# Crop vs Full Frame - DoF



## outdoors (Jul 22, 2011)

Is there a significant difference in the DoF on a Full Frame vs a Crop?


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## KmH (Jul 22, 2011)

Yes, there is a significant difference.


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## jake337 (Jul 22, 2011)

Google is your friend.

Photo Technique #007 @Digital Outback Photo

Depth of Field, Digital Photography and Crop Sensor Cameras - Bob Atkins Photography

Depth of field

I copied this from another forum.

&#8226; Using the same lens on a EOS 10D and a 35mm film body, the 10D image has 1.6x LESS depth of field than the 35mm image would have (but they would be different images of course since the field of view would be different)

&#8226; If you use the same lens on a EOS 10D and a 35mm film body and crop the 35mm image to give the same view as the digital image, the depth of field is IDENTICAL

&#8226; If you use the same lens on an EOS 10D and a 35mm film body, then shoot from different distances so that the view is the same, the 10D image will have 1.6x MORE DOF then the film image.

&#8226; Close to the hyperfocal distance, the EOS 10D has a much more than 1.6x the DOF of a 35mm film camera. The hyperfocal distance of the EOS 10D is 1.6x less than that of a 35mm film camera when used with a lens giving the same field of view."


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## Derrel (Jul 22, 2011)

The articles that jake337 links to above are ones I myself have read and studied extensively. I think one additional fact from the Atkins article is worth bringing up here: when the focusing distance is close to the hyperfocal distance, with a lens of a focal length of 31.25mm, the above-mentioned 10D Canon or APS-C 1.6x sensor size camera will yield a depth of field that is not merely 1.6x more than a 35mm camera would, but 2.85x more.

As Atkins writes, "Note that as the focus distance approaches the hyperfocal distance, DOF increases rapidly. Since this happens for the a Canon APS-C crop sensor camera with a 31.25mm lens first (because the hyperfocal distance is least), the ratio of the DOF of the a Canon APS-C crop sensor camera to that of 35mm full frame becomes larger than the ~1.6x that you would get if the lens was focused at a distance much shorter than the hyperfocal distance. The plot below shows this graphically. Between about 0.2m and 3m the Canon APS-C crop sensor camera shows about 1.6-1.7x the DOF of 35mm full frame. At very close distances the ratio goes up, and as the distance approaches the hyperfocal distance for a 31.25mm lens at f8 on a Canon APS-C crop sensor camera (6.6m) the ratio rapidly rises - this is because the DOF behind the subject in the Canon APS-C crop sensor camera image is rapidly moving towards infinity."

What this means in PRACTICAL terms is that with short focal length lenses, on any APS-C camera, is that once the short focal length, wider-angle lenses are focused around 25 to 20 feet, the depth of field is so immense that it's almost impossible to make the background be unrecognizable. With shorter focal length lenses, and on farther-away subjects, when one uses an APS-C sized sensor, even areas that are outside of the band of acceptable sharpness, are often quite "recognizable"; even if say, a tree is not rendered in perfect crisp detail, it might very easily be "readable" by a human.


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## outdoors (Jul 22, 2011)

Interested in the choice between full frame vs crop when it comes to DoF. For example, if you have both available do you always use the full frame if you want a narrow DoF and conversly always use the crop if you want a huge DoF? Put another way, if a friend was in the market for a new body and his main purpose was for portraits with narrow DoF would you suggest a full frame over crop?


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## Derrel (Jul 22, 2011)

outdoors said:


> Interested in the choice between full frame vs crop when it comes to DoF. For example, if you have both available do you always use the full frame if you want a narrow DoF and conversly always use the crop if you want a huge DoF? Put another way, if a friend was in the market for a new body and his main purpose was for portraits with narrow DoF would you suggest a full frame over crop?



For portraiture and "people" work, FF is a better choice in many cases. Not all, but typically, FF allows one to use the "portrait lenses" like the 85,105,and 135 as they were intended to be used. I always give this example: 85mm lens, 1.6x Canon body, needs to be 34 feet away to properly frame a standing man and woman; with a FF 5D Canon, the same lens shoots the same picture height from 20 feet away, with shallower depth of field and MUCH MORE background separation than with the crop-body camera. With longer lenses, like 100,105,135,180,200, with the crop-sensor cameras, the photographer must be a looooong ways away from the people to do anything except tight headshots; at loooooong ranges, depth of field increases at a huge rate as the lens approaches hyperfocal distance.

With wide-angle work indoors, the crop-bodies lead to lots of too-close camera positioning, and very short focal lengths as well, due to the loss of field of view. For portraiture and people, the 24x36mm capture size has proven its worth over many decades; not so with APS-C, which was a stopgap measure.


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## Robin Usagani (Jul 22, 2011)

Sigh..  This topic again.  Basically if you shoot with with a full frame, using cropped sensor would give you the same thing except you crop some of the picture around it.  As simple as that.


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## djacobox372 (Jul 22, 2011)

Technically speaking the dof is the same regardless of sensor size, only aperture, distance to subject, and focal length affect dof.

However, with a larger sensor you end up using longer focal lengths to achieve the same composition, the end result is a smaller dof due to the longer focal length or shorter distance to the subject.


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## djacobox372 (Jul 22, 2011)

Schwettylens said:


> Sigh..  This topic again.  Basically if you shoot with with a full frame, using cropped sensor would give you the same thing except you crop some of the picture around it.  As simple as that.


True, but if u "crop" the full frame optically (use a longer lens) the dof shrinks significantly.  For example a 35mm 1.4 on a crop sensor has a similar fov as a 50mm 1.4 on ff, but the dof on the 50 at the same aperture and focus distance is much more narrow.


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## Derrel (Jul 22, 2011)

Schwettylens said:


> Sigh..  This topic again.  Basically if you shoot with with a full frame, using cropped sensor would give you the same thing except you crop some of the picture around it.  As simple as that.



Yes, this topic again; you might note that the OP has 12 posts to his name...the queartioin comes up quite often...I've tried to give some real information about the FF vs APS-C DIFFERENCES without sighing over a repetitive post topic.

Your thought process in this post isn't clear to me Schwetty. Not sure what you mean "using cropped sensor would give you the same thing except you crop some of the picture around it. A simple as that." Uh, no, it's not as simple as that, and the images made with a crop-body and a FF body are often vastly different, and are nowhere near the same thing.

Try using a 135mm lens on a 1.6x Canon body indoors; then, actually ENJOY being able TO use the same 135mm lens, indoors. Sorry, but the much larger sensor area of 24x36, either film or digital, is quite a bit different than capturing on APS-C or 4/3 or other tiny sensors. Schwetty, I see you're shooting with full-frame digital; why not APS-C digital? How did you arrive at your current format of choice? Were you after the superior High-ISO performance of the full-frame cameras?


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## Overread (Jul 22, 2011)

I can't add much to what has been said already simply to add that as another example of where depth of field shifts between the fullframe and crop sensors is in macro work - at 1:1 between the same macro lens on a fullframe and crop sensor camera body (ie focal length, aperture and distances all the same) the crop sensor will have around one stop more depth of field compared to the fullframe. 

In the macro world this is oft countered by the fact that you typically get one stop more to close down before diffraction softening kicks in with the fullframe bodies.


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## djd3mo (Jul 31, 2011)

Schwettylens said:


> Sigh..  This topic again.  Basically if you shoot with a full frame, using cropped sensor would give you the same thing except you crop some of the picture around it.  As simple as that.



True. Depth of Field is strictly dependent upon the lens and the subject distance. NOT sensor size. DoF increases when:
- subject distance increases;
- focal length decreases (Field of View increases);
- aperture decreases (f-number increases);
- size of lens type decreases.

If the first three may be easy to grasp, the last one is a bit strange but let me go through with it. An FX 50mm lens produces a wider FoV than a DX 50mm lens. If the FoV is bigger but the focal length is the same then what changed ? Well, the size of the optical elements grew. The lens is thicker and another "side" effect of this growth is a shallower DoF. So an FX 50mm lens not only produces a wider FoV but also a shallower DoF than a DX 50mm lens. That's why you can never mimic all the aspects of a full frame photo with a cropped sensor photo. You may be able to get the same FoV as the FX 75mm lens using a DX 50mm lens but the DoF will be bigger. Or you can use the same FX 75mm lens to get the same DoF but then the sensor will only record a cropped FoV.

Hope it helped !


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## Helen B (Jul 31, 2011)

There are _four_ main factors that determine depth of field: distance to the object that is focused on, relative aperture (f-number), focal length of lens and maximum acceptable diameter of the circle of confusion (how much blur can be tolerated in the image on the film/sensor before it appears to be out of focus in the final, viewed, image - with the same CoC criterion being applied to both of the viewed images). 

The latter comes into play when comparing different sensor sizes (and even sensors of the same size but different photosite sizes). To get the same size of viewed image, the image from a small sensor has to be enlarged more than the image from a large sensor, therefore it needs to be sharper to begin with - ie the maximum acceptable CoC is smaller. This partly offsets the advantage of using lenses of shorter focal length when at the same subject distance, but the focal length has more effect on the DoF (DoF is approximately inversely proportional to the square of the focal length) than the CoC diameter does (approx. simple proportionality). At the same subject distance, field-of-view and relative aperture the crop sensor will have more DoF than the larger sensor, ignoring diffraction, lens aberrations and sensor/film resolution.

This does mean that if you hold everything else constant (ie distance, focal length, aperture and size of final viewed image) the image from a cropped sensor will generally look less sharp than one from a full-frame (using the full frame of course). This situation is not the usual one for comparing DoF because the framing of the two images in terms of field-of-view is different. 

Best,
Helen


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## Robin Usagani (Jul 31, 2011)

I am getting confused reading all of this.


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## Robin Usagani (Jul 31, 2011)

This is from Bob Atkin's website Jake posted.:
&#8226; If you use the *same* lens on a Canon APS-C crop sensor camera and a 35mm full frame body and *crop*    the full frame 35mm image to give the same view as the APS-C crop image, the depth of field is *IDENTICAL*



Overread said:


> I can't add much to what has been said already simply to add that as another example of where depth of field shifts between the fullframe and crop sensors is in macro work - at 1:1 *between the same macro lens on a fullframe and crop sensor camera body (ie focal length, aperture and distances all the same) the crop sensor will have around one stop more depth of field compared to the fullframe.
> 
> *In the macro world this is oft countered by the fact that you typically get one stop more to close down before diffraction softening kicks in with the fullframe bodies.


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## Helen B (Jul 31, 2011)

Schwettylens said:


> This is from Bob Atkin's website Jake posted.:
> &#8226; If you use the *same* lens on a Canon APS-C crop sensor camera and a 35mm full frame body and *crop*    the full frame 35mm image to give the same view as the APS-C crop image, the depth of field is *IDENTICAL*



Well, yes. You are using the full-frame sensor as if it was a crop sensor. Of course the results will be identical in terms of DoF. The difference comes when you use the full area of the larger sensor.

Best,
Helen


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## djd3mo (Jul 31, 2011)

Helen B said:


> There are _four_ main factors that determine depth of field: distance to the object that is focused on, relative aperture (f-number), focal length of lens and maximum acceptable diameter of the circle of confusion (how much blur can be tolerated in the image on the film/sensor before it appears to be out of focus in the final, viewed, image - with the same CoC criterion being applied to both of the viewed images).
> 
> The latter comes into play when comparing different sensor sizes (and even sensors of the same size but different photosite sizes)...



Actually it doesn't care about sensor size. You are right, it's the Circle of Confusion the fourth element (but I didn't want to add more confusion  ). But the CoC is also a lens parameter and it's independent of the sensor size or pixel density. Those being said, for FX lenses we have a CoC of ~0.03mm and for DX lenses we have a CoC of ~0.02mm. Indeed these values were chosen when the lenses were built considering the final print, but they aren't related to the sensor size.


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## Helen B (Jul 31, 2011)

Sorry, but I have the impression that you don't understand this issue.



Best,
Helen


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## Robin Usagani (Jul 31, 2011)

Then to fill the sensor with the subject for the full frame, you have to come closer.  That means the distance is not the same.  But this is limited to macro world because you are already at the minimum focus distance usually.


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## djd3mo (Jul 31, 2011)

Helen B said:


> Sorry, but i have the impression that you don't understand this issue.
> 
> Best,
> helen



And why would you have this impression ?


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## frisii (Jul 31, 2011)

outdoors said:


> Is there a significant difference in the DoF on a Full Frame vs a Crop?



Yes


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## Helen B (Jul 31, 2011)

djd3mo said:


> Helen B said:
> 
> 
> > Sorry, but i have the impression that you don't understand this issue.
> ...



_"But the CoC is also a lens parameter and it's independent of the sensor size or pixel density. Those being said, for FX lenses we have a CoC of ~0.03mm and for DX lenses we have a CoC of ~0.02mm."_

No. Those CoCs have nothing to do with the lens itself. They are chosen for the sensor size.

_"If the FoV is bigger but the focal length is the same then what  changed ?  Well, the size of the optical elements grew. The lens is  thicker and  another "side" effect of this growth is a shallower DoF."_

No. If that was true an FX lens on a DX body would produce a different DoF than a DX lens on a DX body. It doesn't.

Best,
Helen


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## djd3mo (Jul 31, 2011)

Helen B said:


> No. If that was true an FX lens on a DX body would produce a different DoF than a DX lens on a DX body. It doesn't.



Well, it does !


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## Helen B (Jul 31, 2011)

djd3mo said:


> Well, it does !



That confirms my suspicion.

Sorry,
Helen


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## Robin Usagani (Jul 31, 2011)

I go with full frame so I look cooler mr derrel.




Derrel said:


> Schwettylens said:
> 
> 
> > Sigh..  This topic again.  Basically if you shoot with with a full frame, using cropped sensor would give you the same thing except you crop some of the picture around it.  As simple as that.
> ...


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## Mike_E (Jul 31, 2011)

Try reading this, it may help..Understanding Depth of Field in Photography


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## djd3mo (Jul 31, 2011)

Helen B said:


> Schwettylens said:
> 
> 
> > This is from Bob Atkin's website Jake posted.:
> ...



You're saying that the original full frame photo has a different DoF than the APS-C photo but after I crop the FF photo to the APS-C size, the DoF is identical ? Wow ! Are the photosites getting closer ?

OK! Enough is enough.

Besides the distance, focal length and aperture, which you already know how they work, we have the circle of confusion. Indeed - confusion.

Once and for all, the Circle of Confusion is a LENS parameter. When a lens is built, it's built for a specific camera format. It's calculated so for a fixed size photo it produces the same clarity. So, if it's built for a FF camera the CoF is ~0.03 and if it's built for a APS-C camera the CoF is ~0.02. The FX CoF is bigger because it's intended to be used on FF camera bodies, therefore bigger sensors, so it can get away with a smaller magnification when printed on the same size paper. But if you look at two pictures taken with two different format lenses, DX and FX, (while camera body, distance, focal length and aperture stay the same) on your desktop at 100% magnification, then the difference is obvious. While if you change the bodies but the lens used is the same then there is no difference at all at 100% magnification.
I cannot give an example for the first situation yet, but I can give you an example for the second one:

Same lens 70-180 mm Zoom-Micro-Nikkor, same aperture f/8, same focal length 180mm, same distance 0.72m, same angle 45 degrees, same crop at 100% magnification.
Different cameras:
D3







And D300






Focused on 15 bar. Credits - Nikon D3 Reviewed. FX vs DX formats
May the light be with you !


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## Helen B (Jul 31, 2011)

You are still misunderstanding this. Please carefully read what I wrote. The example you show demonstrates one of the statements I made, and contradicts nothing I have written. Please note that at the outset I stated that the DoF comparisons I was giving were for when the final image is presented at the same size (using the full size of the initial image). The example you show is for the same final magnification (subject to 'print') - this is a different case. It may sound complicated, but once you understand how and why the maximum CoC criterion is arrived at it becomes clear.

I'll reiterate the fact that the CoC is chosen for the format. Lenses are indeed designed for optimum performance and coverage for a particular format, but this has more effect on their maximum resolution and may have no effect on DoF, simply because DoF is all about objects that are not in perfect focus. 

Even within a format it is often advisable to use different CoC criteria for different situations. There's little point in setting the maximum CoC to a value significantly smaller than the size of a photosite, for example. The more the format is magnified to the final image, or the higher the resolution of the recording medium the more likely it is that a smaller maximum CoC criterion will be justifiable. This is also noticeable in film - I shoot large format for both magazine covers and for very large prints, and I can use different CoC criteria for each application. Same with 16 mm film - we had to decrease our CoCs for the same lenses as film improved.

Best,
Helen

Best,
Helen


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## djd3mo (Jul 31, 2011)

You perfectly understand the sensor to print process and how a CoC is determined, but you don't get the optics ! After the CoC is established, the lens is built to reach that value. CoC is a characteristic of the lens. It represents the maximum spot diameter of the projected image of a focused point onto the surface of the film/sensor. It's actually the diameter of the spot of light. And it DOES affect the DoF !!! I will give the examples at the end of this post.

You are talking about DoF from the perspective of the final print but take into consideration that a lot of cropping can be done in between taking the photo and printing. You cannot say that for every different crop you may have a different DoF. If I print the two photos from the previous post at a 4x6 format they will look the same. They will have the same depth of field.

Let me give you another example. The DX crop of a D3x 24.5MP photo is a 10.5MP photo and a D80 photo has 10.1MP. The D3x DX cropped photo and D80 photo would have the same size and roughly the same pixel density, therefore you can print them at the same paper size. Where is the difference now ?

Now let's get back to the last part of your statement:_ "Lenses are indeed designed for optimum performance and coverage for a particular format, but this has more effect on their maximum resolution *and may have no effect on DoF, simply because DoF is all about objects that are not in perfect focus*."
_
Now let me show a couple of pictures and then you tell me if the different DoF has anything to do with the different lenses:
Same camera Nikon D80, same distance (not measured but I didn't move the tripod nor changed camera angle or elevation), same focal length 135mm, same aperture f/8, same photographer (  ).
Different lenses:
Nikon AF-S 55-200mm f/4-5.6 G ED *DX *VR:






And Sigma 70-300mm f/4-5.6 DG APO Macro - Nikon AF-D *FX*:






You may safely say that the DoF increases with the CoC, while the CoC is a characteristic of the lens. I admit I mistook the direction of the change, but there is definitely a difference, you may easily see it !


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## Dao (Jul 31, 2011)

From Wikipedia: " the circle of confusion diameter limit (CoC) for the final image is  often defined as the largest blur spot that will still be perceived by  the human eye as a point."


From Bob Atkin: "It's important to note that DOF isn't a lens characteristic like focal length or aperture. It takes into account some subjective factors like print size and viewing distance. That's the reason different values for the CoC are used for different formats. Larger formats need to be enlarged less than smaller formats, and so a larger CoC can be used."


From NikonUSA "In photography, the circle of confusion (CoC) is used to determine the  depth of field, the part of an image that is acceptably sharp. A  standard value of CoC is often associated with each *image format*, but  the most apprpriate value depends on *visual acuity*,* viewing conditions*  and the *amount of enlargement*."


I strongly believe CoC is not a physical property of a lens.

My Canon APS-C camera CoC is 0.018mm or 18 microns, it is 18 microns when I use my 50mm lens.  It is 18 microns when I use my 85mm lens.  And it is going to be 18 microns when I use my 14mm lens.  However, when I mount those lens to my EOS film body, the CoC becomes 29 microns (or 0.029mm).


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## djd3mo (Aug 1, 2011)

Who am I to shatter your strong beliefs, Dao, when even the visual examples weren't able to do that ?


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## jake337 (Aug 1, 2011)

Buy a FF and take pictures.

Buy a DX and take pictures.

Buy a cell phone and take pictures.

Lets just take some pictures.


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## djd3mo (Aug 1, 2011)

I took the pictures and I also posted them here. What else ?


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## Dao (Aug 1, 2011)

djd3mo said:


> Who am I to shatter your strong beliefs, Dao, when even the visual examples weren't able to do that ?


When I first came across with the term Circle of Confusion in 2008, I did a great deal of reading about it as well as DoF.  And all the articles, opinions from other sites make me believe that is the correct.   

So I have no reason to believe you when you said "CoC is a characteristic of the lens".  Sorry.

Unless, Bob Atkin was wrong, information I read from Wikipedia was wrong, Nikon USA post wrong information, dpreview.com post wrong definition about CoC 

Since you are the only one I found (so far) said CoC (of DoF) has nothing to do with sensor size (recording medium) and it is a characteristic of the lens, so I will stay with what I believe.


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## djd3mo (Aug 1, 2011)

Let me rephrase it:
Don't mind me, look at the pictures !


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## Dao (Aug 1, 2011)

May I repeat what Helen said "Sorry, but I have the impression that you don't understand this issue."


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## Helen B (Aug 1, 2011)

djd3mo said:


> You perfectly understand the sensor to print process and how a CoC is determined, but you don't get the optics ! After the CoC is established, the lens is built to reach that value. CoC is a characteristic of the lens. It represents the maximum spot diameter of the projected image of a *focused* point onto the surface of the film/sensor. It's actually the diameter of the spot of light. And it DOES affect the DoF !!! I will give the examples at the end of this post.



You have got mixed up between the minimum CoC a lens is capable of (the smallest blur area the lens makes for an object point in focus &#8211; which is a property of the individual lens design, but which has nothing to do with DoF); and the maximum acceptable CoC that is created by out-of focus objects before they appear to be out of focus in the image at its intended viewing size. This is not part of the lens design, but it is what determines DoF.



> Once and for all, the Circle of Confusion is a LENS parameter. When a lens is built, it's built for a specific camera format. It's calculated so for a fixed size photo it produces the same clarity. So, if it's built for a FF camera the CoF is ~0.03 and if it's built for a APS-C camera the CoF is ~0.02.


 
Have you thought about this? You are insistent on it being true, but it is complete nonsense. 0.03 mm is 30 microns. The pixel pitch of the D3 (which isn&#8217;t a leader in terms of pixel density) is 8.45 microns. Are you really suggesting that FX lenses are designed to produce a CoC that is 3.5 pixels wide on a D3? That&#8217;s crazy.




> You are talking about DoF from the perspective of the final print but take into consideration that a lot of cropping can be done in between taking the photo and printing. You cannot say that for every different crop you may have a different DoF. If I print the two photos from the previous post at a 4x6 format they will look the same. They will have the same depth of field.



4x6 is not very good for the consideration of DoF because the criterion is quite relaxed at that size.  Different crops of the same original image do indeed show different DoFs when they are enlarged to the same size. This is easy to imagine and easy to see. It all depends on the degree of magnification between the originally-recorded image and the final print. The more you enlarge a slightly blurred detail, the more it is likely to be visible as a blurred detail and not perceived as a point. What is so hard about understanding that?




> Let me give you another example. The DX crop of a D3x 24.5MP photo is a 10.5MP photo and a D80 photo has 10.1MP. The D3x DX cropped photo and D80 photo would have the same size and roughly the same pixel density, therefore you can print them at the same paper size. Where is the difference now ?



I&#8217;ve already covered this and said that there is no difference, so why do you bring it up as a point of argument? Don't you understand what I have written?





> Now let's get back to the last part of your statement:_ "Lenses are indeed designed for optimum performance and coverage for a particular format, but this has more effect on their maximum resolution *and may have no effect on DoF, simply because DoF is all about objects that are not in perfect focus*."
> _
> Now let me show a couple of pictures and then you tell me if the different DoF has anything to do with the different lenses:
> Same camera Nikon D80, same distance (not measured but I didn't move the tripod nor changed camera angle or elevation), same focal length 135mm, same aperture f/8, same photographer (  ).



I&#8217;m afraid that these examples show nothing other than your lack of understanding. You are trying to show a depth of field comparison. To do that you need to show:
-the exact point that is in perfect focus (that is not the same as focusing on the same point &#8211; there must be no errors)
-the transition from objects that appear to be in focus to those that appear to be out of focus. DoF is about objects that are not in the plane of focus, but still appear to be in focus. It is not about objects that appear to be out of focus.


Best,
Helen


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## Robin Usagani (Aug 1, 2011)

No wonder they call it circle of "confusion".  I am confused as heck!


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## Mike_E (Aug 1, 2011)

Schwettylens said:


> No wonder they call it circle of "confusion".  I am confused as heck!



And all of this for something that differs when you change glasses.


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## Helen B (Aug 1, 2011)

For my own amusement I compared a couple of zooms I have - one old FX for my D3 and one DX for my D40x, both on the D3. Set to ~60 mm. f/5.6, 1.2 m distance, tethered, focused using Live View in Camera Control 2 and focus checked in Capture NX2 at 100%, DX lens carefully adjusted until it matched the FX lens in terms of focal length (actually image size on the sensor). The split between the two images occurs between the two sets of bars:







The lenses have very slightly different resolutions (the older FX lens has slightly higher resolution than the DX lens). Apart from that there isn't a significant difference in the steady defocusing away from the focus point, I think.

Best,
Helen


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## djacobox372 (Aug 2, 2011)

Those of you that think sensor size doesn't affect dof should try shooting 8x10 film--you'd be blown away how small the dof is at f8.

There are only three things that affect dof: 

1) aperture (wider narrows dof)
2) focal length (longer narrows dof)
3) distance to the subject (closer narrows dof)

When shooting with a smaller sensor/film you have to either increase distance or shorten focal length, both of which will widen your dof.

A "normal" lens on a crop sensor is 35mm which has a wider dof then a 50mm (normal for fx) at the same aperture and focus distance.

A "normal" lens for an 8x10" film camera is a whopping 300mm! Which means your dof will be very narrow even at higher apertures.


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## Sw1tchFX (Aug 2, 2011)

I don't know if it makes any difference, but I was doing a comparison between Fuji and Noritsu scanners, and at the same time medium format vs. 35mm for DOF. Take a look at this in regards to DOF (don't mind the scanning):

The LEFT is the Mamiya 645AFD @ 80mm, f/2.8. The RIGHT is an F100 @ 50mm, f/1.4





Look at how strikingly similar the background looks(aside from the crappy noritsu scanning). One was shot on medium format film, the other 35mm. Exposures were equivalent to each other.


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