Why would i need full frame?

mikeassk wrote in post #4103645
This makes me a believer...

http://www.digitaljour​nalist.org/issue0710/t​ech-tips.html

"If all three factors [aperture, focal length, distance to subject] are the same on both cameras [crop and FF], then depth of field is identical..."
I'm so glad to read that! It is exactly what I thought, but was afraid to state for fear of seeming a fool.

xarqi wrote in post #4103705
"If all three factors [aperture, focal length, distance to subject] are the same on both cameras [crop and FF], then depth of field is identical..."
I'm so glad to read that! It is exactly what I thought, but was afraid to state for fear of seeming a fool.

Never be afraid of stating...just never be 100% sure until you can prove it.

xarqi wrote in post #4103705
"If all three factors [aperture, focal length, distance to subject] are the same on both cameras [crop and FF], then depth of field is identical..."
I'm so glad to read that! It is exactly what I thought, but was afraid to state for fear of seeming a fool.

Except it's not quite right, because when the two images are shown side by side at the same size, the crop camera's image will be a blown-up version of the middle part of the FF image, making parts of the FF image that were 'acceptably sharp' less sharp. This is why DOF calculators assume a smaller acceptable circle of confussion for APS-C cameras than for FF ones.

In other words the more you blow up an image, the smaller the depth of field appears to be. This is a simple test anyone can verify for themselves.

mikeassk wrote in post #4103645
This makes me a believer...

http://www.digitaljour​nalist.org/issue0710/t​ech-tips.html

For those wondering about Depth Of Field "differences between a 5D/ff camera and an xxD/xxxD/crop camera:

The discussion cited in the above post is in fact accurate. Anyone confused about the Depth Of Field issue should read it. Those who think they know the facts might also want to read it! There is a lot of confusion about this and sometimes misleading terms get tossed out which add to the confusion, such as "equivalent focal length" when trying to discuss DOF.

Thanks, Mike, for pointing us to an accurate explantion!

Tony

Tony Long Photos on PBase

Madweasel wrote in post #4106346
Except it's not quite right, because when the two images are shown side by side at the same size, the crop camera's image will be a blown-up version of the middle part of the FF image, making parts of the FF image that were 'acceptably sharp' less sharp. This is why DOF calculators assume a smaller acceptable circle of confussion for APS-C cameras than for FF ones.

In other words the more you blow up an image, the smaller the depth of field appears to be. This is a simple test anyone can verify for themselves.

Here, though, you are mixing Actual depth of field up with Perceived depth of field. The Actual depth of field is identical: if you crop the ff image to the same field of view as the crop sensor's image you will have the exact same image in terms of Actual depth of field.

Obviously, when you view the uncropped ff image, the Perceived depth of field will be different, since you will be viewing a wider field of view, but that doesn't change the Actual depth of field, which is what the cited discussion was about.

Remember, you are using the exact same lens with the same aperture on both cameras, not the same "equivalent focal length", so the image captured on the crop sensor will be the same as the center portion of the image captured on the ff sensor in every characteristic (except of course whatever difference in resolution and IQ).

Tony

Tony Long Photos on PBase

bwolford wrote in post #4068707
http://jamesmskipper.t​ripod.com …mskipper/perspe​ctive.html

http://web.canon.jp …g/enjoydslr/par​t3/3B.html - look "The sensor size also affects the 'coverage' even with the same lens."

http://web.canon.jp …g/enjoydslr/par​t3/3C.html - Scroll to the bottom.

This should, resolve this once and for all. Maybe not...

This is good stuff!

To look cool?

tonylong wrote in post #4106635
For those wondering about Depth Of Field "differences between a 5D/ff camera and an xxD/xxxD/crop camera:

The discussion cited in the above post is in fact accurate. Anyone confused about the Depth Of Field issue should read it. Those who think they know the facts might also want to read it! There is a lot of confusion about this and sometimes misleading terms get tossed out which add to the confusion, such as "equivalent focal length" when trying to discuss DOF.

Thanks, Mike, for pointing us to an accurate explantion!

Tony

Tony Long Photos on PBase

Ya, No worries.
This seems to be one of the most difficult concepts for some to grasp?

mike

Yeah, initially you have to sort it out in your head, it can be confusing since DOF is affected by 3 different physical things. People get confused about cropping sensors, people tossing in bokeh, discussions of equivalent focal lengths, all of which can be ignored in the "actual" DOF.

In practice, it's fortunately pretty simple, as long as you know the basics.

Tony

---------------

Several Canon cameras, too many lenses and stuff to list

Tony Long Photos on PBase

Madweasel wrote in post #4106346
Except it's not quite right, because when the two images are shown side by side at the same size, the crop camera's image will be a blown-up version of the middle part of the FF image, making parts of the FF image that were 'acceptably sharp' less sharp. This is why DOF calculators assume a smaller acceptable circle of confussion for APS-C cameras than for FF ones.

In other words the more you blow up an image, the smaller the depth of field appears to be. This is a simple test anyone can verify for themselves.

That circle of confusion is aptly named! Just when I thought I was unconfused, I'm back where I started!

tonylong wrote in post #4106692
Here, though, you are mixing Actual depth of field up with Perceived depth of field. The Actual depth of field is identical: if you crop the ff image to the same field of view as the crop sensor's image you will have the exact same image in terms of Actual depth of field.

Obviously, when you view the uncropped ff image, the Perceived depth of field will be different, since you will be viewing a wider field of view, but that doesn't change the Actual depth of field, which is what the cited discussion was about.

Remember, you are using the exact same lens with the same aperture on both cameras, not the same "equivalent focal length", so the image captured on the crop sensor will be the same as the center portion of the image captured on the ff sensor in every characteristic (except of course whatever difference in resolution and IQ).

Tony

Tony Long Photos on PBase

Yes, I am talking about what YOU are calling 'perceived' DOF, but what is it if not perceived? There is no such thing as 'actual' DOF. All that DOF means is the depth of focus that is acceptably sharp, and that depends on how much you magnify the image. In principle there is only one point (distance from the sensor plane) of focus, and points either side of that get progressively more out of focus. There is no absolute. We decide for ourselves what looks sharp, and that depends on how much you enlarge the image.

Think of it this way; ultimately if the circle of confusion is smaller than the finest detail that the sensor can resolve, then it looks sharp. If you increase resolution that is no longer true, even for the very same lens, aperture and focus distance.

Ask yourself why all the on-line DOF calculators will give a different result for different sensor sizes. They use a different size value for the acceptable circle of confusion.

sootyvrs wrote in post #4054910
I think the biggest advantage for me using FF is the additional DOF control.

With a APS-C camera a f1.4 prime would only give you equivalent DOF as a FF camera @ f2.2. This can be quite significant when you want to get creative.

True but there are some cases were APS-C has the advantage in DOF like in Macros and landscapes

xarqi wrote in post #4103705
"If all three factors [aperture, focal length, distance to subject] are the same on both cameras [crop and FF], then depth of field is identical...".

If you quote, quote accurately
"If all three factors are the same on both cameras, then depth of field is identical, but the angles of view are not." (emphasis mine)

This is what happens if you change FL to get the same FoV.
Here is the whole explanation.

René Damkot wrote in post #4112053
If you quote, quote accurately
"If all three factors are the same on both cameras, then depth of field is identical, but the angles of view are not." (emphasis mine)

This is what happens if you change FL to get the same FoV.
Here is the whole explanation.

I stand by the accuracy of my quote. It omitted only those parts that were irrelevant (that FoV changed, something that was quite obvious to me), and added, in brackets, text necessary to understand the context.

Thanks for the links. The first one explores the focal length/FoV aspect, which I'm already comfortable with; the second confirms what was stated, and on which I originally commented:

Madweasel wrote in post #4111979
If you increase resolution that is no longer true, even for the very same lens, aperture and focus distance.

Your beating this into the ground,
that has nothing to do with sensor size and is exceptionally negligible change what does exist in ACTUAL depth of field.