Lee Jay

Lee Jay

Lives in United States CO, United States
Works as a Electrical Engineer / Wind Energy Research
Joined on Oct 17, 2003

Comments

Total: 512, showing: 81 – 100
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On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

nigelht: Physically masking a 36MP FF sensor to the same size as a m43 sensor results in an equivalent 9MP m43 sensor.

You won't see increased noise in this masked sensor which indicates that "total light" has little impact on noise or DR because it should be well understood that these characteristics are based on sensor/adc design and pixel size.

The "idea of equivalence" doesn't tell you anything about the noise potential low light performance of the sensor (relative to same generation sensors). The pixel size does. Larger pixels = less noise.

"Equivalent aperture" only addresses DOF equivalence.

"You won't see increased noise in this masked sensor..."

Yes, you will.

Direct link | Posted on Jul 10, 2014 at 02:17 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

StevenMajor: Way Way Way to much information. Reading this will suck ounces of creative energy from most readers.
Do your self a favor, read the "Why should i care" section at the very end. It states..."Ultimately, (the info in the article is) "unlikely to make much difference to your day-to-day shooting".
Rude and insulting of DPREVIEW to offer a long and complex article and at the end tell the reader their was little or no reason to read it.
Pathetic.

It's supposed to help you pick cameras and lenses, not help your day-to-day shooting.

Direct link | Posted on Jul 10, 2014 at 02:15 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

quezra: This article goes to show that people will believe what they want to believe, and all the detailed evidence and careful explanation in the world won't change that. The enormous number of posters jumping in to flatly assert the article is wrong (or make claims that clearly show zero understanding of the article) is getting into the double figures now. Fun to watch actually :D

Given the same sensor technology, this applies. And, usually, the difference between m4/3 and full frame is at least two stops.

Direct link | Posted on Jul 9, 2014 at 22:53 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

ljmeis78: The f stop we know and love (focal length/divi ded by aperture) is known as relative aperture because the actual size of the hole varies from lens to lens. It is useful because it produces uniform expose regardless of lens used, all other factors equal. So why are smaller sensors more noisy?
Small sensors have small pixels, collecting fewer photons than larger ones for given exposure. This requires more amplification after A/D conversion. Moe amp, more noise as any audio phile will tell you. Effective aperture depends on lens design and controls DOF

Pixel size has almost nothing to do with it.

Direct link | Posted on Jul 9, 2014 at 03:00 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

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.

Quadrupling the pixel count, and then down sampling the image to the same final size will result in about the same final images. In your example, down sampling the 50MP full frame image to the 1MP of the hypothetical smaller sensor will result in a drastically lower noise image than the native image from the smaller sensor.

Direct link | Posted on Jul 9, 2014 at 02:50 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

mostlyboringphotog: In shooting experience of FZ1000, another thread seems to be developing FL/F-stop equivalent because Panasonic engraved the equivalent FL on the barrel.
My point as I humbly present is that the solution is not to engrave equivalent F-stop added on the barrel but to remove the equivalent FL markings.

Respectfully,

Same difference. Either use equivalents for both or neither. Either option is honest.

Direct link | Posted on Jul 9, 2014 at 02:35 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

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.

Because signal to noise ratio equals the square root of the total number of photons collected. And the image is formed by the entire sensor. This is why a full frame camera captures a better image at f/2 than a cell phone does at the same f-stop.

Direct link | Posted on Jul 9, 2014 at 02:33 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

quezra: This article goes to show that people will believe what they want to believe, and all the detailed evidence and careful explanation in the world won't change that. The enormous number of posters jumping in to flatly assert the article is wrong (or make claims that clearly show zero understanding of the article) is getting into the double figures now. Fun to watch actually :D

It's not just on DOF. It's also on total light and therefore shot noise, and on diffraction. And equivalent focal length is on angle of view. Between the two, they're on everything that matters in this area.

Direct link | Posted on Jul 9, 2014 at 02:02 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

mostlyboringphotog: Lastly, F-stop is useful because it indicates "equivalent" amount of light passing per unit time/area regardless of FL or the aperture diameter. Now by creating another derivative, what does it help?

Does it really help to normalize lens performance or its relative merits?

A lot of posters think so and so may be it's useful but I think it comes at a cost of mudding the definition of "F-stop" and understanding DOF.

Is there not a better way to communicate the difference that a sensor size affects your image making?

Again, thank you all for your patience.

It just says half size. It doesn't say if that's linear or areal, and it obviously means linear (i.e. 2x crop).

Direct link | Posted on Jul 8, 2014 at 20:20 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

Lights: I kinda think products like the Metabones adapters for APS-C and M43 are an interesting side-track in the Equivalence debate.

They do, just in reverse. Teleconverter and wideconverter are the same except for which side of "1" you're on.

Direct link | Posted on Jul 8, 2014 at 19:04 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

mostlyboringphotog: Lastly, F-stop is useful because it indicates "equivalent" amount of light passing per unit time/area regardless of FL or the aperture diameter. Now by creating another derivative, what does it help?

Does it really help to normalize lens performance or its relative merits?

A lot of posters think so and so may be it's useful but I think it comes at a cost of mudding the definition of "F-stop" and understanding DOF.

Is there not a better way to communicate the difference that a sensor size affects your image making?

Again, thank you all for your patience.

I have a little drawing that's supposed to relate that idea to people:

http://photos.imageevent.com/sipphoto/samplepictures/Format%20drawing.jpg

Direct link | Posted on Jul 8, 2014 at 18:30 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

mostlyboringphotog: Lastly, F-stop is useful because it indicates "equivalent" amount of light passing per unit time/area regardless of FL or the aperture diameter. Now by creating another derivative, what does it help?

Does it really help to normalize lens performance or its relative merits?

A lot of posters think so and so may be it's useful but I think it comes at a cost of mudding the definition of "F-stop" and understanding DOF.

Is there not a better way to communicate the difference that a sensor size affects your image making?

Again, thank you all for your patience.

Equivalents are about comparing systems using different formats They aren't about setting exposure in your camera.

Direct link | Posted on Jul 8, 2014 at 15:34 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

mostlyboringphotog: Lastly, F-stop is useful because it indicates "equivalent" amount of light passing per unit time/area regardless of FL or the aperture diameter. Now by creating another derivative, what does it help?

Does it really help to normalize lens performance or its relative merits?

A lot of posters think so and so may be it's useful but I think it comes at a cost of mudding the definition of "F-stop" and understanding DOF.

Is there not a better way to communicate the difference that a sensor size affects your image making?

Again, thank you all for your patience.

The important parameters for a lens (the ones that control the image) are angle-of-view and aperture diameter. Yet, we specify focal length and f-stop instead. To get back to what matters, use equivalence. This assures that the angle-of-view is specified (in 35mm equivalent terms) and the the aperture is specified correctly through the equivalent f-stop.

Direct link | Posted on Jul 8, 2014 at 14:35 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

mislav: I don't care

"I won't shoot 8x10" and 35 mm to get same size print."

Rational people know that the final print size is often dictated by the customer, not the photographer, and that it's choice has nothing to do with the format used in the camera.

No one is redefining f-number.

f-number = focal length / aperture

If focal length is referenced to 35mm as a base, instead of using optical focal length, then the equation becomes:

f-number (equivalent) = focal length (equivalent) / aperture

The problem comes in when people use an equivalent focal length but not an equivalent f-number (which is what's often done with compact cameras), since that DOES redefine the equation, since the aperture is no longer the actual entrance pupil diameter.

Direct link | Posted on Jul 8, 2014 at 14:32 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

mislav: I don't care

mislav, you're extremely lost. At the same final size, you most certainly would get finer grain on the 8x10 contact print than you would on the 35mm enlargement.

Read the article. It's absolutely accurate, and it's been repeatedly verified as accurate by actual tests. If you think it's wrong, than it's your thinking that's wrong.

Direct link | Posted on Jul 8, 2014 at 14:02 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

mostlyboringphotog: Lastly, F-stop is useful because it indicates "equivalent" amount of light passing per unit time/area regardless of FL or the aperture diameter. Now by creating another derivative, what does it help?

Does it really help to normalize lens performance or its relative merits?

A lot of posters think so and so may be it's useful but I think it comes at a cost of mudding the definition of "F-stop" and understanding DOF.

Is there not a better way to communicate the difference that a sensor size affects your image making?

Again, thank you all for your patience.

The concept of an f-stop is already very "muddled" in the minds of many people. Just look down at how many people think that f-stop defines the amount of light that passes through the lens and onto the sensor, when it actually controls the light intensity (illuminance) instead.

Direct link | Posted on Jul 8, 2014 at 13:31 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

mislav: I don't care

How can the truth be BS?

Direct link | Posted on Jul 8, 2014 at 12:01 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

WT21: Incredibly useful concept that sadly leads to some of the most boring and droning discussions on photo forum boards.

Good article that will hopefully clear it up for most.

I discovered (or, rather, rediscovered) equivalence on my own in 2005, and it has guided my purchases and shooting when using multiple formats ever since.

Direct link | Posted on Jul 8, 2014 at 12:01 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

Lights: I kinda think products like the Metabones adapters for APS-C and M43 are an interesting side-track in the Equivalence debate.

Why?

Want a short explanation of equivalence?

Crop factor = teleconverter.

Likewise, 1/crop factor = wide converter.

Direct link | Posted on Jul 8, 2014 at 11:56 UTC
On What is equivalence and why should I care? article (2064 comments in total)
In reply to:

hybert46: So finally what is the more compact, potentially cheapest or easiest lens to produce, a FF 100mm f/4 or a m43 50mm f/2? Both should have a roughly similar size of entrance pupil as it is defined by the ratio of focal length over the f-number. Anyone care to elaborate on this, could be interesting!

A lens need not be as long or longer than its focal length. In fact, the definition of a telephoto lens is a lens that's shorter physically than its focal length.

To answer the question, in most cases for equivalent kits, the larger sensor Lena system is smaller and cheaper.

Direct link | Posted on Jul 8, 2014 at 11:51 UTC
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