[jsherman999]

No, I won't use equivalence even if I would go "FF". I just don't need it.

You don't need to use it very much in day to day shooting, but you really need it when you're deciding what lenses to buy, or whether or not (for example) you would gain anything by moving up to FF from a smaller format for your typical shooting. It's really very important at that point, because it can save you money and equipment churn and disappointment.

... Then, there's the practical issue: no manufacturer would want to be the first, to try and sell cameras with f-numbers so much higher than the others and ISOs so much smaller. Let's get real: "equivalence" is unenforceable.

I don't disagree, kinda what I said up there. It's not gonna happen, because they could lose sales to larger formats if they published the truth right there on the front of the lens

... let's say I have an Olympus m4/3 camera with the 75mm f/1.8, and a Pentax APS-C with the APS-C only (?) Pentax 50mm f/1.8 and a FF Pentax 77mm f/1.8.
I will use the APS-C 50mm and the FF 77mm on the Pentax camera. I will also use all 3 lenses, m4/3, APS-C and FF, on the Olympus.
Now, the funny part: I also have a permanent marker and want to write the "equivalent" values on each lens. What should I write?

You wouldn't write anything, you would continue to think of the relative FOVs in terms you're most comfortable with, which sounds like it would be aps-c-centric, and that's fine.

Where you might help yourself out, especially if you were a newbie - or where the manufacturer might help you, if they were so inclined - is when you were buying new lenses for either format or especially if you were considering moving into another format, if you were tallying the pros and cons and attaching dollar values to things.

You would be able to easily and transparently see how a $1000 lens on m43 for example may not bring as much capability to you as a $250 lens on FF would, making the "I'm saving money by going smaller-format" rationalization less real. Having to dive into these issues after you're already $3000 in to a system purchase after stumbling on the equivalency concept in a forum isn't as good from a consumer-centric perspective as seeing the information up front, from the manufacturer.

I think that's Tony's main point, and I agree with it. It's never going to happen on the front on an m43 lens barrel, but it could start happening with some regularity in lens and system reviews, maybe even in equipment summary pages on sites like Amazon, B&H. (remember - the manufacturer of an m43 or aps-c lens has a real incentive to keep that info hidden - Amazon or B&H doesn't, as much, because they also benefit from cross-manufacturer up-sell.)


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Last edited by jsherman999; 05-19-2014 at 06:53 PM.

[Hiroshi]

He is equalizing for noise not exposure. The exposure will be the same, but the smaller sensor will produce more noise. Take 3200 ISO as an example. We can set and shoot for the same exposure, but the smaller sensor will display more noise at 3200 than the larger sensor all else being equal. Camera manufacturers fudge their ISO ratings a little bit. Just look at DxO. When you get into the higher end MF systems they tend to hold true to ISO rating and work fine with hand held light meters, but consumer and enthusiast cameras tend to fudge the numbers. My K-3 under exposes by 1/3 of a stop.

---------- Post added 05-18-14 at 07:09 PM ----------



If you hold everything else constant (ISO/Shutter/Aperture) then you will get a different field of view, and the smaller sensor will have a lower signal to noise ratio (more noise). Of course the increase in noise might not be visible in final output. The smaller APS-C image has to be magnified more than the FF image and this will make the noise more visible and there is a compression effect caused by the magnification that will be visible in larger prints.

Winder,

Thanks for answering my question on full frame lenses on an APS-C. I think I got it!

[Winder]

Winder,

Thanks for answering my question on full frame lenses on an APS-C. I think I got it!

It gets complicated because ISO for film is all about the sensitivity of the film, but with digital its about equalizing for exposure/brightness. The manufacturers follow the same ISO standard for exposure so that your meter will still work, but manufacturer A might apply more digital gain (amplification) to the image than manufacturer B to get the same level of exposure/brightness, but more noise in the process. Different companies are using different technology and applying different levels of amplification to achieve the same ISO.

The same applies with sensor size. Since the smaller sensor is capturing less light (everything else equal) they have to increase the amplification of the signal to display an image that is of equal exposure to the larger sensor.

[Kunzite]

besides seriously, if equivalence doesnt matter to you or "you dont need it" why do you bother going into a thread that talks about it and and try to shoot down other ppl's attempts at adding some value to the topic/helping newbies. dont be so negative and if you dont like it, make a better video.

Are you seriously saying that bad ideas aggressively promoted all over the place shouldn't be challenged?
I noted how you ignored all my arguments and instead picked on the "I don't need it" part.

You don't need to use it very much in day to day shooting, but you really need it when you're deciding what lenses to buy, or whether or not (for example) you would gain anything by moving up to FF from a smaller format for your typical shooting. It's really very important at that point, because it can save you money and equipment churn and disappointment..

You are mistaken; or maybe trying to convince yourself that the mankind really needs "equivalence". Well, it doesn't. The old ways are better, because they're universal and consistent.
Btw, I did go from FF to APS-C some time ago, and didn't need "equivalence", I just learned the new format.

You wouldn't write anything, you would continue to think of the relative FOVs in terms you're most comfortable with, which sounds like it would be aps-c-centric, and that's fine.

That's a non-answer. But you probably realized this is an insurmountable issue with the "equivalence" system, and the best way to act on it is... to simply ignore it (and every other issue). Typical.
Let's get the facts straight: lens manufacturers were accused of lying by putting the real focal length and aperture values on their lenses, but none of them can sell a lens with the oh-so-much-better "equivalence" system because the system falls apart as soon as you put that lens on a camera with a different sensor size.

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Last edited by Kunzite; 05-20-2014 at 12:50 AM.

[repaap]

This is quite interesting, to see all of this baffle with this video.

Nice Video Tony. Interesting stuff and might really answer to some questions if one would seriously think why I'm not getting that kind of Bokeh, with f2.8 lens on my aps-c, compared to let's say FF camera. And also your comparing of sensor noise was really clear. and it is up to physics...now clear to see why and how.

Anyhow, I' already knew what my APS-C is giving me. I like it. And also I think that it is really interesting that many seems to like that Sigma 18-35/1.8 lens for 'FF effect'. but if it is what they are after, then FF would be better solution for them...no? Now about that equivalence...If I'd buy bigger format camera, I'd need to hunt down primes with same focal length that I like to shoot with APS-C. That would be my priority nro.1. But I'd need to learn it all over again anyway.

One thing what I can be interested is distortion between formats. in video there is that you get equivalent objects with their field of view, but how is distortion comparable. New lenses seems to have that under control...but let's say MF seems to have less distortion than APS-C or FF...pure mambo jambo...my gut feeling?

[audiobomber]

Let's get the facts straight: lens manufacturers were accused of lying by putting the real focal length and aperture values on their lenses, but none of them can sell a lens with the oh-so-much-better "equivalence" system because the system falls apart as soon as you put that lens on a camera with a different sensor size.

When Pentax calls their lens a DA 35mm f2.8 Limited Macro, they are not lying. If they were to call it a 53mm f2.8 equivalent, that would be lying. That is what happens commonly and what provoked the anti-manufacturer statements in the video. Call it mixed equivalence.

There's not much point in saying that equivalence shouldn't exist. It does exist and clearly most find it useful because it is used by manufacturers, reviewers and consumers. The problem is that equivalent focal lengths are being mixed with non-equivalent aperture values, which confuses non-sophisticated consumers. Bridge cam users will happily tell you they have a 25-600mm f2.8 lens. Most Olympus owners multiply the focal length, never the aperture. They honestly believe that a Zuiko 150mm f2 is a 300mm f2 equivalent lens.

Marketers lie, but reviewers should tell the truth. Stop mixing equivalent focal lengths with unadjusted apertures. Stop putting up carefully crafted test scene images that are based on the capricious ISO system. Start educating the consumer, not perpetuating the lies. How can you be against this?

[Kunzite]

They would be lying if they would call it anything else than a 35mm f/2.8 lens. If you don't think so, then please answer my question regarding using it on different formats.

"Equivalence" as it's promoted is an abomination that should not exist. There's no reason I wouldn't want only to compare angle of views, for example. There's no reason I wouldn't have different DoF requirements for different formats. There's no reason different formats cameras wouldn't have very different sensor technologies.

"Equivalence" is lying; you're messing with the most basic optics notion, and pretend to be right about it. This video is spreading lies and accusing people telling the truth of lying. How can you support this? How can you call this "educating the consumer"?

[Rondec]

The problem I have with equivalence is that it assumes that I want to "match" shots between formats. This may be true, but usually only in the opposite way that proponents of it mean. I want to shoot with a certain depth of field and "adequate" depth of field. This means that I would shoot longer full frame lenses, stopped down. With shots other than landscape (where I am really trying for maximal depth of field), depth of field just doesn't matter a lot, except in situations where there is too little.



This shot is shot with a 55mm at f2.2. I could have shot it on full frame with 85mm at f3.2 or so, but who cares? If I had been stopped down a little more, it wouldn't have made a hill of beans difference, since the background was relatively far off. At the same time, having an 85mm f1.4 lens would have given me "another stop of depth of field control" as I have been told many times by full frame proponents and it would have made no difference at all, since I wouldn't have used it anyway.

[audiobomber]

When Pentax calls their lens a DA 35mm f2.8 Limited Macro, they are not lying.

They would be lying if they would call it anything else than a 35mm f/2.8 lens. If you don't think so, then please answer my question regarding using it on different formats.

I already stated that Pentax is not lying. It is a 35mm f/2.8 lens. It is a 53mm f/4.2 equivalent lens used with its native APS-C bodies. Mount it on a Q7, it is still a 35mm f/2.8 lens, but now it becomes a 160mm f/13 equivalent lens.

"Equivalence" as it's promoted is an abomination that should not exist. There's no reason I wouldn't want only to compare angle of views, for example. There's no reason I wouldn't have different DoF requirements for different formats. There's no reason different formats cameras wouldn't have very different sensor technologies.

"Equivalence" is lying; you're messing with the most basic optics notion, and pretend to be right about it. This video is spreading lies and accusing people telling the truth of lying. How can you support this? How can you call this "educating the consumer"?

You keep saying that equivalence shouldn't exist, BUT IT DOES. It is used a bazillion times a day, and many of those times it is misused. The misuse is what bothers some of us, i.e. mixed equivalence.

If I want to compare my 8.5mm f/1.9 on a Q vs. Q7, I don't know of any better way than to convert both to FF equivalence. That would tell me that on my Q, it is a 47mm f/11. If I mount it on a Q7, it is a 39mm f/9 equivalent. I will gain about 1/3 stop for equivalent DOF and noise performance. I can also use this info to compare it to my FA 28 mm f2.8 (42mm f/4.2), and have a better understanding of what a small sensor means in terms of performance.

The only caveat to the above is that sensor technology has to be somewhat similar. You can always use equivalence to predict focal length and DOF, but you can't use equivalence to predict noise performance with dissimilar technologies. Old sensors had worse SNR than current state of the art. Foveon is a different technology and noise performance is different. You can use equivalence to compare noise in current Olympus, Sony, Pentax, Nikon, Fuji and Panasonic, because they have similar levels of technology.

Nothing is perfect. Equivalence is imperfect. Mixed equivalence is just plain wrong.

[GateCityRadio]

I guess you really have to shoot multiple formats to understand what he's saying. I shoot APS-C, 35mm, and MF (6x4.5). I think most people who shoot FF or started out on 35mm film know that 50mm is a "normal" focal length, but on a APS-C sensor it is not a "normal", it becomes a short tele because of the 1.5x crop factor and 50mm on a MF camera is a wide angle lens. The 50mm "normal" equivalent on a APS-C would be 30-35mm and on 645 MF it would be 75-80mm.

Being familiar with FF from the start, I had to do the math to come up with lenses with equivalent FOV for both APS-C and 6x4.5.

[Kunzite]

I already stated that Pentax is not lying. It is a 35mm f/2.8 lens. It is a 53mm f/4.2 equivalent lens used with its native APS-C bodies. Mount it on a Q7, it is still a 35mm f/2.8 lens, but now it becomes a 160mm f/13 equivalent lens.

1. What should they write on this APS-C lens? (the point made in the video is that manufacturers like Pentax are lying)
2. What if I crop?

I disagree, forcing "equivalence" on people doesn't make any sense. What if I only care about similar angles of view? What if I care about AF precision, and I want to benefit from f/2.8 AF points present on some cameras? What if size is a consideration, more than maximum aperture?
There are so many situations when the "equivalence" fails I'm amazed at the stubbornness in promoting it. And there is only one scenario where it somewhat works, which is purely theoretical.

I don't have to "predict" noise through "equivalence"; it can be measured/observed.

GateCityRadio, merely seeing which focal lengths are offering similar angles of view on different formats is not "equivalence"; and it's shunned by "equivalence" fans as being "plain wrong". Apparently you're not allowed to do that.

[jsherman999]

"Equivalence" as it's promoted is an abomination that should not exist.

A set of physical facts is "an abomination that should not exist." You sound like the Catholic Church talking to Galileo.


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---------- Post added 05-20-14 at 11:03 AM ----------

... The old ways are better, because they're universal and consistent.
Btw, I did go from FF to APS-C some time ago, and didn't need "equivalence", I just learned the new format.

You "learned the new format" by using equivalence. You apparently only used it half way, because you didn't convert the F-stops (only FLs,) but I'm guessing that didn't matter for you because you were fine with whatever DOF and noise you got - and that's perfectly fine. No-one is saying you need to personally concern yourself with anything you don't want to - but you shouldn't push your viewpoint on others if it depends on only half the facts being presented.

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[Kunzite]

A set of physical facts is "an abomination that should not exist." You sound like the Catholic Church talking to Galileo.

Wrong; that's a personal opinion, and if there is a pseudo-religious view regarding this matter it belongs to you. Should I say, "The Equivalence Inquisition"?
Physical facts are things like focal length, which was claimed to be a lie. Logical facts are things like "equivalence" breaking apart if you use the same lens on multiple formats, and if you crop.

You "learned the new format" by using equivalence. You apparently only used it half way, because you didn't convert the F-stops (only FLs,) but I'm guessing that didn't matter for you because you were fine with whatever DOF and noise you got - and that's perfectly fine. No-one is saying you need to personally concern yourself with anything you don't want to - but you shouldn't push your viewpoint on others if it depends on only half the facts being presented.

Wrong. I learned the new format by using it.
Your vision is so rigid and inflexible, you simply cannot accept other people's requirements being different than your "3 things that must be equal". When I did the switch:
- I bought new lenses, one by one, by asking myself what I need on the new format; never thinking about film.
- I like my 35mm f/2.8 for different reasons I liked the 50mm f/1.7, namely its excellent closeup capabilities.
- the final medium changed dramatically, so any discussion about seeking "equivalent" DoF is pointless.
- the noise characteristics changed dramatically from film to digital, then from my first digital camera (*istDS) to the current K-5IIs.

[repaap]

I would say that in APS-C world and in FF world the difference is not so dramatical. Sure one should point out that markings on the lens is not what you get on APS-C. Actually you can see Focal in FF eq. But not f.stop. It could turn things too complicated for most. It is not because someone is misleading some one, so much as it is in smaller formats. Which was mentioned with super zooms.

So many times when you try to be simple and accurate, it might be too complicated for most. Suddenly it is bad thing that 600 mm tele is being used at f13. My A400/5.6 is great around f8-10. In FF terms it would be higher. No? Well it just happens to be where I like it best. Sometimes there is much noise, when I bump ISO at 1600-2500 or even 3600. But it is not too bad.

So missleading customers..perhaps. Should everyone own FF. What if and when they need to use teleconverter...again it gets difficult.

That would be it for me.

[audiobomber]

Physical facts are things like focal length, which was claimed to be a lie.

Where are you getting this from? The video never says that, because it would be wrong. Focal length is fact. The DA 35mm f2.8 is a lens with a 35mm focal length and 35/2.8 = 12.5mm aperture. The Sony RX10 has a lens with variable 8.8-73.3mm focal length and 3-26mm aperture.

What is incorrect is to call the Sony lens a 24-200mm f2.8 lens. That is the lie, mixed equivalence. I think you need to watch the video again. It is all explained quite clearly there.