Equivalence: read this, then argue

I sometimes get a bit tired of the old (and largely uninformed) debates around format wars, lenses of different format wars, iso wars, you name it... anyway, the above article should be required reading for any would-be participant. I've only skimmed through it and read through a couple of sections, it's already apparent that it's a pretty authoritative piece.

The advantages and disadvantages of different sensor sizes are rather more complex than would first seem apparent; as usual, choice of sensor size is about which compromises you want to make and which you don't. Absolutist judgement about "better" or "worse" systems simply aren't applicable. This is a good philosophical position.

I went to dinner last night with much-loved relatives, rejecting the X-T1, battery grip and 56 in favour of the X-E1 and 35; right choice, on grounds of size and weight. In terms of IQ, the difference is not huge so it was on the thin margin of physical difference that the choice was made, this with almost identical cameras, never mind formats or sensor sizes. The compromises we are happy with can be very finely balanced; let us respect that in each other.

Very well written piece of information.
But it won't let the trolls and the 'uninformed' stop making the same arguments.
They just can't believe, or won't want to believe. Even if the arguments given are honest.

There's a lot of truth in this part which is most important to which camera you want to buy

"which is best is completely subjective. While for me, personally, I prefer FF, it is my opinion that the vast majority are better served with smaller formats. As all systems continue to improve, the number of situations where FF has a significant advantage over smaller formats narrows. Of course, if size, weight, and price were not considerations, then larger is almost always better. However, since size, weight, and price not only matter, but are often (usually) the primary considerations, then it is my opinion that the advantages of FF over smaller formats are not enough to offset the disadvantages for most people in most situations."

Therewith it comes down to personal preference and personal needs, to which system is better suited for you as a user.

Anyway thanks for sharing.

57LowRider said:

http://www.josephjamesphotography.com/equivalence/index.htm#quick

I sometimes get a bit tired of the old (and largely uninformed) debates around format wars, lenses of different format wars, iso wars, you name it... anyway, the above article should be required reading for any would-be participant. I've only skimmed through it and read through a couple of sections, it's already apparent that it's a pretty authoritative piece.

The advantages and disadvantages of different sensor sizes are rather more complex than would first seem apparent; as usual, choice of sensor size is about which compromises you want to make and which you don't. Absolutist judgement about "better" or "worse" systems simply aren't applicable. This is a good philosophical position.

I went to dinner last night with much-loved relatives, rejecting the X-T1, battery grip and 56 in favour of the X-E1 and 35; right choice, on grounds of size and weight. In terms of IQ, the difference is not huge so it was on the thin margin of physical difference that the choice was made, this with almost identical cameras, never mind formats or sensor sizes. The compromises we are happy with can be very finely balanced; let us respect that in each other.

Click to expand...

From my experience:

- most people know about the equivalent focal length even if there is some confusion

-lot's of people know about the equivalent aperture for dof. But strangely, they consider that this applies only to dof, not light. They keep comparing their lenses with FF lenses with the same aperture, not with the equivalent aperture. They make unfair comparisons.

- the advantage of FF at base ISO is often not mentioned. In fact , in the reviews, they focua on the high ISO FF performance. But this is just a consequence of equivalence !! I am more impressed at the performance of FF at low ISO !!!!

Shooting with a 18m f2.8 lens with APS-C is like shooting with a 27mm f4.2 with a FF AND having a FF body which can shoot at 225 ISO for the base ISO (or 450 ISO if base ISO is 200, just like Fuji).. Optically, this is really equivalent.

If people knew a bit more about equivalence, we could remove maybe 10% of endless debates/discussions in DPR forums. Some people keep denying it, especially m43 users, DPR could write an article about equivalence to avoid people always pretending that you are wrong when you say that they should compare lenses (price, weight) which have max equivalent aperture.

Well written article, but a bit outdated. FF (bodies) are no longer bigger, heavier and more expensive than APSC. The Sony A7 can be found for a price close to that of the XT1. Yes, the lenses tend to be bigger but "equivalent lenses" (as defined by the article) will have similar sizes. And we've all seen how f1.2 APSC lens price compares to f1.8 FF ones. IMO, nowadays APSC sensors are plenty good but FF sensor is still better. However lenses and ergonomics are even a bigger factor to consider, which is why I'm still with Fuji.

hellocrowley said:

Well written article, but a bit outdated. FF (bodies) are no longer bigger, heavier and more expensive than APSC. The Sony A7 can be found for a price close to that of the XT1. Yes, the lenses tend to be bigger but "equivalent lenses" (as defined by the article) will have similar sizes. And we've all seen how f1.2 APSC lens price compares to f1.8 FF ones. IMO, nowadays APSC sensors are plenty good but FF sensor is still better. However lenses and ergonomics are even a bigger factor to consider, which is why I'm still with Fuji.

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A few points.

1. Equivalent lenses still have to be bigger on larger sensors, at very least because the minimum lens attachment has to support the much bigger fast lenses.

2. Manufacturers don't tend to make quality slow lenses so to get equal lens quality in larger formats you end up having to purchase and lug around much bigger heavier fast lenses.

3. Manufacturers of SLR's...notably Canon and Nikon, have mostly ignored APS-C pro lenses altogether. So, in order to have pro quality lenses you need to buy FF lenses for your APS-C SLR bodies.

4. Sony's A-series FF bodies are a steal. The price of their lenses, however quickly negates the cost savings.

hellocrowley said:

Well written article, but a bit outdated. FF (bodies) are no longer bigger, heavier and more expensive than APSC. The Sony A7 can be found for a price close to that of the XT1. Yes, the lenses tend to be bigger but "equivalent lenses" (as defined by the article) will have similar sizes. And we've all seen how f1.2 APSC lens price compares to f1.8 FF ones. IMO, nowadays APSC sensors are plenty good but FF sensor is still better. However lenses and ergonomics are even a bigger factor to consider, which is why I'm still with Fuji.

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I have 2 FF cameras and 3 APS-C cameras. Certainly no pro photographer, but if Pros can shoot with APS-C and sell their work I am pretty sure APS-C is good enough for me.

One stop of light, narrower DOF just really don't come into play much because Fuji lenses make up the difference. I rarely bring the FF cameras out of the bag. A7R if I am going out for landscape shooting, that's about it.

Seems fairly good overall, but he's technically incorrect about DOF.

hyperfocal distance = focal length ^2 / (f/stop * circle of confusion)

Make the crop factor adjustments for focal length (angle of view constant) and aperture, but that value for circle of confusion remains different for different formats. There's no circle of confusion "crop factor" and so smaller format cameras do deliver more DOF that larger format cameras.

57LowRider said:

I sometimes get a bit tired of the old (and largely uninformed) debates around format wars,

Click to expand...

So you thought you'd start another?

Interesting article. Lots of info in there to be misunderstood, misquoted, misrepresented and generally be fallen-out about, even when people are unaware they are really agreeing.

My money is going on this thread reaching 150 within the week, maybe even within 5 days.

For me though, it is all academic and meaningless to the average user in real terms. Even for people who do understand these issues, very little matters in the real world of day to day photography. And I say that as someone who studied physics, including optics, and qualified to Degree and PgD in related disciplines, and worked for many years in high tech, scientific and engineering environments, although not for the last 10 years. Unless it actually helps people take better pictures, what is the point of all the theories, numbers and debate unless you are designing cameras and lenses?

Building cameras is science and engineering. Taking photographs is an art.

Of course you do need to know the basic concepts of focal length, f stop, shutter speed, ISO, etc. and how these affect your photograph.

The only real issue about sensor size is that the DoF will increase with smaller sensors and that will affect your choice of camera.

There isn't very much difference between FF and APS-C in real usage. When selecting the aperture I still think in 35mm terms but it is usually near enough for my purposes in APS-C. I wouldn't want to go much smaller than APS-C as it would become a limiting factor. But the practical differences are better to be experienced than calculated. Who does these calculations in real usage? I've yet to see a really creative image, made possible only by being taken by someone who understood the minor intricacies of the numbers. Do understood the broad principles, yes, but people will learn more from shooting with their cameras and in doing so gain experience more than any calculations.

"The stone age was marked by man's clever use of crude tools; the information age, to date, has been marked by man's crude use of clever tools."-- Anon

57LowRider said:

http://www.josephjamesphotography.com/equivalence/index.htm#quick

I sometimes get a bit tired of the old (and largely uninformed) debates around format wars, lenses of different format wars, iso wars, you name it... anyway, the above article should be required reading for any would-be participant. I've only skimmed through it and read through a couple of sections, it's already apparent that it's a pretty authoritative piece.

Click to expand...

Wow, an article started with E=mc^2! But I am unable read pass the third bullet points! Even if all the points can be proofed with E=mc^2. They are still ignoring all practical aspect of photography.

I myself found no equality between different size sensors in practice! So we need more then one sensor size!

Any reasonable person understands that everything in life is a series of compromises. Since most of my photography is done during travel and other activities these days, my full frame equipment only comes out a few times a year. Even my Fuji system bodies and lenses are often too large.

I just got home from a week in London. It was a business trip and I had little free time. However, I can walk to and from meetings with an X100S in my hand and get in a few shots while my colleagues are taking pictures with their cell phones. Anything larger would a bit conspicuous in such situations.

For me the the X100S seems to be the right set of trade-offs for about 65% of my photography. My other Fuji bodies and lenses cover about 30%, and my Nikon equipment is used about 5% of the time, when I set up lighting and tripods, etc.

Rich

57LowRider said:

http://www.josephjamesphotography.com/equivalence/index.htm#quick

I sometimes get a bit tired of the old (and largely uninformed) debates around format wars, lenses of different format wars, iso wars, you name it... anyway, the above article should be required reading for any would-be participant. I've only skimmed through it and read through a couple of sections, it's already apparent that it's a pretty authoritative piece.

Click to expand...

Academically it is not authoritative because the author doesn't give references to make us believe it is authoritative (e.g., references to peer reviewed articles in trade journals; authors holding degrees in optics, engineering, photography). But, it is a good summary of what the author picked up.

57LowRider said:

The advantages and disadvantages of different sensor sizes are rather more complex than would first seem apparent; as usual, choice of sensor size is about which compromises you want to make and which you don't. Absolutist judgement about "better" or "worse" systems simply aren't applicable. This is a good philosophical position.

Click to expand...

Depends on what you are using for criteria to measure what is "better" or "worse". Usually cost fits in there somewhere.

Personally I don't think reading this article would be sufficient to improve arguments. Fully understanding what the article says (which is a tall order) and where it leaves off (i.e., bridging common definitions to what's currently available for most of us to purchase).

57LowRider said:

I went to dinner last night with much-loved relatives, rejecting the X-T1, battery grip and 56 in favour of the X-E1 and 35; right choice, on grounds of size and weight. In terms of IQ, the difference is not huge so it was on the thin margin of physical difference that the choice was made, this with almost identical cameras, never mind formats or sensor sizes. The compromises we are happy with can be very finely balanced; let us respect that in each other.

Click to expand...

On different family dinners, I brought my X-T1 and X-E1. From those experiences I observe that the smallest camera bag I own fits the X-T1 and X-E1 with anything bigger than a pancake equally well. The weight of the camera bag on shoulder with either camera feels the same. So personally I believe the X-T1 is the superior choice over bringing the X-E1 because the X-T1 focuses better in low light than the X-E1.

I might argue differently if the question wasn't about which of two cameras I already own to bring, but, a question of I don't own either camera and have limited budget, so which camera should I buy for now?

Where I think Joseph James' article comes in handy is when you get an opening post that says "Camera system X is just as good as/better than system Y". Having a common vocabulary would to ask questions and judge answers would help.

Eoanthropus said:

Seems fairly good overall, but he's technically incorrect about DOF.

hyperfocal distance = focal length ^2 / (f/stop * circle of confusion)

Make the crop factor adjustments for focal length (angle of view constant) and aperture, but that value for circle of confusion remains different for different formats. There's no circle of confusion "crop factor" and so smaller format cameras do deliver more DOF that larger format cameras.

Click to expand...

Could you check before posting ?? You are completely inventing ? Actually he is right. You have dof calculators to check..

At equivalent settings, the focal length is multiplied by c (crop factor). Both the f/stop and circle of confusion are multiplied by c. So the hyperfocal distance is the same.

Article was too long for me to read right now but thanks for posting, looks very indepth.

noyo said:

57LowRider said:

I sometimes get a bit tired of the old (and largely uninformed) debates around format wars,

Click to expand...

So you thought you'd start another?

Interesting article. Lots of info in there to be misunderstood, misquoted, misrepresented and generally be fallen-out about, even when people are unaware they are really agreeing.

My money is going on this thread reaching 150 within the week, maybe even within 5 days.

Click to expand...

Oh lawks, I hope this doesn't set a fire! I just read the section about noise again and found it informative - then wondered if the X-Trans sensors are "ISO-less"? The impression I have is that they are close to ISO-less whereas a Foveon, for example, is not; I have taken great liberties with RAF files that are not really noticeable in the final output.

What I really intended by posting, though, was to give everyone a useful link to point argumentative types at and say "read this first, then come back and argue". It's a tactic that could, of course, blow up in our faces

.... Let alone understand it..., I'll just keep shooting with my 1" and APSC sensors and enjoy them...

57LowRider said:

http://www.josephjamesphotography.com/equivalence/index.htm#quick

I sometimes get a bit tired of the old (and largely uninformed) debates around format wars, lenses of different format wars, iso wars, you name it... anyway, the above article should be required reading for any would-be participant. I've only skimmed through it and read through a couple of sections, it's already apparent that it's a pretty authoritative piece.

The advantages and disadvantages of different sensor sizes are rather more complex than would first seem apparent; as usual, choice of sensor size is about which compromises you want to make and which you don't. Absolutist judgement about "better" or "worse" systems simply aren't applicable. This is a good philosophical position.

I went to dinner last night with much-loved relatives, rejecting the X-T1, battery grip and 56 in favour of the X-E1 and 35; right choice, on grounds of size and weight. In terms of IQ, the difference is not huge so it was on the thin margin of physical difference that the choice was made, this with almost identical cameras, never mind formats or sensor sizes. The compromises we are happy with can be very finely balanced; let us respect that in each other.

Click to expand...

Are you the charlatan great bustard touting for business?

olypan said:

57LowRider said:

http://www.josephjamesphotography.com/equivalence/index.htm#quick

I sometimes get a bit tired of the old (and largely uninformed) debates around format wars, lenses of different format wars, iso wars, you name it... anyway, the above article should be required reading for any would-be participant. I've only skimmed through it and read through a couple of sections, it's already apparent that it's a pretty authoritative piece.

The advantages and disadvantages of different sensor sizes are rather more complex than would first seem apparent; as usual, choice of sensor size is about which compromises you want to make and which you don't. Absolutist judgement about "better" or "worse" systems simply aren't applicable. This is a good philosophical position.

I went to dinner last night with much-loved relatives, rejecting the X-T1, battery grip and 56 in favour of the X-E1 and 35; right choice, on grounds of size and weight. In terms of IQ, the difference is not huge so it was on the thin margin of physical difference that the choice was made, this with almost identical cameras, never mind formats or sensor sizes. The compromises we are happy with can be very finely balanced; let us respect that in each other.

Click to expand...

Are you the charlatan great bustard touting for business?

Click to expand...

Probably not. He's also probably not aware of the gang of buddies, Joe Mama, Great Bustard, Tyrone Wellhung, Crocodile Gena (aka Joe Mama) and a couple dozen sock puppets that chimed in to lend their support to their pet topics, equivalence being one of several.

Joe Mama posted several files describing his DPR history and listed his many banned sock puppets. Those files lasted at least many months, possibly a year or two, but they're all gone now, although their domain (www.josephjamesphotography.com) still exists. I believe that DPR created a technology forum for them to play in, because banning was ineffective and it was a way to keep them from polluting many forums with contentious threads that occasionally flared up with insults, baiting and flame filled posts.

The full frame vs dx debate is never going to end. I can remember it from when I got my first dx size sensor camera.

I would love a full frame camera but cost, size and weight rule it out for me. I am not having trouble getting the IQ I need from my trusty x-e1 so I have not worried about it. If I get one comment from an agency about needing better IQ I will be going full frame but so far it has not happened.

Which brings me to my point: There can not be a right or wrong side to this debate.

Trudy

Hi ,

I seems to me that these equivalence arguments come up in DPR when people argue about their specific goals - eg

• people trying to reduce DOF, ie to achieve the shallowest DOF
• people comparing very high ISO performance (resolution, noise, etc)
• people comparing (and often seeking to justify) purchases of different camera systems

Personally I couldn't care less about the first two. I'm into landscape, travel and sometimes architecture. I know what shallow DOF is of course, but I just don't do much of that style of photography. And I avoid high ISOs wherever possible. Though others might find ISO6400, 12500 or whatever usable, I don't. I am very interested in selecting my own camera systems carefully, but I don't care what other people buy. That's for them to decide. I actually own three different sensor sizes and know their benefits and limitations.

The article is substantially theory, though I don't doubt Mr James' authority or his content. In practice, one buys into a camera system - bodies, lenses, the lot. And systems don't offer the same products and they aren't really 'equivalent'. Camera processing is different. Lens ranges are different, and lens characteristics are different. So are different SW systems for PP. One finds what one likes. We often have to accept what is feasible with our systems and it ultimately doesn't matter what is' equivalent'.

Further, factors like personal preference, ergonomics, cost, size, availability, reliability, service, and a dozen other things which aren't about image-making, nevertheless feature in our choices.

Better to enjoy using what we have and do some photography.

Cheers, Rod

The debate is about relevance.

The other issue with these debates is the glaringly obvious point that all sensors are not equivalent. Noise, DR and other considerations a moot as soon as you pick a Canon sensor and compare it with a Sony one.

How would compare a Fuji/Panasonic organic sensor with a regular one? It could have more than a stop improvement in QE.

Similarly you cannot compare Canon lenses with Fuji lenses and try and work out what is equivalent to what. There will be variations of more than a stop in either direction depending on performance characteristics (like what is the useful max aperture of a given lens?)

Since no two cameras are ever directly comparable, this wonderful technical diatribe is largely irrelevant in the real world. I would say you could pick a combination of lenses and an APSC camera that would give you WORKING equivalence over many FF setups over most of the important shooting scenarios. Fuji are closer than most because of the quality of the primes, which are very well behaved wide open, unlike most of my Nikkors.

I use a D800 mainly because it has 36MP, not because its FF. All things being equal FF will give you more resolution for a given MP count provided your lenses have good edge performance. However if the Xpro2 has a 24MP organic filter sensor, it may well outperform the D800. The lenses are certainly good enough.