOR AT THE TIME BROKE ME OF THE HABIT OF STOPPING DURING PANS IN A BRUTALLY SADISTIC WAY: HE SENT ME TO TRACK MEETS WITH A TLR (TWIN LENS REFLEX). YOU LOOK DOWN INTO THE VIEWFINDER OF A TLR. BUT HERE'S THE THING: LEFT TO RIGHT IS REVERSED. SO IF THE SUBJECT IS MOVING RIGHT TO LEFT IN FRONT OF YOU, THEY APPEAR LEFT TO RIGHT IN THE VIEWFINDER. YOU DON'T HAVE A CHANCE OF FOLLOWING MOTION WITH A TLR UNLESS YOU CAN RELAX YOUR BRAIN AND MAKE IT JUST MIMIC THE MOTION OF YOUR SUBJECT IN YOUR OWN BODY'S MOTION. YOU CAN'T LOOK AND REACT, LOOK AND REACT.
6. IF YOU'RE IF YOU'RE PANNING CORRECTLY, VR/IS SHOULD PROBABLY BE ON.
Yet another aspect of VR/IS that confuses people is activation. Nikon's manuals don't make this very clear, but it really is quite simple: only the shutter release activates the VR system. A partial press of the shutter release engages it and allows it to begin a sequence of corrections. A quick full press of the shutter release engages it but it really doesn't get much in the way of samples to rely upon and make predictions from (on the pro bodies we're talking 1/33 of a second or so between the press and the shot being taken). Basically, if you engage VR/IS prior to the shot, you tend to get slightly better and more consistent results. That doesn't mean you should always wait for VR/IS to engage before fully pressing the shutter release. If it's time to take the picture, take the picture! VR/IS will give it its best shot at fixing your motion when you just punch the shutter release. But there are two factors that tend to make early VR engagement a better choice if you can do it: first, the VR/IS system gets a stream of data it can predict from; and second, it's difficult to move the camera as much by jabbing the release if you've already partially pressed the release!
The usual issue that comes up with the preceding is the line in Nikon's manual about "VR doesn't function when the AF-ON button is pressed." This is one of those places where the translation in Nikon's manuals is out and out misleading. If the line had read "VR doesn't engage when the AF-ON button is pressed" it would be more correct. In my testing VR is not "turned off" by using the AF-ON button, it simply isn't engaged by that button press. Only the shutter release button engages VR. Thus, if you use AF-ON to focus instead of a partial shutter release, VR is not engaged during the pre-shot focusing. But it is during the shot.
This, of course, creates a slight issue. Optimally, we want VR/IS to have a stream of data just prior to pressing the shutter release fully. If we're using AF-ON to focus, our fingers usually aren't pushing the shutter release partially down, too. But you should practice doing just that. Sigh. That right hand is starting to do a pretty complicated dance: AF-ON up and down for focus, shutter release partially down for VR/IS, right thumb dialing in shutter or aperture or exposure adjustments, maybe right middle finger dialing in aperture adjustments, shutter release fully down with the index finger for the shot. This, by the way, is one of the reasons why I prefer Nikon's ergonomics to Canon's: at least when I'm doing all that hand juggling, my hand and finger positions aren't really moving, especially my shutter release finger. With Canon the tendency is to move the index finger between the top control wheel and shutter release. You can react with the shutter release faster if you're not moving that finger.
There are a few more caveats. If you've got a built-in flash on your camera (basically everything but the D1, D2, and D3 series), while the flash is recharging the VR system is inactive. That's because VR/IS takes power to perform and the assumption is that you want the flash recharged as fast as possible. Thus, the camera turns off the power to the VR system while it's charging up the camera's flash capacitor. If you're shooting flash near full power and doing a lot of consecutive flashes, the flash recharge time can start taking a few seconds. How do you know if power is restored to the VR/IS system? Well, you can't, exactly, but the flash indicator in the viewfinder is a fairly reliable indicator: if it's not present with the flash up and active, VR/IS is probably Off.
7: If you rely upon VR/IS and use flash, use an external flash instead of the internal one if you can.
I'VE BEEN HOLDING OFF ON THE TRIPOD ISSUE TO THE END OF THIS ARTICLE, PARTLY BECAUSE IT'S NOT AS CLEAR CUT AS NIKON SEEMS TO THINK IT IS. BUT BY NOW YOU'VE PROBABLY TURNED VR OFF, ANYWAY ;~). PART OF THE PROBLEM IS THAT NIKON HASN'T CLEARLY LABELED AND DISTINGUISHED THEIR VARIOUS VR/IS SYSTEM ITERATIONS. TECHNICALLY, THE VR II SYSTEM ON SOME OF THE MODERN LENSES SHOULD DETECT WHEN THE CAMERA IS ON A STABLE PLATFORM AND NOT TRY TO JUMP IN AND CORRECT. BUT NOT ALL MODERN LENSES HAVE WHAT MOST OF US REGARD AS THE FULL VR II. THE RECENTLY INTRODUCED 16-35MM, FOR EXAMPLE, COMES LONG AFTER THE INTRO OF VR II, BUT IT DOES NOT APPEAR TO HAVE TRIPOD RECOGNITION. THUS, WE HAVE ANOTHER RULE BEFORE WE GET TO THE REAL RULE:
8. YOU MUST READ YOUR LENS MANUAL AND SEE WHAT IT SAYS ABOUT USE ON TRIPODS.
Two basic possibilities exist:
1. The manual says turn VR/IS off when on a tripod (sometimes adding "unless the head is unsecured")
2. The manual specifically says that the VR/IS system detects when the camera is on a tripod
Okay, I lied. Forget what the manual says.
Rule #8 For Real: If your camera is on a tripod, even if you're using something like a Wimberley head where it is almost always loose, turn VR off. If your tripod is on a moving platform or one that has vibrations in it, strongly consider turning VR on, but test it to be sure you need it.
So why do I disagree with Nikon? Even with a loose head on a tripod, motion should be fairly easy to control, and you should have removed one possible motion almost completely (ditto with monopods). The problem I have, and which many other pros have noticed, is that the VR/IS tripod detection system sometimes has "false negatives." In other words, the tripod detection mode of the VR II system should be detecting when the system is "quiet enough" to turn off corrections. Most of the time it does just that (Nikon says that the system is smart enough to detect as many as three different types of motion--handholding, platform vibration, and support system movement--because the "vibrations" caused by each of these are recognizable different in wave form). Every now and then, though, VR/IS thinks it needs to correct when it doesn't (or perhaps is still correcting for a previously detected motion that will no longer be present in the next sampling). When that happens, the VR/IS element(s) are moving when they shouldn't be. Usually not a lot, but enough to make for less than optimal results.
Indeed, this is the very same problem as with using VR/IS over 1/500: sometimes it works, sometimes is doesn't. The problem is that you won't like it when it doesn't, and you won't know when it does. If I were to tell you that out of 100 shots you take 10 were going to be bad due to the VR/IS doing the wrong thing, would you still use VR? Remember, when you're on a tripod, all 100 shots should be good without VR (otherwise you have the wrong tripod and head, or you're using poor technique). I'm not a gambler: I prefer the known to the unknown, so I don't like having random shots spoiled by VR/IS.
Which brings up a whole different topic: what does a spoiled-by-VR/IS shot look like? Well, "spoiled" is perhaps too harsh a term. Sub-optimal is probably a better one. An optimal shot has very clean and well defined edge acuity. Assuming a "perfect lens," edges should be recorded basically as good as the anti-aliasing filter, sensor, and Bayer demosaic allow. What a lot of us find when VR/IS is not quite correcting as well as it can/should is that edges get a little bit of "growth" to them, and sometimes there's a directionality to that growth. It's sort of like camera movement, only much more subtle. I tend to say that the detail "looks busy" when VR/IS isn't fully doing its job or is on when it shouldn't be. And when you apply sharpening to busy edges, that busy-ness gets busy-er. Without VR/IS active at all while on a stable tripod, it's like a veil gets lifted and you suddenly see how sharp your lens really is (assuming you correctly obtained focus on your subject and had a stable platform, that is ;~).
Yes, there's some nitpicking going on here. V/IS not correcting right is a bit like tripod mount slop (fixed with a Really Right Stuff Long Lens Support) or ringing vibrations in the tripod legs (fixed by using the right legs for your equipment): you don't see it until it's gone, and even then usually only if you're pixel peeping. But someone using a 400mm f/2.8G VR/IS lens on a D3x spent a lot of money on equipment to get the best results. They expect to be able to catch every bit of detail and blow it up into a large print. As always on this site, you need to understand that I always write about the search for optimal bits. If you're shooting with a 16-85mm on a D300 and putting 640x480 images on the Web from that, well, whether the VR/IS missed doing its job by a little bit probably isn't so important.
Concerning VR/IS (According to Thom Hogan)
1. The first and most important rule of VR/IS is this: never turn VR/IS on unless it's actually needed.
YES, THIS RULE FLIES IN THE FACE OF WHAT MOST EVERYONE IN THE WORLD SEEMS TO DO AND WHAT NIKON IMPLIES WITH THEIR ADVERTISING AND MARKETING. THE SIMPLE FACT IS THAT VR/IS IS A SOLUTION TO A PROBLEM, AND IF YOU DON'T HAVE THAT PROBLEM USING VR/IS CAN BECOME A PROBLEM OF ITS OWN.
To understand that, you have to understand how VR/IS works. In the Nikon system, VR is essentially a element group in the lens that is moved to compensate for any detected camera motion. Because this element group is usually deep in the middle of the lens, usually near the aperture opening but not exactly at the opening, you have to think about what is happening to the optical path when VR is active. Are there times when it shifts where it imparts a change to the image quality other than pure stabilization? I believe there are, though the impact is visually subtle. Some of the mid-range distance bokeh of certain VR/IS lenses appears to be impacted by VR being on. Put another way, the background in the scene is slightly moving differently than the focus point in the optical path. This results in what I call "busy bokeh," or bokeh that doesn't have that simple shape and regularity we expect out of the highest quality glass.
Most people using VR/IS don't question the mechanics of the system. They simply believe it's some special form of magic. It's not. Physics are involved, not magic. And one of the physics issues is the sampling frequency. The sampling frequency of the motion detection mechanism determines what kind and how much movement can be removed. Care to guess what the sampling frequency might be? 1000Hz according to Nikon. That sounds pretty good, doesn't it? Nope. 1000Hz is 1/1000 of a second. Nyquist tells us that we can only really resolve data accurately below half the sampling frequency, thus it can accurately only take out movements as small as 500Hz (1/500 second). While this sampling frequency is of the camera motion, it is not completely uncorrelated with shutter speed. For example, the shutter curtains only travel across the sensor at speeds above 1/250, exposing only a portion of the image at a time. Another aspect of the VR system is that it "recenters" the moving element(s) just prior to the shutter opening. Simply put, there's a lot that has to be right at very short shutter speeds in order for there not to be a small visual impact, especially with long lenses.
BUT THAT'S NOT ALL: WHEN YOU HAVE VR/IS TURNED ON, YOUR COMPOSITION ISN'T GOING TO BE EXACTLY WHAT YOU FRAMED. YES, THE VIEWFINDER SHOWS THE VR/IS IMPACT, BUT NIKON'S VR SYSTEM RE-CENTERS THE VR ELEMENTS JUST PRIOR TO THE SHUTTER OPENING. THIS MEANS THAT YOU CAN GET SLIGHTLY DIFFERENT FRAMING THAN YOU SAW.
2. VR/IS SHOULD NORMALLY BE OFF IF YOUR SHUTTER SPEED IS OVER 1/500.
Indeed, if you go down to the sidelines of a football game and check all those photographers to see how their lens is set, you can tell the ones that are really pros: VR is usually off (unless they're on a portion of the stadium that is vibrating from fan action). Those pros have all encountered the same thing you will some day: if you have a shutter speed faster than the sampling frequency, sometimes the system is running a correction that's not in sync with the shutter speed. The results look a bit like the lens being run with the wrong AF Fine Tune: slightly off.
THE INTERESTING THING IS THAT PROS DEMANDED VR (IS IN THE CASE OF CANON) IN THE LONG LENSES, THEN IT TURNS OUT THAT THEY VERY RARELY USE IT! I'D SAY THAT LESS THAN 10% OF THE SHOOTING I DO WITH MY 400MM F/2.8 HAS VR TURNED ON (AND BY THE WAY, I HATE THE ROTATING VR SWITCH ON SOME OF THESE LENSES--IT'S SO EASY TO NOT NOTICE WHAT POSITION IT IS IN). A WORD OF ADVICE: SOME OF THOSE PREVIOUS GENERATION NON-VR EXOTICS ARE RELATIVE BARGAINS NOW. CONSIDER IT THE VR BUBBLE. SOME DAY PEOPLE WILL STOP PAYING SUCH SILLY PREMIUMS FOR VR OVER NON-VR. AT LEAST THEY SHOULD. I KNOW OF SEVERAL PHOTOGRAPHERS WHO BLEW US$3000+ MAKING THE SWITCH FROM NON-VR TO VR VERSIONS OF LENSES. THAT'S TOO MUCH OF A PREMIUM, I THINK.
ANECDOTAL EVIDENCE CONTINUES TO PILE UP ABOUT VR AND HIGH SHUTTER SPEEDS. IN HUNDREDS OF CASES I'VE EXAMINED NOW THE RESULTS ARE THE SAME: THE LENS SEEMS TO HAVE MORE ACUITY WITH VR OFF ABOVE 1/500. THAT'S MY OWN EXPERIENCE, AS WELL. A SMALL HANDFUL OF PEOPLE HAVE PRESENTED WITH ME WITH EVIDENCE OF THE OPPOSITE (VR IMPROVES THEIR RESULTS ABOVE 1/500). IN MOST OF THOSE CASES I'VE BEEN ABLE TO FIND THAT IT'S NOT VR ITSELF THAT'S HELPING REMOVE CAMERA MOTION, BUT THAT THEIR HANDHOLDING OR TRIPOD TECHNIQUE IS SUCH THAT THEY'RE NOT GETTING CONSISTENT AUTOFOCUS WITHOUT VR, BUT THEY ARE WITH IT. MY CONTENTION IS THAT THEY'D SEE EVEN MORE IMPROVEMENT BY DEALING WITH THE HANDLING AND FOCUS CONSISTENCY ISSUE AND TURNING VR BACK OFF ABOVE 1/500
However, as with virtually everything in photography, there's a caveat to the above. For instance, what if you're sitting in a helicopter shooting at 1/1000, should you use VR/IS? One of the things that Nikon just doesn't explain well enough is the concept of "moving camera" versus "camera on moving platform." If the source of motion is your holding the camera steady, then what I wrote above about turning VR off above 1/500 is absolutely true. Ditto for semi-steady situations, such as shooting off a monopod. However, if there's a platform underneath you causing vibrations (car, boat, train, plane, helicopter, etc.), things are a bit different. This is what Active VR versus Normal VR is all about, by the way. Active VR/IS should be used when you're on one of those moving platforms. Normal VR/IS should be used when you're on solid ground and it's just you that's shaking. Basically, if you're vibrating due to outside source, Active VR/IS should be On. If you're the only source of camera movement, then use Normal.
3.IF SOMETHING IS MOVING YOU, USE ACTIVE. IF IT'S JUST YOU MOVING THE CAMERA, USE NORMAL.
4, If your subject is moving, you still need a shutter speed that will stop that movement.
THIS IS A TOUGH THING TO LEARN, AND IT'S USUALLY LEARNED THE HARD WAY. BECAUSE CAMERA MAKERS ESSENTIALLY TOUT VR/IS BY MAKING ASSERTIONS LIKE "ALLOWS A FOUR-STOP IMPROVEMENT OVER HAND HOLDING," USERS START THINKING LIKE THIS: "IF I CAN HANDHOLD MY 100MM LENS AT 1/100, THEN VR/IS WOULD ALLOW ME TO HAND HOLD IT AT 1/6." WELL, MAYBE. BUT THE ONLY MOTION BEING REMOVED IS CAMERA MOTION. IF YOUR SUBJECT MOVES DURING THAT 1/6, IT'S STILL GOING TO PRODUCE SUBJECT BLUR. LOOKING BACK AT MY NIKON FIELD GUIDE (PAGE 51 FOR THOSE OF YOU FOLLOWING ALONG), WE GET 1/125 FOR THE MINIMUM SHUTTER SPEED NECESSARY TO FREEZE A PERSON WALKING ACROSS THE FRAME (1/30 IF THEY'RE WALKING TOWARDS YOU). THIS IS, OF COURSE, A GENERALIZATION. THERE'S A MORE DETAILED TABLE BELOW THE ONE I JUST REFERENCED THAT SHOWS HOW DISTANCE IMPACTS THE SHUTTER SPEED, TOO. PLUS THE SIZE OF THE SUBJECT IN THE OVERALL FRAME MAKES A DIFFERENCE. EXPECTING VR/IS TO REMOVE ALL MOTION IS SOMETHING EVERYONE HAS TO GET OVER:
5, VR doesn't remove all motion, it only removes camera motion.
ANOTHER TYPE OF MOTION COMES WITH PANNING THE CAMERA, AND VR/IS HAS IMPACTS THERE, TOO. I'VE SEEN PEOPLE SAY THAT THEY THINK YOU SHOULD TURN VR/IS OFF WHEN YOU PAN WITH A SUBJECT. THERE MAY BE TIMES WHEN THAT'S TRUE, BUT MY EXPERIENCE IS THAT VR SHOULD BE ON WHILE PANNING. THAT'S BECAUSE THE NIKON VR SYSTEM IS VERY GOOD ABOUT DETECTING A CONSTANT CAMERA MOVEMENT. IF YOU'RE DOING A SMOOTH PAN IN ONE DIRECTION, THE VR/IS SYSTEM WILL FOCUS ON REMOVING ONLY MOTION ON THE OPPOSITE AXIS. THAT'S THE WAY IT'S DESIGNED TO OPERATE. THE TRICK IS TO MAKE SURE THAT YOUR PAN IS RELATIVELY SMOOTH, AND NOT JERKY. MOST PEOPLE START TO JERK WHEN THEY PRESS THE SHUTTER RELEASE DURING PANS. YOU NEED TO PRACTICE NOT DOING THAT AND TO CONTINUE THE PAN WHILE THE SHUTTER IS OPEN, NOT STOPPING. INDEED, TRY PRACTICING THIS AT YOUR LOCAL TRACK (OR OTHER PLACE WITH SOME RUNNERS PRESENT). PAN WITH THE RUNNER AND TAKE A PICTURE. WHEN THE MIRROR RETURNED AND THE VIEWFINDER VIEW IS RESTORED AFTER THE SHOT IS THE RUNNER STILL IN THE SAME SPOT IN THE FRAME? NO? THEN YOU DIDN'T CONTINUE PANNING THROUGH THE SHOT. TSK TSK. TRY AGAIN. PRACTICE UNTIL YOU CAN TAKE A SERIES OF SHOTS AND THE RUNNER STAYS IN THE SAME SPOT THROUGH THE ENTIRE SEQUENCE, BOTH IN THE SHOTS AND WHILE YOU'RE PANNING BETWEEN SHOTS. YOU SHOULDN'T BE HAVING TO CATCH UP TO THE RUNNER.
ASIDE: BACK IN HIGH SCHOOL MY PHOTOGRAPHY MENTOR AT THE TIME BROKE ME OF THE HABIT OF STOPPING DURING PANS IN A BRUTALLY SADISTIC WAY: HE SENT ME TO TRACK MEETS WITH A TLR (TWIN LENS REFLEX). YOU LOOK DOWN INTO THE VIEWFINDER OF A TLR. BUT HERE'S THE THING: LEFT TO RIGHT IS REVERSED. SO IF THE SUBJECT IS MOVING RIGHT TO LEFT IN FRONT OF YOU, THEY APPEAR LEFT TO RIGHT IN THE VIEWFINDER. YOU DON'T HAVE A CHANCE OF FOLLOWING MOTION WITH A TLR UNLESS YOU CAN RELAX YOUR BRAIN AND MAKE IT JUST MIMIC THE MOTION OF YOUR SUBJECT IN YOUR OWN BODY'S MOTION. YOU CAN'T LOOK AND REACT, LOOK AND REACT.
6. IF YOU'RE IF YOU'RE PANNING CORRECTLY, VR/IS SHOULD PROBABLY BE ON.
Yet another aspect of VR/IS that confuses people is activation. Nikon's manuals don't make this very clear, but it really is quite simple: only the shutter release activates the VR system. A partial press of the shutter release engages it and allows it to begin a sequence of corrections. A quick full press of the shutter release engages it but it really doesn't get much in the way of samples to rely upon and make predictions from (on the pro bodies we're talking 1/33 of a second or so between the press and the shot being taken). Basically, if you engage VR/IS prior to the shot, you tend to get slightly better and more consistent results. That doesn't mean you should always wait for VR/IS to engage before fully pressing the shutter release. If it's time to take the picture, take the picture! VR/IS will give it its best shot at fixing your motion when you just punch the shutter release. But there are two factors that tend to make early VR engagement a better choice if you can do it: first, the VR/IS system gets a stream of data it can predict from; and second, it's difficult to move the camera as much by jabbing the release if you've already partially pressed the release!
The usual issue that comes up with the preceding is the line in Nikon's manual about "VR doesn't function when the AF-ON button is pressed." This is one of those places where the translation in Nikon's manuals is out and out misleading. If the line had read "VR doesn't engage when the AF-ON button is pressed" it would be more correct. In my testing VR is not "turned off" by using the AF-ON button, it simply isn't engaged by that button press. Only the shutter release button engages VR. Thus, if you use AF-ON to focus instead of a partial shutter release, VR is not engaged during the pre-shot focusing. But it is during the shot.
This, of course, creates a slight issue. Optimally, we want VR/IS to have a stream of data just prior to pressing the shutter release fully. If we're using AF-ON to focus, our fingers usually aren't pushing the shutter release partially down, too. But you should practice doing just that. Sigh. That right hand is starting to do a pretty complicated dance: AF-ON up and down for focus, shutter release partially down for VR/IS, right thumb dialing in shutter or aperture or exposure adjustments, maybe right middle finger dialing in aperture adjustments, shutter release fully down with the index finger for the shot. This, by the way, is one of the reasons why I prefer Nikon's ergonomics to Canon's: at least when I'm doing all that hand juggling, my hand and finger positions aren't really moving, especially my shutter release finger. With Canon the tendency is to move the index finger between the top control wheel and shutter release. You can react with the shutter release faster if you're not moving that finger.
There are a few more caveats. If you've got a built-in flash on your camera (basically everything but the D1, D2, and D3 series), while the flash is recharging the VR system is inactive. That's because VR/IS takes power to perform and the assumption is that you want the flash recharged as fast as possible. Thus, the camera turns off the power to the VR system while it's charging up the camera's flash capacitor. If you're shooting flash near full power and doing a lot of consecutive flashes, the flash recharge time can start taking a few seconds. How do you know if power is restored to the VR/IS system? Well, you can't, exactly, but the flash indicator in the viewfinder is a fairly reliable indicator: if it's not present with the flash up and active, VR/IS is probably Off.
7: If you rely upon VR/IS and use flash, use an external flash instead of the internal one if you can.
I'VE BEEN HOLDING OFF ON THE TRIPOD ISSUE TO THE END OF THIS ARTICLE, PARTLY BECAUSE IT'S NOT AS CLEAR CUT AS NIKON SEEMS TO THINK IT IS. BUT BY NOW YOU'VE PROBABLY TURNED VR OFF, ANYWAY ;~). PART OF THE PROBLEM IS THAT NIKON HASN'T CLEARLY LABELED AND DISTINGUISHED THEIR VARIOUS VR/IS SYSTEM ITERATIONS. TECHNICALLY, THE VR II SYSTEM ON SOME OF THE MODERN LENSES SHOULD DETECT WHEN THE CAMERA IS ON A STABLE PLATFORM AND NOT TRY TO JUMP IN AND CORRECT. BUT NOT ALL MODERN LENSES HAVE WHAT MOST OF US REGARD AS THE FULL VR II. THE RECENTLY INTRODUCED 16-35MM, FOR EXAMPLE, COMES LONG AFTER THE INTRO OF VR II, BUT IT DOES NOT APPEAR TO HAVE TRIPOD RECOGNITION. THUS, WE HAVE ANOTHER RULE BEFORE WE GET TO THE REAL RULE:
8. YOU MUST READ YOUR LENS MANUAL AND SEE WHAT IT SAYS ABOUT USE ON TRIPODS.
Two basic possibilities exist:
1. The manual says turn VR/IS off when on a tripod (sometimes adding "unless the head is unsecured")
2. The manual specifically says that the VR/IS system detects when the camera is on a tripod
Okay, I lied. Forget what the manual says.
Rule #8 For Real: If your camera is on a tripod, even if you're using something like a Wimberley head where it is almost always loose, turn VR off. If your tripod is on a moving platform or one that has vibrations in it, strongly consider turning VR on, but test it to be sure you need it.
So why do I disagree with Nikon? Even with a loose head on a tripod, motion should be fairly easy to control, and you should have removed one possible motion almost completely (ditto with monopods). The problem I have, and which many other pros have noticed, is that the VR/IS tripod detection system sometimes has "false negatives." In other words, the tripod detection mode of the VR II system should be detecting when the system is "quiet enough" to turn off corrections. Most of the time it does just that (Nikon says that the system is smart enough to detect as many as three different types of motion--handholding, platform vibration, and support system movement--because the "vibrations" caused by each of these are recognizable different in wave form). Every now and then, though, VR/IS thinks it needs to correct when it doesn't (or perhaps is still correcting for a previously detected motion that will no longer be present in the next sampling). When that happens, the VR/IS element(s) are moving when they shouldn't be. Usually not a lot, but enough to make for less than optimal results.
Indeed, this is the very same problem as with using VR/IS over 1/500: sometimes it works, sometimes is doesn't. The problem is that you won't like it when it doesn't, and you won't know when it does. If I were to tell you that out of 100 shots you take 10 were going to be bad due to the VR/IS doing the wrong thing, would you still use VR? Remember, when you're on a tripod, all 100 shots should be good without VR (otherwise you have the wrong tripod and head, or you're using poor technique). I'm not a gambler: I prefer the known to the unknown, so I don't like having random shots spoiled by VR/IS.
Which brings up a whole different topic: what does a spoiled-by-VR/IS shot look like? Well, "spoiled" is perhaps too harsh a term. Sub-optimal is probably a better one. An optimal shot has very clean and well defined edge acuity. Assuming a "perfect lens," edges should be recorded basically as good as the anti-aliasing filter, sensor, and Bayer demosaic allow. What a lot of us find when VR/IS is not quite correcting as well as it can/should is that edges get a little bit of "growth" to them, and sometimes there's a directionality to that growth. It's sort of like camera movement, only much more subtle. I tend to say that the detail "looks busy" when VR/IS isn't fully doing its job or is on when it shouldn't be. And when you apply sharpening to busy edges, that busy-ness gets busy-er. Without VR/IS active at all while on a stable tripod, it's like a veil gets lifted and you suddenly see how sharp your lens really is (assuming you correctly obtained focus on your subject and had a stable platform, that is ;~).
Yes, there's some nitpicking going on here. V/IS not correcting right is a bit like tripod mount slop (fixed with a Really Right Stuff Long Lens Support) or ringing vibrations in the tripod legs (fixed by using the right legs for your equipment): you don't see it until it's gone, and even then usually only if you're pixel peeping. But someone using a 400mm f/2.8G VR/IS lens on a D3x spent a lot of money on equipment to get the best results. They expect to be able to catch every bit of detail and blow it up into a large print. As always on this site, you need to understand that I always write about the search for optimal bits. If you're shooting with a 16-85mm on a D300 and putting 640x480 images on the Web from that, well, whether the VR/IS missed doing its job by a little bit probably isn't so important.
May 23, 2013 08:35:14 #
May 23, 2013 08:37:46 #
Wow! Now I know not to buy a Nikon. It seems too much like work! I was about to buy a d800 and go full frame, but I think I will stick with my Kodak. It gets the job done. Thanks for the heads up!
May 23, 2013 08:49:09 #
tainkc wrote:
Wow! Now I know not to buy a Nikon. It seems too much like work! I was about to buy a d800 and go full frame, but I think I will stick with my Kodak. It gets the job done. Thanks for the heads up!
I thought you were using an iPhone. :D
May 23, 2013 09:00:17 #
There are dickheads in audio as well. Oxygen free copper, $1000 interconnects, gold plated contacts, what the article states may or may not be valid but in practice I am certain there are many, many other aspects of photography which actually make a perceptible difference and VR on or off as described is not one of them. Rob.
May 23, 2013 09:14:46 #
This rather long epistle is very interesting, but unnecessarily technical for my little mind. I basically know how VR/IS/OS works, but I have some simple rules & I don't get too bogged down with theory & technical jargon.
For what it's worth, I shoot hand held almost all the time, & VR stays on all the time, whether it's needed or not. On the rare occasion that I use a tripod, I turn VR off, if I think of it. Most times I forget to switch it off, but the pics still turn out okay...My policy--switch on VR & forget it. Just my two cents worth.
For what it's worth, I shoot hand held almost all the time, & VR stays on all the time, whether it's needed or not. On the rare occasion that I use a tripod, I turn VR off, if I think of it. Most times I forget to switch it off, but the pics still turn out okay...My policy--switch on VR & forget it. Just my two cents worth.
May 23, 2013 09:18:41 #
DOOK wrote:
This rather long epistle is very interesting, but ... (show quote)
Gives them something to blame their crook photos on.....
Check out The Dynamics of Photographic Lighting section of our forum.
May 23, 2013 09:42:42 #
Sorry, Nekon, too hard to read (CAPITALS), too much to read, and impossible to retain. My brain just isn't as agile now as it once was. But I think, maybe great for the real techies among us.
As well, I guess I have the best of both worlds: IS on or off: I just set it to Automatic. That and WB are usually the only two things I have set to automatic, the rest I like to do myself ;-)
EstherP
As well, I guess I have the best of both worlds: IS on or off: I just set it to Automatic. That and WB are usually the only two things I have set to automatic, the rest I like to do myself ;-)
EstherP
May 23, 2013 12:19:15 #
jerryc41 wrote:
Sold the Kodak as well.I thought you were using an iPhone. :D
May 23, 2013 19:25:56 #
DOOK wrote:
This rather long epistle is very interesting, but ... (show quote)
Basically all I am stating is, "If you don't need it, turn it off." -If you leave it on and there is no shake to counter, in trying to counterract shake, it will cause shake.
May 23, 2013 19:29:26 #
EstherP wrote:
Sorry, Nekon, too hard to read (CAPITALS), too much to read, and impossible to retain. My brain just isn't as agile now as it once was. But I think, maybe great for the real techies among us.
As well, I guess I have the best of both worlds: IS on or off: I just set it to Automatic. That and WB are usually the only two things I have set to automatic, the rest I like to do myself ;-)
EstherP
As well, I guess I have the best of both worlds: IS on or off: I just set it to Automatic. That and WB are usually the only two things I have set to automatic, the rest I like to do myself ;-)
EstherP
White balance is the essence of digital photography and auto WB doesn't do it justice
Check out Commercial and Industrial Photography section of our forum.
May 23, 2013 19:34:18 #
nekon wrote:
White balance is the essence of digital photography and auto WB doesn't do it justice
Says who?
Do you know my camera?
Have you been able to compare the various WB setting with that camera?
EstherP
May 23, 2013 19:38:17 #
EstherP wrote:
Says who?
Do you know my camera?
Have you been able to compare the various WB setting with that camera?
EstherP
Do you know my camera?
Have you been able to compare the various WB setting with that camera?
EstherP
I don't need to know your camera- I know photography, been a pro photographer for 50 years- ten with digital, I am retired now, and I teach digital photography, one on one.
May 23, 2013 19:42:45 #
nekon wrote:
White balance is the essence of digital photography and auto WB doesn't do it justice
Do you take photographs based on theory? Get real and write about something that actually makes a difference in the real world....
May 23, 2013 19:43:44 #
winterrose wrote:
Do you take photographs based on theory? Get real and write about something that actually makes a difference in the real world....
No I make images based on proven facts-did you learn photography from the back of a cornflakes packet?
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