5D Mark II Lens?

[KeithPratt]

To my knowledge, sensor-size also doesn't have an effect on DOF, at all.

Technically sensor size doesn't affect DoF, but real world it kinda does. I'm struggling for a word or phrase to use here; best I can come up with is "blur per inch". Whilst there is no more "blur per inch" on the sensor, when you take footage from a smaller sensor and play it back on a TV screen, there is. Sort of like if you crop an image in Photoshop then display it the same size as the uncropped image, there ends up being more unfocused image on the screen.

Different glass and aperture blade designs in lenses also affect the apparent depth and softness of the image.

 

[surferfromuk]

Make sure you are fully aware of the rolling shutter issues with the current generation DSLR Video and the lack of XLR inputs before you commit.

 

[namethisfile]

Technically sensor size doesn't affect DoF, but real world it kinda does. I'm struggling for a word or phrase to use here; best I can come up with is "blur per inch". Whilst there is no more "blur per inch" on the sensor, when you take footage from a smaller sensor and play it back on a TV screen, there is. Sort of like if you crop an image in Photoshop then display it the same size as the uncropped image, there ends up being more unfocused image on the screen.

Different glass and aperture blade designs in lenses also affect the apparent depth and softness of the image.

i have never heard of "blur per inch." i think it's funny tho that u r making up your own term. good for you. still, i think what you end up explaining is not DOF, but cropping an image and then blowing it up. hence, the resolution is compromised and the "digital artifacts," or pixels or whatnot are more visible.

DOF, from my knowledge is completely "lens independent control." there, i just made up my own term, too. hahaha. let me explain.

"Lens independent control" or LIC is just what it says. Besides DOF, other lens independent control are: aperture, focus and framing. i can't get any simpler than that.

 

[Macinposh]

To my knowledge, sensor-size also doesn't have an effect on DOF, at all.

Duude....
What can I say.

[picture] picard makes the facepalm [/picture]



I recommend stepping away from the keyboard.Pronto.


Sensor size has everything,everything to do with DOF.
The bigger the physical size of the sensor/film is,the bigger the image circle needs to be=the larger distance to the filmplane=longer focal length to achieve the same FOV=shorter DOF.



Once again...duuude....

 

[namethisfile]

Duude....
What can I say.

[picture] picard makes the facepalm [/picture]



I recommend stepping away from the keyboard.Pronto.


Sensor size has everything,everything to do with DOP.
The bigger the physical size of the sensor/film is,the bigger the image circle needs to be=the larger distance to the filmplane=longer focal length to achieve the same FOV=shorter DOP.



Once again...duuude....

What's DOP?

I thought it was DOF mispelled at first but you misspell it twice.

that circle is called a bokeh and this is controlled by the aperture ring. the wider the aperture ring, the bigger is the bokeh. last time i checked, the aperture ring itself is in the lens. the sensor, if anything, only records this information. hence, my claim that DOF has nothing to do with the sensor.

i don't even know how the distance of the filmplane is relevant in this because... first of all, you cannot change this setting.

but, FOV or field of vision does, but not in the way you equate it. Actually, FOV is another "LIC" or Lens Independent Control" that I explained earlier and this is controlled with the zoom, if your lens has this capability. Generally, the wider you get, the less the DOF and the shallower you zoom in, the more DOF. But, this also depends on your aperture.

 

[macjonny1]

i have never heard of "blur per inch." i think it's funny tho that u r making up your own term. good for you. still, i think what you end up explaining is not DOF, but cropping an image and then blowing it up. hence, the resolution is compromised and the "digital artifacts," or pixels or whatnot are more visible.

DOF, from my knowledge is completely "lens independent control." there, i just made up my own term, too. hahaha. let me explain.

"Lens independent control" or LIC is just what it says. Besides DOF, other lens independent control are: aperture, focus and framing. i can't get any simpler than that.

I think it is funny that both of you have no idea what you are talking about, but present it as truth. Here's a link to learn:

http://photo.net/learn/optics/dofdigital/

 

[LethalWolfe]

i don't even know how the distance of the filmplane is relevant in this because... first of all, you cannot change this setting.

Sensor size does come into play which is why, for example, with all other things being equal a video camera w/a 1/4" imager won't won't have the same DOF as a video camera w/a 2/3" imager.


Lethal

 

[namethisfile]

DOF or not DOF. That is not a question.

mathematically it makes sense. and i maybe wrong mathematically that DOF has nothing to do with the sensor. But, I am gonna go on a limb and say that I still hold my ground firmly in the camp of DOF being the effect generated in tandem with the lens, aperture and subject-distance.

 

[macjonny1]

mathematically it makes sense. and i maybe wrong mathematically that DOF has nothing to do with the sensor. But, I am gonna go on a limb and say that I still hold my ground firmly in the camp of DOF being the effect generated in tandem with the lens, aperture and subject-distance.

I hear ya. I'm holding my ground that the world is flat.

 

[imdjay]

jeez guys, be practical....

bright shots: 5dmkii, darks shots: 30d
both taken with the same 50mm at F8 at the same distance focusing on the same point

If you read the link macjonny1 posted, this should make more sense now, if you haven't. go read it and understand why you can't see the differrence in DOF between either camera (1.6x vs FF)

Now realize that i had to crop the 5D shots to match the 30D shots because the FF camera has a wider field of view, but the circles of confusion are still the same. Now, had i zoomed in on the 5d to match the field of view on the 30d, the circles of confusion would expand and created a more blurred bokeh.

circles of confusion relate to but are different than DOF, DOF is how much is in focus, while the circles of confusion tell you just how blurry the out of focus parts are.

any questions?

 

[namethisfile]

I hear ya. I'm holding my ground that the world is flat.

huh? the world isn't flat?

 

[namethisfile]

bright shots: 5dmkii, darks shots: 30d
both taken with the same 50mm at F8 at the same distance focusing on the same point

If you read the link macjonny1 posted, this should make more sense now, if you haven't. go read it and understand why you can't see the differrence in DOF between either camera (1.6x vs FF)

Now realize that i had to crop the 5D shots to match the 30D shots because the FF camera has a wider field of view, but the circles of confusion are still the same. Now, had i zoomed in on the 5d to match the field of view on the 30d, the circles of confusion would expand and created a more blurred bokeh.

circles of confusion relate to but are different than DOF, DOF is how much is in focus, while the circles of confusion tell you just how blurry the out of focus parts are.

any questions?

why is one darker than the other?

the DOF looks identical to me btwn the dark and lighter ones.

maybe if you actually point it out w/ markers on the images, it would help more.

 

[imdjay]

why is one darker than the other?

the DOF looks identical to me btwn the dark and lighter ones.

maybe if you actually point it out w/ markers on the images, it would help more.

sorry,

it's painfully obvious you are ignoring the technical points i made and didn't at all read the other link posted which explains things clearly. So until you actually read that information and we can have an informed conversation, i really can waste my braincells on something more interesting... like clipping my toenails.

oh and they are different brightnesses because the sensors have different sensitivities and i used different ISOs, but that's a whole nother' discussion i don't think you would fare well in.

toodles,

 

[KeithPratt]

I think it is funny that both of you have no idea what you are talking about, but present it as truth. Here's a link to learn:

http://photo.net/learn/optics/dofdigital/

It's hilarious when someone does that isn't it?

My point was that, speaking theoretical terms, sensor size does not affect DoF. In practical terms it does a little, but not as most people here seem to think. I think this might have been misunderstood in my earlier post, so please allow me a second attempt:

Do this (don't do this, it's obviously a terrible idea):

* Find a scene that will not change, like a studio with controlled subject and lighting.

* Get your Canon 5D mkII and your 50mm f/1.2, and pop it on a tripod. Take a photo.

* Now, very carefully, remove the sensor from the 5D. Measure a 1.6 crop on it and mask that area off with some black electrical tape.

* Put the sensor back in the camera and take another photo (changing no settings).

* Now import the two photos into Photoshop. They'll look something like this:





Crop out the black region on second pic and then crop the first image to match. You'll get something like this:





The images are the same, no? The DoF, the FoV, both the same. Conclusion: sensor size — theoretically — does not affect DoF.

In practical terms, little inconsistencies mean there will be a difference. So too will moving three feet back to get the same FoV with the 50mm on a 1.6 crop as a full frame. But that's not the sensor size, that's you.


Prove me wrong kids, prove me wrong.

 

[namethisfile]

sorry,

it's painfully obvious you are ignoring the technical points i made and didn't at all read the other link posted which explains things clearly. So until you actually read that information and we can have an informed conversation, i really can waste my braincells on something more interesting... like clipping my toenails.

oh and they are different brightnesses because the sensors have different sensitivities and i used different ISOs, but that's a whole nother' discussion i don't think you would fare well in.

toodles,

i read that article but it is painful as anyone can attest. and if they say they enjoyed reading it then they r lying. all i can say is that i tried reading it. now, r u happy? and then here u r, with your visual examples just pointing out my doubts how little, if at all, sensor would affect DOF in real world practical terms.

but there's more, you purposely made one brighter than the other to make an arbitrary point about one sensor being more sensitive than the other. i don't even wanna begin to go there. a better attempt could have been made (if what you say about sensor-sensitivity is true) to make the exposures more EVEN. even, if it means the setting being different because exposure has nothing to do with DOF. unless, i am wrong there, too.

 

[Edge100]

Sensor size only affects DOF in one way: to get the same FOV from a 35mm sensor vs. a (e.g.) 1.6x crop sensor, once has to get closer to the subject (since effective focal length is 60% longer in the 1.6x crop sensor).

As you move closer to the subject, DOF gets smaller. Thus, if I'm composing a shot for a particular FOV, using a full-frame, 35mm sensor camera (likethe 5DII)and composing the same shot with a 1.6x crop camera (like the 7D), ceteris paribus, I am closer to the subject with the full-frame camera than I am with the 1.6x crop camera, and consequently, my DOF is smaller.

So, the larger sensor doesn't affect DOF, per se, but does force you to get closer to the subject than you might otherwise. And that most certainly DOES affect DOF.

Edit: My post is equivalent to point #1 in the linked article above.

 

[namethisfile]

. Thus, if I'm composing a shot for a particular FOV, using a full-frame, 35mm sensor camera (likethe 5DII)and composing the same shot with a 1.6x crop camera (like the 7D), ceteris paribus, I am closer to the subject with the full-frame camera than I am with the 1.6x crop camera, and consequently, my DOF is smaller.

i understand now.