“Full Frame Equivalence” and Why It Doesn’t Matter

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“Full Frame Equivalence” and Why It Doesn’t Matter

carstenw
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p.3 #1 · “Full Frame Equivalence” and Why It Doesn’t Matter

Why not for shutter speed? Same aperture, same equivalent focal length.

Feb 03, 2013 at 09:40 AM

alundeb
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p.3 #2 · “Full Frame Equivalence” and Why It Doesn’t Matter

carstenw wrote:
Why not for shutter speed? Same aperture, same equivalent focal length.

When high shutter speeds are wanted, you will always try to find a trade-off versus noise. If noise wasn't an issue, you could always up the ISO to get the shutter speed you wanted with any camera, any lens.

If are making a comparison, I think we should use the basis that to compare what shutter speed you get with each system, we should go for the same noise level in the image with both systems.

Feb 03, 2013 at 10:08 AM

carstenw
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p.3 #3 · “Full Frame Equivalence” and Why It Doesn’t Matter

But this discussion is not about noise or other IQ factors. Ultimately there is no good comparison across all factors, due to differences in sensors. For example, an OM-D shooting a 25/1.4 can easily shoot with less noise than a NEX with a 30/1.4 or 35/1.4, for example, due to its IBIS. System differences are much too complex to equalize. Equivalency is relatively simple in comparison.

Back to my point: for the purposes of exposure and holding the camera stably, an MFT 35-100/2.8 and a FF 70-200/2.8 are equivalent.

Edited on Feb 03, 2013 at 10:30 AM · View previous versions

Feb 03, 2013 at 10:25 AM

15Bit
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p.3 #4 · “Full Frame Equivalence” and Why It Doesn’t Matter

alundeb wrote:
If are making a comparison, I think we should use the basis that to compare what shutter speed you get with each system, we should go for the same noise level in the image with both systems.

I agree this is a better metric, but not the whole. The equivalency of any two images is more fully measured in terms of Exposure, Angle of View, DOF and noise/detail. For these to be the same for images caught on two different sensor systems there is an inherent requirement that focal length, f-stop and ISO be different.It follows that there is no way to fully label lenses as "equivalent", because the sensor is included in the calculation.

Still, i do find the equivalent focal length metric to be useful - when buying a compact it is easier to understand "28-112mm equivalent on 35mm" than "7.1 - 28.4 mm with a 2/3 inch sensor". Of course using AOV would be even better, but as with so many things in life, history and inertia have us locked into a deficient system and we just have to live with it

Feb 03, 2013 at 10:27 AM

alundeb
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p.3 #5 · “Full Frame Equivalence” and Why It Doesn’t Matter

Carsten, I don't know why you deny me to discuss noise, but allow yourself to bring in handholding and image stabilization.
If image quality is held outside, it is not meaningful to discuss these matters.

There are other ways to make a camera stable than IBIS, and the lens in the example was the Canon 20-700 2.8 IS

Feb 03, 2013 at 10:34 AM

carstenw
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p.3 #6 · “Full Frame Equivalence” and Why It Doesn’t Matter

You can discuss noise if you like, of course, but whereas lenses always have the same equivalency on any camera within a system, noise varies from camera to camera, dramatically so, so that an MFT camera may even have better noise characteristics than some FF camera, so you are limited to making comparisons only between specific models. Even blind system comparisons, invalid as they are, have the additional problem that, for example, not all APS-C sensors are the same physical size, and almost all have different numbers of pixels.

In my opinion the only sensible thing to do is to pick a camera which has rendering and noise characteristics which you like, and the available lenses you want, and then use equivalency to choose your lenses. The rest is just armchair quarterbacking.

Feb 03, 2013 at 10:45 AM

Makten
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p.3 #7 · “Full Frame Equivalence” and Why It Doesn’t Matter

There are both FF and APS-C cameras with IBIS, so that argument for the OM-D isn't really valid either. Equivalence is about the physical properties of sensor size and aperture, not how the camera is compared to similar sensor sizes.

On the other hand, true equivalence isn't even possible in theory due to restrictions from aberrations at (relative) large apertures. A 500 horsepower, 2 liter, 4 cylinder engine is not gonna behave like a 500 horsepower, 4 liter, 8 cylinder engine. Just like an MFT camera with a 25/1.4 is not gonna behave like a FF camera with 50/2.8 even if they indeed can collect the same amount of light per time (with equal sensor technology).

The same goes for medium format versus FF. There is just no way to get the look of for example the Pentax 67 105/2.4 from an equivalent ~50/1.2 on FF. The MF camera will render a much sharper image with much nicer bokeh and lesser spherical aberration.

In my opinion, larger is almost always better except for price and size.

Feb 03, 2013 at 11:23 AM

carstenw
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p.3 #8 · “Full Frame Equivalence” and Why It Doesn’t Matter

Makten wrote:
There are both FF and APS-C cameras with IBIS, so that argument for the OM-D isn't really valid either. Equivalence is about the physical properties of sensor size and aperture, not how the camera is compared to similar sensor sizes.

It isn't an argument *for* the OM-D, it is a point about the impossibility of making good comparisons between systems. You can of course state that in general an APS-C system has 1 to 1 1/2 stop advantage over MFT, and FF has 2 stops advantage over APS-C, and so on, but beyond that, everything becomes specific camera against specific camera. Talking about noise characteristics between systems specifically is just impossible, as the various sensors have such different characteristics, even within systems.

The equivalency talk isn't about look, but about raw DoF and light gathering, as well as angle of view.

In my opinion, larger is almost always better except for price and size.

Agreed. I would probably carry a 24MP 6x6 or 6x7 medium format digital camera all the time if it weren't for the price, size, weight and non-existence of the relevant sensor.

Feb 03, 2013 at 11:47 AM

Jman13
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p.3 #9 · “Full Frame Equivalence” and Why It Doesn’t Matter

alundeb wrote:
Jman13 wrote:
The article wasn't written for FMers...you guys know this stuff.

Thanks for that clarification! I thought the remarks about people going on about equivalence included some of us here. I should have remembered that if you write articles of interest to us, you share them here yourself.

About the rabiat fanboys, I can understand that some people feel provoked. Like when you say that a 35-100 mm f/2.8 lens is equivalent to a 70-200 mm f/2.8 except DOF. You know that this is not the case, not for shutter speed. IMO you are fuelling the attacks yourself by pretending the smaller format has advantages that are not real, even though you know better.

I don't believe anywhere in the article do I say that smaller formats are better than larger formats for any reason. I do poi t out several situations where the image quality advantage of larger formats are negated, and these cases are absolutely true.

There seems to be a base misunderstanding that I'm trying to put smaller formats above full frame. I'm not. In no way shape or form. I also am not saying it isn't useful if you think in terms of 35mm FOV via focal length. And I even say so in the article. That is what crop factors are useful for. The main gist is that people need to stop immediately looking at something like the 35-100/2.8 and saying things like, "its really only a 70-200 f/5.6"...it should cost $200.

It gives similar FOV and minimum depth of field as that on full frame but that is only relevant if you are somehow trying to gain back full frame levels of shallow depth of field, or you are somehow trying to get m4/3 to exactly match the output of a full frame system, which is a fools errand. The formats are not equivalent. Why should discussions of lenses be framed in a way that assumes they should be?

Edited on Feb 03, 2013 at 12:11 PM · View previous versions

Feb 03, 2013 at 12:08 PM

carstenw
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p.3 #10 · “Full Frame Equivalence” and Why It Doesn’t Matter

Exactly.

Feb 03, 2013 at 12:11 PM

alundeb
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p.3 #11 · “Full Frame Equivalence” and Why It Doesn’t Matter

Jman13 wrote:
I don't believe anywhere in the article do I say that smaller formats are better than larger formats for any reason.

Quote from the article:

"
Studio work, where apertures are typically f/8 to f/11 for full frame users to get a person’s face completely in focus. With the smaller format, you can use strobes at 1/4 the power as the full frame user can, allowing for flashguns instead of studio strobes, or faster recycle for the same strobes.

Landscape photography when it’s windy, or you’re trying to stop motion – being able to shoot at f/8 rather than f/16 can be quite helpful.

Macro photography, where inherently deeper depth of field is most desirable, especially when lighting is problematic.
"

Jman13 wrote:
The main gist is that people need to stop immediately looking at something like the 35-100/2.8 and saying things like, "its really only a 70-200 f/5.6".

The error in saying so is smaller than the error in saying it is like a 70-200 2.8, like you do.

Feb 03, 2013 at 01:19 PM

Jman13
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p.3 #12 · “Full Frame Equivalence” and Why It Doesn’t Matter

Where have I ever said its a 70-200mm f/2.8 equivalent? I understand there's no free lunch...but it is an f/2.8 lens. And it is equivalent to a 70-200mm lens on 135 in field of view. Harping on the mini,um depth of field seems far more archaic to me than trying to purport that it somehow isn't 'really' f/2.8.

And those situations are not situations where I purport that smaller sensors are superior, but rather situations where the image quality advantages are negated.

Quote from the article "Now, sure, you can up the ISO two stops on the full frame camera to compensate (or 1-1/3 stops when comparing to APS-C), but now, the full frame camera has just lost ALL of its image quality advantages".

Feb 03, 2013 at 01:24 PM

carstenw
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p.3 #13 · “Full Frame Equivalence” and Why It Doesn’t Matter

alundeb wrote:
The error in saying so is smaller than the error in saying it is like a 70-200 2.8, like you do.

Huh? How do you even quantify the sizes of these errors? Clearly you are basing this on your personal opinion, in which the depth of field is more important than the light gathering ability. This is far from a universal opinion.

Feb 03, 2013 at 01:38 PM

alundeb
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p.3 #14 · “Full Frame Equivalence” and Why It Doesn’t Matter

Jman13 wrote:
Where have I ever said its a 70-200mm f/2.8 equivalent? .

You said it in the very first sentence here:

http://www.fredmiranda.com/forum/topic/1166128/0?keyword=35-100#11119141

I am not harping about DOF. I am talking about shutter speed and image noise equivalence. Of existing lenses, it is much closer to an equivalent to the 70-200 f/4 IS, on the safe side from my point of view.

Look, I know that you understand all of this. I am just syaing that you write in a provocative way , first claiming advantages of the smaller format, then you say that the advantage of the smaller format can be cancelled by the larger format by using a higher ISO.

Feb 03, 2013 at 01:41 PM

carstenw
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p.3 #15 · “Full Frame Equivalence” and Why It Doesn’t Matter

Why is that provocative, and the opposite not? I just don't see it. They are equivalent

Feb 03, 2013 at 01:44 PM

alundeb
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p.3 #16 · “Full Frame Equivalence” and Why It Doesn’t Matter

carstenw wrote:
alundeb wrote:
The error in saying so is smaller than the error in saying it is like a 70-200 2.8, like you do.

Huh? How do you even quantify the sizes of these errors? Clearly you are basing this on your personal opinion, in which the depth of field is more important than the light gathering ability. This is far from a universal opinion.

In this case, I quantify the errors using Jordans example in his article, of noise comparison with current generation sensors. The FF sensor has a 1 2/3 stop advantage. By saying it is 70-200 f/5.6 you make an error of 1/3 stop, by saying it is a 70-200 f/2.8 you are making an error of 1 1/3 stop. Assuming the lens has IS to avoid the IBIS argument.

Feb 03, 2013 at 01:47 PM

Jman13
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p.3 #17 · “Full Frame Equivalence” and Why It Doesn’t Matter

alundeb wrote:
Jman13 wrote:
Where have I ever said its a 70-200mm f/2.8 equivalent? .

You said it in the very first sentence here:

http://www.fredmiranda.com/forum/topic/1166128/0?keyword=35-100#11119141

Geez - you're bringing up an off the cuff sentence from a post from several months ago? Come on, man. First off, I was not purporting that it was the exact same...I was using shorthand in a forum post to denote that I was waiting for an f/2.8 zoom with the equivalent view of a 70-200mm lens. Yes, you're right, in a forum post from several months ago, I should have been more longwinded to express my excitement over a new lens. We discussed that briefly there....it's f/2.8...why must it be compared to full frame in all respects?

Have you seen me running around saying I've got a 70-200 f/2.8...no, I call it the 35-100mm f/2.8.

Edited on Feb 03, 2013 at 02:13 PM · View previous versions

Feb 03, 2013 at 02:04 PM

Jman13
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p.3 #18 · “Full Frame Equivalence” and Why It Doesn’t Matter

alundeb wrote:
Look, I know that you understand all of this. I am just syaing that you write in a provocative way , first claiming advantages of the smaller format, then you say that the advantage of the smaller format can be cancelled by the larger format by using a higher ISO.

I get your point. I also don't believe I had said that the smaller format was better using those examples, but that there were benefits to having greater depth of field at the same aperture in many situations. I then mention that the full frame camera can use higher ISO, but that negates the advantages of the larger format. The whole point is that when people deride smaller format lenses because the aperture doesn't give as shallow depth of field as the same FOV lens on full frame, they never ever seem to mention the situations where you WANT that depth of field. And why should I carry much larger lenses to get the exact same image quality (by raising ISO)?

I have made some minor changes to the article to help clarify some of my intent, and to potentially tone down perceived inflammatory tone. It was not my intention....the intent was basically to get people to stop harping on this stuff, as well as give a basic outline of the realities of the situation from all angles. Most readers have gotten a very positive look out of this...and a handful have misinterpreted the intentions. And some have basically not read the article and posted really crazy stuff.

(not referring to people here).

Feb 03, 2013 at 02:10 PM

carstenw
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p.3 #19 · “Full Frame Equivalence” and Why It Doesn’t Matter

You are still measuring an error which you imagine is an important advantage for the larger format, but this is only actually the case in very narrow circumstances, for example if you equalise everything from a noise perspective and ignore the image effects which come from that. If you shoot for equivalent depth of field, then they come out even in the noise comparison, since the MFT camera can gather two stops more light at equivalent depth of field.

Since the connection between noise levels and image results is much more indirect and variable than the effects of depth of field, I consider it to be primarily a theoretical concern. There are very few cameras today which cannot deliver excellent results in most situations. Depth of field is a primary concern, given that it changes how the image looks directly. And thus you see that what for you is a primary concern is nothing more than a few numbers on a piece of paper for me. This is all about opinion, not facts.

Anyway, the 1 2/3 stops is also imaginary, and doesn't apply to any actual cameras with very few exceptions. If you have an interest in specific cameras, the numbers are probably quite different. The noise comparison between the OM-D and the 5DII, to take two very popular cameras in this forum, representing MFT and FF, is nowhere near 1 2/3 stops, and is probably less than 1 stop, with the OM-D being better in some aspects, probably including low-ISO noise floor.

This discussion can go on forever, but two things are clear: if you are concerned primarily about theoretical aspects of performance, or if you are primarily concerned with narrow depth of field, buy the largest sensor you can afford. For all other concerns, the larger sensor camera may not be the best for your needs.

FWIW, I own FF and MFT and am happy with both for their use.

Feb 03, 2013 at 02:16 PM

Jonas B
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p.3 #20 · “Full Frame Equivalence” and Why It Doesn’t Matter

carstenw wrote:
This discussion can go on forever, but two things are clear: if you are concerned primarily about theoretical aspects of performance, or if you are primarily concerned with narrow depth of field, buy the largest sensor you can afford. For all other concerns, the larger sensor camera may not be the best for your needs.

FWIW, I own FF and MFT and am happy with both for their use.

Hmm. Two things there:
I am not primarily concerned with narrow depth of field but I'm interested in being able to get it when I want do. So, that's a third option. I'm also much more happy with the images from a FF camera taken at 50/2 than I am with images taken with a micro 4/3 camera at 25/0.95. Just as you mentioned somewhere; images taken with bigger sensors and bigger lenses are "more relaxed" (or something to that effect).

If you could have one system only Carsten, would you be happy with µ4/3 then? Philippe told me rehab will come quick to me... and now that I don't take any images I have time to think about which way to go when the day comes.

Feb 03, 2013 at 02:26 PM

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