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07-22-2015, 01:16 PM   #136
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QuoteOriginally posted by Professor Batty Quote
The "equivalent" in comparing lenses from cameras with different sized sensors means field of view, and field of view only. If manufacturers said that in their ads, nobody would be confused.
some people would be happy with that, but someone will still be confused.

gotta love how some camera manufactures choose to omit information from the ad or use very small print when it might be detrimental to the sales of a product yet include it in big bold block print when they think it can help sales

07-22-2015, 01:53 PM - 2 Likes   #137
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The Word Of Equivalence (WOE) to you! ;)

QuoteOriginally posted by Parallax Quote
????
... nor do I understand why anyone who uses only cameras with sensors smaller than 24x36 would have any need to understand equivalence.
It would be a problem if they were suckered into buying something based on half-converted equivalents.

Like the tiny, magical "24-200 f/2.8" lens on that Sony bridge camera. Sony was sly with that marketing campaign.

The micro-four-thirds forums on dpreview used to be filed with folks** who had been convinced by someone like a camera store clerk that they had bought these magical lenses. If those folks had known about equivalence beforehand, they'd go into those stores a bit smarter and may have saved some money. Even if that's what they really wanted (m43) it's better to go into a sales situation armed with a little knowledge, no?

** Less and less of them these days, though. I think Joseph James, Falk Lumo, Bob Atkins, Bob Newman, Joseph Wizniewski, John Sheehan, etc, etc have done some good work spreading the Word Of Equivalence in the years since
07-22-2015, 02:12 PM   #138
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QuoteOriginally posted by jsherman999 Quote
It would be a problem if they were suckered into buying something based on half-converted equivalents.

Like the tiny, magical "24-200 f/2.8" lens on that Sony bridge camera. Sony was sly with that marketing campaign.

The micro-four-thirds forums on dpreview used to be filed with folks** who had been convinced by someone like a camera store clerk that they had bought these magical lenses. If those folks had known about equivalence beforehand, they'd go into those stores a bit smarter and may have saved some money. Even if that's what they really wanted (m43) it's better to go into a sales situation armed with a little knowledge, no?

** Less and less of them these days, though. I think Joseph James, Falk Lumo, Bob Atkins, Bob Newman, Joseph Wizniewski, John Sheehan, etc, etc have done some good work spreading the Word Of Equivalence in the years since
It feels like the only "confused" folks at this point are the Fuji users who believe that Fuji has somehow broken the code on how to achieve amazing dynamic range and low noise images at high iso with a smaller sensor. I just don't see many folks buying a bridge camera or even four thirds camera and bragging about how much better it is than a full frame camera. They know it isn't, but at the same time, there is no superzoom-- full frame combo (however slow you want to make the lens) that will be as portable as most bridge cameras (and that's why folks still buy them).
07-22-2015, 02:26 PM   #139
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QuoteOriginally posted by jsherman999 Quote
It would be a problem if they were suckered into buying something based on half-converted equivalents.

Like the tiny, magical "24-200 f/2.8" lens on that Sony bridge camera. Sony was sly with that marketing campaign.

The micro-four-thirds forums on dpreview used to be filed with folks** who had been convinced by someone like a camera store clerk that they had bought these magical lenses. If those folks had known about equivalence beforehand, they'd go into those stores a bit smarter and may have saved some money. Even if that's what they really wanted (m43) it's better to go into a sales situation armed with a little knowledge, no?

** Less and less of them these days, though. I think Joseph James, Falk Lumo, Bob Atkins, Bob Newman, Joseph Wizniewski, John Sheehan, etc, etc have done some good work spreading the Word Of Equivalence in the years since
Jay, you are absolutely right... that Sony (or Lumix) bridge camera marketing words are plain wrong and misleading people (including many of my Canikon friends).

Here is typical wordings found in articles marketing the bridge cameras (from whatdigitalcamera.com).
"The camera features the same 1 in sensor in the acclaimed RX100 II, while also featuring an impressive Carl Zeiss zoom covering an equivalent focal range of 24-200mm and with a constant f/2.8 maximum aperture." That size of 24-200/f2.8 on the bridge camera is defying physics and that is what people believe in. And I might add, these are not beginners (not by camera ownership) but owners of big heavy Canikon camera/lens models with 'impressive' tags. I am scratching my heads....

---------- Post added 07-22-2015 at 05:38 PM ----------

QuoteOriginally posted by Rondec Quote
It feels like the only "confused" folks at this point are the Fuji users who believe that Fuji has somehow broken the code on how to achieve amazing dynamic range and low noise images at high iso with a smaller sensor. I just don't see many folks buying a bridge camera or even four thirds camera and bragging about how much better it is than a full frame camera. They know it isn't, but at the same time, there is no superzoom-- full frame combo (however slow you want to make the lens) that will be as portable as most bridge cameras (and that's why folks still buy them).
These marketing words are making people believers (those who are willingly believe without questioning). I have this friend who owns a 5D and 24-105L and he ended using a Lumix FZ200 instead and keeping the 5D on shelf, claiming that the FZ200 is just as good and sometimes better than the pictures he took using the 5D/L glass. He claims that the bridge camera is lighter, bigger zoom and IQ wise the same. Out of curiosity, I asked how much he paid; and it surprises me that it costs him almost the same as my k-3 body. He also convinced another friend who owns a 5D MK II to do the same.... That is the power of marketing...


Last edited by aleonx3; 07-22-2015 at 02:39 PM.
07-22-2015, 02:48 PM   #140
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QuoteOriginally posted by emptyd83 Quote
I think it's quite simple: 50mm f2 at 3 meters (or whatever f-stop and distance) will give the same dof on ff-, aps-c-, mft- or whatever-sensors. but because you want to get a specific angle (not focal length), you will take a few steps back when using a smaller sensor - and that changes your dof (further away=more dof).
That's one way to look at it, but you wouldn't have the same photo anymore. The foreground and background will look more compressed. So, apart from DoF, other things have also changed.

I don't think we can close this argument once and for all. If that were possible, it would have already happened. I suggest doing your own research and finding out what you make of it.
07-22-2015, 03:16 PM   #141
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QuoteOriginally posted by max_pyne Quote
= same lens mounted on the two formats delivers the same DOF.
This is not correct.

There is a magnification factor at the output stage which affects DOF when combined with the change in FOV.

---------- Post added 23-07-15 at 07:56 AM ----------

QuoteOriginally posted by Adam Quote
The depth of field at the same focal length never changes, regardless of sensor format.

However, when comparing larger sensors to smaller ones, you'll indeed get less depth of field at the same angle of view with the larger sensor. Let's take a focal length of 24mm on full frame and 18mm on aps-c as an example. Both will deliver the same angle of view, but the full frame lens will have less depth of field since it's a longer focal length.
This statement is incorrect. The DOF within the image is not only dependent on the lens. Whilst the actual lens doesn't change, the system does, as well as the output magnification, assuming that a standard output size is common to each format. Obviously there are limits as to what size a lower resolution sensor can be printed.
Attached Images
   

Last edited by bossa; 07-22-2015 at 03:32 PM.
07-22-2015, 04:11 PM   #142
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QuoteOriginally posted by aleonx3 Quote
Jay, you are absolutely right... that Sony (or Lumix) bridge camera marketing words are plain wrong and misleading people (including many of my Canikon friends).

Here is typical wordings found in articles marketing the bridge cameras (from whatdigitalcamera.com).
"The camera features the same 1 in sensor in the acclaimed RX100 II, while also featuring an impressive Carl Zeiss zoom covering an equivalent focal range of 24-200mm and with a constant f/2.8 maximum aperture." That size of 24-200/f2.8 on the bridge camera is defying physics and that is what people believe in. And I might add, these are not beginners (not by camera ownership) but owners of big heavy Canikon camera/lens models with 'impressive' tags. I am scratching my heads....

---------- Post added 07-22-2015 at 05:38 PM ----------



These marketing words are making people believers (those who are willingly believe without questioning). I have this friend who owns a 5D and 24-105L and he ended using a Lumix FZ200 instead and keeping the 5D on shelf, claiming that the FZ200 is just as good and sometimes better than the pictures he took using the 5D/L glass. He claims that the bridge camera is lighter, bigger zoom and IQ wise the same. Out of curiosity, I asked how much he paid; and it surprises me that it costs him almost the same as my k-3 body. He also convinced another friend who owns a 5D MK II to do the same.... That is the power of marketing...
I have recommended bridge cameras to photographers, but I never use equivalence terms to explain why I think those would be best for them and they wouldn't understand it if I would. Folks purchasing bridge cameras for the most part are people who want an all in one camera that has a super zoom and isn't too big. As I said before, you run out of options once you set those as your parameters, whatever speed you want to make the lens. But most people aren't coming to these cameras from full frame cameras either.
07-22-2015, 04:41 PM - 2 Likes   #143
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QuoteOriginally posted by kh1234567890 Quote
So, 'equivalence' is a pretty pointless concept in practice.
Really, is this still being discussed at pentaxforums.com? In 2015?

This discussion is so , ... , 2010 ...

For the question of usefulness: equivalence reduces four parameters (focal length, fstop, iso, sensor size) into three parameters (field of view, aperture, noiselevel).

Dealing with three parameters is a lot easier than dealing with four parameters, assuming you have a shot in mind ...

If you ever wondered ... this is how the fstop was created: to get rid of a redundant parameter!

And that's why most photographers stopped discussing equivalence and just use it in their daily photography life. Years ago... Like fstop, decades ago ..

07-22-2015, 04:49 PM   #144
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QuoteOriginally posted by falconeye Quote
Really, is this still being discussed at pentaxforums.com? In 2015?

This discussion is so , ... , 2010 ...
we like to stir the pot and see what trolls come out and play...
07-22-2015, 04:51 PM   #145
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QuoteOriginally posted by falconeye Quote
And that's why most photographers stopped discussing equivalence and just use it in their daily photography life. Years ago... Like fstop, decades ago ..
In other words, if you learn how to use your equipment, equivalence is irrelevant.
07-22-2015, 05:01 PM   #146
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QuoteOriginally posted by Rondec Quote
With wildlife photography you will use the longest/fastest lens that you can afford and wield. End of story.
And when those two aren't the same lens?

QuoteOriginally posted by Rondec Quote
Has nothing to do with equivalence.
Disagree. I can immediately determine which lens will provide which benefit by using very, very simple mathematics.

QuoteOriginally posted by Rondec Quote
As to whether or not you should use a full frame camera, probably not, because you'll probably be cropping your D800 past APS-C levels. Once again, not an equivalence thing, just common sense. If you aren't using the outer one half of your sensor, why pay for it?
This was a hypothetical, in which I was already using my APS-C camera.

FWIW, my FF system was cheaper than my APS-C system. YMMV.
07-22-2015, 05:02 PM   #147
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QuoteOriginally posted by Parallax Quote
In other words, if you learn how to use your equipment, equivalence is irrelevant.
Like it is irrelevant if one knows that fstop means focal length divided by aperture diameter?

Then yes, it just matters to use it properly.

So yes, just use 35mm-equivalent focal, 35mm-equivalent fstop and 35mm-equivalent iso properly and don't waste your time discussing it.

But not using it at all is like scaling your exposure meter reading with the focal length all the time because you never learned to cope with the concept of f/aperture ratio. Not irrelevant but dumb.

I insist that by 2015, every photographer who is at a pro or semi-pro (enthusiast) level has fully digested the concept of equivalence and adopts it where fit like he does with fstop or the 1/f motion blur rule of thumb. There won't be a desire left to discuss. There may be a desire to learn more about it, of course.

Last edited by falconeye; 07-22-2015 at 05:19 PM.
07-22-2015, 05:05 PM   #148
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QuoteOriginally posted by Rondec Quote
Is the iso on your camera better at 100 or 400? I tried to figure it out with equivalence but couldn't come up with an answer. /sarc
Your question is wrong, of course, but even if you had asked 'is the SNR better at 100 or 400', of course, the answer depends on the amount of cropping and is thus quickly determined by equivalence.

If you don't mind the moose running away while you're taking your shot, you can just haul an extra lens and swap lenses of course.
07-22-2015, 05:39 PM - 2 Likes   #149
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QuoteOriginally posted by Rondec Quote
In the end, I find equivalence is mainly brought out by full frame proponents to say why fast lenses on crop cameras aren't really fast and why full frame is better.
In my experience, that is not really the case.

The usual pattern is
  1. Someone writes something about an APS-C lens.
  2. A claim is made that the APS-C lens is smaller, lighter, and less expensive than an FF lens, but delivers the same effective focal range and f-stop.
  3. Someone who understands optics points out that the above claim is false and uses "equivalence" to explain why.
Now, with any other topic, we would be happy about point 3., wouldn't we?

If someone claimed, that shutter speed never affects the contribution of flash to the exposure, no matter whether you stay below or go above the sync-speed, we would welcome someone responding by pointing out that flash exposure is affected by shutter speed once one exceeds the sync-speed, would we not?

However, when someone points out a factual error made when someone mixes FF-equivalent focal length with APS-C f-stops then they are accused of "not understanding exposure", "derailing the discussion with a bogus concept", receive the advice to "go out and shoot", or are told that they are "pushing FF cameras" without understanding the "benefits of smaller formats".

If people stopped making unsound claims about how their APS-C equipment compares to the "Oh so heavy, large, and expensive FF equipment" then I don't think we'd be having nearly as many equivalence discussions.

Just as one recent example to support my claim that it is the false claims that start the discussion, as opposed to an FF fanboy jumping in unprovoked, have a look at the "50-135 Pentax best zoom ever" thread in which it did not take clackers long to point out how "small and light compared to the [FF, f/2.8]70-200s" the 50-135/2.8 is.
07-22-2015, 05:49 PM   #150
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QuoteOriginally posted by Not a Number Quote
In one thread on the DOF markings on legacy MF lens one poster kept insisting you had to apply to crop equivalency factor to the scale. I didn't bother to argue.
It is good that you did not bother to argue because you would have incorrectly opposed to a correct assertion.

Due to the different enlargement factors between APS-C and FF, you cannot use the DOF markings on lenses designed for FF, as direct indicators for the DOF you obtain when using the lenses on APS-C. The DOF that you'll get on an APS-C camera is shallower than the markings indicate.
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