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View Poll Results: Has the K-5 changed your perspective on Full Frame dSLRs?
I never wanted/needed a FF dSLR 17750.86%
I've changed my mind - I don't want/need a FF dSLR anymore 5916.95%
I've changed my mind - I want/need a FF dSLR now 82.30%
I've always wanted/needed a FF dSLR and still do 10429.89%
Voters: 348. You may not vote on this poll

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10-23-2010, 03:20 AM   #76
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FF does not have anything inherently to do with DOF. The apparent DOF advantage FF cameras appear to have is an artifact of distance to subject.

For a given focal length, to obtain the same "magnfication" (relative amount of space the subject takes up in the frame) one has to move closer to the subject with an FF than an APS-C. Because you are closer to the subject with an FF, this causes the DOF to be shallower. If you stand in the same spot with the same lens/focal length at the same aperture, the DOF on the FF and APS-C cameras will be exactly the same. The only thing different is that the subject will be smaller relative to the entire frame on the FF.

It makes sense if you think about it. The lens doesn't care what sensor is behind it. An FA lens will produce exactly the same image whether what's behind it is FF, APS-C, MF, film or nothing at all. The reason it's called a "crop factor" is because it literally is a crop of the image of the lens: the APS-C sensor will capture a smaller portion of the image than the FF, but that doesn't change the fact that it is the same image, and therefore the same DOF.

10-23-2010, 04:40 AM   #77
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QuoteOriginally posted by Cannikin Quote
FF does not have anything inherently to do with DOF. The apparent DOF advantage FF cameras appear to have is an artifact of distance to subject.

For a given focal length, to obtain the same "magnfication" (relative amount of space the subject takes up in the frame) one has to move closer to the subject with an FF than an APS-C. Because you are closer to the subject with an FF, this causes the DOF to be shallower. If you stand in the same spot with the same lens/focal length at the same aperture, the DOF on the FF and APS-C cameras will be exactly the same. The only thing different is that the subject will be smaller relative to the entire frame on the FF.

It makes sense if you think about it. The lens doesn't care what sensor is behind it. An FA lens will produce exactly the same image whether what's behind it is FF, APS-C, MF, film or nothing at all. The reason it's called a "crop factor" is because it literally is a crop of the image of the lens: the APS-C sensor will capture a smaller portion of the image than the FF, but that doesn't change the fact that it is the same image, and therefore the same DOF.
Maybe I'm poor in English, but...it's absolutely nonsense.

Explain us, please, how to get the same photo in terms of DOF at APS-C camera
as you can get with FF camera + 50/1.4 wide-opened.

Or with FF + 31/1.8 wide-opened, or with 43/1.9 wide-opened.
10-23-2010, 05:06 AM   #78
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QuoteOriginally posted by ogl Quote
Maybe I'm poor in English, but...it's absolutely nonsense.

Explain us, please, how to get the same photo in terms of DOF at APS-C camera
as you can get with FF camera + 50/1.4 wide-opened.

Or with FF + 31/1.8 wide-opened, or with 43/1.9 wide-opened.
Did you not read my post at all, or did you just read the first sentence and jump to post?

A given lens at a given focal length, subject distance and aperture will always produce the same image no matter what is behind it. The image is produced solely by the lens and therefore the DOF has nothing to do with the sensor. An image is nothing but projected light rays. This is a very simple fact that should be incredibly obvious.

An FF sensor does not have "magical blurring capabilities" any more than film did. Explain how a piece of 36x24mm chemical coated plastic (film) would somehow change anything about the image as opposed to cutting that piece of film up into a piece of 24x16mm chemical coated plastic?

The reason why FF appears to have shallower DOF at the same magnification is because you are standing closer to the subject to get the same magnification. If you stand in that very same spot with an APS-C camera, the lens will produce the same image with the same DOF, but the APS-C sensor is only recording a smaller portion of it.

Last edited by Cannikin; 10-23-2010 at 05:22 AM.
10-23-2010, 05:17 AM   #79
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QuoteOriginally posted by ogl Quote
Maybe I'm poor in English, but...it's absolutely nonsense.

Explain us, please, how to get the same photo in terms of DOF at APS-C camera
as you can get with FF camera + 50/1.4 wide-opened.
Ogl, you might wanna read this page if you didn't yet, or even maybe translate to your language with translate.google.com

Depth of Field by Bob Atkins


Last edited by cbaytan; 10-23-2010 at 05:21 AM. Reason: preventing nationality mistakes
10-23-2010, 05:23 AM   #80
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QuoteOriginally posted by Cannikin Quote
Did you not read my post at all, or did you just read the first sentence and jump to post?
The problem is APS-C system has no such fast lenses. You can't get the same photo with APS-C camera as you can get with FF with 31/1.8 wide-opened in terms of DOF.

Last edited by ogl; 10-23-2010 at 05:30 AM.
10-23-2010, 05:24 AM   #81
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QuoteOriginally posted by cbaytan Quote
Ogl, you might wanna read this page if you didn't yet, or even maybe translate to your language with translate.google.com
I don't need to read something about DOF, 'coz I know it very good. You can use any DOF calculator in the web and understand what I mean.
10-23-2010, 06:51 AM - 1 Like   #82
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QuoteOriginally posted by ogl Quote
I don't need to read something about DOF, 'coz I know it very good. You can use any DOF calculator in the web and understand what I mean.
Using a DOF calculator to understand you?? Well....
10-23-2010, 09:06 AM   #83
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QuoteOriginally posted by ogl Quote
Maybe I'm poor in English, but...it's absolutely nonsense.

Explain us, please, how to get the same photo in terms of DOF at APS-C camera
as you can get with FF camera + 50/1.4 wide-opened.

Or with FF + 31/1.8 wide-opened, or with 43/1.9 wide-opened.
This is like comparing the quality of one beach to another by counting grains of sand and saying this one is vastly superior because it has a bucket more sand than that one.
I'ts just not that important.

10-23-2010, 02:24 PM   #84
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QuoteOriginally posted by Cannikin Quote
FF does not have anything inherently to do with DOF. The apparent DOF advantage FF cameras appear to have is an artifact of distance to subject.

For a given focal length, to obtain the same "magnfication" (relative amount of space the subject takes up in the frame) one has to move closer to the subject with an FF than an APS-C. Because you are closer to the subject with an FF, this causes the DOF to be shallower. If you stand in the same spot with the same lens/focal length at the same aperture, the DOF on the FF and APS-C cameras will be exactly the same. The only thing different is that the subject will be smaller relative to the entire frame on the FF.

It makes sense if you think about it. The lens doesn't care what sensor is behind it. An FA lens will produce exactly the same image whether what's behind it is FF, APS-C, MF, film or nothing at all. The reason it's called a "crop factor" is because it literally is a crop of the image of the lens: the APS-C sensor will capture a smaller portion of the image than the FF, but that doesn't change the fact that it is the same image, and therefore the same DOF.
actually at 5 feet away a 55/1.4 Pentax on a K5 with have .14 DOF. A pentax K1000 with an 85/1.4 will have a .08 DOF. Do the math.
10-23-2010, 02:38 PM   #85
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QuoteOriginally posted by eccentricphotography Quote
actually at 5 feet away a 55/1.4 Pentax on a K5 with have .14 DOF. A pentax K1000 with an 85/1.4 will have a .08 DOF. Do the math.
They're at different focal lengths, so of course the DOF is different.

Note that I specifically said:

QuoteQuote:
If you stand in the same spot with the same lens/focal length at the same aperture...
10-23-2010, 02:45 PM   #86
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I find the aps-c sensor shallow enough for creative purposes. Recently I used my super tak 50/1.4 wide open on a music video shoot @ 3 ft away from the lead vocals. Produced a perfect razor thin focus plane. Nice bokeh
10-23-2010, 03:03 PM   #87
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QuoteOriginally posted by Cannikin Quote
They're at different focal lengths, so of course the DOF is different.
Field of view for the purpose of photography is about the same. So you'll achieve the same photo with a very noticeable DOF difference.
10-24-2010, 07:53 AM   #88
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QuoteOriginally posted by ogl Quote
I don't need to read something about DOF, 'coz I know it very good. You can use any DOF calculator in the web and understand what I mean.
Yes, but did you try to understand what he meant?
10-24-2010, 08:24 AM   #89
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Can everybody please refrain from mentioning DoF when it comes to FF? It becomes incredibly boring.
QuoteOriginally posted by Cannikin Quote

A given lens at a given focal length, subject distance and aperture will always produce the same image no matter what is behind it. The image is produced solely by the lens and therefore the DOF has nothing to do with the sensor. An image is nothing but projected light rays. This is a very simple fact that should be incredibly obvious.
Cannikin, please don't use this thread to do your resarch regarding DoF. Thank You.

As a starting point, please note that some image properties are defined at an image level rather than a pixel level. In your example, you're right, the lens is rendering the same pixels but not the same images as an FF image simply has more of them. DoF is defined at an image level and therefore, your statement can be proven to be wrong. However, I won't do it in this thread...

I recommend reading the article on equivalent lenses on Luminous Landscape before replying, too.
10-24-2010, 09:13 AM   #90
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QuoteOriginally posted by falconeye Quote
Can everybody please refrain from mentioning DoF when it comes to FF? It becomes incredibly boring.


Cannikin, please don't use this thread to do your resarch regarding DoF. Thank You.

As a starting point, please note that some image properties are defined at an image level rather than a pixel level. In your example, you're right, the lens is rendering the same pixels but not the same images as an FF image simply has more of them. DoF is defined at an image level and therefore, your statement can be proven to be wrong. However, I won't do it in this thread...

I recommend reading the article on equivalent lenses on Luminous Landscape before replying, too.

In deed, it is incredibly boring - with the amount details one can get from high ISO images from APS-C sensor, the advantage of FF over APS-C is getting smaller and smaller.

I don't think I will ever need a FF, but that is just me. Unless of course, I want the bragging rights of owning expensive camera.
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