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Messages - weixing

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106
EOS Bodies / Re: EOS not good for NASA?
« on: February 13, 2013, 07:47:12 AM »
Hi,
Sorry if I ruined ur post but all I could see was that giant lenscap

    This is the HyperStar ( http://www.hyperstarimaging.com ) imaging configuration which made the 2350mm F10 telescope to a 540mm F2.3 imaging system.

    Have a nice day.

107
EOS Bodies / Re: EOS not good for NASA?
« on: February 13, 2013, 12:09:25 AM »
Hi,
But how does one explain some of the pictures taken from the space station with a 1200mm lens?

    May be they use a telescope...  ;D

    Anyway, they recent install a modified Celestron CPC 9.25" telescope with Canon 7D DSLR for the ISERV (International Space Station SERVIR Environmental Research and Visualization System) project.


(image source: http://www.nasa.gov/mission_pages/station/research/news/iserv.html )

   Have a nice day.

108

What's "100% crop" video?
Daniel

There is a mode on the 60D where you can shoot 640x480 video taken from the 640x480 pixels at the center of the sensor. It's VERY usefull for image stacking in astrophotography....
   Also very good for taking video clip of small birds or birds that are far away...

   Have a nice day.

109
Hi,
   For me, I'm not greedy:
   - Improve AF,
   - Improve low light AF
   - 1 stop improvement in noise over current 7D (but preserve all the noise information like all the current Canon DSLR)
   - 2nd SD card slot
   - 100% crop 1080p HD video
   - the rest can remain same as current 7D including price (hopefully)
   
   Have a nice day.

110
Canon General / Re: Cannon / Nikon Meme
« on: February 09, 2013, 12:40:51 AM »
Hi,
    Wrong colour scheme... it's should be WHITE with RED band... ha ha ha  :P

    Have a nice day.

111
Hi,
    I also shoot birds and using the 400mm F5.6L on 60D... can't afford anything longer or better than that, so IMHO, for budget birder, APS-C is still very attractive.

    Anyway, I plan to wait till May or June and look at the review of the 5D3 F8 implementation, if it's really good, reliable and AF not slow down by too much, I might change to 5D3... 400mm + 1.4x on 22MP FF DSLR will had very similar reach to 400mm on 18MP APS-C DSLR.

   Have a nice day.

112
EOS Bodies / Re: EOS not good for NASA?
« on: January 15, 2013, 08:01:39 PM »
Hi,
    I think they do use Canon EOS, but just not in space.

http://www.popphoto.com/gear/2011/07/how-does-nasa-get-nikon-d2xs-ready-to-go-to-space

    Anyway, this photo ( http://www.nasa.gov/images/content/565184main_jsc2011e040349_hires.jpg ) you mention is taken with a EOS 5D II (So they may be use Nikon to take photo of space and Canon to took photo on Earth?? ha ha ha :-P ). If you look at NASA image archive ( http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts135/multimedia/preflight/Image_Gallery_Collection_archive_38.html ), you'll see quite a lot of them taken with Canon EOS (5D II, 7D & ID4).

    Have a nice day.
   

113
Hi,
Good to hear the problem's solved.
This is now getting off topic, but I'd like some advice/comments please. I've never actually used LiveView in any real way. So here's what I need to know:
I want to go out and photograph star trails, you know the kind, several hundred shots stacked to make to final image. Now if I set my camera for 30second exposures, continuous shooting and lock my cable release, it'll obviously keep taking shots until a) I tell it not to or b) the battery runs out.
The question: If i use LiveView to focus and avoid all those nasty tremors and slaps, will the screen stay on all the time and drain my battery? Can I tell it not to stay on?
I'm shooting a 7D.
    What you should do is switch to manual focus, focus manually via life view and then turn off the LCD during actual shooting. You don't need life view or mirror lockup for long exposure, so off the LCD which will preserve battery power and reduce the heat generate by the LCD (improve noise performance).

As the 7D has a top display, so while taking the photo in live view, the rear screen will display nothing.

However, astro photographers normally uses stacking in combination with a motorised equatorial mount - that way each shot will be of the same bit of sky with no motion blur of the stars, and the stacking software puts the frames together to reduce noise and increase the detail of the stars.

Star trail photos are made with very long exposures - just put your camera in bulb mode for that type of shot.


    The ideal way of taking Star trail is to use a single long exposure via bulb mode, but using DSLR, we can take the digital way... by taking many part of the trail using shorter exposure and then combine them together to form a single trail... the different is not obvious if you plan it carefully, the lens is wide enough and you don't 100% pixel peek. The advantage of this method is that you can limit the noise and you still can take a long star trail if your sky is quite light polluted.

    Anyway, IMHO, 30s is still a bit too short for this type of shooting unless he don't have an external timer controller.

    Have a nice day.

114
Hi,
    On more advantage for live view over mirror lockup is that with mirror lockup, you can't prevent or limit motion blur cause by subject moment, but with live view, since you can see the subject (at 10x), you can took the shot at the moment when the subject is perfectly stationary... good for birding at low light without flash...  ;D

   Have a nice day.

115
Hi,
    IMHO, if you don't need very fast AF, the 70-200mm F2.8 IS II + 2xIII is a better option.

    Have a nice day.

116
EOS Bodies / Re: What will be the issue with the 6D
« on: November 24, 2012, 01:35:23 PM »
Hi,
Really, the only problems I have are 3 things. The wifi is small, and either won't work for long ranges, or will drain too mush battery. The gps will be like new apple maps, because, it's experimental. And lastly the buttons, the original 60d's buttons were horrible, so I'm a little upset they are throwing the 6d in a 60d body.
    I own a 60D and I actually prefer the 60D buttons (those beside the top LCD) compare to 7D buttons. One button, one function... clean and simple.  ;D

   Have a nice day.

117
EOS Bodies - For Stills / Re: 5D mark III or 7D and 5D mark II
« on: November 20, 2012, 12:38:30 PM »
Hi,
    I'm currently using a 400mm F5.6L and 60D for birds photography and I'm also consider changing to a FF (I'm thinking of 6D), so here is what I think at the moment.

     The advantage of FF is better image quality, better high ISO performance and better low light AF (both 5D3 and 6D had better low light AF than current crop sensor DSLR on paper), but the disadvantage is "lesser reach". Also, with a crop sensor, you are using the center "sweet spot" of the lens image circle, so your image is relatively sharper across the entire image compare using a FF.

    With a 1.4x TC on 5D3 or 6D (on paper, 6D had better low light AF at center AF point than 5D3, so hoping it'll get F8 AF), you get closer to the "reach" of a crop sensor, but with a 1.4x TC, your AF will be slower which is not good for birds photography... now, the question is how much slower?

    So I'm waiting for the 7DII specification to be out before I decide. Hopefully, the 7DII will have better low light AF and 1 to 2 stop better high ISO performance than current model... if not, I might change to a FF if F8 AF is not that slow.

    Just my $0.02.

    Have a nice day.

118
EOS Bodies - For Stills / Re: 5d2 vs 6d
« on: November 19, 2012, 06:46:41 AM »
Question - if you're going to be shooting at -0.5EV or lower then wouldn't you be using a tripod and or flash? Those low levels of light require long shutter speeds unless you use very high ISO? Correct? Why not use MF with live view? Is AF really necessary? Are you trying to capture candid shots of people?

Sure it would be awesome to use AF in low light but photographers have been capturing images for years without that ability.

I'm just curious.
Hi,
    For example, you want to capture the children blowing the candles in a birthday party with only the light from the candle or may be event or performance at the night where flash are not allow and light is low. With low light AF capability, the success rate will be a lot higher.

    IMHO, if the low light AF work as advertise and high ISO as good as the 5DIII (which I expect it will as it's had a large pixel size), I think this camera will sell very well... IMHO, a lot of people don't need that many AF points, just one super AF center point will be enough for many.

    Have a nice day.

119
Hi,
After all the rebates, it's 199 from B&H, I think I'd be insane to not get this as I cannot get calibrated to my only local lab as well as I'd like. I use Epson 3880's at school off and on with impeccable results but I don't always have access.

Hmmmmmmmm….
    Now most printer manufacturer don't sell printer, they sell ink... ha ha ha

    Have a nice day.

120
Hi,
   IMHO, once you have life view, video is just a software feature that can be easily add in... the additional hardware cost for the video is actually minimum (only mic). By removing video, you only save firmware space, but lost a huge advantage in marketing... unless they can come out with a feature that is desire by still photographers to replace the video feature. Hmm... may be an advanced RAW image processing module (like an embedded DPP or Photoshop plugin) with the space left by the video module in the firmware memory... better if the camera can have two type of firmware, one is with video and the other with the DPP plugin... let user decide ;D

    Anyway, once you included a feature, it's hard to remove without user complaints... look how many user complaint when Canon remove the micro adjustment feature from the xxD and I was one of them.

   Have a nice day.

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