Where to compare dof between the 6D and 1D4?

Since the 6D uses a FF sensor, it should allow for less dof than my 1D4 (1.3 sensor).

Is there a site that compares images from these two cameras? For example, if both cameras had a 24mm lens @ f2.8, I'd like to see how much less dof the 6D provides.

I bought my 1D4 for air shows, for the fast and accurate AF. But I like to shoot car shows (static displays) and museums, and for that it seems the 6D will give me these advantages...

Less dof for blurred back grounds

Wider fov when used with the 24-70 f2.8 II

Better at lifting shadows and recovering highlights (at least I think it might be)

Smaller and lighter body.

http://www.dofmaster.com/dofjs.html

You can google "dof calculator" for more links.

Edit: the calculator shows "dof" but not actual image.  I'm not aware of any dof that shows actual images, as there are infinitely many sensor size, aperture size, subject distance, etc.

The crop factor between the 1D4 and the 6D is 1.26.

So, a 24-70 / 2.8 on a 6D is equivalent to a 19-56 / 2.2 on a 1D4, and a 24-70 / 2.8 on a 1D4 is equivalent to a 30-88 / 3.5 on a 6D.

Thus, if you took a pic at 24mm f/2.8 on a 1D4, it would have the same AOV and DOF as 30mm f/3.5 on a 6D.  If you took a pic at 30mm f/2.8 on a 6D, it would have the same AOV and DOF as 24mm f/2.2 on a 1D4.

There is a DOF calculation you can google which gives all relevant info.  

--
Alan.
It is better to keep your mouth closed and let people think you are a fool than to open it and remove all doubt.
Mark Twain

not so simple, i think you are imagining....the f2.8 aperture remains the same and does not change due to the size of sensor!

cheerz.

Maybe this will help:

http://www.josephjamesphotography.com/equivalence/index.htm#introduction

A 50mm f/2 lens is a 50mm f/2 lens regardless of the sensor that sits behind it.  However, the effect of 50mm f/2, in terms of the visual properties of the recorded photo, depend very much on the sensor that sits behind the lens:

50mm f/2 on 4/3 (mFT) is equivalent to 62.5mm f/2.5 on 1.6x (Canon APS-C), 67mm f/2.7 on 1.5x (APS-C for everyone else), and 100mm f/4 on FF (FX), where "equivalent to" means:

• The photos all have the same AOV (diagonal angle of view) and aperture (entrance pupil) diameter: 50mm / 2 = 62.5mm / 2.5 = 67mm / 2.7 = 100mm / 4 = 25mm.

• The photos all have the same DOF (as well as diffraction softening) when they have same perspective (subject-camera distance), AOV, aperture diameter, and display size.

• The photos all have the same motion blur and the same total amount of light falls on the sensor when the aperture diameter and shutter speed are the same (e.g. ISO 100 on mFT, ISO 160 on APS-C, and ISO 400 on FF).

• The photos all have the same same noise when the same total amount of light falls on the sensor if the sensors are equally efficient (less noise if the sensor is more efficient, more noise if the sensor is less efficient).

• Other elements of IQ, such as resolution, bokeh, flare resistance, etc., as well as elements of operation, such as AF speed/accuracy, size, weight, etc., are not covered in this use of the term "equivalent".

that is pseudo science...aka B$! here is a simple test...take any lens at any F stop and use it on any sensor camera and check your EXIF and see what you find. i think you'll find out that joseph james is wrong!

cheerz.

Well said Joe. However just want to make clear for crop cameras to use smaller F number such as in your case mFT 50/2.0 lens at F2.0, for the same FOV, FF shooters do NOT have to shoot at F4 at 100mm in order to have the same DOF. It's a holy "principle" some crop especially some mFT zealots arguing about. I'd prefer to shoot at F2.8 or F3.2 for better back ground rendering to popup the subject. I stop down some lenses not because I want deeper DOF but to increase sharpness. Fortunately new Canon lenses such as 70-200L/2.8 IS II and 24-70L/2.8 II are very sharp even at F2.8 so I don't have to stop down in low light, the purpose of fast-aperture lenses.

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OK, I guess you're right.  No reason to believe all the actual photos demonstrating the above:

http://ezstrobesphoto.blogspot.com/2009/01/more-d300-and-d700-equivalent-images_25.html

http://ezstrobesphoto.blogspot.com/2009/01/nikon-d300-vs-d700.html

etc., etc., etc.

This is not the way we shoot in real world. With the same lens such as 85/1.4, D700 shooter can move closer to frame the subject into the same FOV and shoot at the same F2.0 with less crop penalty - sharper, can shoot slower shutter (D300 shooter should shoot at 1/85*1.5 = 1/125 while D700 can shoot at 1/80 or 1/90 for the same pixel-level sharpness), cleaner and more separation of the subject from the background to popup the subject further. The ONLY advantage of crop format is pixel density when you are unable to move closer or don't have long enough lens.

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http://qianp2k.zenfolio.com/

In the "real world", we do not shoot a scene with two different cameras.  However, given that we need a particular perspective, framing, DOF, and shutter speed, yes, we would shoot systems with the Equivalent settings.

Moving changes the perspective.  We can compare one system to another in any number of ways, including keeping the lens cap on one camera and aiming the other one directly into the sun.  However, unless one system can use a perspective, framing, DOF, and/or shutter speed that the other system can't, and that these attributes result in a better photo, why would one compare on unequal basis?

Note that DOF is not the only criteria here.  However, since you bring it up:

http://www.josephjamesphotography.com/equivalence/#dofbox

And even then, only when the FF sensor has less pixel density than the crop sensor being compared against. There is no reason why this must be the case, of course. And if you compared a D800 to, say, a 20D, there would be no advantage at all in this respect.

However, there areother advantages to crop cameras, of course.

so based on JJ's finding, when i purchase a lens, the indicated f stop is not really what i am getting depending what crop or FF sensor my camera has? wouldn't that be a misrepresentation of the lens' f stop on manufacturers part, aren't the manufacturers aware of this fact? i still think it is nothing but illusion when he speaks of visual properties of the recorded photo, this sounds moor like oxymoron when afterwards he says everything down his list stays the same!

cheerz.

Nah - not really a misrepresentation - at least, no more than the focal length. Just the same as how a 100mm lens becomes, effectively, a 160mm lens when mounted on a crop.

What he says is right, but I certainly agree that it takes some time to fully wrap your head around. Stick with it though, it's not essential for the art of photography by any means, but if you are at all interested in the technicalities of attempting to compare different sensor sizes, then equivalence is a useful tool to understand.

Let's go right back to the first line of the link I gave you:

http://www.josephjamesphotography.com/equivalence/index.htm#introduction

A 50mm f/2 lens is a 50mm f/2 lens regardless of the sensor that sits behind it. However, the effect of 50mm f/2, in terms of the visual properties of the recorded photo, depend very much on the sensor that sits behind the lens:

So, yes, both the focal length and the f-ratio written on the lens are exactly what they say they are, but the effect of the f-ratio (DOF and total light projected on the sensor for a given shutter speed) scales in the exact same proportion as the effect of the focal length (AOV).

As I said, the lens is stamped with what it is.  But when comparing different formats, the effect of those numbers has a different meaning.  Just as 50mm on crop has a different AOV as 50mm on FF, f/1.4 on crop results in a different DOF and projects a different amount of light on the sensor for a given shutter speed, and these effects all scale in the same proportion.

Take a pic of a scene from the same position at 50mm f/1.8 on 1.6x and 80mm f/2.8 on FF with the same shutter speed.  Display the photos at the same size.  They will have the same perspective, framing, and DOF.  In addition, if the sensors are equally efficient, the photos will have the same noise.

By doing so you'd have to increase ISO on FF. But in reality you could shoot with a FF camera at the same F1.8 at the same ISO for the same FOV (or AOV), no reason to stop down to F2.8 to create the same pseudo DOF.  50mm on 1.6x is not the same as native 80mm on FF but only has the same FOV. If FF camera has sufficient amount of pixels such as 36mp D800 or future 46mp FF, so-call "extra reach" from crop format is the same as you also take with the same 50mm lens but then crop out to the same FOV to have the same IQ if the pixel density is the same between crop and FF. No mention you might be able to move closer (such as in portrait) to frame the subject into the same FOV without cropping (sure this will change the perspective). From my perspective the same FOV matters but not the same DOF Shallower DOF many times result more attractive 3-D look photos.  I shoot a FF camera no different from shooting a crop camera. I don't have to stop down.

As I said earlier crop camera's ONLY advantage (besides operation advantages) is pixel density (such as Canon 18mp sensor is equivalent to 46mp FF sensor) but that gap is narrowing such as in 36mp D800.  Then FF has every advantage.

Crop format = digital magnification = digital zooming = FF then crop out to the same FOV.

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Price is an advantage for crop. Weight and size can be an advantage to crop. Built-in flash can be an advantage. There are others too. Horses for courses - but pixel density is most definitely not the "ONLY" (as you keep shouting) advantage.

They are all other operation advantages but not optical and IQ advantages.

So for those advantages you might want to consider this announcement on mFT format although they are not necessarily much cheaper. They are not at the level of 85L/1.2 and 300L/2.8 IS II with FF cameras together. mFT would need 42.5mm/0.6 and 150mm/1.4 lenses to match FF counterparts but not only probably physical impossible but even possible would be very huge, very heavy and very expensive. We see Olympus 35-100mm F2.0 zoom (w/o 'IS') is even bigger, even heavier and even more expensive than Canon 70-200L/2.8 IS II, but only equivalent to F4.0 FF zoom.

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All that does is increase the output brightness of a jpg and decrease the read noise a bit.  In the end, as I said, if the sensors are equally efficient, the photos will have the same noise.

Same difference.  That is, if we have a FF sensor with the same pixel density as the 1.6x sensor, shoot both with the same focal length, f-ratio, and shutter speed, crop the FF photo to the framing as the 1.6x sensor, the photos wouldn't be merely Equivalent, but identical.

If the pixel densities are not the same (which they aren't for APS-C and FF), then using the same focal length, f-ratio, and shutter speed on both systems, cropping the FF photo to the same framing as the APS-C photo, the IQ advantage will go to APS-C, since the same total amount of light made up the photo, but more pixels are on the APS-C photo.

FF will still not have every advantage even given that it has the same pixel density -- it will still be a larger, heavier, and more expensive setup.

In any case, what kind of incompetent photographer shoots FF at 50mm f/1.8 with the intention to crop to the same framing as 50mm would give you on crop?  So, while 50mm f/1.8 on FF cropped to the same framing as 50mm f/1.8 on crop will result in the same DOF, who cares?  No competent photographer would ever do such a thing.

However, framing wider and cropping does apply when the photographer is either focal length or magnification limited.

Ant it's a complete waste of money to buy a FF DSLR to do that.  If you are focal length or magnification limited, use a smaller format, and save the size, weight, and money.  And guess what?  That's exactly what competent photographers do.