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06-03-2013, 06:36 PM   #1936
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That was a long commercial... can we now go back to the K-3...

06-03-2013, 07:09 PM   #1937
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QuoteOriginally posted by Digitalis Quote
DOF is not equal to COC - As an instructor in advanced photographic technique I'm amazed about how little photographers understand about their craft. I can see how much of it can be considered to be psudo science by the un-temepered mind.
Wrong brand, but...

http://software.canon-europe.com/files/documents/EF_Lens_Work_Book_10_EN.pdf
06-03-2013, 07:43 PM   #1938
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QuoteOriginally posted by Docrwm Quote
Nikon types write in and say 5200 or 7100 too. That doesn't mean they're the same camera.

As for new - wow, you seem to be saying that unless it has a new sensor then its not a new camera model. Processor upgrades, AF upgrades, improvements in low light focus and performance, addition of an f2.8 sensor, introduction of the K-01 (whatever you think of it), Q & Q10 - weren't those all done after the K-5 was released?
My K-5 and my Q had AF upgrades and upgrades in low light focus performance, too, and that was after I bought them.

The K-01 was definitely a new model, and showed that Pentax was investing something in the brand. It was a swing-and-a-miss for me and, I think, for most of the marketplace but it doesn't matter how many people hate your product... what matters is how many people love your product.

And FWIW a camera doesn't need a new sensor to be a new model. The 60D and the 7D, for instance, are clearly different models, with very different LCD's and very different AF. The K-r and the K-5 had different sensors, different viewfinders, etc., etc.
06-04-2013, 12:20 AM   #1939
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QuoteOriginally posted by falconeye Quote
Really people, I cannot but wonder. I thought this forum had evolved into a more mature one. My bad.

Equivalence is a theorem, not a belief, religion, argument or opinion. As such, it needs to be taught to newbies not knowing it yet.

The fact that normalizing 1. focal length, 2. fstop, 3. iso leads to a specification of a photo's capture parameters which are entirely independent of sensor size (i.e., the sensor size cannot be deduced from the resulting photo's properties, even if you look at noise or diffraction or bokeh or other artefacts) is a surprising yet fundamental truth which any knowledgeable photographer needs to know and to use in a discussion involving more than one sensor size. It is now a textbook content for any lecture on photography. Just like fstop is.

As such, it isn't trivial at all. To many, it comes as a surprise so big that they can't understand it. It isn't clear a priori that the equivalence normalization has this property. After all, e.g. if you look at "depth of field" formulae, it seems to depend on focal lengths and image circle diameters ... Equivalence is the beautiful theorem that it and any other optical property doesn't upon closer inspection. I.e., a camera can be specified 100% without specifying its image circle.

All this debate just obfuscates this simple to state yet powerful and therefore inherently beautiful truth. It is driving me nuts if I see people trample on beauty.

I'll leave this topic alone now (in this thread). I only contribute to few threads on PF anymore nowadays. The experience in this thread wasn't a rewarding one. Anyway, the topic was K-3, right?
Equivalence is an often useless tool which generates more problems than it tries to solve. It's not beautiful at all IMO, and it shouldn't be compared with the f-stop system (which the equivalence tends to destroy). I also believe it should not be taught to beginners, thus replacing the basic notions.
We could discuss this subjects at lengths, but I agree this is not the place to do it.


Last edited by Blue; 06-04-2013 at 08:38 AM. Reason: edited the quote
06-04-2013, 12:38 AM - 1 Like   #1940
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QuoteOriginally posted by Kunzite Quote
Equivalence is an often useless tool which generates more problems than it tries to solve. It's not beautiful at all IMO, and it shouldn't be compared with the f-stop system (which the equivalence tends to destroy). I also believe it should not be taught to beginners, thus replacing the basic notions.
We could discuss this subjects at lengths, but I agree this is not the place to do it.
I have to agree with Kunzite here. Equivalence is something to investigate out of curiosity, or as part of the learning curve. And after that to quickly forget it, because it makes things unnecessary complicated. A lens has its own focal length and aperture.
06-04-2013, 05:06 AM   #1941
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QuoteOriginally posted by falconeye Quote
Really people, I cannot but wonder. I thought this forum had evolved into a more mature one. My bad.

Equivalence is a theorem, not a belief, religion, [edited], argument or opinion. As such, it needs to be taught to newbies not knowing it yet.

The fact that normalizing 1. focal length, 2. fstop, 3. iso leads to a specification of a photo's capture parameters which are entirely independent of sensor size (i.e., the sensor size cannot be deduced from the resulting photo's properties, even if you look at noise or diffraction or bokeh or other artefacts) is a surprising yet fundamental truth which any knowledgeable photographer needs to know and to use in a discussion involving more than one sensor size. It is now a textbook content for any lecture on photography. Just like fstop is.

As such, it isn't trivial at all. To many, it comes as a surprise so big that they can't understand it. It isn't clear a priori that the equivalence normalization has this property. After all, e.g. if you look at "depth of field" formulae, it seems to depend on focal lengths and image circle diameters ... Equivalence is the beautiful theorem that it and any other optical property doesn't upon closer inspection. I.e., a camera can be specified 100% without specifying its image circle.

All this debate just obfuscates this simple to state yet powerful and therefore inherently beautiful truth. It is driving me nuts if I see people trample on beauty.

I'll leave this topic alone now (in this thread). I only contribute to few threads on PF anymore nowadays. The experience in this thread wasn't a rewarding one. Anyway, the topic was K-3, right?
Falk, you've been a valuable contributor to this forum for as long as I can remember. I don't visit as often as i used to, but I hope that you don't leave entirely.

Now regarding equivalence...

Equivalence is a very useful tool for those moving from or between one sensor size to another, or having discussions with photographers using different sensor sizes. That's fine, and part of the craft of photography. But I get frustrated when people use equivalence as a weapon, declaring larger sensors as "better" than smaller sensors, thus implying that better cameras with bigger sensors are capable of better photographs.

Great photos are taken by great photographers, not great cameras.

Last edited by Blue; 06-04-2013 at 03:43 PM. Reason: quoted an edite post
06-04-2013, 07:03 AM - 1 Like   #1942
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QuoteOriginally posted by Kunzite Quote
Equivalence is [...] not beautiful at all IMO, and it shouldn't be compared with the f-stop system (which the equivalence tends to destroy).

So maybe, all of us must calm down a bit

Below, I explain the rationale behind calling equivalence "beautiful". There is no reason anybody must share my opinion, but maybe I should explain at least.

QuoteOriginally posted by johnmflores Quote
I get frustrated when people use equivalence as a weapon
I do agree entirely.

And now about beauty in science.

I am interested in photography, science and women because I find beauty in all of them. It may be less obvious for science.

I give you one example:

When Dirac in 1928 looked at his equations, he noticed that things are more symmetrical (read beautiful) if he gave ALL possible mathematical solutions a physical meaning. Which led him to predict anti matter. Which actually exists as has been verified years later.

Group theory in mathematics would be another example.

It is a surprising attitude of nature that, if its laws can be made more beautiful, it obeys.

An extremely simple yet very known example is F-Stop, the ratio of aperture and focal length. Because it turns out that a correct exposure (for a given sensitivity of an emulsion) only depends on this ratio, not both focal length and aperture diameter. Which is a simplification and makes the "laws" of photography more beautiful. Nobody today would complain that fstop isn't a lens' real aperture (which is to be measured in mm or inch, like it still is for scopes).

A more recent example now is equivalence. Just like fstop replaces aperture by the ratio of aperture and focal, equivalence replaces image circle, focal, fstop and iso by scaled values, aka "equivalent" focal, fstop and iso. Because it turns out (somewhat hard to prove why I wrote a paper about) that ALL image properties only depend on "equivalent" focal, fstop, iso (and exposure time). And not on sensor size or real focal, fstop, iso. This is a massive simplification of the "laws" of photography. A much bigger break-through than fstop was. And makes the "laws" of photography a lot more beautiful. Something to write home about.

Therefore, somebody saying "equivalence destroys real fstop" is making the biggest joke he can actually make

That's my personal opinion.

Which may explain why I am so passionate about it.

Last edited by Blue; 06-04-2013 at 08:44 AM.
06-04-2013, 07:21 AM   #1943
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QuoteOriginally posted by Alizarine Quote
That was a long commercial... can we now go back to the K-3...
+1

06-04-2013, 07:31 AM   #1944
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Equivalence is a weapon.

I crack open a magazine and there is Nikon advertising stating that the D600 is the full frame camera we've been waiting for...

Equivalence is just relative properties. For Nikon, it's the relative property of their FF product versus all that came before. We've been "waiting..." We. All of us. Pentaxians too.

That's the really simplified version and use of equivalence. Some cameras are more equal than others...

Of course, lost in the hyperbole is that the visible difference in web imagery is most often indistinguishable. But weapons like equivalence helps to create insecurity and that creates demand which then sells over-powered cameras to people who really do not need them.
06-04-2013, 08:36 AM   #1945
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QuoteOriginally posted by johnmflores Quote
Falk, you've been a valuable contributor to this forum for as long as I can remember. I don't visit as often as i used to, but I hope that you don't leave entirely.

Now regarding equivalence...

Equivalence is a very useful tool for those moving from or between one sensor size to another, or having discussions with photographers using different sensor sizes. That's fine, and part of the craft of photography. But I get frustrated when people use equivalence as a weapon, declaring larger sensors as "better" than smaller sensors, thus implying that better cameras with bigger sensors are capable of better photographs.

Great photos are taken by great photographers, not great cameras.
I fully agree with you on this one : even a Q can help talented photographer to smart rendering
06-04-2013, 10:12 AM   #1946
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QuoteOriginally posted by Aristophanes Quote
1. Equivalence is a weapon.
2. Equivalence is just relative properties.
3. Some cameras are more equal than others...
1. No
2. Sentence makes no sense
3. Not related to equivalence

Aristophanes, at some moment in time, you decided to read something into the term equivalence which isn't there. Stop it please for your on sake. You are missing the ball.

A law of physics is completely neutral. We live (or at least, most of us live) in the Age of Enlightenment and such things cannot be turned into belief anymore.

If at all, equivalence can be used to explain in a scientific manner to full frame addicts that cameras with a smaller sensor often produce indistinguishable results. A bit different from your (possibly selective) perception.
06-04-2013, 10:20 AM   #1947
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QuoteOriginally posted by Zygonyx Quote
I fully agree with you on this one : even a Q can help talented photographer to smart rendering
Thats fine and all...the problem you run into is when youve been shooting FF your whole life (or any other format, it doesnt really matter). You are interested in a Q, you pick up the lens and it reads 5-15mm. You might think to yourself "holy cow, that is the widest lens I have ever seen". Then you see the fstop, 2.8-4.5 and you say to yourself "I can really get thin DOF with the f2.8". Of course, you would be wrong on both counts.
That's how I use equivalence.
06-04-2013, 10:28 AM   #1948
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QuoteOriginally posted by cali92rs Quote
That's how I use equivalence.
That's what I mean. If cameras (zoom ring, aperture ring, iso lever) were labelled in some equivalent way, we NEVER EVER again would have to think about sensor sizes. Just pick up any camera and compose artistically useful images.

And the beauty lies within the fact that this is actually possible. That the sensor size (or image circle) can be entirely removed from ALL equations, regardless of the optical property under consideration.

In the digital age, I am sure that it will happen anyway. We will be annoyed sooner or later to always cross-translate camera properties (between e.g., our mobile phone, compact and system cameras).
06-04-2013, 10:48 AM   #1949
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You can already pick up any camera and produce artistic images. (Well, YOU maybe, not so much me...)

Anyway, the equivalence you're looking for is field of view. Focal length does not translate to field of view directly, even on the same format camera. Case-in-point, at 17mm, the 10-17 zoom is 100 degrees, compared to the DA Limited 15mm which is 86 degrees. The relationship between focal length and field of view should be considered a "rule of thumb" instead of an immutable physical constant.
06-04-2013, 10:52 AM   #1950
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I simply pick up a camera and look through the viewfinder (or LCD) to see what I want, then take the shot. I make sure that the aperture, ISO, and shutter speed are what I need unless it's with my phone or a P&S and then I go for it! I'd rather enjoy taking pictures without worrying about format. Photography to me is all about what I see that I think is beautiful, so I capture it to share with people so they can see what I did.
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