Has There Been a Nuclear Incident in the Arctic? • Hacker News Board

Re: Has There Been a Nuclear Incident in the Arctic?

#201

Post by semi-extrinsic » Mon, Feb 20, 2017, 5:50 PM UTC

chris_overseas wrote: post #181

semi-extrinsic wrote: post #174

Earlier quoted context omitted.

The biggest question to my mind, when it comes to camera shootouts, is how close could you get to this kind of quality with a superzoom? Take a Canon SX60, having a lens that's 21-1365mm ( sic ) 35 mm equivalent. Admittedly the sensor is much worse, etc., but this covers most of that 6 lens range (apart from wide apertures at high tele).

Somewhat anecdotal evidence, but I was on safari with a guy who had a superzoom camera (can't remember which sorry but it went to 1200mm or so). He was mocking the size of my full frame DSLR + 800mm Canon prime, saying he had far more reach with his almost pocketable camera - which was of course true. I was curious to see what the difference was in practice so we both took photos of a waterbuck in the distance (him a…

I have a superzoom myself, and I'm not surprised at this. I guess you saw not just the difference in optical resolution, but particularly in hazy conditions, that the much larger front aperture on your 800mm prime means is "averaging out" blur from haze and air motion to a much greater extent, giving in total a much higher clarity.

In the middle of a hot summer day, the 800mm end on my superzoom is near-useless, but at or after sunset it's much better. Still very noticeable difference from your 800mm prime, I guess, but less so than at midday.

Re: Has There Been a Nuclear Incident in the Arctic?

#202

Post by PuffinBlue » Mon, Feb 20, 2017, 6:20 PM UTC

neom wrote: post #194

sjwright wrote: post #166

Earlier quoted context omitted.

A 50mm 1.2 lens on a Canon APS-C body has a full frame equivalent focal length of 80mm and a full frame equivalent aperture of f/1.9 — giving it the characteristics of a comparatively inexpensive lens. In other words, your $1300 lens on a crop body will have comparable performance of a $350 lens on the full frame body.

Go put a 50 1.2 L on a 300D and tell me it looks like the 85 1.4 on a 5D. In fact, I'm so confident you're incorrect I'd happily drive up to B&H and snap some raws to prove it.

It seems you're mixing your arguments. From your education you are aware that the 'equivalence' between APS-C and full-frame extends beyond focal length and into aperture and ISO performance I presume?

That's the point the parent you're replying to is making.

It is physically impossible to achieve the kind of equivalence you mentioned in your first post because the 'crop factor' is also applied to aperture and the crop-factor squared is applied to the ISO.

That's a point that's not well known and often dismissed, so I'll repeat it: The crop factor is applied to aperture and the square of the crop factor is applied to the ISO.

If you are not aware of this/don't believe it, see here:

https://www.youtube.com/watch?v=DtDotqLx6nA

Manufacturers like to gloss over that and constantly talk about 'equivalent' focal length whilst skirting the other equivalents, because they would clearly show the physical (as in physics) limitations of the smaller sensor.

It may well be that a 50mm f1.2 on a 300D would look 'nicer' than a cheaper 85mm f1.4, but that could be due to lens construction/coatings etc and it literally cannot be due to achieving the same focal length/aperture/ISO performance. You cannot physically achieve the same depth of field (let alone focal length) for instance with a 50mm f1.2 on APS-C as an 85mm f1.4 lens on a full frame.

That's the technicality you are being picked up on (albeit in a slightly imprecise manner), so save that trip to B&H because it'll be impossible to achieve what you are saying.

Source: Former pro photographer (and less important but I've used the lenses you mention).

Re: Has There Been a Nuclear Incident in the Arctic?

#203

Post by njharman » Mon, Feb 20, 2017, 6:30 PM UTC

jefe_ wrote: post #177

Really shows the size and capability of U.S.A.F. when they have a plane and team they can casually deploy to what appears to be a highly specific situation. The article says the aircraft is specifically designed to use atmospheric data to determine cause and nature of nuclear incidents. Imagining the manpower and testing and everything that goes into designing and implementing a system like this, and then multiplying…

Considering nuclear warfare has been there primary mission for 60+ years, I'm not impressed.

Re: Has There Been a Nuclear Incident in the Arctic?

#204

Post by benibela » Mon, Feb 20, 2017, 6:40 PM UTC

coldtea wrote: post #128

pratyushag2 wrote: post #126

Earlier quoted context omitted.

These are incredible pictures. What kind of camera did you use to click these?

> What kind of camera did you use to click these? This is an incredible comment. What keyboard did you use to write it? (Camera choice doesn't matter beyond certain ergonomics and certain capabilities (low noise, more room for cropping, shallow DOF, etc, a lot of which depend on the lens as well). Any $300+ DSLR can give you the exact same results, as can a lot of mirrorless with a speedy lens. And for most of the pi…

I do not know about that comment, but this comment is being written with a Coolermaster mechanical keyboard with true Cherry MX brown switches. Each key has its own spring, and multicolored LED backlight that is individually programmable to show/blink in any lighting pattern. It has its own ARM processor and you can play Snake on the keyboard itself without any additional computer using the backlight LEDs as display.

Re: Has There Been a Nuclear Incident in the Arctic?

#205

Post by NickNameNick » Mon, Feb 20, 2017, 7:07 PM UTC

Chris2048 wrote: post #131

hackuser wrote: post #94

Earlier quoted context omitted.

> People lost faith in media after their support for Iraq war. These criticisms toward the media and 'it's not like it used to be' allegations have been going on for generations.

So? Maybe they're valid now.

They were valid 'then' too.

'Yellow journalism' dates back to before the spanish-american war.

Re: Has There Been a Nuclear Incident in the Arctic?

#206

Post by xupybd » Mon, Feb 20, 2017, 7:17 PM UTC

mfukar wrote: post #121

xupybd wrote: post #117

Earlier quoted context omitted.

The "media" has a major problem. Its main driver is its entertainment value. News is more entertaining when sensationalised and heavily biased. I don't think there is a conspiracy or negligence causing this. Just simple economic drivers. It's the same thing we see with fast food. Yeah it's bad, but it's exactly what the market demands.

Despite what anyone will claim, good journalism still exists. I am not going to discuss obviously false generalisations.

Good journalism still exists, yes I couldn't agree more. But I don't think it's rewarded as much as poor journalism. This is the problem.

Re: Has There Been a Nuclear Incident in the Arctic?

#207

Post by 0xffff2 » Mon, Feb 20, 2017, 7:49 PM UTC

JumpCrisscross wrote: post #197

Animats wrote: post #17

Earlier quoted context omitted.

That's because it's mostly wing. It dates from the Dash-80 era of slim, pure jets and low-bypass engines. Today's high-bypass engines are big shrouded fans with a jet engine at the center to spin them. Fuel economy is much better, but the engines look bloated.

> pure jets and low-bypass engines Any reason a low-bypass engine might be preferred for an atmospheric-sensing platform like this one?

It's just a function of when the aircraft was designed. The WC-135 aircraft are modified C-135s produced in the 60's. The C-135 was designed in the mid-50's. At the time, high-bypass engines simply didn't exist yet.

Re: Has There Been a Nuclear Incident in the Arctic?

#208

Post by mwfunk » Mon, Feb 20, 2017, 7:51 PM UTC

coldtea wrote: post #128

pratyushag2 wrote: post #126

Earlier quoted context omitted.

These are incredible pictures. What kind of camera did you use to click these?

> What kind of camera did you use to click these? This is an incredible comment. What keyboard did you use to write it? (Camera choice doesn't matter beyond certain ergonomics and certain capabilities (low noise, more room for cropping, shallow DOF, etc, a lot of which depend on the lens as well). Any $300+ DSLR can give you the exact same results, as can a lot of mirrorless with a speedy lens. And for most of the pi…

Just because someone asked what camera was used doesn't mean that person is implying that the photographer isn't talented. Maybe the poster is a kid who doesn't know much (or anything) about photography and wants to learn about these things; who knows. No need to be rude by assuming the worst about them.

Re: Has There Been a Nuclear Incident in the Arctic?

#209

Post by dwringer » Mon, Feb 20, 2017, 7:52 PM UTC

PuffinBlue wrote: post #202

neom wrote: post #194

Earlier quoted context omitted.

Go put a 50 1.2 L on a 300D and tell me it looks like the 85 1.4 on a 5D. In fact, I'm so confident you're incorrect I'd happily drive up to B&H and snap some raws to prove it.

It seems you're mixing your arguments. From your education you are aware that the 'equivalence' between APS-C and full-frame extends beyond focal length and into aperture and ISO performance I presume? That's the point the parent you're replying to is making. It is physically impossible to achieve the kind of equivalence you mentioned in your first post because the 'crop factor' is also applied to aperture and the cr…

The difference in DOF is more of a minor technicality than a "Your 1500 dollar lens performs like a 350 dollar one!" though. OP is correct that you are exaggerating, though OP was definitely wrong to ignore the difference.

Re: Has There Been a Nuclear Incident in the Arctic?

#210

Post by jonwachob91 » Mon, Feb 20, 2017, 8:00 PM UTC

xelxebar wrote: post #63

patcheudor wrote: post #46

It's interesting the author mentioned the nuclear generators and whatnot used in lighthouses and for small portable power generation. Those use strontium-90 and other byproducts of nastier energetic fissions which if my amateur nuclear physics brain is functioning correctly don't produce iodine-131. Iodine-131 is a byproduct of uranium-235/238 decay & fission. Since practical fusion doesn't yet exist, iodine-131 can…

Kind of off topic, but mind sharing how you molded such an amateur nuclear physics brain?

The US Navy has multiple study guides to help prepare future nukes for school. You won't find any classified material or functionalities of the US Fleet, but it does cover the introductory work.

http://www.navsea.navy.mil/Home/NNPTC/Power-School/StudyMate...