Tourlou

Lives in Canada St-Bruno-de-Montarville, Canada
Works as a Engineer
Joined on Mar 9, 2011

Comments

Total: 170, showing: 1 – 20
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In reply to:

IamJF: It seems there is some missconception about Sonys high temperature setting.
The standard temperature setting is here to protect the USER, not the camera! It prevents the camera surface to get to hot for save handholding. The hardware can take higher temperatures and I never heared of cameras failed cause of "melted" components - so it seems to work.
I'm not sure if the case of handholding such a camera for an hour of video exists ... it will sit on a tripod. Better be save instead of get sued.

The problem with the Canon - recording to early users the camera doesn't get even hot! This means it can't exchange heat efficiently. And R6 seems worse cause of the cheaper build.
Canon seem to know pretty well how much their hardware can take - they even where able to implement a timer how much time you have left. So they needed to do some temperature modeling of the situation to estimate recording times. Which is btw pretty cool engineering - hope the other companies copy that detail ;-)

@!amJF
Electronic components are usually rated up to 50C. Semiconductors resistivity is affected by temperature changes. When you develop electronic circuits, you test them in hot and cold rooms to ensure they work properly in the temperature range you want them to operate. I'm sure that the temperature limit has nothing to do with operator comfort. It's all about saving the electronics.

Link | Posted on Aug 4, 2020 at 10:46 UTC
In reply to:

falconeyes: Anybody notice how light appears to travel faster than light on its way back? That's perfectly normal though ;)

@Playright
Speed of light is constant within a medium, but changes when you change the medium through which the light is moving. The ratio of the speed of light in vacuum to the speed of light in a medium is the same as the refractive index relative to vacuum. What we observe here is counterintuitive as we use to witness phenomena much slower than the light we use to see them. But in this video, the packet of photons released by the laser travel at the same speed as the light signal that goes to the camera lens. When the laser hits the last mirror, some of the light scatters and heads towards the lens of the camera but the laser keeps coming towards the observer at the same speed. So, for any given point in space, it will take the same time to the laser and to the scattered light to reach a point in or close to the direction the laser is heading. This makes the laser appear to travels instantly when it goes towards the observer.

Link | Posted on Aug 3, 2020 at 14:16 UTC
In reply to:

falconeyes: Anybody notice how light appears to travel faster than light on its way back? That's perfectly normal though ;)

@Falconeyes
Yes, I know about that effect, but never expected it to show on such a short distance/time. Just did the maths. It's infinite. As the signal travels at the same speed as the photon packet, the light will appear to move instantly towards the camera.

Link | Posted on Aug 3, 2020 at 11:57 UTC
In reply to:

Jeff Greenberg: ---
> camera likewise has very fast shutter speed -- up to 3.8 nanoseconds

From photon POV, any distance traveled = 0 nanoseconds, right...?
So what was shutter speed from photon POV???

From the photon point of view, time doesn't exist. So, 3.8 ns or a million year in our time reference make no difference for the photon. That's how life is at the speed of light. But in the photon's reference system, 3.8 ns is eternity!!!

Link | Posted on Aug 3, 2020 at 11:09 UTC
In reply to:

Tungsten Nordstein: >the camera works by converting photons into electrical signals

isn't this a description of how all digital cameras work?

>but the photons do shed particles into the air

Photons shed particles? Particles of what? A photon is an elementary particle (boson), so not sure what even more elementary particle it can shed. I can only imagine that photons bounce of dust in the air and into the lens.

Lol!!! Let's say it's a very high energy laser and what we see is a stream of Higgs Boson. This would explain the "shedding of particles in the air" part!!!

Link | Posted on Aug 3, 2020 at 10:59 UTC
In reply to:

ewelch: This is way cool. I would like to hear about the implications of what being able to see it like this tells us about the nature of light.

This is fundamental research. We can't really know until we do the research. By the way, researchers now have the T-CUP camera, developped by the INRS here in Quebec and a guy in CalTech. This one can go up to 10,000,000,000 frames per second. Way faster than the little toy they used for that experiment!!!

Link | Posted on Aug 3, 2020 at 10:37 UTC
In reply to:

Currantos: This is SO misleading and wrong.
They are capturing light at different places, not capturing the SAME light traveling through space.
Very poorly written and sloppily edited. Typical of any scientifically minded articles on most websites. Just throw something up there and nobody would know the difference.
Happens ALL the time on DPR

Well, that's what happens when someone writes about something he doesn't understand. Physicists like me and other people here know just by looking at the numbers that it just doesn't work. They're just pulsing the laser and offseting the camera trigger a few hundred femtoseconds each time. And then, they make time lapse movie with it.

Link | Posted on Aug 3, 2020 at 10:27 UTC
In reply to:

falconeyes: Anybody notice how light appears to travel faster than light on its way back? That's perfectly normal though ;)

Mr Bolton, Doppler effect precisely happens because the speed of sound is invariable in air for fixed atmospheric conditions. Same thing happens with light. That's what astronomer refer to as red shift when the source is distancing us or blue shift when the source is closing on us. Speed of light varies in different media, but is constant within a medium.

Link | Posted on Aug 2, 2020 at 23:56 UTC
In reply to:

gonzalu: Color me stupid. I don't get it. We've had cameras that can capture much higher frame rates.. so what's the big deal here?

https://petapixel.com/2018/10/15/the-worlds-fastest-camera-can-shoot-10-trillion-frames-per-second/

Yep, that's a fast one.

Link | Posted on Aug 2, 2020 at 20:48 UTC
In reply to:

T Olivier: 1) Wow, "photons do shed particles into the air" is a very courageous hypothesis. By the way, photons are always "in flight", otherwise they do not exist.
2) if the shutter speed of the camera was (and let's assume for a while, it was constant and not "up to" 3.8ns) and the "flight" of the photon lasted 5.8ns, the shutter had only time to "blink" once and capture just one frame. Clearly, what we see in the video are several frames (that's why, it's a _video_ and not a static picture). I wonder, how that can be explained?

Just read the experiment report PDF. The link is at the end of the article.

Link | Posted on Aug 2, 2020 at 19:27 UTC
In reply to:

falconeyes: Anybody notice how light appears to travel faster than light on its way back? That's perfectly normal though ;)

"Light *does* appear to travel faster towards the observer."
Can you explain the phenomenon please? Where is that affirmation coming from?
Speed of light isn't supposed to change within a given continuous medium.

Link | Posted on Aug 2, 2020 at 14:00 UTC
In reply to:

falconeyes: Anybody notice how light appears to travel faster than light on its way back? That's perfectly normal though ;)

Read the study, PDF at the bottom of the post. The method used explains the small differences.

Link | Posted on Aug 2, 2020 at 10:56 UTC
In reply to:

MikeRan: It’s disappointing some of the purists getting annoyed about these images being post processed. Most of these images are impossible to capture by pointing a camera in the sky on a tripod and taking a picture. Enjoy the imagery. No one is saying you have to participate in astrophotography.

The reality is this is how it’s done.

Je suis pas mal en dessous du compte. Une évaluation réaliste du nombre d'arbres abattus frise les 15,000. Bonne journée!

Link | Posted on Jul 24, 2020 at 11:52 UTC
On article What you need to know about the new Nikon Z5 (304 comments in total)
In reply to:

Richard Kwon: If it had the BSI sensor, I would of purchaed it... I think it should be around $1000 since it has the last generation sensor tech...

There's a tiny difference when you look at it from up close. The DXO sensor database may hold part of the answer for us. The Nikon D750 and Z6 have very similar sensors but The D750 is FSI and the Z6 is BSI. Now, the global sensitivity index to light of the D750 is 81 and that of the Z7 is 83. Here are the complete results:
D750: https://www.dxomark.com/Cameras/Nikon/D750---Measurements
Z6: https://www.dxomark.com/Cameras/Nikon/Z6---Measurements

Go to color response tab.
So, there would be something like a 2.5% difference... But it may not be linked to the sensor being FSI or BSI. It's minor.
Regards.
Ron

Link | Posted on Jul 23, 2020 at 13:18 UTC
In reply to:

MikeRan: It’s disappointing some of the purists getting annoyed about these images being post processed. Most of these images are impossible to capture by pointing a camera in the sky on a tripod and taking a picture. Enjoy the imagery. No one is saying you have to participate in astrophotography.

The reality is this is how it’s done.

@Karroly, Je suis présentement en confinement obligatoire dans un hôtel de Montréal et j'utilise le dessous d'une des tablettes de l'armoire comme planche à découper pour cuisiner. Et même si la tablette n'a pas été conçue pour faire de la découpe, ça ne veut pas dire qu'on ne peut pas l'utiliser à cet effet! Et t'as raison pour le I-PAD de plus, la surface de verre aurait tendance à émousser les lames rapidement. En ce qui a trait à la scie à chaîne, disons que j'ai dû abattre plus d'arbres dans ma vie qu'il y en a à Grenoble et je peux te confirmer qu'une scie à chaîne n'est pas plus conçue pour couper le moteur arrêté qu'un I-PAD pour être utilisé comme planche à découper. La chaîne étant libre de tourner, on ne ferait qu'égratigner l'écorce... donc, ta comparaison ne me semble pas moins absurde que la mienne!!! Lol!!!

Link | Posted on Jul 23, 2020 at 13:05 UTC
On article What you need to know about the new Nikon Z5 (304 comments in total)
In reply to:

StevieF: I’d like to ask those that had it why they got rid of it?

It's not sold yet. No-one had it despite what's writtent there.

Link | Posted on Jul 22, 2020 at 20:09 UTC
In reply to:

David610: Sony A7 III still has EVF with 2.36 Million Dots (2011) compared to 3.69 Million Dots of Z5. Given A7 S III will have the world's best EVF with 9.44 million dot resolution shows how far behind the basic A7 has fallen.

Mirror vivration has been a problem for me only above 500mm of focal length with unstabilised manual lenses. Quiet shutter release mode fixed the problem. But it's true though that focus peeking would be nice to have with old manual lenses. One of my friend has a Z7. We were planning to go out and do some astro photos using my 1000mm lens (MTO-11 CA) but we've both been all over the place in the last 6 months. Maybe this summer.

Link | Posted on Jul 22, 2020 at 14:02 UTC
In reply to:

MikeRan: It’s disappointing some of the purists getting annoyed about these images being post processed. Most of these images are impossible to capture by pointing a camera in the sky on a tripod and taking a picture. Enjoy the imagery. No one is saying you have to participate in astrophotography.

The reality is this is how it’s done.

Some have probably been taken with an array of bandpass filters and treated in false colors in final render. That's what observatories do all over the words to show wavelengths not visible to the eye. It's easy to complain about something you know nothing about!!! Talking about purists, one day I was talking with a guy that just purchased the latest model from Fuji. He said he was a purist because he was using it only in fully manual mode. I told him that it was like buying the latest I-Pad and use it as a cutting board in the kitchen. I thing he didn't understant.

Link | Posted on Jul 22, 2020 at 13:23 UTC
In reply to:

vscd: Saturn is smaller than the moon. Picture 7 is the proof! ;)

Happily, the telescope was already set to infinity at moon distance!

Link | Posted on Jul 22, 2020 at 13:16 UTC
In reply to:

David610: Sony A7 III still has EVF with 2.36 Million Dots (2011) compared to 3.69 Million Dots of Z5. Given A7 S III will have the world's best EVF with 9.44 million dot resolution shows how far behind the basic A7 has fallen.

My optical viewfinder is still better than that of a A7 S III. And it doesn't drain the battery. Man is a stupid animal that can be tricked into beleiving that anything new is, without a doubt, better and that anything new makes the previous iteration of a product obsolete...

Link | Posted on Jul 22, 2020 at 13:09 UTC
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