[jsherman999]

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Taken with an 18mm f/1.8 on aps-c:



Not 'one eye in focus', not an attempt at hokey no-DOF 'art', just an everyday WA snap that has a little more subject isolation, a little more pop on the subject, while retaining the background for environmental feel and context.

And of course it can be stopped down, too:



The 18mm f/1.8? Actually my $280 Tamron 28-75 f/2.8 on FF!


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[ElJamoquio]

Not 'one eye in focus',

That's always been an embarrassing strawman.

[jsherman999]

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Good to see: What is Equivalence and Why Should I Care?

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[Kunzite]

There's nothing good about it, some beginner might think this "equivalence" thing is actually useful (as ridiculous as it sounds).

By the way, the DPReview article is quite different from the claims made in the video you posted when starting this thread. Which version is correct?

[bxf]

I am not disputing visual evidence, but I don't find it easy to understand why more "total light" yields lower noise, given that his larger quantity of light is being used to make a bigger picture. i.e. it is spread over a larger area. Why should the quality of any particular square millimetre of the image be influenced by the fact that there are more square millimetres in the image? Logically, one would have thought that light intensity should be the determining factor.

[eyeswideshut]

You've put your finger on what is probably the most controversial part of equivalism: Exposure.
Imagine the great aperture in the sky opening up and rain falling on two adjacent farms. Equivalists argue that not only will the farmer with more acres receive more rain, but his crops will be better for it. It's an intersting read, but be prepared for quite a bit of redifinition of terms that you thought you knew what they meant.

www.josephjamesphotography.com/equivalence/index.htm#exposure

[bxf]

It's easy to verbally refute some claims and arguments by using logic or common sense, but if I'm not mistaken, it has been demonstrated repeatedly that larger sensors do yield lower noise. And therein lies the problem.

I am not arguing in favour of FF, so please feel free to correct me.

"Equivalists argue that not only will the farmer with more acres receive more rain, but his crops will be better"

Funny.

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Last edited by bxf; 07-26-2014 at 03:36 AM.

[Rondec]

It's easy to verbally refute some claims and arguments by using logic or common sense, but if I'm not mistaken, it has been demonstrated repeatedly that larger sensors do yield lower noise. And therein lies the problem.

I am not arguing in favour of FF, so please feel free to correct me.

"Equivalists argue that not only will the farmer with more acres receive more rain, but his crops will be better"

Funny.

The farmer with more acres will still have the same yield per acre. He just ends up having a greater yield per farm. Per pixel noise on a D800 is the same as on a K5 it is just that if you are printing the same size, you'll see that noise faster with the smaller sensor, assuming the same print or viewing size.

[jsherman999]

There's nothing good about it, some beginner might think this "equivalence" thing is actually useful (as ridiculous as it sounds).

By the way, the DPReview article is quite different from the claims made in the video you posted when starting this thread. Which version is correct?

Curious - Name one specific thing that's different - beyond Tony's assertion that the lens manufacturers should label the lens barrels. Everything he was pointing out was generally valid and he showed some nice visual representations of what effect the format change has on F-stop for that FOV.

You, on the other hand, have struggled mightily against these concepts through the entire thread, making incremental progress almost accidentally as you skim JJ's article, trying to find inconsistencies - which you couldn't.

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---------- Post added 07-26-14 at 08:55 AM ----------

It's easy to verbally refute some claims and arguments by using logic or common sense, but if I'm not mistaken, it has been demonstrated repeatedly that larger sensors do yield lower noise. And therein lies the problem.

I am not arguing in favour of FF, so please feel free to correct me.

You are correct, larger sensors can yield less noise because they are able to use a larger physical aperture for the same FOV/distance. But logic, common sense and physical facts themselves are, for some reason, not enough to bury these discussions, because some will refuse... see the equivalent light. Exhibit A: (link to an funny thread) :

"Equivalists argue that not only will the farmer with more acres receive more rain, but his crops will be better"

Funny.

More acres will yield more of the crop - exactly like a larger sensor will yield more total light. A farmer selling a commodity like corn finds that a 'better' crop indeed! (just like a noise-avoiding photographer likes that extra light his expanded acres allow. )

[Kunzite]

Curious - Name one specific thing that's different - beyond Tony's assertion that the lens manufacturers should label the lens barrels. Everything he was pointing out was generally valid and he showed some visual representations of what effect the format change has on F-stop for that FOV.

You, on the other hand, have struggled mightily against these concepts through the entire thread, making incremental progress almost accidentally as you skim JJ's article, trying to find inconsistencies - which you couldn't.

That assertion - based on the idea that "focal length", "aperture" and "ISO" are "lies" except on a specific format - was a central point in his video, so I wouldn't simply ignore it.
If you want to build a credible "equivalence" theory, then you should not simply accept everything that's "pro" and reject everything that's "against".

You have a most imaginative and selective memory. There are only two things I'm struggling with:
1. which "equivalence" are we discussing today? (and why can't we agree on some "standard equivalence"?)
2. why some people are insisting so much with this "equivalence", when its practical application is so extremely limited?

[jsherman999]

That assertion - based on the idea that "focal length", "aperture" and "ISO" are "lies" except on a specific format - was a central point in his video, so I wouldn't simply ignore it.

I've said I think "lies" is going too far, unless you characterize it more of a "lie by omission". The "28-300 f/2.8" lens Olympus is selling, for example, is the manufacturer leaving out some information, selectively changing it partially to make their product more enticing, make it seem like that P&S is a valid replacement for an aps-c or FF camera. They benefit from telling half the story, using only part of the equivalence relationship.

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There are only two things I'm struggling with:
1. which "equivalence" are we discussing today? (and why can't we agree on some "standard equivalence"?)

It's all encapsulated here, which is completely consistent with what I've been saying for three years (and in this thread,) consistent with what Falk Lumo's pointed out in his article, and as far as I've seen is consistent with what's in the new dpreview article, and is not refuting anything Tony states in his video re equivalence. What definition are you using?

(I suspect you just like to troll/argue, but good things can come from these discussions)

2. why some people are insisting so much with this "equivalence", when its practical application is so extremely limited?

It's exactly no more 'limited' than knowing what happens when you open your lens up one stop - and using that knowledge.

It helps you decide what system to buy, or if changing formats would help you for your typical shooting. It can save time, effort, equipment churn, and can end up getting you better results which make you a slightly happier shooter.

If you only ever shoot one format, it's of much less value to you. But folks who only intend to shoot one format don't engage in these discussions.... do they?


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[Kunzite]

I've said I think "lies" is going too far, unless you characterize it more of a "lie by omission". The "28-300 f/2.8" lens Olympus is selling, for example, is the manufacturer leaving out some information, selectively changing it partially to make their product more enticing, make it seem like that P&S is a valid replacement for an aps-c or FF camera. They benefit from telling half the story, using only part of the equivalence relationship.

Not when he's making incredibly misinforming statements like "focal length stops being useful". We already discussed this, didn't we? All I wanted was a recognition from your part that he got some things terribly wrong.

It's all encapsulated here, which is completely consistent with what I've been saying for three years (and in this thread,) consistent with what Falk Lumo's pointed out in his article, and as far as I've seen is consistent with what's in the new dpreview article, and is not refuting anything Tony states in his video re equivalence. What definition are you using?

I'm not using "equivalence", but Joseph James' is one of the more scientifically sound version - a total opposite of Tony's. And contrary to what you just said, JJ is never claiming that focal length should measure angle of view.

(I suspect you just like to troll/argue, but good things can come from these discussions)

I suspect you just don't want "equivalence" to be challenged in any way; just blindly accepted, in any form (including Tony's). So people expressing an opinion which is not complete acceptance must be trolling.

It's exactly no more 'limited' than knowing what happens when you open your lens up one stop - and using that knowledge.

Wrong; it's much more restrictive (in its more complete forms, at least).
Basic knowledge, applied with a specific purpose in mind, is extremely useful, of course. Such knowledge can be applied without the restriction of using and trying to match several parameters at the same time.

It helps you decide what system to buy, or if changing formats would help you for your typical shooting. It can save time, effort, equipment churn, and can end up getting you better results which make you a slightly happier shooter.

Funny thing is, it didn't help me at all when I switched from "full frame" to APS-C and had to buy new lenses, and it won't help me at all when I'll switch back. The main reason why I want a "full frame" camera has nothing to do with "equivalence" anyway.

[jsherman999]

... All I wanted was a recognition from your part that he got some things terribly wrong.

All right - I think he went too far in some of his assertions, but I suspect he did it in part for effect, because he knows framing something in a controversial way get hits, sometimes massive hits, and it did in this case. In that way he's no different than someone like Thom Hogan, who often takes a controversial position to get hits (although he hides it better.) I really don't like Tony's use of 'bokeh' when he means DOF, it's factually wrong and confuses things where the terms are clear. But other than that, he's highlighting an obscure (for some) concept in a very effective way, and he gets the aperture/FOV concepts right and is consistent with JJ, et al.

Funny thing is, it didn't help me at all when I switched from "full frame" to APS-C and had to buy new lenses, and it won't help me at all when I'll switch back.

I think you implied you only used it half-way - to choose the FL's you needed, not worrying about the F-stop, because you just took what you could get. That's fine. What you can't do is argue that someone planning two systems gets no use out of a full equivalence conversion during the planning stage. For the life of me I have no idea why someone planning to spend $1000's of dollars on a new lens or system wouldn't take the time to understand and accept these simple concepts first.

[Kunzite]

All right - I think he went too far in some of his assertions, but I suspect he did it in part for effect, because he knows framing something in a controversial way get hits, sometimes massive hits, and it did in this case. In that way he's no different than someone like Thom Hogan, who often takes a controversial position to get hits (although he hides it better.) I really don't like Tony's use of 'bokeh' when he means DOF, it's factually wrong and confuses things where the terms are clear.

Thank you.

I think you implied you only used it half-way - to choose the FL's you needed, not worrying about the F-stop, because you just took what you could get. That's fine. What you can't do is argue that someone planning two systems gets no use out of a full equivalence conversion during the planning stage. For the life of me I have no idea why someone planning to spend $1000's of dollars on a new lens or system wouldn't take the time to understand and accept these simple concepts first.

Nope, that was the assumption others made - but I didn't used "equivalence" at all, in any form. As I explained some time ago (the explanation being outright rejected, because it contradicted the assumption) I started with what I had, then gradually building up an APS-C centric kit - not even once referring to another format (an option I didn't had in most cases). I simply found out what I want - wider, narrower, macro etc, found a suitable match in Pentax' offering and bought it. And guess what, not a single miss!
I'll do the same when switching back; I'll use what I have as a starting point, without thinking how to get exactly the same as on APS-C - but to what I want on that format; I will keep my mind open to new possibilities. Quite likely, I'll end up with non-"equivalent" lenses.
I understand all the necessary "simple concepts" very well, thank you. And - most important - I know how and when to apply them, unrestricted by the shackles of "equivalence".

Great Bustard is Joseph James relentlessly promoting his own article/blog; Allan Olesen's post is arrogant and rude. DPReview's Open Talk section is full of derogatory comments and threads about "equivalence denialists", with claims like "they don't know how to multiply" and other BS like that.
I'm not sure why did you quote them.

[cali92rs]

When the people that reject equivalence switch from APS-C to FF, I hope they don't come back on these forums and maintain their dishonesty by saying that their 28mm is a normal lens and that their 50mm is a short telephoto.
Of course they can also claim that they didn't use equivalence when choosing their lenses, that they stuck a 28mm on their camera and found out that way that their 28mm is a wide angle with a FF camera.

The rest of the population with common sense can use equivalence and a seconds worth of math to figure out what a focal length looks like without taking the time to drive to a camera store which may or may not have your lens in stock.