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DPChallenge Forums >> Hardware and Software >> Whoa! IS and focus button, Canon
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Showing posts 1 - 24 of 24, (reverse)
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06/29/2011 02:27:28 PM · #1
Just found out something I had no clue about. Unless I'm misunderstanding what I am reading...

Originally posted by Canon 24-105mm f/4L manual, and others:

If you set the camera's Custom Function to change the assigned button to operate the AF, the Image Stabilizer will operate when you press the newly assigned AF button.


Now, I've been using the button on the back of my 5D to focus, and the shutter button to grab exposure. According to the manual, IS begins to operate when you press the shutter button halfway. Reading the above, I'm left with the nagging suspicion that maybe the shutter button doesn't activate the IS when the Custom Function is enabled. But it's possible the IS activation off the button is in addition to, rather than instead of, shutter button activation.

Does anyone know the answer to this for sure? 'Cuz if this is the case, Penny and I have been wasting our IS capabilities for some time now, including all of the California trip :-( And it might explain why I had a lot of disappointingly not-especially-sharp images on that trip...

R.
06/29/2011 02:34:27 PM · #2
Put on your 100-400 and try both. Have Penny listen for the whir of the gyros. It's easy to hear and should answer your question.
06/29/2011 02:37:09 PM · #3
On my 50D, I also use the back button for AF. My IS turns on any time I use that back button, or when I use the shutter-half-press to get exposure. My old 70-300 was very noisy when IS was engaged, so I'm positive of this.
06/29/2011 02:46:25 PM · #4
Just tried it with a 5DMKII and a 24-105 and half-way shutter of AF-on button do the same thing. Both autofocus and engage the IS.
06/29/2011 02:59:52 PM · #5
Well, that's good news I guess. Though it leaves me wondering how come I had so many not-quite-sharp shots in California. Maybe I just forgot the IS altogether :-)

R.
06/29/2011 03:21:13 PM · #6
Originally posted by Bear_Music:

Well, that's good news I guess. Though it leaves me wondering how come I had so many not-quite-sharp shots in California. Maybe I just forgot the IS altogether :-)

R.


Two things I know about the 100-400...

A. Even with IS shutter speeds of <1/500 are prone to blurring
B. Anything faster than about f/7.1 isn't optimally sharp.

And one thing I know about IS - You need to wait for about 2 seconds for it to fully engage..

Did you have your camera set to a level below those thresholds? Did you not wait long enough for IS to engage properly? If not then something else may have been at play..

ETA: B. May be more applicable to my 15mp 1.6x sensor than your full frame 12mp sensor....

Message edited by author 2011-06-29 15:27:36.
06/29/2011 03:27:45 PM · #7
Originally posted by Cory:

Two things I know about the 100-400...

A. Even with IS shutter speeds of <1/500 are prone to blurring
B. Anything faster than about f/7.1 isn't optimally sharp.

Did you have your camera set to a level below those thresholds? If not then something else may have been at play..

ETA: B. May be more applicable to my 15mp 1.6x sensor than your full frame 12mp sensor....


I try to shoot the big gun at f/8 to f/16, and I'll bump the ISO to do it. But anyway, that wasn't the issue as much as the 100mm; I did OK with the long lens. I did a whole morning of shooting with ' . substr('//www.dpchallenge.com/images/user_icon/31.gif', strrpos('//www.dpchallenge.com/images/user_icon/31.gif', '/') + 1) . ' mousie at a formal garden and the results were disappointing. That was all with the 100mm. I probably forgot to turn the IS on...

R.
06/29/2011 03:34:08 PM · #8
I had the IS off all morning too... simply forgot to engage it and didn't notice... and I'm still pretty happy with my results. :)
06/29/2011 03:35:36 PM · #9
Originally posted by Mousie:

I had the IS off all morning too... simply forgot to engage it and didn't notice... and I'm still pretty happy with my results. :)


You're younger than I am, you have steadier hands. That's my story, and I'm sticking to it :-) Did my BIL ever call about the MacBook Pro?

R.
06/29/2011 03:42:38 PM · #10
When I first got my 7D I had a lot of shots that weren't as sharp as I wanted (or blurry enough to be considered arty). Turned out I had it on A1 servo or A1 focus; can't remember which one. ' . substr('//www.dpchallenge.com/images/user_icon/21_N.gif', strrpos('//www.dpchallenge.com/images/user_icon/21_N.gif', '/') + 1) . ' Melethia clued me in, and I set to to One Shot, and have been fine ever since. Evidently, I had it on the one that assumes that your subject is moving, so if you shoot a stationary object, it "moves" because it doesn't know any better. Lousy explanation of something you undoubtedly know better than I. (Goes back to making marmalade.)
06/29/2011 04:23:02 PM · #11
Hmmm, vacation in California with blurred photographs. I'm pretty sure I know what the problem is :)
06/29/2011 05:31:53 PM · #12
Originally posted by Cory:

And one thing I know about IS - You need to wait for about 2 seconds for it to fully engage.

I've never come across this before and I have to ask - why on earth would it take 2 seconds to come ready?
06/29/2011 06:55:34 PM · #13
Originally posted by giantmike:

Hmmm, vacation in California with blurred photographs. I'm pretty sure I know what the problem is :)


Yeah thinking the same thing... but they generally give you small tests, so that could not be the issue cause I'm sure a dozen or two amount to nothing still :-)
06/29/2011 06:58:01 PM · #14
Originally posted by Germaine:

When I first got my 7D I had a lot of shots that weren't as sharp as I wanted (or blurry enough to be considered arty). Turned out I had it on A1 servo or A1 focus; can't remember which one. ' . substr('//www.dpchallenge.com/images/user_icon/21_N.gif', strrpos('//www.dpchallenge.com/images/user_icon/21_N.gif', '/') + 1) . ' Melethia clued me in, and I set to to One Shot, and have been fine ever since. Evidently, I had it on the one that assumes that your subject is moving, so if you shoot a stationary object, it "moves" because it doesn't know any better. Lousy explanation of something you undoubtedly know better than I. (Goes back to making marmalade.)


I'm so glad I read this. I've just changed the setting on my camera. I've had some photos with wrong focus lately including a couple for my bonsai club which were taken on a tripod at F11 using mirror lockup. I put it down to human error, but hopefully this will prevent a recurrence.
06/29/2011 10:08:42 PM · #15
Originally posted by ganders:

Originally posted by Cory:

And one thing I know about IS - You need to wait for about 2 seconds for it to fully engage.

I've never come across this before and I have to ask - why on earth would it take 2 seconds to come ready?


Because it is driven by gyroscopes and needs to find it's "balance" before really working well... As a matter of a fact, IS in the first few moments after half-press can actually CAUSE blur when it tries to find center...
06/29/2011 10:15:11 PM · #16
Gina, you probably already know that IS should be turned off when using a tripod.
06/30/2011 10:28:33 AM · #17
Originally posted by Cory:

Originally posted by ganders:

Originally posted by Cory:

And one thing I know about IS - You need to wait for about 2 seconds for it to fully engage.

I've never come across this before and I have to ask - why on earth would it take 2 seconds to come ready?


Because it is driven by gyroscopes and needs to find it's "balance" before really working well... As a matter of a fact, IS in the first few moments after half-press can actually CAUSE blur when it tries to find center...

Meh. Sure, it's driven by gyroscopes but they're not massive things that need seconds to spin up - I'd be surprised if it took any longer than, say, to focus (which involves shifting some considerably heavier elements).

You can see the IS working through the viewfinder; there's no way I've ever seen it take seconds to "balance". Maybe the latest generations of IS have got a bigger delay or something, although that sounds deeply unlikely.
06/30/2011 10:59:48 AM · #18
Originally posted by ganders:


You can see the IS working through the viewfinder; there's no way I've ever seen it take seconds to "balance". Maybe the latest generations of IS have got a bigger delay or something, although that sounds deeply unlikely.


+1
IS does have a settling time, but it is at most a couple tenths of a second. The sensing elements are not really gyroscopes, but accelerometers, and they are MEMS devices (silicon, very fast response).
06/30/2011 12:39:48 PM · #19
Originally posted by kirbic:

Originally posted by ganders:


You can see the IS working through the viewfinder; there's no way I've ever seen it take seconds to "balance". Maybe the latest generations of IS have got a bigger delay or something, although that sounds deeply unlikely.


+1
IS does have a settling time, but it is at most a couple tenths of a second. The sensing elements are not really gyroscopes, but accelerometers, and they are MEMS devices (silicon, very fast response).


+2
If the gyroscope worked against you for the first second or two, that would be a massive product flaw. Would you consider a lens where you had to hold the focus button for two seconds before every picture a useful one?
06/30/2011 02:09:21 PM · #20
I'm a neophyte on this IS thing, but it's my observation that the IS on the 100-400mm takes longer to go into effect from a cold start than the one on my 100mm macro. This presumably is accounted for by the fact that the 100-400mm IS is 2 generations behind the current one.

R.

Message edited by author 2011-06-30 14:09:42.
06/30/2011 02:50:43 PM · #21
Originally posted by DrAchoo:

Originally posted by kirbic:

Originally posted by ganders:


You can see the IS working through the viewfinder; there's no way I've ever seen it take seconds to "balance". Maybe the latest generations of IS have got a bigger delay or something, although that sounds deeply unlikely.


+1
IS does have a settling time, but it is at most a couple tenths of a second. The sensing elements are not really gyroscopes, but accelerometers, and they are MEMS devices (silicon, very fast response).


+2
If the gyroscope worked against you for the first second or two, that would be a massive product flaw. Would you consider a lens where you had to hold the focus button for two seconds before every picture a useful one?


I may have clearly over stated the time required for the IS to be ready... But I do stand by the theory. And I can absolutely tell you that going from no-press to full-press without a pause has definitely resulted in blur that I could only attribute to the IS. And yes, the IS in my 15-85 is FAR superior to that in my 100-400...

Message edited by author 2011-06-30 14:55:05.
06/30/2011 03:59:29 PM · #22
Originally posted by Cory:

...I can absolutely tell you that going from no-press to full-press without a pause has definitely resulted in blur that I could only attribute to the IS. And yes, the IS in my 15-85 is FAR superior to that in my 100-400...


No doubt in my mind at all that an immediate full-press will not allow sufficient time for IS to stabilize. Typical shutter lag for DLSRs ranges from about 40ms to about 90ms, in any case less than 1/10s. I think it's safe to say IS needs a little longer to stabilize, probably on the order of 200 to 300ms, certainly less than 500ms (1/2s).
Newer generations of IS are certainly a big improvement over the original generation.
06/30/2011 04:05:43 PM · #23
Originally posted by kirbic:

Originally posted by Cory:

...I can absolutely tell you that going from no-press to full-press without a pause has definitely resulted in blur that I could only attribute to the IS. And yes, the IS in my 15-85 is FAR superior to that in my 100-400...


No doubt in my mind at all that an immediate full-press will not allow sufficient time for IS to stabilize. Typical shutter lag for DLSRs ranges from about 40ms to about 90ms, in any case less than 1/10s. I think it's safe to say IS needs a little longer to stabilize, probably on the order of 200 to 300ms, certainly less than 500ms (1/2s).
Newer generations of IS are certainly a big improvement over the original generation.


I think this would be a very interesting subject to study in detail.
06/30/2011 05:15:47 PM · #24
Originally posted by MelonMusketeer:

Gina, you probably already know that IS should be turned off when using a tripod.


Yes I know that. I do occasionally forget, but when I look at an image zoomed in, it reminds me very quickly.
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