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Author Topic: Full Frame Vs Crop Sensor  (Read 125310 times)

sanj

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Re: Full Frame Vs Crop Sensor
« Reply #210 on: February 27, 2014, 07:24:22 AM »
I don't begrudge people the whole field of view argument with crop v. full because a 50mm is indeed like an 85mm... and I'm not sure why, but with full frame, depth of field is greater, though with comparable framing, the full frame's depth of field is thinner...

I've heard the argument about the f/2.8 is comparable to f/4.5 (or whatever), but I didn't bother to ask what they meant.

So if I'm shooting with a 135L f/2 in moderate light and at iso 800 I'm shooting at 1/2000 of a second... that should still be the same achieved shutter speed regardless of crop or full.

And if you keep the same distance between, the depth of field should be comparable.  So why is f/1.4 now f/2.2?

Ok, but I choose quality over quantity. I don't need to "cover the range" and it is only one L lens less for FF, really. What you'd get from your list on APSC is:
Tokina 18-26/4.5
Canon 38-112/4.5
Sigma 56/2.2
Canon 80/2.2
A 160/4.5 IS
A 216/3.5
A 112-320/6.3 IS


If the light is constant and you compare an image from a crop sensor and FF. both shot in M mode, at the same aperture and SS you'll notice the FF image to be brighter. I think it's like 2/3 of a stop. Could be more. However, in Av mode both cameras should spit out the same as the camera adjusts the SS accordingly. I did this experiment with my 5D2 and 7D. The FF gathers more light. So in low light it does make a difference. In bright sunlight that wouldn't be an issue as your SS can be whatever.

What I also like about FF is that f/4 is now a quite shallow dof at 50mm and above. The slow zooms that I had on my 7D become a lot more useful.

Separate argument about the upgrade path - I agree that FF needs good lenses and if someone asked me to upgrade lens or body first I'd say lens. However, if someone already owns decent primes I think they'll benefit more from going t2i - 5D3 rather than change the already good prime to L prime.

I wish I had just bought a 5D2 + 24-105L from day one tbh. All beginner advice be dammed. I just ended up at the same place 3 yrs later anyway and slightly poorer having sold off cameras at a loss. My advice to myself would have been buy the best camera you can afford that will last you at least 5 yrs then build up your lens collection.

What I don't get is the contradiction between those who claim IQ is their no1 priority and have the best L lenses, because they were told lenses are more important than camera and are using only a crop sensor body with those L lenses. Obviously not counting sports shooters and other people who have reason to (in which case IQ is not their priority anymore it's making money!). I'm talking the rebel t1i with 200mm f/2.

Huh?

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Re: Full Frame Vs Crop Sensor
« Reply #210 on: February 27, 2014, 07:24:22 AM »

Zv

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Re: Full Frame Vs Crop Sensor
« Reply #211 on: February 27, 2014, 08:02:00 AM »
I don't begrudge people the whole field of view argument with crop v. full because a 50mm is indeed like an 85mm... and I'm not sure why, but with full frame, depth of field is greater, though with comparable framing, the full frame's depth of field is thinner...

I've heard the argument about the f/2.8 is comparable to f/4.5 (or whatever), but I didn't bother to ask what they meant.

So if I'm shooting with a 135L f/2 in moderate light and at iso 800 I'm shooting at 1/2000 of a second... that should still be the same achieved shutter speed regardless of crop or full.

And if you keep the same distance between, the depth of field should be comparable.  So why is f/1.4 now f/2.2?

Ok, but I choose quality over quantity. I don't need to "cover the range" and it is only one L lens less for FF, really. What you'd get from your list on APSC is:
Tokina 18-26/4.5
Canon 38-112/4.5
Sigma 56/2.2
Canon 80/2.2
A 160/4.5 IS
A 216/3.5
A 112-320/6.3 IS


If the light is constant and you compare an image from a crop sensor and FF. both shot in M mode, at the same aperture and SS you'll notice the FF image to be brighter. I think it's like 2/3 of a stop. Could be more. However, in Av mode both cameras should spit out the same as the camera adjusts the SS accordingly. I did this experiment with my 5D2 and 7D. The FF gathers more light. So in low light it does make a difference. In bright sunlight that wouldn't be an issue as your SS can be whatever.

What I also like about FF is that f/4 is now a quite shallow dof at 50mm and above. The slow zooms that I had on my 7D become a lot more useful.

Separate argument about the upgrade path - I agree that FF needs good lenses and if someone asked me to upgrade lens or body first I'd say lens. However, if someone already owns decent primes I think they'll benefit more from going t2i - 5D3 rather than change the already good prime to L prime.

I wish I had just bought a 5D2 + 24-105L from day one tbh. All beginner advice be dammed. I just ended up at the same place 3 yrs later anyway and slightly poorer having sold off cameras at a loss. My advice to myself would have been buy the best camera you can afford that will last you at least 5 yrs then build up your lens collection.

What I don't get is the contradiction between those who claim IQ is their no1 priority and have the best L lenses, because they were told lenses are more important than camera and are using only a crop sensor body with those L lenses. Obviously not counting sports shooters and other people who have reason to (in which case IQ is not their priority anymore it's making money!). I'm talking the rebel t1i with 200mm f/2.

Huh?

Sorry, I may have been wrong. Never mind. I'll edit the post. Today I learned .....
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jdramirez

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Re: Full Frame Vs Crop Sensor
« Reply #212 on: February 27, 2014, 08:08:23 AM »
I'm stool a little confused... but I'm glad the topic of conversation has gone back to full v crop and how we measure the difference... having said that... I'm still just as confused as when I first posed the question...
Upgrade  path.->means the former was sold for the latter.

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ecka

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Re: Full Frame Vs Crop Sensor
« Reply #213 on: February 27, 2014, 10:54:02 AM »
I'm stool a little confused... but I'm glad the topic of conversation has gone back to full v crop and how we measure the difference... having said that... I'm still just as confused as when I first posed the question...

Maybe you are asking the wrong question?
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unfocused

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Re: Full Frame Vs Crop Sensor
« Reply #214 on: February 27, 2014, 01:11:43 PM »
I'm still a little confused... but I'm glad the topic of conversation has gone back to full v crop and how we measure the difference... having said that... I'm still just as confused as when I first posed the question...

Maybe you are asking the wrong question?

Or more accurately, maybe because there is no correct answer...just never-ending commentary on web forums from people who are convinced they are right, when if they would just listen they would know that I am the one who is right. :)

bseitz234

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Re: Full Frame Vs Crop Sensor
« Reply #215 on: February 27, 2014, 01:28:56 PM »
I'm stool a little confused... but I'm glad the topic of conversation has gone back to full v crop and how we measure the difference... having said that... I'm still just as confused as when I first posed the question...

If I understand the question, see if this helps make sense of it:

Depth of field is affected by two things: absolute aperture and subject magnification. In terms of exposure, sensor size doesn't change anything, the whole "2.8 on crop is like 4.5 on FF" only refers to DoF.

If you took a picture, with a given aperture and subject distance, on FF and crop, you would get the same depth of field on both, just framed differently. (The FF image would have a wider angle of view.) if you framed them identically, your subject distance would have to change, therefore changing depth of field as well.

I just don't worry about it, as I'm quite happy with my 7d and the depth of field it gives me. :-)

Edited to steal PBD's words, since I had ignored focal length.
« Last Edit: February 27, 2014, 02:05:26 PM by bseitz234 »
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privatebydesign

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Re: Full Frame Vs Crop Sensor
« Reply #216 on: February 27, 2014, 01:35:21 PM »

Depth of field is affected by two things: aperture and subject distance.

No, dof is affected by two things, aperture size (not number) and subject magnification.

A 17mm and 200mm shot from the same place with the same aperture value have different dof, your statement says they would be the same.

Too often we lose sight of the fact that photography is about capturing light, if we have the ability to take control of that light then we grow exponentially as photographers. More often than not the image is not about lens speed, sensor size, DR, MP's or AF, it is about the light.

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Re: Full Frame Vs Crop Sensor
« Reply #216 on: February 27, 2014, 01:35:21 PM »

bseitz234

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Re: Full Frame Vs Crop Sensor
« Reply #217 on: February 27, 2014, 02:04:09 PM »

Depth of field is affected by two things: aperture and subject distance.

No, dof is affected by two things, aperture size (not number) and subject magnification.

A 17mm and 200mm shot from the same place with the same aperture value have different dof, your statement says they would be the same.

Ok good point. I was taking FL as static, basically trying to distinguish lens from sensor. But that is more accurate, I will edit.
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DanielW

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Re: Full Frame Vs Crop Sensor ( somewhat adrift)
« Reply #218 on: February 27, 2014, 03:42:48 PM »
However in my opinion - this is becoming less and less about photography - and more and more about PP and graphic design.

Where has all that crop vs FF discussion gone?  :P
I understand PP is a philosophical rather than technical argument and that there will be no winner.
Take for instance David Nightingale's B&W work. It's terrific. (I highly recommend this course of his: https://www.udemy.com/the-art-of-black-and-white-photography/) He manages to get B&W images that really stand out, even though they're not accurate representations of the real scene. There's a dull photo of a wrecked ship that he converts to B&W with such a dramatic sky that you think it's Noah's ark and the flood is about to come. It's far from an accurate representation, but it looks rather good. Right? Wrong? I don't care.
On the other hand, I've learned through the years that correcting in PS is not my thing. I'm not into removing power lines from an image; it feels (to me!) like cheating. I do crop to hide a few things, however... :)
To each his own, but to me it works like this: I like PP when it helps you get something that you could not achieve in camera, but I'm not fond of it for "correcting" things.
I like this one very much, from Zack Arias: “If you find yourself out shooting a client and you’re sayin’ in your head ‘oh I’ll just fix that later in photoshop’ stop what you’re doing and slap yourself as hard as you can.’”
Cheers
Daniel
« Last Edit: February 27, 2014, 04:23:02 PM by DanielW »

privatebydesign

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Re: Full Frame Vs Crop Sensor
« Reply #219 on: February 27, 2014, 09:37:49 PM »

Depth of field is affected by two things: aperture and subject distance.

No, dof is affected by two things, aperture size (not number) and subject magnification.

A 17mm and 200mm shot from the same place with the same aperture value have different dof, your statement says they would be the same.

Ok good point. I was taking FL as static, basically trying to distinguish lens from sensor. But that is more accurate, I will edit.

Well we still aren't quite there. If you take the same picture from the same place with the same lens and settings and on a crop and ff cameras, then make two prints the same size, the image is different (obviously) and the dof is less in the crop camera image.

If you have two different sized prints, such that the subjects were the same size then the dof would be the same from both cameras.

DOF is dependent on magnification, to get a same sized print you have to enlarge the crop camera more so it has less dof.

It isn't until people accept that dof is subjective and dependent on magnification, that it clicks that crop cameras can have, more, less, or the same, dof as a ff camera.
Too often we lose sight of the fact that photography is about capturing light, if we have the ability to take control of that light then we grow exponentially as photographers. More often than not the image is not about lens speed, sensor size, DR, MP's or AF, it is about the light.

jdramirez

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Re: Full Frame Vs Crop Sensor
« Reply #220 on: February 27, 2014, 10:48:55 PM »

Depth of field is affected by two things: aperture and subject distance.

No, dof is affected by two things, aperture size (not number) and subject magnification.

A 17mm and 200mm shot from the same place with the same aperture value have different dof, your statement says they would be the same.

Ok good point. I was taking FL as static, basically trying to distinguish lens from sensor. But that is more accurate, I will edit.

Well we still aren't quite there. If you take the same picture from the same place with the same lens and settings and on a crop and ff cameras, then make two prints the same size, the image is different (obviously) and the dof is less in the crop camera image.

If you have two different sized prints, such that the subjects were the same size then the dof would be the same from both cameras.

DOF is dependent on magnification, to get a same sized print you have to enlarge the crop camera more so it has less dof.

It isn't until people accept that dof is subjective and dependent on magnification, that it clicks that crop cameras can have, more, less, or the same, dof as a ff camera.

Maybe it will click tomorrow... but tonight... I'm enjoying my gambling winnings from a triple overtime game.
Upgrade  path.->means the former was sold for the latter.

XS->60D->5d Mkiii:18-55->24-105L:75-300->55-250->70-300->70-200 f4L USM->70-200 f/2.8L USM->70-200 f/2.8L IS Mkii:50 f/1.8->50 f/1.4->100L-> 85mm f/1.8 USM-> 8mm -> 85mm f/1.2L mkii

Kit.

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Re: Full Frame Vs Crop Sensor
« Reply #221 on: February 28, 2014, 06:40:58 AM »

Depth of field is affected by two things: aperture and subject distance.

No, dof is affected by two things, aperture size (not number) and subject magnification.

A 17mm and 200mm shot from the same place with the same aperture value have different dof, your statement says they would be the same.
DoF is affected by 3 things:
1. entrance pupil ("aperture") size - D,
2. distance from the plane of focus (i.e. from the plane of an object we are shooting) to the entrance pupil - L,
3. diameter of the acceptable unsharpness measured in the plane of focus (i.e. as a property of the object we are shooting) - d.

If lf is front DoF and lb is back DoF, then:

(L-lf) / D = lf / d
(L+lb) / D = lb / d


If lf and lb are much smaller than L (as in macro), then lb ~= lf ~= L * d / D.

That can be derived from simple geometrical optics if we study where rays passing through a point in the front or the back DoF plane cross the plane of focus and the entrance pupil plane. No information about what happens behind the lens entrance pupil (except the information that is already contained in the choice of d) is actually needed or relevant.

The difference in the DoF of 17mm and 200mm lenses (other than from the obvious difference in D) comes from the fact that d acceptable for shooting most "17mm" subjects (sometimes up to centimeters) is unacceptable for shooting most "200mm" subjects (usually well below a millimeter, as we need to resolve hair/fabric structure).
« Last Edit: February 28, 2014, 07:32:36 AM by Kit. »

neuroanatomist

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Re: Full Frame Vs Crop Sensor
« Reply #222 on: February 28, 2014, 08:00:01 AM »
DoF is affected by 3 things:
1. entrance pupil ("aperture") size - D,
2. distance from the plane of focus (i.e. from the plane of an object we are shooting) to the entrance pupil - L,
3. diameter of the acceptable unsharpness measured in the plane of focus (i.e. as a property of the object we are shooting) - d.

If lf is front DoF and lb is back DoF, then:

(L-lf) / D = lf / d
(L+lb) / D = lb / d


If lf and lb are much smaller than L (as in macro), then lb ~= lf ~= L * d / D.

That can be derived from simple geometrical optics if we study where rays passing through a point in the front or the back DoF plane cross the plane of focus and the entrance pupil plane. No information about what happens behind the lens entrance pupil (except the information that is already contained in the choice of d) is actually needed or relevant.

The difference in the DoF of 17mm and 200mm lenses comes from the fact that d acceptable for shooting most "17mm" subjects (sometimes up to centimeters) is unacceptable for shooting most "200mm" subjects (usually well below a millimeter, as we need to resolve hair/fabric structure).

By attributing the DoF difference between a 17mm lens and a 200mm lens at the same distance to d, you're suggesting that D, the physical diameter of the aperture, is the same for a 17mm lens and a 200mm lens set to the same f/stop.  That's clearly not the case - and it's that latter difference that accounts for the DoF differential between 17mm f/4 and 200mm f/4 at the same subject distance.

I suppose you could hold D constant (for example, comparing 17mm f/2.8 with 200mm f/32 would get you close), but I'm not sure why you would want to do that.
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Re: Full Frame Vs Crop Sensor
« Reply #222 on: February 28, 2014, 08:00:01 AM »

Kit.

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Re: Full Frame Vs Crop Sensor
« Reply #223 on: February 28, 2014, 09:05:42 AM »
Yes, I've added it in the edition of my post after the one you are quoting. Still, the difference in D alone is not enough to explain the difference in acceptable DoF of wide-angle and telephoto shots.

neuroanatomist

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Re: Full Frame Vs Crop Sensor
« Reply #224 on: February 28, 2014, 09:33:47 AM »
Yes, I've added it in the edition of my post after the one you are quoting. Still, the difference in D alone is not enough to explain the difference in acceptable DoF of wide-angle and telephoto shots.

The difference in DoF based on D alone between 17mm f/4 and 200mm f/4 is massive.  17mm f/4 with a subject 20 feet away yields a DoF extending from 14 feet in front of the subject to infinity, whereas 200mm f/4 with a subject at 20 feet yields a DoF that extends approxiamtely 4 inches on either side of the subject.  Not is that difference (e.g. 8" vs. infinity) more than sufficient to explain the difference in DoF, the difference is so great that d becomes basically irrelevant. 

I also have to disagree with the idea that, "d acceptable for shooting most "17mm" subjects (sometimes up to centimeters) is unacceptable for shooting most "200mm" subjects (usually well below a millimeter, as we need to resolve hair/fabric structure)."  One of the most efective uses of wide angle lenses (and particularly ultrawide lenses) is with extremely close subjects in the foreground, taking advantage of the perspective distortion that results from close subject placement to emphasize that subject within the wide FoV.  In that case, I want the foreground subject to be as sharp as possible (although there's a practical limit on that with the resolution delivered by most ultrawide lenses, particularly if the subject is not at the center of the frame).
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Re: Full Frame Vs Crop Sensor
« Reply #224 on: February 28, 2014, 09:33:47 AM »