[normhead]

Equivalence is important to understand as a debating concept, but it's more important to understand each piece of equipment you shoot with. You can understand equivalence by understanding your output. And you have to do that anyway. When looking at something like equivalence you have to ask, is this a tool or a distraction.

Given that you still have to learn each lens, each piece of gear and their characteristic, it's a distraction. You can go down that road if it appeals to you, but, for most it's a waste of time. I look at it as kind of hobby some photographers love to engage in.

[dakight]

Equivalence is important to understand as a debating concept, but it's more important to understand each piece of equipment you shoot with. You can understand equivalence by understanding your output. And you have to do that anyway. When looking at something like equivalence you have to ask, is this a tool or a distraction.

Given that you still have to learn each lens, each piece of gear and their characteristic, it's a distraction. You can go down that road if it appeals to you, but, for most it's a waste of time. I look at it as kind of hobby some photographers love to engage in.

By "equivalence" I assume you mean applying the crop factor to the focal length and maximum/minimum aperture of a lens in an attempt to understand its characteristics vs. 35 mm full frame, or possibly some other format. With that assumption in mind I'll say that it is a crutch or at best a bridge to help one make the transition from one format to another. It seems to me that in time the photographer must become fluent in the architecture and ecosystem in which they intend to work. It would be tedious at best to have to constantly think about equivalence to another system. I hope that eventually, sooner rather than later, that I will look at a shot and instinctively know what tool is the best one for that situation and not have to think in terms of 35 mm film then go through the conversion process to arrive at an equivalent.

[ElJamoquio]

Equivalence is important to understand as a debating concept, but it's more important to understand each piece of equipment you shoot with. You can understand equivalence by understanding your output. And you have to do that anyway. When looking at something like equivalence you have to ask, is this a tool or a distraction.

Given that you still have to learn each lens, each piece of gear and their characteristic, it's a distraction. You can go down that road if it appeals to you, but, for most it's a waste of time. I look at it as kind of hobby some photographers love to engage in.

Ultra low light - should you use a 135 F/2 and crop or use a 70-200 f/2.8 at, say, 170mm?

Easy question to answer one way, exceedingly difficult the other way...

[normhead]

By "equivalence" I assume you mean applying the crop factor to the focal length and maximum/minimum aperture of a lens in an attempt to understand its characteristics vs. 35 mm full frame, or possibly some other format. With that assumption in mind I'll say that it is a crutch or at best a bridge to help one make the transition from one format to another. It seems to me that in time the photographer must become fluent in the architecture and ecosystem in which they intend to work. It would be tedious at best to have to constantly think about equivalence to another system. I hope that eventually, sooner rather than later, that I will look at a shot and instinctively know what tool is the best one for that situation and not have to think in terms of 35 mm film then go through the conversion process to arrive at an equivalent.

That's exactly it. You're not a basketball player when you understand the physics. You're a basketball player when the lessons you've learned have passed into muscle memory and you act without thinking. Having to think about equivalence means you aren't there yet. The photographer instinctively reaches for the right gear at the right time because he's seen so many pictures taken with that lens or that body, he/she knows exactly what it will give him/her, and that's the look he/she wants... he/she doesn't start figuring out in his head what lens is the best for the format he's shooting. That kind of stuff is for amateurs.

[Kunzite]

The answer to my question was quite trivial to find... about fifteen seconds.... because I understand the simplicity of equivalence.


The question posed was rhetorical. I know the answers. The response is "ah yes, equivalence is important, even beyond choosing between camera systems".

Riiight. Thank you again for making my point. I'm afraid you don't understand "equivalence", applying it blindly instead.
Fact #1: You can only estimate SNR differences due to photon noise. All other types of noise are excluded (this is obfuscated under the "same technology" premise)
Fact #2: "Equivalence" doesn't touch the resolution subject - which could only possibly work with spherical cows in a vacuum "perfect" lenses, diffraction limited and with identical behavior; and with "perfect" sensors.

Norm is right, "equivalence" is a distraction - and I'll add, a dangerous one. It promotes a limited, flawed understanding; its promises are big and its limitations, hidden.

[normhead]

Ultra low light - should you use a 135 F/2 and crop or use a 70-200 f/2.8 at, say, 170mm?

Easy question to answer one way, exceedingly difficult the other way...

I was in the lot where birders hang out the other day... I was interested in the Tamron 150-600 and a guy had one there on a Nikon D800, I ask him, hey can I look through your lens? I look through this lens test out the autofocus, watch the viewfinder change as I run the zoom in an out. I now know more about that lens than anyone who's analyzed it using equivalence will ever know. I know that lens isn't for me, and I know why. FF or APS-c, equivalence, it's all useless information. For some reason, that lens isn't for me, and that's all I need to know. And I'm not going to let some theory like equivalence talk me in to it.

You can say well. equivalence it is 250-900mm on APS-c, but it doesn't matter. Equivalence describes very little of what I look for in a lens.

[ElJamoquio]

Riiight.

Glad you finally agree.

FYI my camera has the same sensor across the entire sensor. All sources of noise are included.

[clackers]

I've referred to him before, he seems to explain things very clearly.

You can't spin his explanation, JSherman - he directly contradicts you.


He finds the pixel pitch and technology, not sensor size, determines low light IQ, and that's what the idealized curves on his graph (completely separate from the dots representing real cameras) reflect.


I urge everyone to look at those lines on the graph labelled "Signal to Noise Ratio on an 18% Gray card at 100 ISO": Clarkvision: Digital Camera Review and Sensor Performance Summary


Pixel pitch is the variable in thirteen graphs on that page. Sensor size is the variable in *none* of them.


IMHO, to wave at later sentences mentioning camera and total exposure is grasping at straws.


Anyway, while I disagree with you over this matter, sir, can I put it aside for a moment for a more important issue and ask, are you also a fan of the Coen Brother's The Big Lebowski?

[clackers]

No, I don't, presuming (big assumption) that I want to take a similar picture as you.

I set to 1/125s, ISO~1600 or so.

Post 56 in this thread was a pretty arrogant one from you, El Jamoquio.


You dismissively invited a challenge of your philosophy, and called on it, you're now ducking, evading and have lost the courage of your Total Light convictions.

For the third time, please provide an answer to the aperture for correct exposure.


If it really is 1/125th, ISO 1600 (noise ahoy!), f22 (diffraction, wahoo!) - or some other number - I want to hear you say it.

[jsherman999]

You can't spin his explanation, JSherman - he directly contradicts you.


He finds the pixel pitch and technology, not sensor size, determines low light IQ, and that's what the idealized curves on his graph (completely separate from the dots representing real cameras) reflect.


I urge everyone to look at those lines on the graph labelled "Signal to Noise Ratio on an 18% Gray card at 100 ISO": Clarkvision: Digital Camera Review and Sensor Performance Summary


Pixel pitch is the variable in thirteen graphs on that page. Sensor size is the variable in *none* of them.


IMHO, to wave at later sentences mentioning camera and total exposure is grasping at straws.


Anyway, while I disagree with you over this matter, sir, can I put it aside for a moment for a more important issue and ask, are you also a fan of the Coen Brother's The Big Lebowski?

The dude abides.

I encourage you to stick with this issue if it interests you. At some point you'll get the difference between read noise and shot noise, and how physical aperture + sensor size affects the latter. Then you'll see what Dr Clark is really saying, and how when he's talking about the effect of read noise he's not conflating it with shot noise - which you still seem to be doing.

Also, email him directly and discuss Total Light (or as he calls it, "real exposure".) He may agree to enlighten you!

.

---------- Post added 10-20-14 at 08:20 AM ----------

Equivalence is important to understand as a debating concept, but it's more important to understand each piece of equipment you shoot with. .

How about a piece or pieces of equipment you don't own yet?

[altopiet]

This is a very enlightening discussion about something totally beyond my comprehension, but I still try to follow here and there, waiting for an answer to a question I've had for a while about all discussed in this thread, and that is....Do anybody have any idea whether anything discussed have any influence in peoples decision to buy a digital camera, and DSLR specifically, and if it does, what percentage of sales are we talking about, more or less?

What I mean is, do all the time everyone in this thread is spending discussing it, have any real influence in the daily life of photographers?

Should any photographer, hobbyist or pro, take note of this in their quest to take better photographs, or is it merely a mental exercise for a few people with some idle time on their hands?

[jsherman999]

Norm is right, "equivalence" is a distraction - and I'll add, a dangerous one. It promotes a limited, flawed understanding; its promises are big and its limitations, hidden.

Is the problem that wine coolers can no longer buy you off? You'll keep coming back into the same bar and telling the same folks to stop talking about horsepower because real drivers don't need to know about it. And it's a dangerous abomination!

Or... are you doing it because of the wine coolers we keep buying you? Ah-ha!

[ElJamoquio]

Post 56 in this thread was a pretty arrogant one from you, El Jamoquio.


You dismissively invited a challenge of your philosophy, and called on it, you're now ducking, evading and have lost the courage of your Total Light convictions.

For the third time, please provide an answer to the aperture for correct exposure.


If it really is 1/125th, ISO 1600 (noise ahoy!), f22 (diffraction, wahoo!) - or some other number - I want to hear you say it.

I'm not ducking. You asked the wrong question and I didnt want to embarrass you publicly any more.

[jsherman999]

This is a very enlightening discussion about something totally beyond my comprehension, but I still try to follow here and there, waiting for an answer to a question I've had for a while about all discussed in this thread, and that is....Do anybody have any idea whether anything discussed have any influence in peoples decision to buy a digital camera, and DSLR specifically, and if it does, what percentage of sales are we talking about, more or less?

It would maybe help to answer this question: Why would you buy an aps-c DSLR (or mirrorless camera) over a superzoom bridge camera with a new, very-efficient BSI sensor that offers a 28-300 f/2.8 "equivalent" fixed lens?

That "28-300 f/2.8" is pretty powerful, no? It would allow the same exposure over the same FOV as a 28-300 lens on FF, and that sensor is brand new and very efficient. If you didn't like primes, didn't care about VF and AF speed and were just concerned with IQ, why would you ever consider a larger sensor DSLR or MILC? Wouldn't it be a waste of money?

Now here's the thing - any answer you give that involves IQ, even if you're not not using the term equivalence, has the concept baked in. As does the 'low light' score in DXOmark. The Total Light is crucial to the reason why.

What this means is that you can just say, "because the aps-c DSLR has a larger sensor, and it's going to have the capability to give me better images than that P&S". Equivalence/Total LIght is implicit in that answer, just like horsepower is (often) going to be baked into "Car A is faster than Car B."

Now, where the background knowledge of why may help you is if some neighbor or salesman says "why bother with a DSLR, this brand new P&S with this 28-300 2/8 lens is just as good, gets you the same exposure, etc." Might be good to have some facts and methodologies at your disposal to be able to call BS. It also would help you if the sensor sizes are much closer than P&S and aps-c - like aps-c & FF, or especially FF and medium format , because depending on the lens + body combo you're considering the larger sensor combo may not be better.

Of course it's completely up to you. IMO, it's unseemly to go through life with half-understandings when the truth is so readily available.

And if you're hangin' in a forum like this... It's kinda going to get talked about.

.

[Kunzite]

My dear Jshermann999, FTR this forum is not your bar and you don't decide that everyone should embrace your "equivalence", or leave.

I understand that you "must" support a fellow "equivalentionist" no matter what, and since you cannot attack my arguments:

Fact #1: You can only estimate SNR differences due to photon noise. All other types of noise are excluded (this is obfuscated under the "same technology" premise)
Fact #2: "Equivalence" doesn't touch the resolution subject - which could only possibly work with spherical cows in a vacuum "perfect" lenses, diffraction limited and with identical behavior; and with "perfect" sensors.

you choose to attack me/shut me up instead.

Well, have fun playing that game - by yourself. You still won't be able to predict resolution from the aperture opening and sensor size alone (like a certain poster wants us to believe).