The Difficulty in Explaining Equivalence

thanks for the read, just about any current FF can equal MF. unless sony added some magic pixie dust to
there MF sensors 🙄

You divide focal length by 4; not f/4.

Yes. This is the elephant in the room that often gets forgotten. Using max zoom as a reference point, as you zoom out wider, the maximum size of the entrance pupil plummets. This is actually worse with constant-f-ratio zooms, than with variable ones. However, people can get tricked more easily with the variable-f-ratio ratio zooms into zooming out wider than necessary. Sometimes people will opt to "zoom out" in low light, taking a wider composition than wanted with more cropping expected, to get a lower f-ratio, which is completely counter-productive for the captured subject, if one was looking for maximum background blur and minimum DOF, more total subject light, and minimal diffraction.

Of course, if a person is also getting closer to the subject as they zoom out, then the greater proximity can improve those characteristics, regardless of the fact that the pupil has gotten smaller.

A good policy is to get as close as you can first (unless you want a more distant perspective), and then zoom in as far as you can without the AOV getting too narrow to work with, and that will give the "large, close pupil" effects mentioned above.

Every large sensor can emulate a smaller one through cropping, so for the underlying analog image (which is what equivalence is concerned with), a FF sensor can do everything an m43 can do and more. The other "meta-equivalence" details about sensor and camera performance could favor the M43, though, in certain situations.

Yes, I get, the fact it is a pretty thankless unpaid job. Amazon and now the new owners have been pretty shrewd getting people to work for free. I suppose it might be a good pastime for a bored pensioner, fed up with watching the TV all day, . It is certainly not something I would want to do. I guess most do it with healthy motivations, but I can imagine some like to be in a position to bully others.

Absolutely; with the right and wrong optics, respectively, FF can equal or surpass a Medium Format.

Can't speak for other manufacturers, but Canon has this "sensor shake" thing that makes "pixel dust" a non-issue. 😉

After a power cycle, but if dirt gets on the sensor while the camera is operating, you can still get in photos, and may jump around if you use mechanical shutter.

The thing is, though, I have always shot Canon, and had known that, for quite some time, Nikon was superior (at least in terms of sensor tech and AF). So, even though I liked my Canon equipment, I was fully cognizant that it wasn't the best. Indeed, I still own the 6D2, which is the laughing stock of the last round of FF DSLRs, yet I really liked it a lot. Same goes for my car -- I absolutely love it. Right from the first test drive. Even told the sales guy, "You don't have to sell me the car -- I want it. It's simply a matter of you meeting my non-negotiable limit of what I will pay. One cent higher, no deal, no matter how much I like the car." And yet, I'm more than certain there were better cars for the money. But, like I said, I love my car, and am quite cognizant of many things it's lacking that I want. And don't get me started about my wife. 😉

So, I guess I don't understand the mindset of denying facts. You can simultaneously love what you have and be cognizant that there are other options that are better in this way or that. People seem to think that mentioning facts that shows what they have is not the absolute best is a personal attack, which, to me, is beyond bizarre.

Found another example of "The Difficulty of Explaining Equivalence":

😁

Okay, I'm sorry to say this thread has become very long and I'm way behind in finishing reading all the posts/replies before wanting to chime in.

I don't see equivalency as a difficult thing to master. It comes down to one thing, and one thing only, the size of the aperture. All things equal (i.e., framing, perspective, exposure, and viewing distance), any two formats will perform more or less the same if the size of the lens aperture is the same.

As to why bother, Bob covered that nicely in a post about how it applies to camera settings on the kit he uses when cycling. Indeed, I cycle too, and I do the same quick and dirty calculations as I change back and forth between my FX and DX cameras (for the tiny formats like my phone's camera, I don't bother). It's also something I think about when I'm making substantial crops, which leads to something counterintuitive, and that is when you crop a shot the DOF decreases (hmmm, smaller format would mean the opposite except that the aperture is the same and the viewing "distance" just got lessened).

That depends some on pixel density. Diffraction diminishes, but does not always eliminate, the advantages of greater pixel density in achieving more "reach."

I've yet to see (or read, until GB's reply below) any western leaders advocating sending troops to Ukraine. The menacing figure in all this is Putin, who has sent many Russians to their deaths there, and threatens nuclear war too.

Let us know when you're done -- there will be a short quiz. 😇

There are many important things that Equivalence does not cover, though: AF speed/accuracy, frame rate, build, ergonomics, etc., etc., etc.. Also, the main contention point of Equivalence -- Noise Equivalence -- is, indeed, dependent on the technology of the sensor and supporting hardware. Likewise, the sensor also plays a significant role in resolution. So, while System A may be equivalent to System B, there can absolutely be critical differences between the two systems that definitely favors one over the other.

Most, if not all, advantages of smaller formats vanish if the system as a whole is not smaller and/or less expensive. With the advent of FF mirrorless, along with some rather inexpensive options (Z5 and R8, for example), Equivalence is more relevant than ever. For example, someone considering, say, an EM1.2 + 12-100 / 4 might well consider a Z6.2 + 24-200 / 4-6.3 (see here for an interesting thread on that point). Even more so if considering an f/1.2 prime for mFT vs an f/1.8 prime for the Z.

The bottom line, though, is that Equivalence is but one consideration when comparing systems. It's an important consideration, but far from the whole story, for sure.

apnews.com/article/paris-conference-support-ukraine-zelenskyy-c458a1df3f9a7626128cdeb84050d469

French President Emmanuel Macron said Monday that sending Western troops on the ground in Ukraine is not “ruled out” in the future after the issue was debated at a gathering of European leaders in Paris, as Russia’s full-scale invasion grinds into a third year.

The French leader said that “we will do everything needed so Russia cannot win the war” after the meeting of over 20 European heads of state and government and other Western officials.

“There’s no consensus today to send in an official, endorsed manner troops on the ground. But in terms of dynamics, nothing can be ruled out,” Macron said in a news conference at the Elysee presidential palace.

But, yeah, there are too many psychopathic heads of state. Russia is, well, Russia, and the US still supporting Israel militarily after what they've been doing is unconscionable. I guess Covid didn't kill enough people so they have gone another direction.

HAND.

what do you mean that m43 isnt equivalent to FF 😊
they look the same size to me 😁

As long as you don't ask me about DPR moderators, Donald's posts, or what Macron wants to do.

I think all of that falls under "all things being equal." It reminds me of a bumper sticker I once saw that read, "If all men are created equal, where's my Porsche?" If I'm on a racetrack, or discovering speed traps on country roads, then I want the Porsche, but if I'm driving more casually or just going to get groceries then I can live with something less than that – YMMV.

Sure, but right now my experience with FX versus DX equivalency revolves around my Tokina 14-20mm f/2 AT-X Pro and Sigma 50-100mm f/1.8 Art on my DX cameras. The equivalent FX lenses would be a 21-30mm f/3 and 75-150mm f/2.7, setting aside I haven't seen those particular FX choices, as a practical matter my Tokina 14-20mm works nicely on my DX cameras and gives me a capability I don't have with any lens I've put on my D850 – namely, handheld sunsets with good edge to edge resolution at the equivalent f/3 aperture. Now I'm sure I could find a solution to handholding my D850 at approximately those AOVs, but it will cost me a lot more than the $400 I spent on the Tokina lens.

I also like the wide open sharpness and ability to zoom around 105mm FX equivalent focal length on the Sigma Art lens. Equivalence simply gives me a starting point to evaluate the relative capabilities of my DX and FX systems and helps guide me to the best solution. Thus, I can make relevant comparisons rather than spurious ones (like using the Tamron wide open, where it doesn't look so great). Here is a typical example of my Tamron 85mm f/1.8 used at f/2.8 on my D850 (on the right below) compared to my Sigma 50-100mm f/1.8 @ f/1.8 and 58mm on my D500 (on the left below):

Getting more into the weeds, the D850 was shot at ISO 200 and the D500 at ISO 100 (totally irrelevant here), both using the same flash level, and the D850 resized to 67% whereas the D500 is at 100% (thus, equal viewing "distance"), with some post processing that gets them close and is part of the real world in which I operate.

Yes, the D850 is bit better here, I think, though this is still greater than 4K display (or a pretty large print viewed up close). That said, the D850/Tamron combo costs $2081 and the D500/Sigma combo costs $1571 (used prices available today at BH in New York). To more closely match the weight and zoom range of the Sigma, I should have used a Nikon 70-200mm f/2.8 VR II (I have the first version, so that's an eventual upgrade I would like to have someday), and that raises the price of this comparison to about $1000 more for FX than DX. It gets worse for FX here though, because if I want to get to 9 fps on my D850 I will need to add a MB-D18 and EN-E18a battery and charger, and that's going to cost me another $500, more or less. Full disclosure, I'm not using that Sigma to shoot fast action, which is why I own the Nikon 28-70mm and 70-200mm f/2.8 AF-S zooms.