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04-07-2014, 08:12 AM   #31
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QuoteOriginally posted by Na Horuk Quote
Yep, and I don't agree with this assumption. I think it is wrong of a photographer to say "I want to recreate the DoF I would get with a different format!" ignoring composition, exposure, motion blur, etc. This is why I don't agree with the DoF equivalence being the base for comparisons.
I want to take... the pictures I want to take. I don't care what the internal dimensions of the camera are. That's why equivalence (much more than 'DOF equivalence', btw) is so incredibly useful when deciding when to use my APS-C camera and when to use my FF camera.

I imagine when Pentax puts out it's FF camera many others here will be affected.

04-07-2014, 08:25 AM   #32
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QuoteOriginally posted by Na Horuk Quote
Any FF lens can also be mounted on an APSC sensor and f1.2 brightness is f1.2 (when ISO and shutter are the same).
No, "f/1.2" is not "f/11.2" independently of the sensor size.

The physical properties of a lens, say that its focal length is 50mm and its widest aperture is f/1.2, does not change when changing sensor sizes, but the effect on the photo does. Surely you will agree that "50mm" is not "50mm" independently of the sensor size (the FOV changes). Likewise you need to recognise that "f/1.2" is not "f/1.2" independently of the sensor size (while the exposure is the same, the total amount of light is not).

Note that the total amount of light matters for IQ, not exposure. Exposure is independent of sensor size and hence unsuitable to be used as a sole indicator of IQ.

QuoteOriginally posted by Na Horuk Quote
Suddenly EV, shutter speed blur, ISO/noise are no longer important features of the photo, only DoF is.
Exactly the opposite is the case.

All the aspects you mention are important to consider when comparing sensor sizes. When comparing different sensor sizes you need to make sure that you are not comparing apples to oranges (e.g., by using the same 50mm on both cameras as this would result in drastically different images due to the different FOV).

You can only make meaningful statements about the advantages of one sensor size of the other by comparing equivalent images, which includes the same DOF. If you are comparing images with different DOF than you are comparing apples to oranges. You would not take a photo with a Nikon at 1/1000 & f/2.8 and another one with a Pentax at 1/10 & f/28 and then conclude that the Nikon is better for shooting sports because there is less motion blur. You could do it and say "I really don't know why in a comparison you insist on using the same shutter speed?" but it would be not be a defensible position.

QuoteOriginally posted by Na Horuk Quote
Regarding some of the earlier comments, I agree that FF has its uses, especially when it comes to improved noise performance (due to larger possible photosites) and wider possible angles (this advantage is shrinking, though).
Please note that "larger photosites" do not provide any noise advantage (if the sensor size is the same).
04-07-2014, 08:26 AM   #33
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Unfortunately, unless I am mistaken, 'equivalence' doesn't apply to dynamic range. A shortcoming in the utility of the concept.
04-07-2014, 08:36 AM   #34
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QuoteOriginally posted by monochrome Quote
This is all so very, very simple.
Only if you dumb it down to "If you think you want system A, buy it. If you think you want system B, buy that".

The above is just trivial advice to make someone obtain something they believe is good for them, whether is actually the best choice or not.

What's more interesting is to figure out which system, for a given set of requirements, is the better choice (independently of what someone "thinks" when they haven't made them themselves knowledgeable yet).

QuoteOriginally posted by monochrome Quote
No one needs to prove anything.
I disagree.

If someone makes the (true) statement, that starting from a certain level of IQ upwards, FF is overall cheaper than APS-C, then they should better support their claim.


QuoteOriginally posted by monochrome Quote
No one thing is 'The Best' for everything.
Yes, very true.

But if you know what you want -- say a certain level of IQ for the lowest price possible -- it is useful to know on what basis you should be making your choice.

04-07-2014, 08:41 AM   #35
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QuoteOriginally posted by rawr Quote
Unfortunately, unless I am mistaken, 'equivalence' doesn't apply to dynamic range. A shortcoming in the utility of the concept.
What makes you think that?

BTW, a comparison of sensor sizes based on "equivalence", reveals that higher dynamic range (everything else being equal) is actually a benefit of larger sensors (whereas better "low-light performance" is not).
04-07-2014, 08:58 AM   #36
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QuoteOriginally posted by Class A Quote
No, "f/1.2" is not "f/11.2" independently of the sensor size.

The physical properties of a lens, say that its focal length is 50mm and its widest aperture is f/1.2, does not change when changing sensor sizes, but the effect on the photo does. Surely you will agree that "50mm" is not "50mm" independently of the sensor size (the FOV changes). Likewise you need to recognise that "f/1.2" is not "f/1.2" independently of the sensor size (while the exposure is the same, the total amount of light is not).

Note that the total amount of light matters for IQ, not exposure. Exposure is independent of sensor size and hence unsuitable to be used as a sole indicator of IQ.


Exactly the opposite is the case.

All the aspects you mention are important to consider when comparing sensor sizes. When comparing different sensor sizes you need to make sure that you are not comparing apples to oranges (e.g., by using the same 50mm on both cameras as this would result in drastically different images due to the different FOV).

You can only make meaningful statements about the advantages of one sensor size of the other by comparing equivalent images, which includes the same DOF. If you are comparing images with different DOF than you are comparing apples to oranges. You would not take a photo with a Nikon at 1/1000 & f/2.8 and another one with a Pentax at 1/10 & f/28 and then conclude that the Nikon is better for shooting sports because there is less motion blur. You could do it and say "I really don't know why in a comparison you insist on using the same shutter speed?" but it would be not be a defensible position.


Please note that "larger photosites" do not provide any noise advantage (if the sensor size is the same).
Obviously you present an extreme example. I think for most shots, the goal is to have a well exposed, accurately focused image that freezes the action. For most images, that will be possible both with APS-C and full frame, but certainly there will be images where full frame will be more capable.

I do think equivalence is important in theory. It just doesn't tell you everything. If you are shooting with an f2.8 70-200 zoom on full frame, it is entirely possible that a 50-135 f2.8 zoom will be "adequate" on APS-C. That is to say you will have well exposed, sharp images in both cases -- maybe with more depth of field with your APS-C camera, but as I said before, that isn't a big deal in the end.
04-07-2014, 09:01 AM   #37
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OK - but until someone can control for all variables other than the area of the sensor we'll really never know the answer.
04-07-2014, 09:44 AM   #38
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QuoteQuote:
There are 3 kinds of lies: Lies, Damned Lies, and Statistics. Benjamin Disraeli
QuoteQuote:
Facts are stubborn, but statistics are more pliable.
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Definition of Statistics: The science of producing unreliable facts from reliable figures.
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Statistics are used much like a drunk uses a lamppost: for support, not illumination.
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Read more at Statistics Quotes - BrainyQuote

FF cameras are so much better than APS cameras. Yawn

FF cameras are an upgrade path for camera users. Sigh

FF cameras have higher resolution than APS cameras. Snore

Most photographers do not need a FF camera, and any number of statistics are not going to change that situation. Me

04-07-2014, 10:05 AM   #39
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QuoteOriginally posted by monochrome Quote
OK - but until someone can control for all variables other than the area of the sensor we'll really never know the answer.
You can control all variables other than the area of the sensor.

Falconeye has done it multiple times.

He produced the answers.

Are you not believing his conclusions because he is only using logical arguments, rather than running actual experiments?

Please note that his conclusions follow from Physics. There is no daring theory that needs to be proven.
04-07-2014, 10:12 AM - 2 Likes   #40
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In theory, there is no difference between theory and practice. In practice, there is
04-07-2014, 10:30 AM   #41
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QuoteOriginally posted by elliott Quote
Must be true, he has a PhD.
QuoteOriginally posted by VoiceOfReason Quote
Piled Higher and Deeper...
You're overlooking the real proof that what he says must be right. He has a blog!
04-07-2014, 10:48 AM   #42
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QuoteOriginally posted by Kunzite Quote
In theory, there is no difference between theory and practice. In practice, there is
The practical results (the OP) agrees with the theory. So in practice, there is no difference in this case.

---------- Post added 04-07-14 at 09:50 AM ----------



Not directed at you, Kunzite....

QuoteOriginally posted by some_pentaxians:
We want a full-frame sensor camera for reasons X, Y, and Z!
QuoteOriginally posted by other_pentaxians:
We're sick of hearing it and your reasons are wrong. We'll make you a subforum so we don't have to pay attention to you any more.

...

QuoteOriginally posted by some_pentaxians_in_the_ff_forum:
We want a full-frame sensor camera for reasons X, Y, and Z!
QuoteOriginally posted by other_pentaxians:
We're sick of hearing it and your reasons are wrong.

Experiment complete.
04-07-2014, 11:37 AM   #43
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Class A - I'm not being obtuse or argumentative. I've been here long enough to have read Falc and understand.

Yet on a resolution test, have we used the exact same sensor technology except for a larger slice of the wafer, the same lens on a camera using the same RAW capture algo and precisely the same processing in some processor - or the exact same in-camera jpeg engine - at the exact same true ISO - i.e. is everything the same except an APSc sensor in a camera instead of a FF sensor in an identical camera?

or have we NOT controlled for all variables other than sensor, and the rest is mathematically inferred (by Falconeye)?

I merely contend we cannot know precisely how much different FF is from APSc even empirically, and we cannot know from tests whther such difference matters in real-world use,other than for several well-explained conditions. Mine is a rather sarcastic rant against all this sniveling about sensor sizes.
04-07-2014, 12:17 PM   #44
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You would need to scale the lens as well.

FWIW I believe falconeye would also 'require' you keep the MP the same and make the sensor thicker for the smaller format. I know I would.
04-07-2014, 12:38 PM   #45
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I will just say that there is no need to justify wanting a certain sensor size. If you want narrower depth of field than you get with a 35mm f1.4 or a 20mm f1.8 on APS-C, it is fine to go with full frame. But putting numbers on it is just a fig leaf. Same as people give when they upgrade from a K5 to a K5 II to a K3.

In the end the goal is to produce images for yourself. And if you are happy then who cares how much you spent on your gear (except maybe your wife/husband)?
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