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Old Dec 3, 2009, 11:30 AM   #11
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Interesting way of looking at shake. And emphasizes the basic assumption of shake and DOF: how good is "good enough" depends on what you are going to do with the photo: in particular, how much magnification is done.

As JimC says, the reason to have higher resolution is to be able to make larger prints. So a camera with 22Mp should be able to magnify linear dimensions 35 % more than a 12Mp. That would mean if you had no shake at 1/60th with the 5D, you would need 1/80th with its big brother.

Given all the subjective issues, and limits on shutter speeds (maybe you could have had no shake at 1/75th with the 5D? Maybe you could have got away with 1/105th with the 5DMkz?), that calculation is in line with your results.
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Old Dec 3, 2009, 12:53 PM   #12
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If you look at a 35mm negative under a microsope, or use it to make a mural, you'll find flaws too. The limitations you're talking about aren't just applicable to digital image sensors.

If you're going to subject an image to greater scrutiny than would be typical, then you're going to find flaws that wouldn't be apparent otherwise. In that situation, rules of thumb don't apply. Expecting a 22MP image sensor to satisfy all the same expectations as a 12MP image sensor is unreasonable, just as is the reverse. Just as Depth of Field is a determination of what is acceptably sharp, so is motion blur due to camera shake, and if you have the tools to be more critical, then "acceptable" is a moving target and you disregard the rules of thumb.
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Old Dec 3, 2009, 1:12 PM   #13
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If you look at a 35mm negative under a microsope, or use it to make a mural, you'll find flaws too. The limitations you're talking about aren't just applicable to digital image sensors.
Of course not. The same limitations will apply to film, which is one reason that some shooters use larger film sizes so they can make larger prints with acceptable quality (and what's acceptable to one person, may not be acceptable to another).

I think one of the key points that peripatetic is trying to make, is that if you want to take advantage of higher resolution sensors (i.e, make larger print sizes, or crop in a way that requires more magnification for a given print size), then you may need to use faster shutter speeds to prevent blur from camera shake (and each user will be different in that area, so a rule of thumb for one user may not apply to another).

Note the "if you want to take advantage of it" part of some his comments" (along with what he's found for the way he uses a camera).

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The extra resolution requires a change of mindset if you want to take advantage of it. Better technique is necessary for higher-resolution cameras.

And for me, somewhere between 12 and 22 Mp the 1/FL rule stops working well.
That makes perfect sense to me. Larger print or viewing sizes are going to need faster shutter speeds to prevent blur from camera shake, and that's the main reason to use a higher resolution sensor.

I think it's a great topic for discussion, since many members may not realize that larger print or viewing sizes may require faster shutter speeds for the same perceived quality (since I can imagine that many buyers are going to higher resolution cameras so they can enlarge the images more).
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Old Dec 3, 2009, 2:34 PM   #14
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But the "Exposure Time = 1 / (Focal Length * Crop Factor)" rule of thumb is useful, and as with any 'Rule of Thumb' there are exceptions. Casting aspersions on it doesn't help members trying to get a grip on what the rest of us are talking about.
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Old Dec 3, 2009, 3:39 PM   #15
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I disagree. I think this is a great topic for discussion and many users may be interested in it. I definitely wouldn't consider it to be "casting asperations". Given larger and larger monitors being used by many users as time passes, combined with higher resolution cameras (and keep in mind that many users may want to crop images which will have the same impact, since you're magnifying the image by cropping for a given viewing size), I think it merits some discussion, and appreciate peripatetic starting the thread with his observations.
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Old Dec 4, 2009, 5:46 AM   #16
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The point is that the whole domain is changing.

What was a useful guideline is becoming less so because resolutions are increasing and people are printing larger than they used to.

And there are constant complaints on the forums about people whose images are not sharp enough. Often the issue does turn out to be blur from camera shake, and as we go forward we should start telling people to consider trying out 1/2xFL instead of 1/FL to reduce blur.

Of course when using film (or digital) for critically sharp work for large prints you should always use a tripod. This is hardly a secret and is no revelation and is the same advice as it ever was.

But the higher resolution DSLR cameras are now in the realm of MF film, [I think someone who seems to be in the mood for an argument has something to that effect in his sig :-) ] and we would all do well to consider adopting MF techniques, and suggesting to others that they consider doing the same, even though we're using smaller format cameras.
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Old Dec 4, 2009, 9:16 AM   #17
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It's not just the resolution.

For example, the Sony A900 and the A700 have almost the same pixel density, even though the A900 has a 24MP image sensor and the A700 uses a 12MP sensor. Using the same lens on each camera will produce the same pixels per degree of angle of view, so the same amount of motion blur due to camera shake would appear in 100% crops from each camera, all other things being equal.

This is a complex issue, and reducing it to an issue of resolution and a flaw in a long standing rule of thumb, does everyone a disservice.

And I'm inclined to beleive that, with the wide availablility of personal photo printers, more 4X6 prints are being produced now more than ever before. So I think fewer people are printing larger images than ever before.

And I'm always up for a good arguement. ;-)
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Old Dec 4, 2009, 12:11 PM   #18
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Usually you have something sensible to say though, this thread you're just arguing for the sake of it and not making any good points at all - either you're just talking nonsense or coming up with platitudes.

It's not the pixel pitch. Otherwise this would all be very evident on P&S cameras and it's not.

It's not that complex, and not very contentious either. The claim is simple: with the new wave of high resolution cameras you may want to consider using a faster shutter speed than you do with lower resolution cameras. That's doing people a disservice? That's really bad advice?

More 4x6 prints now than before? Possibly, but I doubt it; people who used to get 4x6 prints from film now mostly share photos digitally.

However, people who were never easily able to make large prints are now far more easily able to produce high quality prints at 8x10 or larger with the photo-inkjet printers. There is absolutely no doubt that photographers are making a LOT more large prints than they ever did before.
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Old Dec 4, 2009, 12:59 PM   #19
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Craig,

IMO, I don't think it's an issue of people printing larger than they used to. I think it's part of the pixel peeping. Let's face it, the vast majority of photographers are still printing occasionally 8x10 or A4. They were doing that with 8mp cameras just fine. The problem is - as you indicated originally - when the images are viewed at 100%

I agree that at 100% you're seeing more issue - but let me ask this follow-up. Take a photo from your 12mp 5d and same from 5dII and print 8x10. Do you really see the affects of more camera shake in the printed image?

So, while I agree the affect your describing occurs, I'm not sure I agree with the impact - I don't think the impact is on the printed image as much as it is on pixel peeping - which is annoying to us as photographers but the final product isn't viewed at 100%. Make sense?
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Old Dec 4, 2009, 1:01 PM   #20
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surely a big factor in camera shake is of course whos taking the picture and how steady they can hold the camera
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