February 27, 2015, 09:26:20 PM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - weixing

Pages: [1] 2 3 ... 27
1
Lenses / Re: Canon EF 11-24mm f/4L Shipping This Week in United States
« on: February 26, 2015, 08:49:40 PM »
Hi,
    Found some images shoot by this lens: https://www.flickr.com/photos/29823753@N02/sets/72157648710973594/

    Have a nice day.

2
Lenses / Re: Canon EF 11-24mm f/4L Shipping This Week in United States
« on: February 23, 2015, 01:12:18 PM »
Hi,
I get needing a 16-35mm F/2.8, but I really can't see any tangible use for a 11-24mm F/2.8 except astrophotography. If you're shooting action at 11mm, your subject is either going to be really, really close, or really really small in the photo. And if your subject is that small, you're going to have focus problems tracking the fast action happening in a small part of the frame.

If shooting events/dances/etc, I've never been bothered by F/4, simply because a close-up subject that can fill 16mm can be lit by color-corrected speedlights, and that gives you a subject-background separation by lighting your subject and thus bringing them out of the background. In that way, I've always found that dances/etc can be easily done with an F/4, because naturally lighting them would be improbable anyway.

I know at the end of the day, photography is creative and about breaking the rules, but if you need a wide, fast lens, there's the 14mm f/2.8, and the 16-35mm F/2.8, and if you're shooting action, I really think there's no need to be wider than 14mm anyway.

Just my opinion and way I shoot, I've loved using my 16-35mm F/4 IS and 70-200mm F/2.8 IS II for news and events, even in abysmal lighting situations;  when I used a 17-55mm F/2.8, I still ended up using a color corrected flash, so it's not a big deal to me.
    Don't be so confidence of yourself... may be later you'll find yourself wanting this lens... ha ha ha ;D

    Anyway, birder and wildlife photographer will be envy of you guys... you "only" need to spend US$3K to get the world widest FF lens... they had to spend double the price just to get the "entry level" F4 super telephoto lens... ha ha ha  ;D

    Have a nice day.

3
EOS Bodies - For Stills / Re: Coincidence or?? MP/SEC
« on: February 17, 2015, 02:05:50 AM »
Output data at 14fps would be JPEG, but the input data from the sensor would still be 14-bit. I don't believe Canon does any kind of downgrading on the bit depth of the ADC units (I've never found any information indicating as much anyway), so I don't believe there is a 12-bit 14fps read mode. The output data rate for JPEG (when writing to the memory card) would certainly be lower, but the input rate into the DIGIC processor would still be 14-bit.

It's difficult for anyone outside of the development team to do any more than speculate, but I'd argue that if the camera can really handle 14 bit readout at 14 FPS, then why force JPEG only on users? The buffer is still there, and if the readout and JPEG engine can keep up with 14 bits, the buffer should be able to too - so instead of forcing JPEGs on the user, why not give them a choice of a smaller buffer depth and raw? Card speeds only become relevant once the buffer fills up, and the target audience of the 1D X should in Canon's eyes be capable of deciding which trade off to choose.

I'm under the impression (falsely or not) that it's JPEG only as the readout doesn't support 14 bit CR2 files at 14 FPS.


The readout is simply transferring charge and converting it to digital numbers. JPEG doesn't come into play until that native signal information has already entered the DIGIC chip, since it is DIGIC that is actually performing the conversion to JPEG. The sensor isn't going to natively spit out 8-bit JPEG data, as that requires processing, like color space conversion, compression and encoding, etc.


Why does Canon limit 14fps to JPEG? I don't know the answer to that. I am just quite certain that neither the sensor nor the off-die ADC units are spitting out JPEG data natively. It could be possible that the ADC units are switching to 12-bit mode at 14fps. Samsung certainly doe it at 15fps. Why Canon even bothers with a 14-bit ADC in the first place when their data barely supports more than 11 bits worth of information because of system noise levels is beyond me. If a 12-bit ADC would allow them to process 17.5fps, without any loss in DR, I don't know why they don't. That said, I've never encountered any information anywhere, including in patents, that indicates Canon switches to 12-bit data output from their ADC units. There could very well be a different reason they had to limit 14fps to JPEG.
Hi,
    Because Canon RAW files include the bias information. And bias information is useful in perform calibration of image.

    By the way, 7D2 is dual pixel meaning that they actually had 40.4MP. Now if the dual-pixel operation is perform in analogue form (before the ADC), that mean the data rate will still at 20.2MP level, but if the dual-pixel AF is perform after the ADC, then the data rate will be at 40.4MP level. Just wondering??

   Have a nice day.

4
Lenses / Re: Why does 7D II seem COMPARATIVELY soft with certain lenses?
« on: February 16, 2015, 11:52:23 AM »
Hi,
    Here is my experience: when use my 7D2 with my Tamron 150-600mm, my keeper rate is not high and AF seem not consistent. When use my 7D2 with my EF 400mm F5.6L, my keeper rate is way higher and AF is fast and consistent. So my conclusion is that my Tamron 150-600mm had some issue with my 7D2.

    By the way, my Tamron 150-600mm had a live view AF issue with my 7D2 (no such issue when I use with 60D and 6D), but not sure does this issue affect the normal AF operation, but will going to do a 1 to 1 exchange tomorrow... after that I'll sell the Tamron and join the EF 100-400mm II club...

    Have a nice day.

5
Lenses / Re: Canon EF 11-24mm f/4L Already Shipping in Asia
« on: February 16, 2015, 10:59:46 AM »
Hi,
    Just wonder is the Sony A7 mount is strong enough to support the lens when the camera is mounted on tripod... hmm... Look like they might need to come out an adapter with a tripod collar so that can support this heavy lens on the smaller mirrorless camera.

   Have a nice day.

6
EOS Bodies / Re: Patent: Optional Image Stabilization Unit
« on: February 16, 2015, 10:54:55 AM »
Hi,
    The EF 400mm 5.6L rear element is very deep inside the lens rear, so may be this will extend the product life cycle of EF 400mm F5.6L.... EF 400mm F5.6L IS  ;D

    Have a nice day.

7
Lenses / Re: 11-24 is here, with images of it compared to Nikon 14-24
« on: February 13, 2015, 03:25:45 AM »
Hi,
    May be next time they should design a ultra wide angle lens with a drop in filter (like those use in the Super-Telephoto lens). Hmm... Or may be someone could design a EF adapter with a drop-in filter for mirrorless camera... Sony mirrorless landscape photographer who want to use this lens will be very happy.

   Have a nice day.

8
Lenses / Re: New Unique Macro Coming? [CR1]
« on: February 09, 2015, 11:57:35 AM »
Hi,
    With dual speed focusing ring?? One for fast focusing and one for very fine focusing??

   Have a nice day.

9
Pricewatch Deals / Re: Official: Preorder the Canon EF 11-24mm f/4L
« on: February 06, 2015, 09:35:03 AM »
Hi,
    So with the new 11-24mm F4L, Canon just need 3 L lens to cover from ultra wide to super telephoto: 11-24mm, 24-105mm and 100-400mm II... :)

    Have a nice day.

10
Lenses / Re: 11-24 is here, with images of it compared to Nikon 14-24
« on: February 06, 2015, 07:19:55 AM »
Hi,
   All description never mention about fluorite elements, but the product page in Canon USA website on this lens indicate that this lens had 2 fluorite elements (fluorite elements icon "CaF2" with a 2 below)... someone cut and paste from another product, but forget to remove the fluorite icon?? Ha ha ha
http://www.usa.canon.com/cusa/professional/products/lenses/ef_lens_lineup/lens_uw_pro/ef_11_24mm_f_4l_usm

     Have a nice day.

11
Lenses / Re: 11-24 is here, with images of it compared to Nikon 14-24
« on: February 06, 2015, 06:51:13 AM »
Hi,
   Found some high resolution sample here (click the "High Res" button):
   http://www.ephotozine.com/article/canon-ef-11-24mm-f-4l-usm-lens-sample-photos-26926

   Have a nice day.

12
EOS Bodies / Re: Bingo! New Canon 5Ds has 50.6 MP new rumored specs
« on: February 04, 2015, 08:10:45 AM »
Hi,
I can see no reason for not building a fully-blown "COMM" module into large DSLR bodies. With the following components, ALL of them - as in many small smartphones:
* WiFi - latest mainstream iteration (currently ac)
* NFC
* GPS
* Canon only: RT commander
all of them separatly switchable by user, of course.
Antenna/s: always built into LCD bezel/frame on rear of camera. More than enough spacxe there. And no shielding metal either. 

And one version, in which the power cable to the COM module is not built in. For those markets where odd-ball communications laws and ferquency crap make communicating devices "illegal".

Problem solved, next please! :)
    If you built in the LCD bezel/frame, only the rear is free of obstruction and shielding... the wifi might not work properly if you are in front of the camera and GPS might take very long to get a position lock. IMHO, people will probably complaint if you don't include the features, but if you include the features and it's not working properly, people will curse and swear... IMHO, if you cannot guarantee it'll work properly, it's better not to have it in the first place.

   Have a nice day.

13
EOS Bodies / Re: 50mp Cameras Coming in March [CR1]
« on: January 25, 2015, 07:08:16 AM »
I gave up waiting and bought a 645z

Don't hate me.

Hope you will relate you experience with the 645z in future posts.
You know we are all secretly jealous....right?

I'm doing a write up on it now. It's really good and the best image quality I've seen on any camera, anywhere.

Plus the skin tones are great. Sony finally sorted their stuff out in that regard.
Hi,
   Err... I thought 645z is a Pentax camera?? Although they use Sony sensor, but the final colour output had nothing to do with the sensor... it's the camera firmware that determine the image colour, not the sensor.

  Have a nice day.

15
Lenses / Re: Canon EF 400mm f/4 DO IS II USM Lens Review
« on: January 19, 2015, 06:32:48 AM »
I really don't understand the whole concept of 400/4 DO II and why anyone would actualy buy it. It's probably my fault.
But let's go back for a second in time when the first generation of 400/4 DO was introduced.

400/4 DO IS - 1940g
300/2.8L IS - 2550g
400/2.8L IS - 5370g

The whole point of the 400/4 DO and the DO technology itself was beeing LIGHT! Much lighter than other lenses. Canon has sacrificed image quality to make a LIGHT lens. It was a welcomed innovation by many. You could choose to have an L lens with superb image quality or a very light (also smaller), "mobile" DO lens. Whichever you needed.
600g difference between 400/4 and 300/2.8 (which is a 420/4 with 1.4X) was significant.

And now...

400/4 DO IS II - 2100g
300/2.8L IS II - 2350g
400/2.8L IS II - 3850g

300/2.8 has improved. A LOT. It's lighter, (all II gen lenses got lighter) it's even better optically than before and also has a shorter minimum focusing distance (2m from previous 2.5m). THAT is improvement.
Meanwhile 400/4 DO got heavier. The previous 600g difference is now only 250g. Minimum focusing distance is 3.3m. Yes, it got better, much better optically. But we already had superb lenses. What we don't have is light lenses. The primary goal of DO should be to reduce weight and size. Image quality only comes second, no matter how strange that could sound to you. The first generation wasn't sold for it's image quality either.
Or maybe is it cheap? It's not.

In my opinion, the 400 DO beeing 2100g is a big FAIL. It does not stand up to the 300/2.8 (+1.4X) at all.
Hi,
    Why big fail?? EF 400mm F4 DO IS II is still smaller, lighter and sharper than EF 300mm F2.8L IS II... basically, the EF 400mm F4 DO IS II is for those who need the smallest, lightest and sharpest 400mm lens out there.

   Have a nice day.

Pages: [1] 2 3 ... 27