p.3 #1 · Official: New Sony A6700 camera with 26MP BSI CMOS sensor
arbitrage wrote:
No I don't think it can. You cant make telephoto lenses smaller for smaller sensors. M43 100-400 is only smaller because it has smaller maximum aperture.
Maybe people think an Olympus 300/4 is a 600/4 but it isn't. It is a 300 f/4 equivalent to a 600 f/8.
My understanding is that the exposure level from the m4/3 300/4 will be the same as FF 600/4, for depth of field and noise then it’s equivalent to f8,
If you zoom in with a FF camera in post with the 300f4 to the same shot taken with 600f4 you will have the same exposure level, a crop or m4/3 is just the same as zooming in post, in fact the higher mp cameras give you the same exposure in crop mode
p.3 #2 · Official: New Sony A6700 camera with 26MP BSI CMOS sensor
Uncle Chip wrote:
My understanding is that the exposure level from the m4/3 300/4 will be the same as FF 600/4, for depth of field and noise then it’s equivalent to f8,
If you zoom in with a FF camera in post with the 300f4 to the same shot taken with 600f4 you will have the same exposure level, a crop or m4/3 is just the same as zooming in post, in fact the higher mp cameras give you the same exposure in crop mode
A 300/4 on a M43 sensor is the same as putting a 300/4 on a FF sensor and cropping in to the size of a M43 sensor. Then everything would be equal if the pixel densities were equal (80MP FF vs 20MP M43).
A 600/4 is a 600/4 and if you want a 600/4 on a M43 you will end up with a lens just as big as the FF version. There are no smaller telephoto lenses for smaller sensors. There is no free lunch. Non-telephotos can be made smaller for smaller sensors.
p.3 #3 · Official: New Sony A6700 camera with 26MP BSI CMOS sensor
What happens when you focus the light, the image circle for a full frame lens is much bigger than it is for a m4/3 lens, the more you focus the light the brighter it gets, so the same lens with a f4 aperture designed for a ff camera will not give the same exposure as the same lens designed for a m4/3 camera, the image circle is a quarter of the size
This is why Panasonic advertise their lenses with 2.8 when they are actually a 5.6, because exposure wise they give you 2.8
p.3 #4 · Official: New Sony A6700 camera with 26MP BSI CMOS sensor
arbitrage wrote:
A 300/4 on a M43 sensor is the same as putting a 300/4 on a FF sensor and cropping in to the size of a M43 sensor. Then everything would be equal if the pixel densities were equal (80MP FF vs 20MP M43).
A 600/4 is a 600/4 and if you want a 600/4 on a M43 you will end up with a lens just as big as the FF version. There are no smaller telephoto lenses for smaller sensors. There is no free lunch. Non-telephotos can be made smaller for smaller sensors.
For telephoto lenses, e.g. a 300/4, the diameter of the front element is the dominating factor for lens size. The front element needs to be 75mm to give an f/4 aperture whether it’s an m4e lens or a full frame lens.
p.3 #5 · Official: New Sony A6700 camera with 26MP BSI CMOS sensor
Uncle Chip wrote:
What happens when you focus the light, the image circle for a full frame lens is much bigger than it is for a m4/3 lens, the more you focus the light the brighter it gets, so the same lens with a f4 aperture designed for a ff camera will not give the same exposure as the same lens designed for a m4/3 camera, the image circle is a quarter of the size
This is why Panasonic advertise their lenses with 2.8 when they are actually a 5.6, because exposure wise they give you 2.8
No, the aperture of a lens is a geometric feature of the lens alone, and its f-stop value a property of the lens alone and is thus independent of sensor size. 600mm is 600mm is 600mm and f/4 is f/4 is f/4 no matter the sensor size or crop in post. Cropping doesn’t alter the aperture, and sub-ff sensor sizes can be thought of as mere cropping.
p.3 #6 · Official: New Sony A6700 camera with 26MP BSI CMOS sensor
Uncle Chip wrote:
What happens when you focus the light, the image circle for a full frame lens is much bigger than it is for a m4/3 lens, the more you focus the light the brighter it gets, so the same lens with a f4 aperture designed for a ff camera will not give the same exposure as the same lens designed for a m4/3 camera, the image circle is a quarter of the size
This is why Panasonic advertise their lenses with 2.8 when they are actually a 5.6, because exposure wise they give you 2.8
This is only true for depth of field, not aperture brightness. As the saying goes, a 2.8 is a 2.8, is a 2.8, etc.....
p.3 #8 · Official: New Sony A6700 camera with 26MP BSI CMOS sensor
I would only care about this release if it involved a re-design of Sony's squared and boxy camera body, as it would signal new designs for the A1, 7 and 9's as well
p.3 #9 · Official: New Sony A6700 camera with 26MP BSI CMOS sensor
I don't mind the A6xxx body design and off center EVF. It needs a front dial though. I want something like a cheaper A7SIII or A9 for the 200-600 as a backup camera and for 4k120 video. I keep the 600 GM glued to the A1.
What I want may not be what Sony makes or anyone else wants.
p.3 #10 · Official: New Sony A6700 camera with 26MP BSI CMOS sensor
arbitrage wrote:
As per the title....anyone care??
I do like the sensor in the FX30, but I think it'll be a little disappointing if the next gen of their top level APS-C camera doesn't have a stacked sensor. I would care more if it did.
p.3 #11 · Official: New Sony A6700 camera with 26MP BSI CMOS sensor
Now Sony has a pretty decent lens line up for their APSc line…wide primes, wide zooms, a great standard zoom…so this camera and those lenses will make a great travel package no doubt…
p.3 #12 · Official: New Sony A6700 camera with 26MP BSI CMOS sensor
I had the Nex 6 and now the 6500 (besides a couple of Sony FF bodies) - I quite like the design w the left corner eyepiece - (a bit like a rangefinder)- so if the new APS-C keep this style with improvements like a front dial etc. that would be OK with me. I'd dearly love a stacked sensor too, but I think that's unlikely
p.3 #17 · Official: New Sony A6700 camera with 26MP BSI CMOS sensor
The 70/350 even though given in FF terms is certainly smaller since its image circle is aps-c. My A mount sigma 50/150 f2.8 is much smaller than a FF equivalent 70/200 f2.8 with its smaller image circle. Arguing equivalency, f stop difference does not make up for image circle which most people regard as telephoto.
Jun 01, 2023 at 06:56 PM
duncang Offline • • • [X]
p.3 #18 · Official: New Sony A6700 camera with 26MP BSI CMOS sensor
arbitrage wrote:
A 300/4 on a M43 sensor is the same as putting a 300/4 on a FF sensor and cropping in to the size of a M43 sensor. Then everything would be equal if the pixel densities were equal (80MP FF vs 20MP M43).
A 600/4 is a 600/4 and if you want a 600/4 on a M43 you will end up with a lens just as big as the FF version. There are no smaller telephoto lenses for smaller sensors. There is no free lunch. Non-telephotos can be made smaller for smaller sensors.
FF lens will throw light on a much bigger area than is required by the cropped sensor, so according to my calculations () a lens designed for a cropped sensor could be 0.65x the FF lens diameter but probably wouldn't change much in length.
I know nothing about lens design so my calculation could be wrong.
p.3 #19 · Official: New Sony A6700 camera with 26MP BSI CMOS sensor
duncang wrote:
FF lens will throw light on a much bigger area than is required by the cropped sensor, so according to my calculations () a lens designed for a cropped sensor could be 0.65x the FF lens diameter but probably wouldn't change much in length.
I know nothing about lens design so my calculation could be wrong.
That last part rings true:-D
The front element captures all the light that is projected onto the sensor plane. A point on the sensor plane corresponds to a direction the light was coming from. If you reduce the front element size, less light gets projected and the image gets darker, not smaller. The projected image circle is usually limited by baffles (or otherwise by the size of elements behind the front element). Reasons to limit the image circle are the required size and weight of the inner elements and to reduce stray light (internal reflections).
PS: there are some ultra wide designs where the front element is a good deal further from the sensor than what would be expected by the focal length. In a sense they have another lens in front of what would be the normal front element. For those there actually is a correlation of outermost front element size and crop circle size.
p.3 #20 · Official: New Sony A6700 camera with 26MP BSI CMOS sensor
duncang wrote:
FF lens will throw light on a much bigger area than is required by the cropped sensor, so according to my calculations () a lens designed for a cropped sensor could be 0.65x the FF lens diameter but probably wouldn't change much in length.
I know nothing about lens design so my calculation could be wrong.
If that's true, manufacturers aren't taking advantage of it. Sony's FE 70-300 and their 70-350, so far as the size of the optics, aren't too different. Oly's 300/4 is as big as anything Canon or Nikon made for their SLRs.
