Canon PowerShot G1 X Mark III Coming Mid October [CR3]

Oct 10, 2015
139
35
Rocky said:
This is a G series camera. I think one of the requirement is "coat pocketable" and versatile. Therefore long Super zoom is out of question, fast medium zoom is out of question, may be even fast short zoom is out of question.

The G1 X is already hardly pocketable. Compare it to G15:

http://camerasize.com/compact/#534,383,ha,t

It is a pure example of a compact camera, not a pocket camera. Nobody is talking about a superzoom. That would be insane.

Couple with changing from 1" to APS-C, that put a lot more restriction on the size. Therefore I do not expect the G1 X III will have a fast lens or long zoom. As for the starting point of the lens. I personally prefer start from 24mm (equivalent) and take what ever short lele I can get with a reasonable size.

First G1 X is not an one inch sensor. The sensor crop ratio is about 1.85 though the way it is used creates a crop ratio of 1.95. What you describe is basically what it already has.
 
Upvote 0
okaro said:
Rocky said:
This is a G series camera. I think one of the requirement is "coat pocketable" and versatile. Therefore long Super zoom is out of question, fast medium zoom is out of question, may be even fast short zoom is out of question.

The G1 X is already hardly pocketable. Compare it to G15:

http://camerasize.com/compact/#534,383,ha,t

It is a pure example of a compact camera, not a pocket camera. Nobody is talking about a superzoom. That would be insane.

Nonsense. Of course you can fit a G1XII in a coat pocket, (not your jeans pocket -your down to Sony RX100 size for that requirement) how else are do you carry the camera about? Oh, don't tell me -you use one of those straps with "Canon Powershot" written on it? I bet you think that this looks cool! ;)

150-220917134302.jpeg


Lots of people fit the Fuji X100 series or the EOS-M with the EF-M 22mm f/2 in their pocket, so why shouldn't the G1XII fit? http://camerasize.com/compact/#534,599.349,383,705,ha,t

okaro said:
Rocky said:
Couple with changing from 1" to APS-C, that put a lot more restriction on the size. Therefore I do not expect the G1 X III will have a fast lens or long zoom. As for the starting point of the lens. I personally prefer start from 24mm (equivalent) and take what ever short lele I can get with a reasonable size.

First G1 X is not an one inch sensor. The sensor crop ratio is about 1.85 though the way it is used creates a crop ratio of 1.95. What you describe is basically what it already has.

There is no difference between a fixed lens camera with a 1" sensor with a 8.8-36.8mm f/1.8-2.8 zoom (e.g. the G5X) and one with an (Canon) APS-C sensor with a 15-62mm f/3.1-4.8 zoom or a full frame fixed lens camera with a 24-100mm f/4.9-7.6 zoom. They will all have exactly the same field-of-view range, capture exactly the same amount of light and have exactly the same depth of field control. They will also probably be exactly the same size. The only advantage would be if the 1" sensor and lens combo was cheaper than the APS-C or full-frame versions.
 
Upvote 0
Oct 10, 2015
139
35
traveller said:
Nonsense. Of course you can fit a G1XII in a coat pocket, (not your jeans pocket -your down to Sony RX100 size for that requirement) how else are do you carry the camera about? Oh, don't tell me -you use one of those straps with "Canon Powershot" written on it? I bet you think that this looks cool! ;)

150-220917134302.jpeg


Lots of people fit the Fuji X100 series or the EOS-M with the EF-M 22mm f/2 in their pocket, so why shouldn't the G1XII fit? http://camerasize.com/compact/#534,599.349,383,705,ha,t

Sure yiou can fit but I do not think a camera weighting over half a kilo is comfortable in a pocket. The G1 X II is much heavier than EOS M with the prime.

There is no difference between a fixed lens camera with a 1" sensor with a 8.8-36.8mm f/1.8-2.8 zoom (e.g. the G5X) and one with an (Canon) APS-C sensor with a 15-62mm f/3.1-4.8 zoom or a full frame fixed lens camera with a 24-100mm f/4.9-7.6 zoom. They will all have exactly the same field-of-view range, capture exactly the same amount of light and have exactly the same depth of field control. They will also probably be exactly the same size. The only advantage would be if the 1" sensor and lens combo was cheaper than the APS-C or full-frame versions.

True, but the G1 X is already f/2.0-3.9 with 1.95 crop. That s effectively 2/3 stops faster than the G5 X.
 
Upvote 0
okaro said:
traveller said:
There is no difference between a fixed lens camera with a 1" sensor with a 8.8-36.8mm f/1.8-2.8 zoom (e.g. the G5X) and one with an (Canon) APS-C sensor with a 15-62mm f/3.1-4.8 zoom or a full frame fixed lens camera with a 24-100mm f/4.9-7.6 zoom. They will all have exactly the same field-of-view range, capture exactly the same amount of light and have exactly the same depth of field control. They will also probably be exactly the same size. The only advantage would be if the 1" sensor and lens combo was cheaper than the APS-C or full-frame versions.

True, but the G1 X is already f/2.0-3.9 with 1.95 crop. That s effectively 2/3 stops faster than the G5 X.

Only at 24mm equivalent. Beyond that, things aren't so clear cut: https://www.dpreview.com/files/p/articles/0226934452/Equiv_Ap.png

P.S. Note how superior the much overlooked LX100 lens is on this chart -this is currently the only zoom lens compact that has tempted me...
 
Upvote 0
Jan 29, 2011
10,675
6,121
stevelee said:
Explain to me how a lens at f/7.6 lets in the same amount of light as at f/2.8.

That's easy.

Take an 8mm f2.8 lens = aperture opening of 8/2.8 = 3.6 mm aperture opening.
Take a 27mm lens set to f7.6 = aperture opening of 27/7.6 = 3.6 mm aperture opening.

They are the same sized hole so they let the same amount of light in.
 
Upvote 0
Oct 10, 2015
139
35
privatebydesign said:
stevelee said:
Explain to me how a lens at f/7.6 lets in the same amount of light as at f/2.8.

That's easy.

Take an 8mm f2.8 lens = aperture opening of 8/2.8 = 3.6 mm aperture opening.
Take a 27mm lens set to f7.6 = aperture opening of 27/7.6 = 3.6 mm aperture opening.

They are the same sized hole so they let the same amount of light in.

Assuming they gather that light from same angle.
 
Upvote 0
Jan 29, 2011
10,675
6,121
okaro said:
privatebydesign said:
stevelee said:
Explain to me how a lens at f/7.6 lets in the same amount of light as at f/2.8.

That's easy.

Take an 8mm f2.8 lens = aperture opening of 8/2.8 = 3.6 mm aperture opening.
Take a 27mm lens set to f7.6 = aperture opening of 27/7.6 = 3.6 mm aperture opening.

They are the same sized hole so they let the same amount of light in.

Assuming they gather that light from same angle.
No, the aperture is at the focal point of the objective in a simple lens, the light path in a complicated one, so the angle of the light is not that relevant. Same hole size, same amount of light.

stevelee said:
I’m still confused. If it is the same amount of light, why does the camera consider it a different exposure?

Even with the same lens and lens opening you don’t always get the same amount of light, such as with extension tubes.

Because the sensors are a different size so each section of sensor by area takes the same amount of time to receive the same amount of light. Ergo, if your sensor is twice as large it will take twice as long to get the same amount of light per area.

But that isn’t the end of it, iso, or sensor sensitivity, means that if you double the sensitivity you get the ‘same’ end result from twice the sensor area, in reality you get a touch more.

So if you use that 8mm lens at f2.8 and the 27mm at f7.6 on two cameras with equivalent sized sensors ( such that the fov from both is the same) you will get the same noise characteristics from both at compensated iso values. So to get two ‘identical images’ from two systems whereby identical mean same fov, dof, noise, shutter speed (for subject movement) etc etc when printed or viewed at the same size from the same place you’d use these camera settings.

8mm f2.8, iso 100, 1/60 sec.
27mm f7.6, iso 1000, 1/60 sec.

These settings will give you equivalent pictures from different sized sensors. To get the definite article on all this read here. http://www.josephjamesphotography.com/equivalence/
 
Upvote 0
Jan 29, 2011
10,675
6,121
P.s. don’t start introducing complex things like extension tubes into the mix, they can be explained, but are just side issues.

An extension tube effectively changes the focal length of the lens, as does focusing closer than infinity but the differences are so small at greater than macro magnifications as to not mess with the basic equations enough to make a visible difference, there fore the focal length/aperture relationship changes so the equivalence calculation changes. It’s all explained much more thoroughly in the linked article.
 
Upvote 0

stevelee

FT-QL
CR Pro
Jul 6, 2017
2,383
1,064
Davidson, NC
OK I follow a lot of that and have said some of the same things myself in this forum. It does seem that the article uses some sleight of hand in saying that there is less exposure on a larger sensor because you have the same light spread over a larger area, and then the more intuitive idea that a crop sensor will get less light since it occupies a smaller part of the circle of light coming from the lens. But if I spend more time with the article, I can probably sort out what he means by the apparent contradiction.

But I don’t follow at all how it is meaningful to say it is the same amount of light when one requires ISO 100 and the other ISO 1000.
 
Upvote 0
Oct 10, 2015
139
35
privatebydesign said:
okaro said:
Assuming they gather that light from same angle.
No, the aperture is at the focal point of the objective in a simple lens, the light path in a complicated one, so the angle of the light is not that relevant. Same hole size, same amount of light.

Totally incorrect. A wide angle lens gathers much more light from same size of aperture. Think about aperture of 10 mm. That could be a 20 mm wide angle at f/2 or a 160 mm Tele at f/16. The former gathers much more light.
 
Upvote 0
Oct 10, 2015
139
35
stevelee said:
I’m still confused. If it is the same amount of light, why does the camera consider it a different exposure?

Even with the same lens and lens opening you don’t always get the same amount of light, such as with extension tubes.

Exposure is determined by light per square area of the sensor. If the light is spread to a larger sensor then one needs a higher ISO for the light to produce correct image. Of course the larger sensor can tolerate that so the overall image qualify is same.
 
Upvote 0
Jan 29, 2011
10,675
6,121
okaro said:
privatebydesign said:
okaro said:
Assuming they gather that light from same angle.
No, the aperture is at the focal point of the objective in a simple lens, the light path in a complicated one, so the angle of the light is not that relevant. Same hole size, same amount of light.

Totally incorrect. A wide angle lens gathers much more light from same size of aperture. Think about aperture of 10 mm. That could be a 20 mm wide angle at f/2 or a 160 mm Tele at f/16. The former gathers much more light.

Not when talking about it in relation to equivalence, which we were and in retrospect I don't make clear in my followup answer. When talking about equivalence the fov from the different focal lengths is the same, so the angle of light captured is the same.
 
Upvote 0

stevelee

FT-QL
CR Pro
Jul 6, 2017
2,383
1,064
Davidson, NC
okaro said:
stevelee said:
I’m still confused. If it is the same amount of light, why does the camera consider it a different exposure?

Even with the same lens and lens opening you don’t always get the same amount of light, such as with extension tubes.

Exposure is determined by light per square area of the sensor. If the light is spread to a larger sensor then one needs a higher ISO for the light to produce correct image. Of course the larger sensor can tolerate that so the overall image qualify is same.

Except that the larger sensor covers more of the circle of light that the lens projects, and a smaller sensor covers a smaller portion of it.
 
Upvote 0