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Old Dec 11, 2007, 9:08 AM   #1
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Its really sad a camera so much hyped is under such a mess. For some, the results have been good(for me i have no issue with its AF-servo performance so far:G).

This is going to impact the 1ds Mk III in a big way. I am guessing how canon is going to defend let alone attack. They got the D3 beating every inch of canon 1ds Mk III at just 5k, whooping 3k lower than the 1ds Mk III.

The pro's for D3 just over weighs the Pros of the 22MP Canon camera.

It would be really interesting to see how canon responds knowing that the 1d Mark III debacle(or i shud say the AF debacle) is in CNet, DPreview(main page) and obviously RG blog.

Any Grown up comments than the usual Dpreview threads :blah::|
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Old Dec 11, 2007, 9:38 AM   #2
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Well... if the E0S-1D Mark II N wasn't so darn good, I doubt RG would have noticed an issue. It's amazing that these cameras can do what they do.

I've got a sneaky feeling that the new user settable lens parameters are part of the issue. From a programming perspective, the code would need to look at these parameters, taking away processing time that could be impacting the Autofocus System's ability to "keep up" at faster frame rates.

That's pure speculation. But, I wouldn't be surprised if developers were pouring over every line of code trying to figure out a way to optimize it so that it can keep up at faster frame rates.

As for the D3, we'll have to wait and see how well it performs. But, from some posts I've seen, the EOS-1D Mark III outperforms the D300. For example, take this test of a runner shot with a D300 using a 300mm f/2.8 wide open at f/2.8.

D300 test showing Continuous AF performance

45% of the photos were out of focus with the D300 (as compared to 40% out of focus with the EOS-1D Mark III using the same type of test).

So, the Nikon isn't exactly perfect either, and I suspect the user settable lens parameters could be part of the issue there, too. Again, that's only speculation. But, given that this is a new feature with both cameras, I think it's a likely suspect (AF algorithms unable to keep up with frame rate due to additional processing overhead from reading these user adjustable parameters).

As for the EOS-1Ds Mark III, I wouldn't assume it will have the same issues as the EOS-1D Mark III. I also wouldn't assume that the D3 will be better. We'll have to wait until these models are on dealer shelves and in the hands of reviewers that test this kind of thing to find out. They are also very different camera models (with the D3 targeting sports shooters more, since most sports shooters won't need the 22MP of resolution the EOS-1Ds Mark III would provide).

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Old Dec 11, 2007, 9:58 AM   #3
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thats an interesting read..

Check this one on similar lines to ur thoughts.

http://www.fredmiranda.com/forum/topic/596128

Interesting read among the other hundred of CUSS threads :G:blah:
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Old Dec 11, 2007, 3:15 PM   #4
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JimC wrote:
Quote:
Well... if the E0S-1D Mark II N wasn't so darn good, I doubt RG would have noticed an issue. It's amazing that these cameras can do what they do.

I've got a sneaky feeling that the new user settable lens parameters are part of the issue. From a programming perspective, the code would need to look at these parameters, taking away processing time that could be impacting the Autofocus System's ability to "keep up" at faster frame rates.
IMO you're on to something... :idea:

Bear in mind that even if the MrkIII is faster, it has actually less time to perform its magic than the MrkII due to its higher frame rate:
MrkII: 8fps -> 125ms between frames
MrkIII: 10fps -> 100ms between frames

That's 25% less time between burst for AF; however, during this interval:
1. The mirror has to go down for the camera to judge the focus
2. The AF algorithm determines front/back focus from the last frame

3. The camera send commands serially to the lens
4. The lens then rotates backward/forward accordingly
5. The lens in turn sends serial acknowledge back to the camera
6. The
AF algorithm may decide T-T-L to repeat step #2 if focus is not achieved (or it times out to meet the burst rate)
7. The mirror flips back up to clear the image sensor
8. The shutter opens for the duration of the set shutter speed
9. The shutter closes for the final step in a burst

... and notice that theses tasks are mostly mechanically driven that no amount of processor overclocking can solve, with the exception of #2 and #6.
Furthermore even if the same old EF-300mm f/2.8L (i.e. red steps #3 to #5), one of the fastest lens in Canon's arsenal is used for the test; This focusing action is fixed between the MrkII or MrkIII which is determined by the lens used so any other slower AF lens would only take away from the total lesser time that the MrkIII already has between burst
-> Aren't we asking too much from the cameras?

-> On the Nikon (I believe the Sony too) you can also set the camera continuous burst to focus priority (and not release priority), 100% AF focus can be achieved this way, but
the frame rate will drop dramatically since the shutter won't release otherwise!
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Old Dec 11, 2007, 6:08 PM   #5
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Lets assume the steps u have told. I feel during High Speed Burst mode, it would be better to keep the mirror up all the time untill the shutter is completely released saving valuable time for the messages to go to and fro between the camera and the lens.

It appears the shutter speed is too high compared to the communication between lens and the camera.

appears like a design flaw. And the result is a cascading effect of one flaw during the design stage.

But, given that the camera works great at temperatures thats cooler it also tells about the DIGIC III's drop in performance to process data at elevated temperatures probably.

My toshiba cries if i let it work in the carpet for 45 minutes to open a spreadsheet let alone photoshop.

The test should be performed with say some cooling device around the camera so we can eliminate the contrast reason at bright lights on the subject..

Its gonna be one heck of a ride for canon either ways only if they are MAN enuff to agree the fault and work for a soluion.




and AF Focus priority is also present in Mark III. Custom functions are provided to set the same. But not exactly as clearly given as the Nikon

"When "Focusing (subject-tracking) priority" is selected and the subject distance changes,the continuous shooting speed may become irregular. When "Drive speed priority" is selected, the focusing might be slightly off, but the shooting speed will be fixed. Setting 2is effective for press photographers who put priority on capturing the moment."
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Old Dec 11, 2007, 6:40 PM   #6
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nymphetamine wrote:
Quote:
Lets assume the steps u have told. I feel during High Speed Burst mode, it would be better to keep the mirror up all the time untill the shutter is completely released saving valuable time for the messages to go to and fro between the camera and the lens.
The AF sensors can't "see" if the mirror is up.


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Old Dec 11, 2007, 7:31 PM   #7
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JimC wrote:
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The AF sensors can't "see" if the mirror is up.
Precisely! :-):lol::G




nymphetamine wrote:
Quote:
Lets assume the steps u have told. I feel during High Speed Burst mode, it would be better to keep the mirror up all the time untill the shutter is completely released saving valuable time for the messages to go to and fro between the camera and the lens.
Think about it this way:
You have two drive modes on your MrkIII, H and L. In the L mode you can see longer between blackout and so does the camera AF.
-> The blackout time is when the camera take the shot and the non blackout time when the mirror is down and you were able to see is when the camera is doing this focusing...


Quote:
... and AF Focus priority is also present in Mark III. Custom functions are provided to set the same. But not exactly as clearly given as the Nikon "When "Focusing (subject-tracking) priority" is selected and the subject distance changes,the continuous shooting speed may become irregular.

When "Drive speed priority" is selected, the focusing might be slightly off, but the shooting speed will be fixed. Setting 2is effective for press photographers who put priority on capturing the moment."
Not exactly... Nikon has this mode too and it's called Release + Focus. The frame rate will slow down, but the camera will still try to release when the focus is not achieved just like Canon; However, Nikon does have an extra Focus priority mode in which the shutter won't release at all until the AF has a locked!
-> When in this mode the Nikon will fail the lens cap test, i.e. put the lens cap on and try to release the shutter and nothing will happen just like the One-shot AF mode on your MrkIII, but in the continuous AF mode - i.e. AI-servo in Canon parlance.
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Old Dec 11, 2007, 9:01 PM   #8
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The main issue could be something as simple as a mirror assembly (although from Rob's latest commentary, that didn't solve all of it). At frame rates that fast, you'd have to be perfectly synchronized, otherwise the mirror may not be correctly positioned to feed the image to the AF sensors between shots. So, I can see how mirror slap, temperature and more could play a role.

But, given than Canon has been designing mirror assemblies for years, I can't help but wonder if the processing overhead for user adjustable parameters for AF could be a contributing factor, since this is the first model with that kind of flexibility.

Of course, now that we're seeing P&S models being announced that can do still images at 60 frames per second, and features like Live View being added to DSLR models, I think it's only a matter of time before we see removable lens models using an EVF, with no mirrors to worry about.

Then, perhaps we'll see higher end cameras incorporate the newer features like face recognition, whiich should contribute to predictive focus algorithms as subject recognition becomes more sophisticated over time.

Or, perhaps a hybrid system instead, using the main imaging sensor for Contrast Detection AF, combined with separate, dedicated AF sensors, using a pellicle type mirror if they can come up with better materials with less light loss.

It would be interesting to find out what is on the "drawing board" at the major camera manufacturers.

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Old Dec 11, 2007, 9:13 PM   #9
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JimC wrote:
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Of course, now that we're seeing P&S models being announced that can do still images at 60 frames per second, and features like Live View being added to DSLR models, I think it's only a matter of time before we see removable lens models using an EVF, with no mirrors to worry about.
Why wait? :lol::-):G
http://www.red.com/technology
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Old Dec 11, 2007, 10:21 PM   #10
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and they are actually not costly.

twice the 1ds Mark III rate with lens just 1k over the L lens in almost all ranges

and did u check those videos..or the 60frames in a video...cracker quality....

at this rate we can see Cell fones boasting 12MP cameras and VIdeo cameras having capabilities to take picutres at HD format and costing under 2K
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