trungthu

trungthu

Lives in Viet Nam Viet Nam
Joined on Jan 28, 2007

Comments

Total: 31, showing: 1 – 20
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On LG launches LG G Pro 2 phablet with 4k video post (27 comments in total)

Very impressive. They all will bring 4K video to daily life users.
From Panasonic GH4, to LG G Pro 2... I like it.

Direct link | Posted on Feb 14, 2014 at 00:21 UTC as 4th comment

""" The outstanding 60x Optical Zoom allows photographers to capture more intimate shots and get closer to their subject, ensuring that images taken from afar retain impressive detail and accuracy.With the option to operate the zoom at double speed, or to go directly from zero to 60x zoom,..."

We should write: ... to go directly from 1x to 60x zoom...
Not from zero.

Direct link | Posted on Jan 8, 2014 at 13:07 UTC as 27th comment
On Tamron to develop 150-600mm F5-6.3 ultra-telephoto zoom article (193 comments in total)

How many stops does this lens can achieve in VC mode?

Direct link | Posted on Nov 8, 2013 at 04:23 UTC as 28th comment

It's only the technology in the sensor, when reducing the pixel dimension, the less light receiving, the more noise grow. And the worst of all is the resolution of the best lens of the present can not see the pixel.

Direct link | Posted on Sep 14, 2013 at 01:04 UTC as 6th comment
On Panasonic GX7 First Impressions Review article (1201 comments in total)
In reply to:

trungthu: Please show more: the lens used, the aperture, the distance from the camera to the object, focusing mode.
I think, in digital picture, beside the quality of the sensor (with the processing inside the camera), there also the quality of the lens (the resolution of the lens, the best aperture).

Thanks R Butler and Stu 5.
When testing the resolution of a camera, why don't we use "the best lens" at that situation, ie, the macro lens...
Thanks all of you, it's only my idea...

Direct link | Posted on Aug 16, 2013 at 02:35 UTC
On Panasonic GX7 First Impressions Review article (1201 comments in total)

Please show more: the lens used, the aperture, the distance from the camera to the object, focusing mode.
I think, in digital picture, beside the quality of the sensor (with the processing inside the camera), there also the quality of the lens (the resolution of the lens, the best aperture).

Direct link | Posted on Aug 15, 2013 at 02:26 UTC as 178th comment | 3 replies

It's a good news.
But I don't know if they can have a relation between the pixel dimension with the lens resolution? Or only making this to present the technologie more than the real usage.
The pixel see, the lens see, and after all, we see...
Thanks.

Direct link | Posted on Jun 12, 2013 at 01:32 UTC as 54th comment
On Sigma 18-35mm F1.8 DC HSM Preview preview (349 comments in total)

""" Sigma's choice of F1.8 as maximum aperture isn't a coincidence; it means that the lens will offer the same control over depth of field as an F2.8 zoom does on full frame."""
When we use the same shooting frame in both sensor sizes (APS-C and Full Frame).
""" What's more, it will also offer effectively the same light-gathering capability as an F2.8 lens on full frame. By this we mean that it will be able to project an image that's just over twice as bright onto a sensor that's slightly less than half the area, meaning the same total amount of light is used to capture the image."""
As I know, in normal condition, the gather of light at each aperture is different with others. The lower number, the more of light. But when we have a quantity of light is "a" to be right exposured, that means the light come to the sensor is "equal" in any aperture (in relate to shutter speed), or any sensor size, not only at f/1.8 (in APS-C) # f/2.8 (in Full Frame)
I don't know why the author say that...

Direct link | Posted on Apr 28, 2013 at 09:22 UTC as 72nd comment | 8 replies
In reply to:

trungthu: "... This means it has only one photosite per output pixel, so won't offer the same color resolution as Canon's EOS C300 professional video camera, which has four capture pixels (a Red, Green, Blue, Green quartet) per output pixel... "

I don't know how it can record color information in only one photosite. While almost all others use three color filter in four pixels (RGBG).
Please help me. Thanks.

Yes, I see.
Bayer filter use four capture pixels to record color informations.
""" .. This means it has only one photosite per output pixel, so won't offer the same color resolution as Canon's EOS C300...""" what does i mean?
Only one photosite per output pixel""" ???
Thanks Brian Lund for your respond.

Direct link | Posted on Mar 6, 2013 at 16:02 UTC

"... This means it has only one photosite per output pixel, so won't offer the same color resolution as Canon's EOS C300 professional video camera, which has four capture pixels (a Red, Green, Blue, Green quartet) per output pixel... "

I don't know how it can record color information in only one photosite. While almost all others use three color filter in four pixels (RGBG).
Please help me. Thanks.

Direct link | Posted on Mar 5, 2013 at 16:53 UTC as 25th comment | 4 replies
On First Impressions: Metabones Speed Booster article (357 comments in total)
In reply to:

trungthu: Because the F-number is the entrance pupil divided by focal length, reducing the focal length without changing the entrance pupil increases the F-number.
I think, it's wrong here.
When reduce the focal length without changing the entrance pupil will DECREASE the F-number. So it's from 50mm f/1.4 will be 35mm f/1.0.

I understood. Thank Revenant very much

Direct link | Posted on Feb 3, 2013 at 16:31 UTC
On First Impressions: Metabones Speed Booster article (357 comments in total)

Because the F-number is the entrance pupil divided by focal length, reducing the focal length without changing the entrance pupil increases the F-number.
I think, it's wrong here.
When reduce the focal length without changing the entrance pupil will DECREASE the F-number. So it's from 50mm f/1.4 will be 35mm f/1.0.

Direct link | Posted on Feb 1, 2013 at 16:49 UTC as 54th comment | 2 replies

It's an interesting news.

Direct link | Posted on Sep 18, 2012 at 15:23 UTC as 97th comment
On Panasonic DMC FZ200 preview (155 comments in total)

With the sensor's dimension = 6.06 x 4.56 mm, and the resolution 4000 x 3000.
I see that 6,06 mm / 4000 pixels = 0.0015 mm/pixel.
And the most importance thing is how can the "Leica lens" SEE THAT PIXEL, with the very low price lens, even with the big brand LEICA?
I want to say about the resolution of the lens, not only the resolution of the sensor.
How and what it can achieve? I don't know, please let me see. Thanks.

Direct link | Posted on Jul 24, 2012 at 00:32 UTC as 34th comment | 4 replies
On Pentax launches smc DA 50mm F1.8 for APS-C cameras article (108 comments in total)

Why all the lenses at 50mm f/1.8 for full frame from other branches have the prices around 100USD, while Pentax has 50mm f/1.8 for APS-C, with a smaller covering power, and a higher price?
Why?

Direct link | Posted on May 23, 2012 at 03:59 UTC as 9th comment | 4 replies
On Just Posted: Sigma SD1 / SD1 Merrill review article (374 comments in total)
In reply to:

trungthu: It's only 15 M positions to receive light to record image, not 15X3=45Mp as Sigma said. But when they don't use AA filter, the detail is better (than other 15Mp camera).
When other camera use two green pizels for one blog to equal to human eyes, Sigma can't do that, so the color is not good.
If Sigma says SD1 with 15Mp, and add one more position to detect green, I hope, it is better. The price stagery is so bad, it's unreal!

Thanks.
I have known Sigma Foveon X3 from SD9, and I knew about it with the more "sharpness of the details" than other 6Mp camera, but, with the less of green in it.
By unused AA filter, SD1 can deliver more detaisl than other camera at 15Mp, that noone have any critique.
Foveon has really "three colors in one position", and other has to interpolate "three color in one position", and Foveon has to "interpolate" to have the size of 15x3Mp, other has really 45Mp in size. The only better one from Foveon is the unused AA filter.
And please wait to see some comparisons between SD1 and D800e (Nikon) in sometime later.
Thanks for your reply.

Direct link | Posted on Apr 11, 2012 at 02:27 UTC
On Just Posted: Sigma SD1 / SD1 Merrill review article (374 comments in total)

It's only 15 M positions to receive light to record image, not 15X3=45Mp as Sigma said. But when they don't use AA filter, the detail is better (than other 15Mp camera).
When other camera use two green pizels for one blog to equal to human eyes, Sigma can't do that, so the color is not good.
If Sigma says SD1 with 15Mp, and add one more position to detect green, I hope, it is better. The price stagery is so bad, it's unreal!

Direct link | Posted on Apr 11, 2012 at 00:55 UTC as 88th comment | 3 replies

I think, the differences is very little in quality between the "normal lenses" and these Zeiss lenses.
Because, the resolution of motion picture is only 2K (about 2Mp), and all the lenses of the camera's maker can adapte this clearity, even the kit lens.
But, the problem maybe only is in the conviniences, and the posibility of making money of the film maker, so the price is "no problem".

Direct link | Posted on Apr 6, 2012 at 02:53 UTC as 14th comment | 5 replies
On Egg in the 1 color (size rule) Please read all... challenge (12 comments in total)

Excelent composition. I love it.
Thanks for sharing.

Direct link | Posted on Mar 24, 2012 at 09:14 UTC as 6th comment
On Facebook adds higher resolution photo viewing article (70 comments in total)

Very good.
Thanks.

Direct link | Posted on Mar 22, 2012 at 16:20 UTC as 22nd comment
Total: 31, showing: 1 – 20
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