No, an aperture is an aperture. An f-stop is the same no matter the focal length. We're talking about it's light-gathering ability. Nothing else. A 45mm f4 is faster than a 55mm f4.5, and a 175mm f5.6 is faster than 210mm f6.3 ALWAYS.
No, I don't intentionally shoot like that and I don't even have a NEX-7, but I have been known to crop the odd photo. The point is that the option is there. If you go out with only a wide angle prime and the need arises for something a little longer, it would be nice to know you could crop a fair bit and still have a high quality 16MP image.
That's true, but this thread is about the NEX-7, and future APS-C sensors will always have the advantage of more MP for the same density over M4/3.
With the NEX-7 you will have the same resolution as the M4/3 sensor.
I didn't make any claims about effective DOF advantages. I like fast lenses for the low light advantage, but if the DOF gets so narrow that I can't keep someone's whole head in focus it becomes unusable for me.
True, most people with NEX cameras probably want to use their whole sensor, but if they were happy to use a M4/3 sensor, they could get the exact same image by cropping a NEX-7 image. I never claimed to shoot wide and crop all my images but that's not the point. The point is that there is no image you can get with the 200mm on the GX7 that you can't also get with the 200mm on the NEX. The difference is that with the NEX you have the option of the wider image as well, so the so called telephoto advantage to the GX7 is really a wide angle advantage to the NEX.
I said nothing about aperture, I am talking about speed. By the looks of your post, you have a fundamental misunderstanding of concept of "lens speed".
If the NEX sensor is 64% larger, it's not just getting 64% more light, it's also getting a 64% larger image so the speed of the lens in regard to shutter speed is the same. Using a crop sensor doesn't make the image darker, it makes it smaller just like if you take an image and then crop it, it doesn't become darker.
You have to be cleaen on what you mean by "larger image"?
No. the whole point is with NEX you can get away with 2/3 stop faster SS.
"darker" or "brighter" is what we describe the final output image, which had gone through brightness adjustment. These concepts are not really compatible with "exposure".
And affordable good native lenses, and many native lenses with very fast AF.
I crop around 99% of my shots, that's why the NEX-7 was bought and I was using m4/3 at the time.
I think you're missing the point entirely. Using a crop sensor is the same as cropping the image afterwards. The smaller sensor isn't throwing away a portion of the light, it is throwing away a portion of the image but the portion that remains gets the same amount of light as it always did. The RX100 has a 1.85 crop factor compared to the NEX-6, so by your theory it should be nearly a full stop slower at the same aperture, but in reality, if I use the same settings I get the same exposure. I just tested this by putting both cameras in manual mode and setting the RX100 so that the metering scale showed ±0.0 for correct exposure, then I set the NEX to the same settings and the metering scale showed the same.
No, I did not miss the point at all, you are confusing brightness and exposure. please see the link provided above to get an understanding of that concept.
That is true but you end up with a different, much smaller framing with the cropped image. It renders any comparison pointless. Thus in any comparison, we are comparing the same framing.
What you got is two images of the same brightness. But it does not mean they received the same amount of light nor have the same IQ. What you should be able to do, is raise NEX6's SS by 85%, your NEX6 image should maintain the same IQ as RX100's.
Yes, of course you would end up with two images with the same brightness, that is what ISO standard all about.
You're right, I can see my test is flawed but isn't the extra noise mostly from the smaller pixels rather than the smaller sensor? I've always read that F1.8 is F1.8 with regard to light gathering. To my understanding, the F number is just a ratio so if everything is relative, ie; you are comparing different size sensors with the same pixel density like a 24MP sensor and a 16MP cropped sensor, then the IQ and exposure should be the same. If you're using the 16MP crop sensor, isn't that the same as cropping a 24MP image after the fact?
no. That is a old internet myth that has been long dis-proven.
F ratio is just an F ratio, it is only comparable for light gathered if the sensor is the same size.
It is, but its a different framing thus you cannot compare them.
Where in the photos we have posted comparing cameras and lenses do you see a 6 pounds 300mm f/2.8? That's the whole point: that the lenses showed and compared have differences of grams. Sorry for those who do (because maybe they are ill or in bad condition) but I just can't find 100 or 200 grams of difference in the lenses compared to be such a deal.
Sony's main telephoto zoom - a 55-210mm f4.5~6.3 weighs 345 grams
The Panasonic 45-75mm f4~5.6. a lens that is both faster AND effectively longer on m4/3, weighs just 210 grams.
Sony's 18-55mm kit lens weighs 210 grams
the Olympus and Panasonic 14-42 kit lenses weigh 112 and 110 grams respectively.
Just the standard 2 zoom lens kit is 235 grams lighter in m4/3 than in NEX. That's more than half a pound difference. it's also noticeably smaller.
Of course, the more we would look at longer telephotos, the worse the difference would get with respect to size and weight for NEX vs. m4/3.
The one I already made: that the GX7 will not only NOT kill the NEX-7 but that if anything it will kill the not so old E-P5.You're probably looking at a difference of 4 inches in length and close to 3 pounds in weight. And even given the argument about more sensor sensitivity allowing smaller apertures, and the larger format offering less depth of field for aperture equivalency - I use a 200mm f3.0 Vivitar Series One lens, that is still noticeably smaller and lighter than a 300mm f4 legacy lens would be.
....will also soon be replaced. So what's your point here?
4- The M43 lenses cheat with their smaller equivalent apertures (laws of physics = more sensor area more light-gathering). Sony or others could for example release truly equivalent tiny f/5.6-8 zooms... but what would be the point when the current ones are small enough and faster by at least a stop?
5- I don't understand why there should not be size benefit in the bodies either. They are making the same mistakes than with Four Thirds.
The only way the GX7 is going to kill the NEX-7 is because this camera will soon be replaced. The poor Olympus E-P5 on the other hand...
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http://antonio.rojilla.com
That's just a mantra. It is also true that 200mm is 200mm but many M43 users don't have a problem converting it magically to 400mm while ignoring that they should also convert the aperture for true equivalency with larger formats. Oh, and they have suddenly accepted without any doubt that a speed booster lens adapter gives them a full extra stop of light! How's that? Wasn't f/1.8 always f/1.8?
What it does is reduce the larger image circle and concentrate it in an smaller area, throwing over the smaller sensor all the light the lens can natively capture (which goes to show you that mounted in its native mount/sensor it is actually brighter that the so called "equivalent" M43 lens). So the result is not that the lens is a stop faster, it's that you are not throwing away part of the light it can collect, which is what happens when the image circle is cropped leaving outside of the sensor a good part of the light that is entering the lens. In short: you gain a stop because you are now using a lens to its full potential, which is greater than "equivalent" M43 lenses. In other words: the speed booster proves that the "f/1.8 is f/1.8" is false or misleading when sensor size varies.
You are talking out of your back end Ultimitsu.
"f/1.8 is f/1.8" is correct whether it is on this or that sensor. The 200/1.8 + speedbooster has different optical properties than the lens alone, therefore the 200/1.8 + speedbooster is not 200/1.8.
There`s is only one way to find out, tie a piece of string to each and bash them together like conkersMarty4650 wrote:
Compare these two cameras. Both are high quality MILC cameras with magnesium alloy bodies. Both are around the same size and weight. Both have similar styling and control layouts. Both will cost around the same. These two cameras are so similar that it would be hard to like one and not like the other.
The Sony NEX7 has one advantage over the Panasonic GX7. It has a larger sensor. But this advantage can also be a disadvantage because it means you will need larger lenses for it. So it cuts both ways.
We haven't seen any tests yet, but the Panasonic GX7 sensor is two years newer than the Sony sensor in the NEX7, so it might be very capable indeed. Interestingly, both sensors have the pixel density, since they have same size pixels. The NEX7 just has more of them due to a larger sensor.
Assuming the GX7 has a very good sensor (at least as good as the Sony sensor in the OM-D, GH3, and EP5), then it could be a much more compelling camera for an enthusiast.
I say this because the GX7 has some advantages of it's own over the Sony NEX7:
What do you think?
- Sensor shift IBIS
- Tilt up EVF
- Better EVF - more screen resolution
- Better LCD - more screen resolution
- Touch screen
- Can shoot in 4 aspect ratios rather than 2
- Higher maximum sensitivity (ISO 25,600 vs 16,000)
- Slightly more powerful built in flash (GN 7 vs GN 6)
- Faster max shutter speed - 1/8000th
- Much smaller lenses
- Much wider variety of lenses
- 40 lenses available vs. 21 lenses available
- Longer exposures possible (60 sec vs 30 sec)
- Has 2X and 4X digital zoom (not that anyone would actually use it)
Will Sony take this as a shot across the bow?
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Marty
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my blog: http://marty4650.blogspot.com/
Olympus E-30
Olympus E-PL2
Olympus OM-D
Sony SLT-A55
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