Itai42

Itai42

Lives in Israel Jerusalem, Israel
Works as a Medical Student
Joined on Nov 2, 2009

Comments

Total: 25, showing: 1 – 20
« First‹ Previous12Next ›Last »
On Rare Canon EF 1200mm f/5.6L USM goes on sale in UK article (218 comments in total)
In reply to:

jpons: A number of years ago, I got a hold of one of these and did a little review, including shooting some video with it as well as handhldong it. Very interesting lens, but a little uncomfortable to use.

Check it out: http://vimeo.com/5164377

nice review. thanks for sharing. takes patience to handle it but looks like it's well made and in the right hands can be a very useful tool. what is it's focusing limit?

Direct link | Posted on Aug 16, 2014 at 16:32 UTC
In reply to:

Swagon: I'm an electrical engineer that works specifically on battery chargers for cell phones. I see stories like this fairly often. Some healthy skepticism is in order. Let's say the cellphone has a modest 2amp-hour battery. To charge in 30 seconds, which is 1/120th of an hour, would take a nominal 240amps. If the battery is the typical 4v or so, then it is nearly 1000 watts (vs a typical notebook charger at 65watts). This is like a microwave oven or a small hair blow dryer. The charger would need to be large and probably have a fan. The connectors need to be much larger. Note that a micro USB connector is rated for about 2amps. All these things are hidden from you in the video link, but you can see the fat cable. I can tell you that 30second charging is just not going to happen in a smartphone.

Cable isn't that thick but AC power is probably a requirement to charge the battery - maybe due to the nature of the technology and maybe due to parallel charging or some other solution they used for that problem.
In any case - seems like they are a third of the way in terms of holding the same operation time as current battery and have quite a way to go in terms of minimizing the size of the thing.
Might not happen as a battery but even charging a lightning quick portable "recharging cell" to put in your bag in 30 seconds before leaving the house in a hurry and then using it to slowly charge your phone in the bag will be an acceptable bridge product to justify further development of the tech.

They used to state in the same certainty that breaking the sound barrier is impossible and that the airplane will fall apart and out of the sky.
The technical barriers were handled quite rapidly once they decided to try anyway and you have aircrafts reaching hypersonic speeds in the atmosphere

Direct link | Posted on Apr 12, 2014 at 19:43 UTC
In reply to:

Itai42: I see a lot of calculations on how much energy will be required to charge the phone assuming it charges at output voltage.

They obviously solved these issues to a degree since the charge they describe is about 500W and by the calculations in the talk-backs it'll require about 100 Amps which is more then the current used by a house full of electric appliances all operating together.

They are using a rather unimpressive connector with no ground while standing quite close to it and not using protective gear - they are not afraid for their lives - they probably overcame the limitation using higher power density in some way...

My point being - you can overcome barriers that are apparent physical impossibilities by modifying the problem and then solving a more solvable problem...

Direct link | Posted on Apr 12, 2014 at 19:22 UTC
In reply to:

Itai42: I see a lot of calculations on how much energy will be required to charge the phone assuming it charges at output voltage.

They obviously solved these issues to a degree since the charge they describe is about 500W and by the calculations in the talk-backs it'll require about 100 Amps which is more then the current used by a house full of electric appliances all operating together.

They are using a rather unimpressive connector with no ground while standing quite close to it and not using protective gear - they are not afraid for their lives - they probably overcame the limitation using higher power density in some way...

An simple way to go about it would be parallel charging... take
10 cells - each 90 mAh & 3.6V (making each 324 Wh). charge them in parallel (using 10 different AC-DC converters integrated into one charger) and now you can get the capacity of the demonstrated pack charged in 30 seconds using 10 Amps.
This is still about 5 times the charging current of the supplied Samsung charger though so it's about 2.5 minutes using the original battery technology.

All that is required off the new tech now is lower overhead for multiple cells +- safe charging at 5 times the current of existing Li-Ion cells.

There are sill several additional technical problems to overcome like the size increase due to wasted space, cost-effectiveness & durability at higher complexity of circuitry, 11 extra pins for charging and probably several issues I can't think of because it is not my field of expertise....

Direct link | Posted on Apr 12, 2014 at 19:21 UTC

I see a lot of calculations on how much energy will be required to charge the phone assuming it charges at output voltage.

They obviously solved these issues to a degree since the charge they describe is about 500W and by the calculations in the talk-backs it'll require about 100 Amps which is more then the current used by a house full of electric appliances all operating together.

They are using a rather unimpressive connector with no ground while standing quite close to it and not using protective gear - they are not afraid for their lives - they probably overcame the limitation using higher power density in some way...

Direct link | Posted on Apr 12, 2014 at 19:21 UTC as 6th comment | 3 replies
On Miggo Strap and Grip review article (86 comments in total)

I got very excited when I saw it - looks nice and seems comfortable and practical, but the strap's too small for my camera+lens combo (D600 + 24-70). Maybe they'll make one for bigger cameras next - seeing that the kickstarter campain is such a big success... Might get a grip for my Sony NEX (still got a few days to decide)

Direct link | Posted on Feb 18, 2014 at 21:38 UTC as 57th comment
On iPhone 5s Studio Comparison article (263 comments in total)
In reply to:

brent collins: Overall the iPhone 5s is clearly superior to any of the others. Add up all the pros vs cons and there is no other conclusion possible to anyone who is objective. Corner sharpness alone crushes the Nokia. None will replace my DSLR, Micor4/3 or even my aging G6, but when it's all you've got I'd take the 5s anyday.

Did you check out the Nokia 1020 (both in full size and print size) the difference is just amazing in resolution and color reproduction. Will probably be more noticeable once they add the low light test as well...

Direct link | Posted on Sep 21, 2013 at 20:00 UTC
On iPhone 5s Studio Comparison article (263 comments in total)

Did you notice the bunch of hair to the right of center is not there on other cameras (e.g. the S4) :)

Direct link | Posted on Sep 21, 2013 at 19:58 UTC as 52nd comment | 1 reply

Definitely performance... "decent camera and long-lasting battery" is dead on target... I'm really waiting for unlocked Lumia 1020 (and the upcoming review - but I expect Nokia nailed it with this phone).

Direct link | Posted on Jul 12, 2013 at 17:26 UTC as 4th comment | 1 reply
On Buying a digital SLR article (149 comments in total)

Nice article.
"In order to focus manually" should be "In order to focus automatically" in the part about Nikon AF-S lenses and low-end Nikon SLRs

Direct link | Posted on Dec 5, 2012 at 19:16 UTC as 47th comment | 1 reply
On Metabones adds autofocus to Canon-NEX adapter article (63 comments in total)
In reply to:

Jim Evidon: To G. Davidson,
I contacted Metabones a few months back about a similar adapter for Nikon lenses since I have a respectable inventory of them. Metabones responded with a categorical NO. It may be something about the Nikon architecture that mitigates against it. Whatever the reason, they do not plan to do so. Photodiox makes a neat adapter that has an aperture ring on it for late model Nikon lenses to MFT bodies, so even if it is manual focus, you can still control the aperture on the lens. I have one and it works very well. It is their Fotodiox NIK(F)G-m4/3 model. You should see my Nikon mount Sigma 50-500 attached to the OM-D, or should I say OM-D attached to the Bigma. It works, though.

I think I heard somewhere that there are similarities between the mounts and therefore designing an adapter is much easier then compared to engineering an adapter for Nikon mount.

There's also an issue of back-focus distance that may be problematic when creating an adapter for Nikon lenses on a canon mount (but allows for easy albeit autofocusless adapters in the other direction). I believe though that in the case of Nikon to NEX system there's no such problem. Not really sure of the details though

Direct link | Posted on Nov 14, 2012 at 10:47 UTC
In reply to:

kennyv9000: On Monday morning regular meeting...
From Canon office,
A: Did you guys saw what ours fanboy comment about Sony rx100 in stupid DP?
B: Ya, they don't like it. And they said ours G and S series still the best! rx is just rubbish!
A: Ya, so now we can hold for couple of years first.
B: So what is our next move? A pink G16 or G1x new facelift?
A: Nah, take it easy, lets have some coffee first...

From Nikon office,
A: See! Our fanboy said ours Nikon 1 have more powerful sensor, rx100 was completely beaten by ours 1 series, and it can't changing lens.
B: Correct, so do we still continue our big sensor compact camera project?
A: Nah hold it first, p7700 is enough for them...

From Panasonic office,
A: I told you guys before, fanboy just need bright lens, rx100 sensor size and high ISO is nothing to them, who need it?
B: Ya, lets just make a f1.2 lens for our next LX8, sure sell like hot cake!
A: Ya, lets do it!

to be continue...

If you think that these things are decided in a meeting of this sorts then you have no idea about R&D and the complexity of developing cameras and imaging platforms at the rate things are evolving thesedays... pushing performance and integrating new technologies in tome for the next release date. It is truely difficult and some do better then others.
Sony do VERY well - both as a supplier to other manufacturers and as a great camera-maker (though I don't think their best innovation this year is this camera).
Camera manufacturers are putting in huge efforts to create products that speak to their customers as much as they can with a set target price...
They have to do a lot of guess-work as to what will speak better to customers and sometimes I find myself very surprised at what actually worked. I never thought the Fuji X100 will make sense - but it even makes some sense to me now (not that it's my cup of tea - but I see the point)

Direct link | Posted on Nov 4, 2012 at 16:06 UTC
In reply to:

argieramos: Those people who talks trash about the rx100 are butthurt that don't know anything about it, and possibly little knowledge about photography as well.

It is a P&S camera that produce a DSLR-like quality pictures that fits inside your jeans. Try doing that with any mirrorless with kit lens attached. RX100 is the FIRST camera that does that. People who thinks that is not revolutionary are hopeless and better stop doing photography.

"in low ISO, 1 full stop down out resolve a 21mp ff camera" (canon 5DII?) -photoclubalpha-

Now that is revolutionary lol

It doesn't outmatch some of it's peers in it's own price-point and it even looses the high-ISO IQ to some cameras cheaper and smaller (though it's MP count is quite high - but MP count isn't the measure to go by)

Direct link | Posted on Nov 4, 2012 at 15:40 UTC

The design innovation was brought back by Fuji (or arguably by Leica) - but they just went retro - so I don't think it deserved to be half an argument for innovation of the year...
The 1" sensor is not as innovative as others this year - again fuji springs to mind with another innovative sensor (this time instead of going crazy geometrically they went with a modified color-filter-array) - and sony themselves released some great sensors this year - much better then the 1" on the RX100 (Including the sensor on my own camera)
This is just a pointless award that smells more of product placement then of rightfully earned place in the list of top innovators or maybe something else - but that's just a great cam - not the most innovative nor the best this year!

Direct link | Posted on Nov 4, 2012 at 15:37 UTC as 60th comment | 2 replies
On A sneak peek at our forthcoming camera test scene article (323 comments in total)
In reply to:

phototransformations: Doesn't' seem to be anything in this scene that will give us an idea about how the camera does with highlights, chromatic aberration, or deep shadow noise. The paper clips, watch, and dark bottles helped with this.

Also - to the left on the middle (under the matches) there's a chocolate of metallic stuff that'll be good for CA and highlights -.
Othere then that there are a couple more like the coins, casino chips and paint brush etc... just have to get used to the new places of things...

Direct link | Posted on Oct 11, 2012 at 05:02 UTC
On A sneak peek at our forthcoming camera test scene article (323 comments in total)
In reply to:

phototransformations: Doesn't' seem to be anything in this scene that will give us an idea about how the camera does with highlights, chromatic aberration, or deep shadow noise. The paper clips, watch, and dark bottles helped with this.

On the bottom left there're gold/silver metalic stuff that sho highlights, also metal ball above the center.
There's another highlight producing ball of sorts in the sadow box above...
Also - near the Canada flag there are some attractive highlights on the binders of the threads.

Direct link | Posted on Oct 10, 2012 at 17:53 UTC
On A sneak peek at our forthcoming camera test scene article (323 comments in total)
In reply to:

Itai42: A couple of notes:
* In the old scene there were fur-balls and threads shades that allowed shadow features to be judged. I see the box on top and assume it's meant to serve this purpose - but the threads aren't there and my guess is that the placement of fur-balls will mean they will be seen very differently with different lenses...

* The globe is missing - it was a good way to judge well lit high-iso resolution and evaluate the jpeg vs. raw output. It was fine black on blue and yellow - which was a good way to judge chroma-noise

* Blue eyed girl on the right is very nice - but skin color there is quite pale - old scene had better skin-color sample with the standard palette
* There's no alcohol anywhere in the picture - this is very wrong!

Actually - it was a good item to compare images from the same camera at different iso and see the effect of chroma-noise.

My point is that looking at uniform area to see the effect of chroma noise is less informative then using the globe - with it's black text over blue and yellow (and less importantly - green). It is not as sensitive to the noise and I always felt it gives a hint of how it will show on the subject in some real-life situations.

I do see your point on how it can be confusing when you see comparison of several cameras and try to use it as the place to check how the resolution of the cameras is...

Direct link | Posted on Oct 10, 2012 at 14:33 UTC
On A sneak peek at our forthcoming camera test scene article (323 comments in total)

* Also - more feathers please :) old scene had just the right amount of fine feathers with enough overlap between them to differentiate the cameras and indicate the ISO at which details went bye-bye...

* One more note - we are all used to the old scene and stared at it enough to have us freak out from having it changed, but I'm sure as we get used to this one we'll have our new favorite places - maybe it won't be a globe and a gray&red thread in the shade- but we'll find our favorite territory... it does look like a good combination of textile, charts, colorful things and fine detail (I like the wildlife-on-a-soundblaster already :)

* Thanks for continuing with your effort to make great resources for us. We DO appreciate the effort it takes to redo all the scene photos

* on a side note - a gin advert is not a gin bottle - we want some real booze

Direct link | Posted on Oct 10, 2012 at 05:58 UTC as 133rd comment | 1 reply
On A sneak peek at our forthcoming camera test scene article (323 comments in total)

A couple of notes:
* In the old scene there were fur-balls and threads shades that allowed shadow features to be judged. I see the box on top and assume it's meant to serve this purpose - but the threads aren't there and my guess is that the placement of fur-balls will mean they will be seen very differently with different lenses...

* The globe is missing - it was a good way to judge well lit high-iso resolution and evaluate the jpeg vs. raw output. It was fine black on blue and yellow - which was a good way to judge chroma-noise

* Blue eyed girl on the right is very nice - but skin color there is quite pale - old scene had better skin-color sample with the standard palette
* There's no alcohol anywhere in the picture - this is very wrong!

Direct link | Posted on Oct 10, 2012 at 05:50 UTC as 135th comment | 2 replies

Thanks for the insight. You got us impressed. Waiting for more info to go on the NASA website (And thanks DPR for the updates)

Direct link | Posted on Aug 9, 2012 at 03:38 UTC as 56th comment
Total: 25, showing: 1 – 20
« First‹ Previous12Next ›Last »