Deorum

Lives in Greece Athens, Greece
Works as a Sports Photographer
Has a website at www.georgespyros.com
Joined on May 4, 2003
About me:

Sports Photography 4_the_win!

Comments

Total: 57, showing: 1 – 20
« First‹ Previous123Next ›Last »

I would swear i have heard the same backround song, in similar timelapses, a hundred times.
(great TL btw)

Link | Posted on Jul 12, 2017 at 16:52 UTC as 37th comment | 3 replies
In reply to:

Moon0326: Who's gonna use 14mm f/1.8? For astro, you can just buy 20mm or 24mm then stitch. Those two focal length with the same F or faster (1.4) absorbs much much more light (at least 3x). I expected 14mm f/1.8 to be cheaper. At this price range, I don't really see a reason to buy one.

The total quantity of light is not directly corellated to the size of "pupil".
Yes, a f2.8 200mm has a much larger pupil entrance, from a 1.8 14mm.
But the 200mm, strives to get as much light from a much smaller cone of light, than the 14mm.
This is not the "TOTAL" ammount of light.
Thus for this simple experiment, you can take 2 manual photos, and just check the histogram.
The 1.4 24mm, doesNOT collect 3times the light than the 14mm.
the 24mm does collects 3 times the light from the area (cone of light - frame) of the 14mm that would be cropped to the same frame, but you forget that the 14mm looks at a much larger area, thus counter balances this.
I repeat, it collects 3 times the light, from the cropped part of the 14mm, that would produce the same frame like the 24mm. But it looks at a much bigger frame.
It is the front element tells more of the whole story (they are pretty equal).

All this can be verified of course ... from the histogram.

Link | Posted on Jun 28, 2017 at 08:42 UTC
In reply to:

Moon0326: Who's gonna use 14mm f/1.8? For astro, you can just buy 20mm or 24mm then stitch. Those two focal length with the same F or faster (1.4) absorbs much much more light (at least 3x). I expected 14mm f/1.8 to be cheaper. At this price range, I don't really see a reason to buy one.

So flawed logic there...

Link | Posted on Jun 25, 2017 at 12:35 UTC

ok, but the sound is tottaly bogus

Link | Posted on Jun 16, 2017 at 14:04 UTC as 15th comment | 1 reply

Please define "professional portraits" . I once shot a race with 1500 runners. I consider all the photos professional (i used a FF dslr + pro lens after all).

Link | Posted on May 30, 2017 at 22:59 UTC as 13th comment
In reply to:

Deorum: Thus cancelling all the advantages of medium-format. Because MF advantage is mostly the fact that you use more mm of lens to achieve the same result. It doesnt matter if the light is converged to a narrow or wider beam, what matters is what was collected in the first place.

@Androole

Theoretically speaking if we could unlink sensor size-from lenses size, yes i argue that it offers no advantage.
Practically now, it is a different matter. and it is practical reasons (like less strain on lenses etc) that produce a better result. Theoretically the sensor could be as large or small. So still a larger sensor/lens offers better IQ, than same DOF exposure of smaller sensors.
Obvsiously converging the light of an FF lens to a pinpoint size sensor, would yield such a strong light with needs of exposure up to 1/20.000 which is impossible. It would even burn throught the shutter curtain.

Link | Posted on May 24, 2017 at 23:25 UTC
In reply to:

Deorum: Thus cancelling all the advantages of medium-format. Because MF advantage is mostly the fact that you use more mm of lens to achieve the same result. It doesnt matter if the light is converged to a narrow or wider beam, what matters is what was collected in the first place.

@Androole
Bigger sensor forces you to use bigger lenses. In the end this is what matters and makes all the difference.

@whumber. This is the theory of filling a well, photodiode is a well that is filled slowly. then you take the average.

Maybe yes, but i think it has to do ultimately with the NUMBER of pixels (because the total light has to fall into specific slots, and not the size of pixels itself. The analogy of the well is a bit flawed, not a fact that bigger wells fill slower.
I would argue that bigger wells, fill easied because the collect more light per well.
I am sorry i didnt understand this.
Longer exposure is better if total exposure is the same? 1/100-F2-iso100<1/25-F4-iso100 ?
Stopping down 1 stop Av, and exposing longer gives better SNR (for same iso?) how?

Link | Posted on May 24, 2017 at 23:07 UTC
In reply to:

Deorum: Thus cancelling all the advantages of medium-format. Because MF advantage is mostly the fact that you use more mm of lens to achieve the same result. It doesnt matter if the light is converged to a narrow or wider beam, what matters is what was collected in the first place.

You get the better SNR ratio of bigger sensors, because you use bigger lenses (more mm of lens) to get the same frame. Not because the sensor is larger it self.

For example, if you use a theoretical 100% efficient boost, you could get the same noise levels with FF-lenses on a crop-body. The 1 stop (or whatever) noise advantage, would be there because the f4 lens would count as 2.8 lens efficiently.

Take a magnifying lens, and play with it. What matters is the light that is collected in the begging. How the final beam is converged (narrow and strong, wide and faint) doesnt change the total output.

FF sensors have the advantage we all know, because they use bigger lenses, not because they are just bigger.

Link | Posted on May 24, 2017 at 19:06 UTC

Thus cancelling all the advantages of medium-format. Because MF advantage is mostly the fact that you use more mm of lens to achieve the same result. It doesnt matter if the light is converged to a narrow or wider beam, what matters is what was collected in the first place.

Link | Posted on May 24, 2017 at 18:16 UTC as 29th comment | 8 replies
In reply to:

Father Bouvier: Should you stick with sRGB? Here how the same picture looks in 6 different browsers: https://petapixel.com/assets/uploads/2012/06/ugPTu.jpg

Does your browser support ICC profiles? Check yourself: http://cameratico.com/tools/web-browser-color-management-test/

According to the The World Wide Web Consortium (W3C), all untagged images and page elements should be considered sRGB by the web browser.

All images (even sent out to be printed i would dare say, unless you really know what you are doing) should be treated as sRGB.
that said, AdobeRGB or other spaces, are still valuable for our own satisfaction when viewing our images.

Link | Posted on Apr 28, 2017 at 22:05 UTC
On article Sony a9 Full Review: Mirrorless Redefined (2726 comments in total)
In reply to:

Deorum: Due to much less materials cost (most of the cost here is R&D i guess) this camera has the potential to be much cheaper in a few years, than a big - pro DSLR has, that carries much more complex mechanical parts.

Sooner or later i guess, this sensor technology will be implemented to most SONY based sensor cameras. I am still hoping this gonna be the same as mobile phones, i hope that this will be mass produced to achieve much better economies of scale. (as in mobile phones).
On the contrary I 100% accept what you say for lenses. (that's why lenses prices have been steadily increasing).
Time will tell i guess...

Link | Posted on Apr 24, 2017 at 09:54 UTC
On article Sony a9 Full Review: Mirrorless Redefined (2726 comments in total)

Due to much less materials cost (most of the cost here is R&D i guess) this camera has the potential to be much cheaper in a few years, than a big - pro DSLR has, that carries much more complex mechanical parts.

Link | Posted on Apr 24, 2017 at 06:37 UTC as 376th comment | 8 replies
On article Extremely dramatic video touts Canon's CMOS technology (196 comments in total)
In reply to:

HB1969: I couldn't see the moonbow in this video, could anyone else?
Another thing: I was curious about the 250mp sensor... I wonder if it's worth combining the output of 4 colour pixels to gain a "single" true colour pixel. You would still end up with 62.5mp resolution but I wonder if the effect would be similar to the foveon sensor (different tech, I know)

Its not that simple. Bayer combines 4pixel to get 1pixel worth of color. But luminosity information still exists in 4pixels, and luminosity channel is still valuable information.

Link | Posted on Feb 17, 2017 at 09:29 UTC
On article Sigma 85mm F1.4 Art DxO results: a new king is crowned (249 comments in total)

Checking this along with 50/ART difference doesnt seem to be so dramatic.
the closest comparison with 50/ART is canon 7D (18mp) - vs 85/ART Nikon D7000 (16mp) and they are equal. Unfortunately FF comparison is pretty unfair, because they only have 85/ART with nikon D800 vs 50/ART canon 5d3, where the megapixel difference is huge.

Of course the focal range is more impressive, but sharpness wise it seems pretty close with 50mm ART.

Link | Posted on Feb 3, 2017 at 08:24 UTC as 25th comment
On article Modern Mirrorless: Canon EOS M5 Review (1644 comments in total)

What is the shutter rating? (It does have a shutter right?)

Link | Posted on Dec 20, 2016 at 19:49 UTC as 156th comment | 1 reply
In reply to:

Tonkotsu Ramen: Maybe nick woodman, the CEO, can stop construction of his est $40 million dollar yacht to pay for these employees to stay until the new year?

But no way, he needs his yacht. This is the 2nd wave of job cutting since he ordered his yacht and their stock tanked.

I'd never support a company run this poorly.

@Tonkotsu Ramen
you didnt overhire in the first place. times are changing, what you needed 5 years ago is not the same as now.
you, as a citizen (i suppose), you are hiring services and goods that are different from what 5 years ago.
you, in a sense, are hiring people to do that, and you are letting them off,

Link | Posted on Dec 5, 2016 at 07:48 UTC
In reply to:

Tonkotsu Ramen: Maybe nick woodman, the CEO, can stop construction of his est $40 million dollar yacht to pay for these employees to stay until the new year?

But no way, he needs his yacht. This is the 2nd wave of job cutting since he ordered his yacht and their stock tanked.

I'd never support a company run this poorly.

If this is true (about the watch) then he still gives job but to different people. The point is to achieve the best possible with minimum cost. Then all of society/world will benefit in the long term. It sounds counterintuitive, but it is

Link | Posted on Dec 1, 2016 at 07:56 UTC
On article Nikon reportedly eliminating 1000 jobs in Japan (518 comments in total)

It never got to the news each time a new job opening was created...

Link | Posted on Nov 8, 2016 at 06:42 UTC as 109th comment | 1 reply
In reply to:

Deorum: http://www.sigma-global.com/en/lenses/cas/product/sports/s_500_4/features/#features03

These 500mm MTF charts, are insane !

Its not insane, it is about 1 stop. I can leave with that for sure

Link | Posted on Sep 21, 2016 at 11:33 UTC

http://www.sigma-global.com/en/lenses/cas/product/sports/s_500_4/features/#features03

These 500mm MTF charts, are insane !

Link | Posted on Sep 20, 2016 at 20:54 UTC as 4th comment | 3 replies
Total: 57, showing: 1 – 20
« First‹ Previous123Next ›Last »