Need Practical Public Photography Guides?

I believe you were given some indications when you posed the question; you can view them, but I will offer some instances for your convenience that have been covered in depth before.

Can I photograph people publicly, in the USA, without their consent?

Photography in public places: Is it allowed or needs permission

What are the laws in Australia surrounding photography in public places?

What are my legal rights when shooting a public event?

Additionally, your point.
Beyond the obvious, I’m not sure what you’re saying.
The point is,
You do need permission to enter someone’s private property; that is true. That is a no-brainer, regardless of whether or not taking photographs is so unimportant to photography and is a universal action to avoid being shot.

Although it mostly concerns commercial photography, some information applies to everyone.

https://pathedits.com/blogs/tips/when-need-photography-permit-laws

usa – What are the practical consequences of getting SSSS on a flight outside the US?

As a result of seemingly being put on some form of US list, for a period of time I was given SSSS on my boarding pass every single time I flew into the US (until I went through the DHS Traveler Redress program at which point it stopped). Between that and a few random times, I have received SSSS on my boarding pass for flights into the US around 10 times.

In every case except one I was subject to additional security checks, although exactly what those checks were depended on the airport I was flying from. In general it ranged from a minimum of an explosives swap of my hands and my luggage, through being scanned with a personal metal detector wand, up to them opening and looking at my carry-on luggage. In some cases this was done at the gate before boarding, in other cases it was done in a secure area away from the gate, after which I was escorted to the plane (presumably so I couldn’t reclaim something I had left in the airport before the checks?)

As a result of going through the process so many times, I also witnessed multiple other people going through the same process – and (again, depending on the airport) it was clear that there was a level of profiling going on as a part of deciding how well to search people. I’m a white male, and I complied with the requests of the security staff, so I was generally given a very cursory check. In some locations other people were clearly given more thorougher checks, including for example a having many of the items in their carry-on luggage removed and inspected.

The one exception to this process was at Ben Gurion Airport in Tel Aviv, which already has sufficiently good security for all passengers that no further checks are carried out if you are SSSS’ed.

customs and immigration – Is a day trip US to Canada currently practical?

The answer is yes, though it will be quite a hassle for just 1 day worth of a visit.

I think I understand why a plan is required: it’s to give border agents more discretion to decide I should not be exempt from quarantine

The official quarantine information page gives the following rationale for the quarantine plan:

Plan your quarantine. Even if you are fully vaccinated, you still need a quarantine plan in case it is determined at the border that you do not meet the necessary requirements.

So your quarantine plan will essentially be… “hop into my car, turn around and go back to New York”. Its not there in case you’re infected during your stay, its only there in case the border agents want you to quarantine upon arrival. So I’d put down the address of the border crossing as your “quarantine location” – after all, that’s the only place in Canada you’ll ever visit in case you’re rejected at the border. For Cornwall, ON this address would be 1 Brookdale Ave, Cornwall, ON K6J 0A9, Canada.

I need to get tested 72 hours before entry. I took the Walgreens test Thursday. The pharmacist said to expect the results Monday, and explained that the 72-hour turnaround they offer is “business hours”. (How that math works out is beyond me.)

Yes, the processing time for free COVID tests is not guaranteed, making it hard to plan a trip. So your options are:

  1. Hope that the test comes within 72 hours, then immediately hop into your car and drive to the border. So i.e. if the test comes on Saturday, you go to Canada on Saturday. If the test result comes later than that (after 72 hours have elapsed), you go for another free test and hope for the best.
  2. Get an express PCR test with a guaranteed turnaround. The closest place to Cornwall that I could find is “Garnet Testing Center” in Burlington, they charge $250 for a same-day result. If you search around, there might be a premium test company closer to where you live.

The third way this venture might not work: what’s the likelihood US customs will let me back in?

If you’re a US citizen or permanent resident, there’s nothing for you to worry about. The official rule states the following:

For purposes of the temporary alteration in certain designated ports
of entry operations authorized under 19 U.S.C. 1318(b)(1)(C) and
(b)(2), travel through the land ports of entry and ferry terminals
along the United States-Canada border shall be limited to “essential
travel,” which includes, but is not limited to

— U.S. citizens and lawful permanent residents returning to the
United States;

You might think that citizens need an “essential” reason too but that’s not true – only foreigners need valid reason like work, medical care or diplomatic travel. US citizens/Green Card holders are “essential” by the very fact that they’re returning home, no other reason required.

movement – What are some good examples of the practical usages of cross product in game development?

I know how to calculate cross product, and know that the cross product of 2 vectors is a third vector that is perpendicular to a plane created by the first 2 vectors.

However, I have not seen any good explanations about the practical usages of cross product in game development.

Would anyone please tell me some practical examples of the usages of cross product in game development ? (If you can share some links to websites that show me some good examples, that will be great too).


I am sorry if this question is vague, and some people may not like it or may even suggest that it should be closed. But, I have tried to google and can’t find any good, practical, and meaningful explanation yet.

security – Practical difference between a DV and EV/OV SSL certificate?

When I view a site’s SSL certficiate from a browser, it always says in the “Issued to” section that the organisation is not part of the certificate.

If end users cannot independently verify my organisation (I assume the browser now does that for them), what is the practical value of having a OV/EV certificate? Is it for some other reason? If so, what?

I see that at the time of writing Comodo says that that not only does OV/EV show the organization details in the certificate, but:

In addition to the secure padlock symbol, EV SSL certificates activate
the “green address bar“ in select web browsers by displaying the
authenticated company name in green adjacent to the web address.

I don’t think either statemet has been true for about a couple of years now for most browsers. They list some other benefits, but these seem marginal (“Comes with the ComodoCA Trust Logo” – is there much evidence that end users know or care about that?).

resolution – Is there any practical difference between saving at 300ppi or 72ppi?

You ask if there is a practical difference. So the answer is yes, albeit a very small one, but some of the other answers have missed it.

You’re right that the only difference is in the metadata: if you save the same image as 300dpi and 72dpi the pixels are exactly the same, only the EXIF data embedded in the image file is different. (I’ve even verified this using a Beyond Compare, a file comparison tool.) If you open the two images on screen you will see absolutely no difference between them.

However, now drag and drop those two images into a word processor and you should see something like this:

enter image description here

Page-setting software like InDesign does the same thing. This is because in both cases the target environment is one that measures things in real-world units (centimetres or inches), so it uses the dpi metadata to decide how to convert your image’s pixel dimensions to real-world dimensions. For example, a 600×600-pixel image at 300dpi will appear on the page at 2×2 inches.

By contrast, most screen-based environments (Photoshop, the web, etc.) measure things in pixels so no conversion is needed: each pixel in your image simply occupies one pixel of your screen.

So, if you’re preparing an image for print on paper or other physical media and you’re asked for a specific dpi (which will usually be 300), you should stick to it to ease the workflow at the print end. (Of course, a page designer can always convert your 72dpi image to 300dpi without losing anything, but why make things difficult?) Note that this only ever applies if your image is going to be placed on a page (for example, in a magazine or book), which is why it so rarely makes a difference. If you’re just printing photos full-page (either on your own printer or sending off for photographic prints) the dpi will make no difference.

dnd 5e – Are there any practical reasons for choosing proficiency in Intelligence saving throws?

Int saves are really good against Mind Flayers and also some other spells

Few powerful spells require you to use Int saving throws, additionally from my experience some of these are often used in Dungeons or by BBEGs to screw PCs over. They are:

  • Feeblemind
  • Symbol (insanity mode)
  • Phantasmal Force
  • Mental Prison
  • Psychic Scream
  • Illusory Dragon (Save for Dragon Breath, Investigation check to see through illusion)
  • Synaptic Static (This is actually a useful AOE for PCs as well)
  • Enemies Abound
  • Contact Other Plane (When cast by you)

The dreaded Mind Flayer’s Mind Blast ability requires an Int saving throw

Mind Blast (Recharge 5–6). The mind flayer magically emits psychic energy in a 60-foot cone. Each creature in that area must succeed on a DC 15 Intelligence saving throw or take 22 (4d8 + 4) psychic damage and be stunned for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

And so do their tentacles

Tentacles. Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. Hit: 15 (2d10 + 4) psychic damage. If the target is Medium or smaller, it is grappled (escape DC 15) and must succeed on a DC 15 Intelligence saving throw or be stunned until this grapple ends.

Having Int save proficiency in campaigns that deal with mind flayers a lot is very usefull


Intellect devourer’s devour intellect is another Int save ability

Devour Intellect. The intellect devourer targets one creature it can see within 10 feet of it that has a brain. The target must succeed on a DC 12 Intelligence saving throw against this magic or take 11 (2d10) psychic damage. Also on a failure, roll 3d6: If the total equals or exceeds the target’s Intelligence score, that score is reduced to 0. The target is stunned until it regains at least one point of Intelligence.


Finally as was pointed out in the comments, a recent Unearthed Arcana contains three psionic focused subclasses and introduces new abilities and spells that require Int saving throws.


For what it’s worth though I agree with the question and as far as I know Intelligence saving throw proficiency is generally considered the weakest one.

lens – What’s the practical difference between two Canon 50mm f/1.2 L lenses?

They’re two totally different designs that just happen to be the same (nominal) focal length and apertures.

The New FD 50mm f/1.2 L debuted in 1980 with 8 elements in 6 groups. As with all FD lenses, it was manual focus. It was very similar, but not optically identical, to the older FD 55mm f/1.2 from 1971. Both are based on double Gauss¹ designs that have been around for over a century.

enter image description here

The RF 50mm f/1.2 L debuted in 2018 with 15 elements in 9 groups, including three Aspherical and one UD lens elements. It’s also got an USM AF motor.

enter image description here

Comparing an FD 50mm f/1.2 L and an RF 50mm f/1.2 is like comparing the differences between a 1980 Corvette with a manual five-speed transmission and the 2022 Corvette Z06 with an automated transmission controlled by a very sophisticated computer that is scheduled to debut this fall.

They’re both made by the Chevrolet Division of General Motors.
They’re both named “Corvette”.
They both have four tires, two doors, and two seats.

The newer model will perform better at the metrics which cars are usually measured: acceleration from 0-60 mph, max g-force on a skid pad, time to 1/4 mile distance, top speed, etc.

On the other hand, some folks may prefer the aesthetics or driving experience of the older model.

It can be much the same with lenses. Newer ones usually have a design optimized to perform well doing flat test chart reproduction, even with the aperture wide open, because that is what the majority of buyers in the lens market these days seems to be obsessed with. But optimizing a lens to do flat field reproduction can mean making it less optimal for other specific tasks. All of that flat field correction, for instance, can make the characteristics of out of focus areas “harsh” or “busy”. This is not a desired quality for a lens used for certain types of portraiture.


(Update based on additions made to the question)

What differences would someone expect between the images produced by a
randomly-selected FD 50mm f/1.2L and a randomly-selected RF 50mm
f/1.2L?

Pretty much the full gamut of aberration correction with two such radically different designs. The older design is basically a modified double Gauss¹ design that has been around since the early 1900s and used in a wide variety of lenses in the 50mm focal length range.

All of the classic optical aberrations appear to be far more heavily corrected in the newer design, as they are in most recent 50mm prime lenses.

Something significant enough to be obvious outside of test charts?

Absolutely. Test charts only measure acutance when imaging a flat two-dimensional target that is parallel to the camera’s imaging plane. When taking photos of the three-dimensional world, all of the same design decisions that result in higher performance for flat field reproduction also affect how things in front of and behind the focus distance will be rendered, and not always in a way that is considered a positive by many experienced photographers.

Autofocus aside, are there situations where the RF would blow the FD out of the water, and if so which are they?

Taking photos of flat test charts that are parallel to the camera’s imaging plane. That’s where the newer designs really excel versus the simpler, older double Gauss¹ designs. That’s what the current market seems to be obsessed with, and any lens that isn’t optimized to do well on flat test chart tests won’t sell very well among those who always have to have the newest / greatest / sharpest lenses. These types of buyers seem to be a higher and higher percentage of the total market for lenses as the interchangeable lens camera market continues to contract in the wake of both the Smartphone revolution and the collapse of photojournalism and photography-for-hire in general as full-time professions.

What photos of test charts don’t tell anyone is how things like highly corrected, moderately corrected, or uncorrected field curvature affects the out of focus areas. Extensive correction for field curvature, and to a lesser extent spherical aberration, tend to make out of focus areas look less smooth than lenses with less or no correction. Objects with details in the background and foreground can appear harsh or busy.

Looking at other tests, such as those done by lensrentals.com founder Roger Cicala in the two articles at the links below, can give hints about how a lens renders a three-dimensional scene. Sometimes, so can looking at the lens’ block diagram.

If a lens excels at flat test chart imaging, then it will also be well suited for document reproduction, art reproduction when the art in question is more or less two dimensional, architectural photography with large flat surfaces that can be shot from a position that places them parallel to the camera’s imaging plane (“brick wall” shots), etc.

Many such highly corrected lenses render three dimensional scenes in a clinical way that many find less attractive than less corrected lenses which may render smoother out of focus areas and provide pleasing bokeh.

In his blog article Practical Use of Field Curvature: Wide and Telephoto Primes (where he also discusses 50mm primes that he had previously examined in a similar article² in comparison to the wide and medium telephoto lenses he looked at) Roger Cicala says this:

You’ve lived this long without needing any of it, obviously. But when
you decide on a lens, knowing how the field curvature behaves will
help you decide what that lens can (and can’t) do well. It also shows
why sometimes you want to move back and use the longer focal length to
get everything in focus on a plane, and other times when the field
curvature can help you isolate your subject. It may tell you when the
far edges of your image will be sharper than the mid-outer portion; or
that you want to avoid out of focus highlights in certain areas of the
field of view.

He goes on to say (emphasis added by me):

Or maybe it just confuses the hell out of you. If that’s the case, I continue to make the point I’ve been trying to make for a couple of years. There’s no “it scores a 79; it’s the best lens” in real life. They are tools, and each is a bit different. How well you know and use your tool has more to do with how good (or not) your images are than what it scored on the latest review. You don’t need fancy lab tests to figure that out, you need some time and taking a lot of images with the lens.

¹ So named for Johann Carl Friedrich Gauss, the inventor of the original Gauss telescope objective lens.

² The Canon New FD 50mm f/1.2 L (1980) design was pretty much the same concept later used for the EF 50mm f/1.2 L (2007), which Roger discusses a bit in this article.

boolean – Practical example of combination of OR gate and AND gate logic circuits

An indirected graph $(V, E)$ is simple if it doesn’t contain any self loop or multiple edges. I have developed a Boolean Algebra of graphs, that’s elements of a Boolean Algebra are simple graphs and binary operation s are graph union and intersection. I have also been able to represent a logic circuits (logic gates) in form of a simple graph, graph union is analogy of OR gate and graph intersection is analogy of AND gate.
Advantage is that using these graph operations, it is very easy to combine any number of AND gates and/or OR gates.

I need a Practical example of a logic gates in which only combination of AND gate and OR gates are used.

online resources – Is there a practical way to change the phone number in Uber app when arriving at a country?

and I also get a local sim card sometimes

I have had a lot of trouble with this for different services while traveling, to the point that now I am making the following. I created a Skype number, which is of course associated with my Skype account.

Then use that number for all/most services. You won’t need the physical SIM card to do anything, so if you are abroad and lose it then no problem. You just need an internet connection and everything works.

I am still in the process of testing it in all apps and services, but Uber is the perfect case. I cannot receive SMS oficially, but when I do an UK number calls me (through skype) and does text-to-speech for me.

Edit: tried linking my Uber app but it gives an unknown error. Contacted Uber and awaiting for an answer.

Edit 2: just tried again and it’s linked without problem