Total: 156, showing: 61 – 80
On article What is equivalence and why should I care? (2471 comments in total)

SouthElginDad: I don't understand why "total light hitting the sensor" matters. The image is captured by pixels, not by the entire sensor. It seems to me that total light -- per pixel -- is roughly the same, whether or not there are more total pixels on a larger sensor. (Granted, a smaller sensor may have smaller pixels in order to maintain resolution, but that's not what this article is saying -- it's saying that the total light hitting the entire sensor, regardless of how many pixels are on that sensor, is what matters.)

I get the part about the DoF, that makes sense. But I don't understand why total light on the entire sensor makes any difference.

Consider two sensors, one is larger than the other. Now, let's say that each sensor only have one large pixel. While the intensity of the light hitting the two sensors are the same, the larger one gets more total light, because of its larger area, of course. Now consider that we divide the sensor up in quarters, for a state-of-the-art 4-pixel camera. Same intensity hits each pixel on both cameras, and both cameras produce the same image, but the pixels on the larger sensor all gets more total light, and each part of the image is therefore less noisy on the larger sensor. Divide the sensor up more, and more, and more, and more, and you'll end up with the megapixels of today, and the principle stays true: While each part of the image, each little square of the sensor is hit by the same intensity of light, the squares on the larger sensor is hit by more total light and therefore is less noisy.

In the end, you compare like for like: Image for image, part for part.

Link | Posted on Jul 9, 2014 at 02:42 UTC
On article What is equivalence and why should I care? (2471 comments in total)

mostlyboringphotog: I guess now I understand why "equivalence" becomes such a heated topic while it's nothing more than manipulating some math values.

Is 2+2 equivalent to 3+1?

What I object to the F-stop equivalence is that I think it buries the understanding of DOF even deeper while creating that DOF is sensor size dependent misconception.

For example, if you crop an image from a FF to a size of crop image, do you now need to crank up to the equivalent exposure using PP to maintain the DOF? Does DOF change if an image is cropped?

DOF is a function of FL, F-stop (EP) AND distance to the subject.
You don't need "equivalent F-stop" if you move closer to the subject with a crop camera to maintain the same DOF of FF.
If you don't want to move, you may change the FL (not equivalent).
And if your lens is not a constant F-stop zoom (or prime), then you can change the F-stop to a DOF calculated F-stop (not equivalent), then adjust ISO or shutter speed or add ND-filter to maintain the same exposure.

DoF is a somewhat contentious subject. Do we speak only of the optical phenomenon or is it a particular characteristic of the final image? Focus stacking to create both wider and narrower depths of field is getting more and more automated in cameras and software, for example.

Also, Depth of Field is sometimes made out to be an entirely objective value, when it is in fact subjective. dependant on viewing distance, eyesight and magnification.

Link | Posted on Jul 8, 2014 at 13:15 UTC
On article What is equivalence and why should I care? (2471 comments in total)

Macx: 1) When considering equivalence (i.e. DoF, diffraction and total light/shot noise) sensor plays second fiddle to the lens: Given the same FoV and the same physical (virtual) aperture, you'll get the same image characteristics, no matter if you're shooting an image on your phone or on your medium format digital back. The thing that is holding your phone back in performance is for most intents and purposes the tiny lens and not the tiny sensor.

2) The difference in DoF and shot noise between different formats only come to play at the extreme ends of the exposure gamut: Bluntly, on a bright day, shooting for a wide depth of field your phone will give you roughly the same performance as your dslr. Only when the phone is out of its comfort zone the difference becomes apparent. Cameras using 1", 4:3 or APS-format sensors are a few stops shy of the comfort zone of current FF cameras. If you're not actually using those stops there is little to distinguish it.

Very true, that is one of the advantages of a FF camera, though in that case we're not comparing equivalent exposures any more.

The problem of having a base ISO might soon have a solution, luckily. Electronic curtains and multiple readouts per shutter actuation may make base ISO practically arbitrary for phone cameras and dslrs alike.

Link | Posted on Jul 8, 2014 at 07:09 UTC
On article What is equivalence and why should I care? (2471 comments in total)

DPJoe2: Please bear with me. I believe what we care about is IQ. IQ is determined by lens quality, sensor size, quality, and the sensors set sensitivity. The same is true for film. I'm treating sensor noise and film grain as equal problems. For each sensor or film sensitivity there is a built-in level of noise. How much is determined by the manufacturer. Unlike film, sensors can have there sensitivity increased electronically. But whether you use film or sensors, increasing the sensitivity increases noise. Noise and sensor size determine how much you can enlarge an image and get an acceptable result. The more you enlarge an image the more noise is visible. If you shoot with a high ISO you increase noise and lower how much you can enlarge the image to get an acceptable result. But if you shoot with a larger sensor, you don't have to enlarge the image as much, and as a result get better IQ. BTW, when I say larger sensor size, I mean the physical size of the sensor, not MegaPixels. Questions?

No, Joe, you're not introducing more electronic noise by raising the ISO, you're reducing it. It's not like an amp. The reason you see more noise in the higher ISO shots is because while you're doing that you're making a smaller exposure.

Link | Posted on Jul 7, 2014 at 21:58 UTC
On article What is equivalence and why should I care? (2471 comments in total)

Macx: 1) When considering equivalence (i.e. DoF, diffraction and total light/shot noise) sensor plays second fiddle to the lens: Given the same FoV and the same physical (virtual) aperture, you'll get the same image characteristics, no matter if you're shooting an image on your phone or on your medium format digital back. The thing that is holding your phone back in performance is for most intents and purposes the tiny lens and not the tiny sensor.

2) The difference in DoF and shot noise between different formats only come to play at the extreme ends of the exposure gamut: Bluntly, on a bright day, shooting for a wide depth of field your phone will give you roughly the same performance as your dslr. Only when the phone is out of its comfort zone the difference becomes apparent. Cameras using 1", 4:3 or APS-format sensors are a few stops shy of the comfort zone of current FF cameras. If you're not actually using those stops there is little to distinguish it.

Bits per colour isn't the same as dynamic range, it's all about the smooth transitions, and the 16-bit per colour you get in medium format is apparently sufficiently better than full frame for the pros to want it. I'm not sure where you've read that medium format has significantly narrower DR than full frame? Modern ones have about 14 stops of dynamic range which seems about equal to the best full frame cameras and even those who only have 13 isn't that poor and not to blame for the poor high-iso performance. Instead the base ISO is often as low as 50 or 35.

Link | Posted on Jul 7, 2014 at 21:13 UTC
On article What is equivalence and why should I care? (2471 comments in total)

Macx: 1) When considering equivalence (i.e. DoF, diffraction and total light/shot noise) sensor plays second fiddle to the lens: Given the same FoV and the same physical (virtual) aperture, you'll get the same image characteristics, no matter if you're shooting an image on your phone or on your medium format digital back. The thing that is holding your phone back in performance is for most intents and purposes the tiny lens and not the tiny sensor.

2) The difference in DoF and shot noise between different formats only come to play at the extreme ends of the exposure gamut: Bluntly, on a bright day, shooting for a wide depth of field your phone will give you roughly the same performance as your dslr. Only when the phone is out of its comfort zone the difference becomes apparent. Cameras using 1", 4:3 or APS-format sensors are a few stops shy of the comfort zone of current FF cameras. If you're not actually using those stops there is little to distinguish it.

Canon shooter: Remember, if we're shooting equivalent shots, ISOs won't be similar across sensor formats. For example, for the same field of view and virtual aperture, you'll be comparing ISO 200 on a 4:3 to ISO 800 on the Full Frame, and then the advantage isn't as apparent.

Link | Posted on Jul 7, 2014 at 18:49 UTC
On article What is equivalence and why should I care? (2471 comments in total)

DPJoe2: Please bear with me. I believe what we care about is IQ. IQ is determined by lens quality, sensor size, quality, and the sensors set sensitivity. The same is true for film. I'm treating sensor noise and film grain as equal problems. For each sensor or film sensitivity there is a built-in level of noise. How much is determined by the manufacturer. Unlike film, sensors can have there sensitivity increased electronically. But whether you use film or sensors, increasing the sensitivity increases noise. Noise and sensor size determine how much you can enlarge an image and get an acceptable result. The more you enlarge an image the more noise is visible. If you shoot with a high ISO you increase noise and lower how much you can enlarge the image to get an acceptable result. But if you shoot with a larger sensor, you don't have to enlarge the image as much, and as a result get better IQ. BTW, when I say larger sensor size, I mean the physical size of the sensor, not MegaPixels. Questions?

DPJoe2: That process is what's being done in-camera when you turn the ISO up to underexpose without getting a darker image output.

Link | Posted on Jul 7, 2014 at 18:39 UTC
On article What is equivalence and why should I care? (2471 comments in total)

Macx: 1) When considering equivalence (i.e. DoF, diffraction and total light/shot noise) sensor plays second fiddle to the lens: Given the same FoV and the same physical (virtual) aperture, you'll get the same image characteristics, no matter if you're shooting an image on your phone or on your medium format digital back. The thing that is holding your phone back in performance is for most intents and purposes the tiny lens and not the tiny sensor.

2) The difference in DoF and shot noise between different formats only come to play at the extreme ends of the exposure gamut: Bluntly, on a bright day, shooting for a wide depth of field your phone will give you roughly the same performance as your dslr. Only when the phone is out of its comfort zone the difference becomes apparent. Cameras using 1", 4:3 or APS-format sensors are a few stops shy of the comfort zone of current FF cameras. If you're not actually using those stops there is little to distinguish it.

BorisK1: Well, this is sort of branching off, and my own experience with medium format is limited to film, so I'm definitely not an expert, but when I talk to professional photographers their main reason for using medium format is first and foremost the colour depth and only secondly resolution.

Link | Posted on Jul 7, 2014 at 18:26 UTC
On article What is equivalence and why should I care? (2471 comments in total)

DPJoe2: Please bear with me. I believe what we care about is IQ. IQ is determined by lens quality, sensor size, quality, and the sensors set sensitivity. The same is true for film. I'm treating sensor noise and film grain as equal problems. For each sensor or film sensitivity there is a built-in level of noise. How much is determined by the manufacturer. Unlike film, sensors can have there sensitivity increased electronically. But whether you use film or sensors, increasing the sensitivity increases noise. Noise and sensor size determine how much you can enlarge an image and get an acceptable result. The more you enlarge an image the more noise is visible. If you shoot with a high ISO you increase noise and lower how much you can enlarge the image to get an acceptable result. But if you shoot with a larger sensor, you don't have to enlarge the image as much, and as a result get better IQ. BTW, when I say larger sensor size, I mean the physical size of the sensor, not MegaPixels. Questions?

You don't change sensitivity on your sensor when you change ISO, and you're not amplifying a signal. These are analogies used to intuit the process, but they're wrong.

Noise (as short-hand for S/N-ratio) have two components: Shot noise and read noise. Read noise is constant, shot noise becomes less apparent the more light you have. In broad terms, when you turn up the ISO you reduce the amount of read noise the sensor produces, but at the same time you limit the amount of light your sensor is capable of recording. If you're not oversaturating the sensor with light, turning up the ISO will therefore produce lower noise than keeping it at the base.

Link | Posted on Jul 7, 2014 at 18:19 UTC
On article What is equivalence and why should I care? (2471 comments in total)

Macx: 1) When considering equivalence (i.e. DoF, diffraction and total light/shot noise) sensor plays second fiddle to the lens: Given the same FoV and the same physical (virtual) aperture, you'll get the same image characteristics, no matter if you're shooting an image on your phone or on your medium format digital back. The thing that is holding your phone back in performance is for most intents and purposes the tiny lens and not the tiny sensor.

2) The difference in DoF and shot noise between different formats only come to play at the extreme ends of the exposure gamut: Bluntly, on a bright day, shooting for a wide depth of field your phone will give you roughly the same performance as your dslr. Only when the phone is out of its comfort zone the difference becomes apparent. Cameras using 1", 4:3 or APS-format sensors are a few stops shy of the comfort zone of current FF cameras. If you're not actually using those stops there is little to distinguish it.

BorisK1: No doubt about that. That is why professional photographers often swear by medium format. I think I was fairly careful about only talking about depth of field, diffraction and noise.

Link | Posted on Jul 7, 2014 at 17:55 UTC
On article What is equivalence and why should I care? (2471 comments in total)

chbde: Very good article. It is however slightly incorrect on the topic of diffraction:
"This is because, like depth-of-field, softening from diffraction depends on the actual size of the aperture, not the F-number."

As "Cambridge in Color" (http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm) explains it very nicely, the size of the diffraction pattern on the sensor depends only on the f-number. This is also the reason why diffraction softening is independent of focal length. But one can see the effect of diffraction if the size of the diffraction patterns exceeds the dimensions of a pixel, so it is dependent on pixel density.

"This means diffraction will have the same impact on two images shot at equivalent apertures"

That sentence remains correct, however, for sensors with equal number of pixels.

As a consequence of this, by the way, on a 16MP 2.3" compact the resolution is already diffraction limited at f2.8!

Link | Posted on Jul 7, 2014 at 17:22 UTC
On article What is equivalence and why should I care? (2471 comments in total)

Macx: 1) When considering equivalence (i.e. DoF, diffraction and total light/shot noise) sensor plays second fiddle to the lens: Given the same FoV and the same physical (virtual) aperture, you'll get the same image characteristics, no matter if you're shooting an image on your phone or on your medium format digital back. The thing that is holding your phone back in performance is for most intents and purposes the tiny lens and not the tiny sensor.

2) The difference in DoF and shot noise between different formats only come to play at the extreme ends of the exposure gamut: Bluntly, on a bright day, shooting for a wide depth of field your phone will give you roughly the same performance as your dslr. Only when the phone is out of its comfort zone the difference becomes apparent. Cameras using 1", 4:3 or APS-format sensors are a few stops shy of the comfort zone of current FF cameras. If you're not actually using those stops there is little to distinguish it.

Canon shooter, the point is that if you step down that f/1.2 until you match the "physical"/virtual aperture of the tiny lens on your phone, your dslr will perform very similar to your camera phone. In the end, the lens is the most important part of the equation, and the big advantage of an interchangeable-lens camera is the fact that you can fit very large lenses on them.

However, if you don't use that advantage, and for example shoot your 85 at f/2, there is no inherent advantage in having a full frame camera compared to shooting a 42.5 at f/1 on a 4:3, for example. It's only when you go down to f/1.2 that there is no equivalent lens for 4:3, thereby giving your complete system the advantage.

There can be advantages regarding other things of course: Ergonomics, type of viewfinder, etc. I'm merely addressing DoF, diffraction and noise here.

Link | Posted on Jul 7, 2014 at 17:21 UTC
On article What is equivalence and why should I care? (2471 comments in total)

Macx: 1) When considering equivalence (i.e. DoF, diffraction and total light/shot noise) sensor plays second fiddle to the lens: Given the same FoV and the same physical (virtual) aperture, you'll get the same image characteristics, no matter if you're shooting an image on your phone or on your medium format digital back. The thing that is holding your phone back in performance is for most intents and purposes the tiny lens and not the tiny sensor.

2) The difference in DoF and shot noise between different formats only come to play at the extreme ends of the exposure gamut: Bluntly, on a bright day, shooting for a wide depth of field your phone will give you roughly the same performance as your dslr. Only when the phone is out of its comfort zone the difference becomes apparent. Cameras using 1", 4:3 or APS-format sensors are a few stops shy of the comfort zone of current FF cameras. If you're not actually using those stops there is little to distinguish it.

It's not fair to say that tiny sensors are inherently more noisy than larger ones. While it may seem that way, it's usually just a matter of the tiny sensor being paired with a tiny lens that's causing the problem.

Now, I don't know how much you've read about the subject, but the first thing anybody need to realise is that there are two components to photographic noise. 1) The "read noise" created during the recording process and 2) "shot noise" the inherent natural tendency for light to behave in a random way. Testing have shown no inherent advantage in sensor/pixel size when it comes to read noise, in fact sometimes it seems smaller sensors outperform larger ones. Instead, the reason you see more noise in the output from the camera phone is because of the shot noise: In low light situations, the less light going through the tiny lens on the phone simply makes for a poorer signal/noise ratio.

In very bright conditions there is a another consideration, but I'm out of characters now.

Link | Posted on Jul 7, 2014 at 17:14 UTC
On article What is equivalence and why should I care? (2471 comments in total)

1) When considering equivalence (i.e. DoF, diffraction and total light/shot noise) sensor plays second fiddle to the lens: Given the same FoV and the same physical (virtual) aperture, you'll get the same image characteristics, no matter if you're shooting an image on your phone or on your medium format digital back. The thing that is holding your phone back in performance is for most intents and purposes the tiny lens and not the tiny sensor.

2) The difference in DoF and shot noise between different formats only come to play at the extreme ends of the exposure gamut: Bluntly, on a bright day, shooting for a wide depth of field your phone will give you roughly the same performance as your dslr. Only when the phone is out of its comfort zone the difference becomes apparent. Cameras using 1", 4:3 or APS-format sensors are a few stops shy of the comfort zone of current FF cameras. If you're not actually using those stops there is little to distinguish it.

Link | Posted on Jul 7, 2014 at 16:27 UTC as 459th comment | 16 replies

JEROME NOLAS: Another lens that will make me a better photographer....and yes, that click, click, click drives me crazy!!! :)

And a 50/1.9 could hardly be called a large aperture lens, yabokkie? I beg to differ.

Link | Posted on Feb 14, 2014 at 05:20 UTC

Jogger: Why is the 25/1.8 more expensive than the already excellent and faster 50/1.8 from other makers? Even the excellent Nikon 35/1.8 is faster and less than \$200.

halfwaythere, that's a good point. Let's take the Nikkor 32/1.2 lens they make for the 1 system. 9 elements in 7 groups like the Zuiko: Nikon's asking price is \$900.

Link | Posted on Jan 29, 2014 at 18:19 UTC

Jogger: Why is the 25/1.8 more expensive than the already excellent and faster 50/1.8 from other makers? Even the excellent Nikon 35/1.8 is faster and less than \$200.

It's partly because of the economies of scale: The more you make of a product, the comparatively cheaper it will be to research, produce and market it. It's the same reason that kit lenses are cheaper.

But it's also a matter of supply and demand. I suspect there are several other manufacturers making relatively fast, normal lenses for the Nikon mount, but for the micro four-thirds mount, the competition is limited.

Link | Posted on Jan 29, 2014 at 16:17 UTC
On article Sony Alpha 7 Review (1597 comments in total)

Rob Sims: Not that I necessarily disagree with points made in this article, but the article does read very negatively - especially considering that this is the cheapest FF camera on the market - the same price as some m43 cameras but with much better image quality (the first important thing...).

I've never taken a JPG photo out of this camera, so perhaps that's why I'm enjoying this camera so much. I'd go as far as to say I'm enjoying this camera even more than when I first got my Nikon D700 five years ago (for almost twice the price), and as a result it's coming everywhere with me (...the other most important thing).

I agree that this system probably just needs to mature a bit, and I look forward to where Sony is taking this. I can't help but be concerned about the choice of mount in combination with the larger sensor, but for all I know it seems to work.

It isn't the first 135 format mirrorless though as Leica has made those for a while now.

Link | Posted on Jan 23, 2014 at 10:43 UTC

ragmanjin: This poll has already been answered by the previous polls, so I can't help but question the motive behind it — especially since, as far as I'm aware, this is the first year one of the leading cameras (let alone the all-out winner) hasn't already received its full review.
I hate to keep kicking a dead horse but is this an attempt to avert attention while you finish up with the K-3?
I mean no disrespect, DPR, I just feel the question needs to be put out there. If you guys were just waiting for the firmware update or the release of the Flucard for wireless tethering, that's totally fine. It would be nice if you would let us know that sort of thing is all I'm saying.

Vinc T: Exactly. The K-3 would be my choice for a DSLR, but if I had to choose between the K-3 and the E-M1, I'd choose the E-M1.

Link | Posted on Jan 6, 2014 at 17:39 UTC
On article Canon announces EOS M2 in Japan (611 comments in total)