Dan Tong

Dan Tong

Lives in United States Chicago, United States
Works as a Computer Consultant, Photographer
Joined on Jan 3, 2003
About me:

Olympus 2100UZ
Minolta Dimage 7i
Canon S400
Canon EOS 300D

Comments

Total: 156, showing: 101 – 120
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In reply to:

LuisGui: I don't dare to underestimate the intelligence and resources of the NASA scientists and engineers.

The less some people actually bother to learn or look up even, the more they foam at the mouth :)

Direct link | Posted on Aug 8, 2012 at 06:26 UTC
In reply to:

cpkuntz: Why do they use 2 mp sensors? Robust build? The Apollo mission used Hasselblads. Why not get some medium format goodness on board one of these rovers?

First of all:

The correct value for the transmission time (time from when it is sent to when it is received is) 11-13 minutes depending on the (min or max distance between Mars & Earth), according to the NASA webpage:

http://www.nasa.gov/vision/universe/solarsystem/world_mars.html

Some of your reasoning, or perhaps your explanation is a bit off I'm afraid. No matter whether transmission is continuous or not (it isn't!), the greater the amount of information, the longer it takes to transmit. Period.
However you are almost certainly correct about priority of non photo image data over photo image data.

Direct link | Posted on Aug 8, 2012 at 02:02 UTC
In reply to:

CameraLabTester: The whole Mars landing is quite an amazing triumph considering it takes at least 6 minutes for any command on Earth to be confirmed. (3 minutes send, 3 minutes echo).

Just like in the Apollo missions, future landers will carry much better equipment.

NASA will eventually be infected with camera upgrade fever.

.

The correct value for the transmission time (time from when it is sent to when it is received is) 11-13 minutes depending on the (min or max distance between Mars & Earth), according to the NASA webpage:

http://www.nasa.gov/vision/universe/solarsystem/world_mars.html

Direct link | Posted on Aug 8, 2012 at 01:57 UTC

R Butler's very helpful link disappeared. So I'm re-posting it.

http://www.truesenseimaging.com/news-and-events/34-msl-landing

Direct link | Posted on Aug 8, 2012 at 01:51 UTC as 74th comment | 1 reply
In reply to:

thisisjh: http://www.physicsforums.com/showthread.php?p=4025122

It says...

The camera need to withstand solar radiation- the cameras we flew (and are still onboard) the space station crapped out after about 2 years- ionizing radiation causes 'latching', resulting in the steady accumulation of hot pixels.

I couldn't find clear evidence of who made the CCDs, possibly Kodak. In any case, it's most likely a rad-hardened CCD chip, which is also why it's not a (high end) consumer grade chip.

thisisjh,

Thanks for the link.

Direct link | Posted on Aug 8, 2012 at 01:47 UTC
On Roger Cicala investigates Canon's AF marketing claims article (89 comments in total)

Ever wonder how our own visual system (eye and brain) focuses so accurately and fast?

Here is an abstract of research with defocus and how that can be used for focusing on natural images, and suggests that this method will soon be developed and used in cameras.

http://www.pnas.org/content/early/2011/09/16/1108491108.abstract

Direct link | Posted on Aug 3, 2012 at 06:59 UTC as 19th comment
On Roger Cicala investigates Canon's AF marketing claims article (89 comments in total)

Another superb Roger Cicala article. It's such a pleasure to read worthwhile article which based on intelligent testing and thinking. I find Cicala's articles by far the most interesting and worthwhile, I always learn something new that explains a lot about photographic equipment, therefore I am awarding Roger Cicala an honorary Ph.D. (that is a Photography Degree :)

All kidding aside, Cicala not only has a great sense of humor but he thinks like a scientist which is praiseworthy, indeed.

Direct link | Posted on Aug 2, 2012 at 03:48 UTC as 39th comment
On Photoshop CS6: Top 5 Features for Photographers article (98 comments in total)
In reply to:

Dan Tong: As far back as I remember you always had the ability to name/rename a layer. This was possible in CS5, but some idiots, managed to take away this option, or hid it so it is hard to find. Why is it so common lately for programs to take away perfectly useful and important features (or change where they are) in subsequent newer "improved" versions ?

Put it BACK!

Hey Graybalanced,

Thanks for the information. I was looking for it to work the same way as it used to in CS5 etc, where it was a menu option after right clicking. So I never tried a left mouse click. With Windows Explorer you right click and choose Rename.

I guess I would claim that it was there but hidden from anyone who expected it to work the way it used to.

In any case I'm delighted that you rescued me from ignorance.

Dan

Direct link | Posted on Jul 10, 2012 at 00:21 UTC
On Photoshop CS6: Top 5 Features for Photographers article (98 comments in total)

As far back as I remember you always had the ability to name/rename a layer. This was possible in CS5, but some idiots, managed to take away this option, or hid it so it is hard to find. Why is it so common lately for programs to take away perfectly useful and important features (or change where they are) in subsequent newer "improved" versions ?

Put it BACK!

Direct link | Posted on Jul 9, 2012 at 00:55 UTC as 15th comment | 2 replies
On Quick Guide to Video Lighting article (33 comments in total)
In reply to:

marike6: Since in general you're not using a meter when lighting for video (or are you?) I assume things like ratios, where you have the key and fill light at different stops, are not an issue. I'm wondering lighting if simple video lighting is done more by eye than with still photography.

On a side note, I sure wish Nikon or someone made a small, short barreled shotgun mike similar to the Nikon ME-1 shown above but with XLRs instead of a 3.5mm mini-plug. I'm looking for a shotgun mike for my D800 but I don't want one that is so long as to appear in the shot with my wide angle zoom. Unfortunately the ME-1 is not a shotgun mike.

Anyway, thanks for the useful article. The setup looks much, much better with the back-light.

I think I see where you are coming from. Those of us photographers who often deal with strobes, may forget that with continuous lighting it is much easier to eyeball the lighting effect without a test shot. I find that my rather dim strobe modeling lights don't help nearly as much as I would like in predicting resulting lighting of the shot. Hence the need for a test shot. With a meter, the outcome is pretty predictable. With continuous lighting it is pretty much "what you see is what you get".

Direct link | Posted on Jun 12, 2012 at 05:07 UTC
On Quick Guide to Video Lighting article (33 comments in total)
In reply to:

marike6: Since in general you're not using a meter when lighting for video (or are you?) I assume things like ratios, where you have the key and fill light at different stops, are not an issue. I'm wondering lighting if simple video lighting is done more by eye than with still photography.

On a side note, I sure wish Nikon or someone made a small, short barreled shotgun mike similar to the Nikon ME-1 shown above but with XLRs instead of a 3.5mm mini-plug. I'm looking for a shotgun mike for my D800 but I don't want one that is so long as to appear in the shot with my wide angle zoom. Unfortunately the ME-1 is not a shotgun mike.

Anyway, thanks for the useful article. The setup looks much, much better with the back-light.

Metering is just as important for video.
Keep in mind that one big difference between video lighting and still photo lighting, aside from requiring continuous light for video, is that if the light is very close to the subject, subject movement may not only change the lighting of the subject a lot, but the lighting equipment may show up in the frame. To the extent that your video is about motion and the subject may often not be stationary, the lighting may need to be placed at more of a distance than for still photos.

Direct link | Posted on Jun 12, 2012 at 04:54 UTC
On Quick Guide to Video Lighting article (33 comments in total)

Nice easy intro to lighting any photo or video. Well done.

Direct link | Posted on Jun 12, 2012 at 04:44 UTC as 6th comment
On Photoshop CS6 Beta: New Features for Photographers article (154 comments in total)

Thanks for this very informative summary of CS6.

Direct link | Posted on Mar 24, 2012 at 21:32 UTC as 33rd comment
In reply to:

rallyfan: This is a winning situation for everyone involved and even those not involved...

The greatest winners are those who bought not Apple products necessarily, but Apple stock. The current price compared to the price before iPhone launch should bring a smile to anyone's face.

Those that don't buy Apple because the i-device lacks an ostensibly critical feature or suffers from a proprietary connector (when in fact these devices are the standards for significant markets in the developed world...) also win, because they won't have to worry about availability of their chosen non-Apple device: it should be ready and waiting for their $.

I doubt, meanwhile, that Apple will be able to produce enough of these to meet demand in the near future and perhaps beyond. In fact, it's almost fortunate that the iPad lacks the oh-so-crucial "standard" connector, SD card slot, bluetooth file sharing, fill-in-the-blank; if it were equipped with these must-have features supply would never meet demand... Heh.

re: AndyML

Nonsense. I don't have a single Apple Product, but I am well aware having tried some, that Apple understands that ergonomics is more than 50% of the success of such products. Other companies claim to make things easy to use, but fail to do so. Worse yet, they don't really pay attention and still don't get it at all.
While Apple may not have been the absolute first with many products, their refinement and improvement of many tech products has led to amazing market changes and, in my opinion, deservedly so. Yes, there are things I wish their products had which would make them even more easy and useful, but that s irrelevant.
I certainly don't buy into the Apple and Steve Jobs worship bit, because Apple is just like other Corps - just look at the terrible work conditions at Foxconn.
Try to leave your most obvious biases at home and attempt to be more neutral.

Direct link | Posted on Mar 8, 2012 at 23:16 UTC
On NHK working on 8k video sensor capable of 120fps article (94 comments in total)
In reply to:

Dan4321: It's not a waste, it gives you the ability to pan, scan, and zoom in your video in post rather than having to do this while taking the video (ie. if you want to follow a single dancer on a stage without having to move the camera). Or even make multiple videos from the same source. Being able to do these things in post opens up a lot more possibilities, and it's also essentially a 120fps sports mode so you'll never miss another instant shot.

It's nice to hear from someone who not only reads the information but also has some brains. Most of the commentary following news releases and other articles is incredibly negative and dumb.

Thanks,

Dan

Direct link | Posted on Feb 24, 2012 at 08:37 UTC
On Nikon D4 & D800: What do the Professionals Think? article (391 comments in total)

Interesting article. It was good to hear from more than one pro, and I enjoyed Dan Chung's wonderful video of Beijing.

Thanks,

Dan

Direct link | Posted on Feb 24, 2012 at 08:22 UTC as 47th comment
On Depth of Field in Macro Photography article (159 comments in total)
In reply to:

Weegee: I have to photograph tiny micro chips 1sq.millimeter. I am using a Nikon D200 with Nikon PB-4 bellows ( shift ) and reversed 60mm micro Nikkor. The image doesn't look sharp at f/5.6 so I have to go to F/22 or sometime f/32. Then I get diffraction problems. Seems like I can't win! Should I go to stacking? If so, do I focus using the focusing ring or moving the camera back and forth?

Sometimes I feel like I'm shooting with a 5000mm lens!

Any ideas, comments? Thanks.
Weegee ( sure is a change from my 4 x 5 Graflex)

Stacking should work for you even better than for "wild life photography" since your objects do not move, nor do you need to worry about wind moving your object (assuming you are indoors). Hence you can take as much time as you like between each racking focus exposure.

You should use whichever focusing method is the most precise and convenient.

Photoshop CS5 has the stacking capability.

Direct link | Posted on Feb 15, 2012 at 23:22 UTC
On Depth of Field in Macro Photography article (159 comments in total)
In reply to:

Mike Griffin: It is my experience that small sensor cameras give superior depth of field for macro photography. I don't buy the diffraction argument. You may have to stop down to f:16 and beyond to get acceptable depth of field with a DSLR and suffer from diffraction limitations but a compact that is diffraction limited at f:4 has great depth of field at f:2.8.
This article explores the argument further.
http://www.eos-magazine-forum.com/showthread.php?4538-Small-sensor-macro

Lucky for you you don't have to "buy" the diffraction argument.
It's completely free! As in no charge.

Direct link | Posted on Feb 15, 2012 at 23:19 UTC
On Depth of Field in Macro Photography article (159 comments in total)
In reply to:

Lee Jay: "The defining characteristic of macro photography is of course that subjects are shot at close distances."

"And this explains why DOF is so shallow in macro; the magnifications are simply much larger than in any other type of photography."

The second statement is correct (magnification defines macro), the first is not. You can shoot macro from long distances given enough focal length.

Of course you are technically correct, but here is another point of view, which in my opinion makes the author's statement right.

Long distances (2-5 feet?) for macro photos are only RELATIVELY long in the context of macro photography. In the context of photography in general (portrait and landscape, and excluding macro) these "long distances" are pretty much "close distances".

Therefore the author's rather general statement which explains the most defining characteristic of macro (vs genera) photography, the explanation is perfectly sensible. People also use the general term "extreme closeup photography" which just about everyone understands right away.

Sadly most people fail to understand "relativity" :)

Direct link | Posted on Feb 15, 2012 at 23:07 UTC
On Depth of Field in Macro Photography article (159 comments in total)

Another wonderful installment in these excellent Macro Photography articles, accompanied, as always, by stunning images.

I'm eagerly awaiting the discussion of hardware, specifically the discussion of special macro lenses vs bellows vs extension tubes vs reversed lenses vs add-on close up lenses. These 3 methods to focus closer are listed in order of most costly to least costly and almost certainly in order of overall effectiveness, but I would very much like to know more about the pros and cons of each from an expert.

Thanks,

Dan

Direct link | Posted on Feb 15, 2012 at 22:50 UTC as 62nd comment
Total: 156, showing: 101 – 120
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