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Author Topic: 70D or 6D  (Read 29084 times)

Pi

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Re: 70D or 6D
« Reply #45 on: July 07, 2013, 09:18:26 AM »
The things I didn't like from it fr trekking were those I mentioned in the list (extra lens weight, AF, lack of flash...), but given your comments on the AF, I may reconsider.

Lenses with the same light gathering abilities for FF are not heavier. For example, the 24-105 is comparable in weight to the 17-55.

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So being able to focus off center in live view would be great for me.  Just set f/10-14, focus on me in live view through a mobile phone, and shoot. Not sure how the 6D would behave with that.

AF in LV? This is entirely different AF. The 6D would not behave any different. If anything, with the same lens, the 6D would gather more light and AF better in LV.
« Last Edit: July 07, 2013, 09:33:13 AM by Pi »

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Re: 70D or 6D
« Reply #45 on: July 07, 2013, 09:18:26 AM »

intxaurrek

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Re: 70D or 6D
« Reply #46 on: July 07, 2013, 10:45:23 AM »


Lenses with the same light gathering abilities for FF are not heavier. For example, the 24-105 is comparable in weight to the 17-55.

(...)

AF in LV? This is entirely different AF. The 6D would not behave any different. If anything, with the same lens, the 6D would gather more light and AF better in LV.

The 17-55 is f2.8. The 24-105 is f4. An f2.8 for a full frame like the 6D would be much heavier.

The lenses needed to gather light for a full frame are larger and heavier, since they need much wider diameter lenses to cover such a sized sensor. It's not only about capturing the same light. It's about having the same light density on the sensor.

And about live view focusing, the 6D does contrast focusing, while the 70D does phase detect in live view. Thus my question. It actuallly DOES AF in a similar maner to normal AF....

« Last Edit: July 07, 2013, 10:48:42 AM by intxaurrek »

neuroanatomist

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Re: 70D or 6D
« Reply #47 on: July 07, 2013, 03:11:25 PM »
Lenses with the same light gathering abilities for FF are not heavier. For example, the 24-105 is comparable in weight to the 17-55.
(...)
AF in LV? This is entirely different AF. The 6D would not behave any different. If anything, with the same lens, the 6D would gather more light and AF better in LV.

The 17-55 is f2.8. The 24-105 is f4. An f2.8 for a full frame like the 6D would be much heavier.

The lenses needed to gather light for a full frame are larger and heavier, since they need much wider diameter lenses to cover such a sized sensor. It's not only about capturing the same light. It's about having the same light density on the sensor.

And about live view focusing, the 6D does contrast focusing, while the 70D does phase detect in live view. Thus my question. It actuallly DOES AF in a similar maner to normal AF....

Actually, it is about the same total light.  The exposure triangle has three sides - so, while f/4 is a stop slower than f/2.8 in terms of light per unit area (independent of sensor size), comparing an f/4 lens on a FF sensor to f/2.8 on APS-C, the latter gives you the DoF of f/4.5 on FF but a stop faster shutter speed, you can bump the ISO up a stop on the FF f/4, and still have less noise than f/2.8 on APS-C.

You're right about the Live View AF on the 70d being better than that on the 6D, at least by spec. But let's wait for the testing - CDAF on the 6D, 7D, and 5DII should be 'the same' but the 6D is both more accurate and more precise than the other two.
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cookinghusband

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Re: 70D or 6D
« Reply #48 on: July 07, 2013, 08:08:25 PM »
I think it really depends on how much video that need auto tracking you will be doing. If this is video you do more, then 70D. If it is still then 6D

However you may need to get a bunch of EF new lens instead of the EF-s lens for 6D

Pi

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Re: 70D or 6D
« Reply #49 on: July 07, 2013, 10:59:36 PM »
The lenses needed to gather light for a full frame are larger and heavier, since they need much wider diameter lenses to cover such a sized sensor.

No, this is wrong. It is quite simple, really - same diameter (more precisely, entrance pupil), same light.

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And about live view focusing, the 6D does contrast focusing, while the 70D does phase detect in live view. Thus my question. It actuallly DOES AF in a similar maner to normal AF....

Yes, I forgot about that. Still - did you say that you will be shooting at f/10, or so? You might be overthinking it.

intxaurrek

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Re: 70D or 6D
« Reply #50 on: July 08, 2013, 01:00:01 AM »

No, this is wrong. It is quite simple, really - same diameter (more precisely, entrance pupil), same light.



You are mistaking light candelas/luxes with lumens. You get the same amount of light in lumens, but not the same light density (luxes/candelas), since the light is spread all over the sensor. The sensor will give you a charge depending on this density of light, and the lens will give you more or less *total* amount of light depending on the aperture (pupil) diameter. Then this light is spread over an area, but a crop lens is designed to focus it on 24mm area, while a full frame lens is designed to cover 35mm... then the 35mm one needs more light entering to yield the same exposure.

For an f2.8, no matter which lens, as far as it's appropriate for the given body, they all produce the same light density on the sensor. Otherwise the exposure settings would need to be different on each body, and you know that's not true. You just cannot compare an f.4 from full frame with an f2.8 on a crop. They do not yield the same photo on the same iso/Tv settings at maximum aperture.

The difference between an f2.8 on a FF and a f2.8 on a crop is that even if they show the same exposure, they are not equivalent in terms of DOF, frame, etc....

But anyway,  there's no point discussing what's already discussed elsewhere, so please better read here:

http://www.josephjamesphotography.com/equivalence/#exposure
« Last Edit: July 08, 2013, 01:11:13 AM by intxaurrek »

intxaurrek

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Re: 70D or 6D
« Reply #51 on: July 08, 2013, 01:14:57 AM »

Actually, it is about the same total light.  The exposure triangle has three sides - so, while f/4 is a stop slower than f/2.8 in terms of light per unit area (independent of sensor size), comparing an f/4 lens on a FF sensor to f/2.8 on APS-C, the latter gives you the DoF of f/4.5 on FF but a stop faster shutter speed, you can bump the ISO up a stop on the FF f/4, and still have less noise than f/2.8 on APS-C.

Well, true, I was trying to compare the images at the same exposure settings (same iso/Av/Tv), and that may not be correct to get equivalent photos in terms of noise and DOF, right.

In your comparison terms, an f4 on a FF is the same as f2.8 on a crop sensor :-) if you alter exposure settings, that is
« Last Edit: July 08, 2013, 01:16:51 AM by intxaurrek »

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Re: 70D or 6D
« Reply #51 on: July 08, 2013, 01:14:57 AM »

Pi

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Re: 70D or 6D
« Reply #52 on: July 08, 2013, 08:02:53 AM »
No, this is wrong. It is quite simple, really - same diameter (more precisely, entrance pupil), same light.

You are mistaking light candelas/luxes with lumens.


No,  you are.

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You get the same amount of light in lumens, but not the same light density (luxes/candelas), since the light is spread all over the sensor.


Right, but you are the only one insisting that intensity has anything to do with the discussion, so ... you get the idea.

Quote
But anyway,  there's no point discussing what's already discussed elsewhere, so please better read here:

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

Yes, good reading. I have been referring to it for years. Did you get to the "total light" part of it?
« Last Edit: July 08, 2013, 08:04:48 AM by Pi »

neuroanatomist

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Re: 70D or 6D
« Reply #53 on: July 08, 2013, 10:06:41 AM »
Yes, good reading. I have been referring to it for years. Did you get to the "total light" part of it?

Apparently not.   ::)
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intxaurrek

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Re: 70D or 6D
« Reply #54 on: July 08, 2013, 01:50:27 PM »
No, this is wrong. It is quite simple, really - same diameter (more precisely, entrance pupil), same light.

You are mistaking light candelas/luxes with lumens.


No,  you are.

Quote
You get the same amount of light in lumens, but not the same light density (luxes/candelas), since the light is spread all over the sensor.


Right, but you are the only one insisting that intensity has anything to do with the discussion, so ... you get the idea.

Quote
But anyway,  there's no point discussing what's already discussed elsewhere, so please better read here:

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

Yes, good reading. I have been referring to it for years. Did you get to the "total light" part of it?


Did you get the equivalence vs exposure part? I was comparing exposure, you were comparing equivalence. What's wrong with that?

1) respect is first
2) justifying your answers is second
3) You did none, so well, go on,...

intxaurrek

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Re: 70D or 6D
« Reply #55 on: July 08, 2013, 01:54:33 PM »
Yes, good reading. I have been referring to it for years. Did you get to the "total light" part of it?

Apparently not.   ::)

Please, if I said anything wrong in the answer to your explanation, whch I believe I agreed, do please correct me. I accept corrections, but  silly "you're wrong" answers like those from "Pi" aren't reasonable. The only thing I said was that I was comparing same exposure value, although you proved total light is what matters for getting quality out. Is that wrong in any sense?


GaabNZ

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Re: 70D or 6D
« Reply #56 on: July 10, 2013, 02:35:47 AM »
Well, I've managed through a friend's wife who works for Canon to get hold of a brand new 6D and 24-105L lens for an amazing price and have ordered it today. 

Hopefully I'll get it by Friday

Here in New Zealand we are paying a lot more for our gear than in the US.

I brought my EF70-200L from B and H photo earlier this year and even getting picked up at customs for tax I saved NZ$350 on the local retail price.

Looking forward to trying out my new toy :)

Pi

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Re: 70D or 6D
« Reply #57 on: July 10, 2013, 10:41:20 AM »
Did you get the equivalence vs exposure part? I was comparing exposure, you were comparing equivalence. What's wrong with that?

Exposure (to total light) is the same for equivalent images. This is what determines the photon noise. You are fixated on intensity per unit sensor area which is not directly related to IQ.
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1) respect is first

Then show some.
« Last Edit: July 10, 2013, 10:52:41 AM by Pi »

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Re: 70D or 6D
« Reply #57 on: July 10, 2013, 10:41:20 AM »

intxaurrek

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Re: 70D or 6D
« Reply #58 on: July 10, 2013, 02:17:09 PM »
Exposure (to total light) is the same for equivalent images. This is what determines the photon noise. You are fixated on intensity per unit sensor area which is not directly related to IQ.


You're completely right on that. I never before cared to compare lenses in terms final IQ, but it's actually the way to do so for photography at least.

About the term "exposure", just not to confuse, I prefer using it in the same definition that the website I linked does (he defines Exposure:  The total light per area (photons / mm²)). Otherwise we may end up talking different things.

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1) respect is first

Then show some.

I thought I did, or tried to, but sorry if I didn't. And honestly, my intention wasn't bothering anyone. There's tons of incorrect things written about photography out there, and the learning path can be slow ...

greger

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Re: 70D or 6D
« Reply #59 on: July 14, 2013, 04:47:31 AM »
GaabNZ congrats on your purchase of the 6D. Please post your feelings on the camera after you have used it for a couple of days. I hope they are all positive.
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Re: 70D or 6D
« Reply #59 on: July 14, 2013, 04:47:31 AM »