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11-24-2016, 07:26 AM   #1
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live view noise and smc dfa 100mm f2.8 macro lens not focusing in live view

live view noise and smc dfa 100mm f2.8 macro lens not focusing in live view

On my brand new Pentax K3ii, why is the live view making a weird noise and also my new 100mm Pentax macro not focusing when in auto focus mode?
I an soooo gutted to the bone that I'm already having problems with my lovely new camera that I though was going to be brilliant!!!
So is this normal and just dont use the macro in live view? I can tell you the other lens works ok in live view! what should i do?

Kind regards ! )

11-24-2016, 07:42 AM   #2
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The noise is the image stabilization at work.

Does it Do AF in viewfinder mode? In live view it is easiest to work with a tripod and focus critically by hand.
11-24-2016, 07:50 AM   #3
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QuoteOriginally posted by tommygunn84 Quote
... and also my new 100mm Pentax macro not focusing when in auto focus mode?
When you try to auto-focus with this lens in live view, is it failing to lock focus or is it doing nothing at all?
11-24-2016, 07:58 AM - 2 Likes   #4
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Hey, welcome!

Here is my advice:
a) Take a couple deep, slow breaths.
b) The humming sound is the SR. The SR normally only activates when you half-press the shutter button (and a little icon lights up in the viewfinder to show you when the SR is active. When taking photos you should give it half a second for the icon to light up before taking the shot). In LIVE VIEW the SR is always active. This is why you constantly hear the buzzing sound. There might be an option to disable SR in live view, which could minimize the sound. But there will always be some sound, because even if SR is not compensating, it still has to hold the sensor in place. Check the camera manual for more details. Also, the sound is not audible if you are on a city street; it is only annoying when you are at home in a quiet room
c) The SR also makes a CLUNK sound when the camera is turned off and shaken. This is normal, but do not rattle the camera to listen to this. We had cases where people got so paranoid about that sound that they kept shaking the camera and finally they managed to damage it. So before you get scared of that sound, I'm letting you know not to worry about it.
d) DFA 100mm has a super long focusing throw, because it is a macro lens. Just point it at something nearby, and manually focus. Then twist the focus ring all the way to infinity. Do you see what a long, massive distance that is, and how different the frame becomes? Macro just means you can focus super close up, more than with regular lenses.
This is why AF needs good LIGHT with this lens. Live view focusing is always much slower and different from the regular AF. IT uses different modules. Live view is just contrast detect, so it will not lock focus if there is not enough contrast on the subject. PD AF, the non-LV AF, is a bit different in how it functions.
Either way, the DFA 100mm has Quickshift. This means if the camera is in AF you, you can just wait for the AF to stop, and then twist the focusing ring by hand, without having to switch camera to MF. The way I use this lens is that I get rough focus by hand, and then use AF at the end to lock it.
IF your camera is not doing ANY AF action with this lens, then there is a problem. Make sure the lens is fully mounted (has to click into place), make sure you hold the AF button long enough, make sure you are not holding the focusing ring while the AF is active. You need to be more specific with what your problem with this lens/camera/AF is if you want more advice
e) Don't give up. You chose a top tier camera and lens. These are demanding tools. IF you want to just point and take snapshots, use a smartphone. But if you want top notch image quality, then you need a DSLR and you need to learn how to use it. It has a steeper learning curve than basic models. You can do it, but it will take some time. You need experience and knowledge.
f) Good luck


You have a great camera and great lens. No question about it. Many people on this forum use that combo to get amazing, stunning photos. Yes, AF is not super fast on macro lenses, but it is still generally usable, especially if you learn QS.

11-24-2016, 08:22 AM   #5
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Great post there! Point e) just above is the most important of all, for sure. Everything else really follows on from that.

Generally, long focal length and high magnification place high strains on the SR system in Live View mode. I personally would try to avoid live view for this type of lens and close-up work combined with SR ..... Use live view with a tripod (no SR needed) or SR combined with viewfinder shooting.
11-24-2016, 08:57 AM - 1 Like   #6
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QuoteOriginally posted by Na Horuk Quote
Hey, welcome!

Here is my advice:
a) Take a couple deep, slow breaths.
b) The humming sound is the SR. The SR normally only activates when you half-press the shutter button (and a little icon lights up in the viewfinder to show you when the SR is active. When taking photos you should give it half a second for the icon to light up before taking the shot). In LIVE VIEW the SR is always active. This is why you constantly hear the buzzing sound. There might be an option to disable SR in live view, which could minimize the sound. But there will always be some sound, because even if SR is not compensating, it still has to hold the sensor in place. Check the camera manual for more details. Also, the sound is not audible if you are on a city street; it is only annoying when you are at home in a quiet room
c) The SR also makes a CLUNK sound when the camera is turned off and shaken. This is normal, but do not rattle the camera to listen to this. We had cases where people got so paranoid about that sound that they kept shaking the camera and finally they managed to damage it. So before you get scared of that sound, I'm letting you know not to worry about it.
d) DFA 100mm has a super long focusing throw, because it is a macro lens. Just point it at something nearby, and manually focus. Then twist the focus ring all the way to infinity. Do you see what a long, massive distance that is, and how different the frame becomes? Macro just means you can focus super close up, more than with regular lenses.
This is why AF needs good LIGHT with this lens. Live view focusing is always much slower and different from the regular AF. IT uses different modules. Live view is just contrast detect, so it will not lock focus if there is not enough contrast on the subject. PD AF, the non-LV AF, is a bit different in how it functions.
Either way, the DFA 100mm has Quickshift. This means if the camera is in AF you, you can just wait for the AF to stop, and then twist the focusing ring by hand, without having to switch camera to MF. The way I use this lens is that I get rough focus by hand, and then use AF at the end to lock it.
IF your camera is not doing ANY AF action with this lens, then there is a problem. Make sure the lens is fully mounted (has to click into place), make sure you hold the AF button long enough, make sure you are not holding the focusing ring while the AF is active. You need to be more specific with what your problem with this lens/camera/AF is if you want more advice
e) Don't give up. You chose a top tier camera and lens. These are demanding tools. IF you want to just point and take snapshots, use a smartphone. But if you want top notch image quality, then you need a DSLR and you need to learn how to use it. It has a steeper learning curve than basic models. You can do it, but it will take some time. You need experience and knowledge.
f) Good luck


You have a great camera and great lens. No question about it. Many people on this forum use that combo to get amazing, stunning photos. Yes, AF is not super fast on macro lenses, but it is still generally usable, especially if you learn QS.
Great advice. OP, I have a K3 and that lens... If you're doing macro work with live view, set it to manual, it is a much better way to work for critical focus. (In my opinion!)
11-24-2016, 11:07 AM   #7
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Oh yes, for actual macro photos, you usually want to use manual focus anyway! Why? Because you get highest magnification at the nearest focus. So you just set the lens to minimum focus manually, then you just move the camera closer/further until the subject comes into focus. For closeups MF is the way to go, 95% of the time
11-24-2016, 08:59 PM   #8
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Lack of focus lock might also be subject related. While we do not know of the precise circumstances causing tommygunn84's problem, if he is having focus trouble in macro mode, it may be that the subject being focussed on is not staying still long enough. Because the depth of field with the lens wide open (which it will be while focussing) is so shallow when subjects are close up and the focus throw of macro lenses so long, just a little bit of movement will defeat the ability of autofocus to secure a lock. Live view exacerbates this problem because live view focus by its nature is slower and also needs to range either of sharp focus to establish just where contrast is maximised, meaning movement can defeat live view focus quite readily. Examples of movement while in macro range that can cause issues:


(1) flowers moving even in the lightest of breezes will bounce in and out of macro focus range such that the autofocus is chasing a moving target and will fail to get a lock
(2) the user is handholding the camera and swaying back and forward ever so slightly without realising this is happening. When very close to the subject, the swaying is enough to pop the subject in and out of range rapidly enough that the autofocus cannot secure a lock. And if it does, the next sway may take it straight back out of focus and result in an out of focus image.


Being inside the minimum focus distance of the lens will also ensure autofocus will not lock. With a 100mm lens, minimum distance can be further away from the front of the lens than might be initially realised.


Macro can be quite technically demanding and takes time to master, and all of the above are technique issues. I've learnt that I'm routinely challenged by point 2 above (swaying back and forth) and so have developed a preference to using a tripod or monopod for close up work to minimise the focus misses (even with manual focus) from my own movement. Other people may be rock steady and not have this problem.


Last edited by southlander; 11-24-2016 at 09:08 PM.
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