1D X FPS limiting factor?

[Malte_P]

what is limiting the maximum FPS for the 1D X?

is it the bandwith/processing power of the DIGIC5+ CPU´s?

or is it the mechanical shutter construction?

could a dual digic 5+ powered camera deliver 10 FPS for a 21-24MP sensor?

[neuroanatomist]

The shutter limits it to 12 fps, the dual Digic 5+ apparently limits it to 14 fps, but it's possible that's a card writing limitation.

[Mt Spokane Photography]

is there any info on how many pixels per second the digic 5+ can process?
any bandwith specs?

Its not specified.  However, many things tend to be limiting, the shutter speed, the card speed, the processing speed.  In a good design, they all tend to be reasonably close in capability.  For example, a faster processor would eat up battery life and give no benefit, a faster shutter would not help if the processor was incapable of faster speeds, and none of this would matter if Card and internal memory speeds were not fast enough.  It is likely that mechanical limitations (Shutter, Autofocus / lens speed) come into play earliest.

[neuroanatomist]

all fine and correct but does not answer my question.

Well, this:

Its not specified.

...seems like a pretty succinct and accurate answer, to me.  Digic 5+ is relatively spec'd as 17-times faster than Digic 4, but since there aren't absolute specs for the latter, that's fairly useless.

the shutter as limiting factor is what i guessed too.. but i would like confirmation.

As I stated above, the 1D X can shoot 12 fps normally, but 14 fps with the mirror locked up. Since 14 fps mode requires JPG and doesn't support RAW, I infer that card writing may be a limiting factor.

[tpatana]

As I stated above, the 1D X can shoot 12 fps normally, but 14 fps with the mirror locked up. Since 14 fps mode requires JPG and doesn't support RAW, I infer that card writing may be a limiting factor.

At that speed it's mostly writing to buffer, and just trying to empty to card as fast as possible. So card speed is not the limiting, but buffer memory speed could be.

My bet would be one of the data-lines, so sensor -> digic, or digic -> buffer (or is the buffer between sensor and digic? I haven't seen block diagram). 18MP x 12fps is plenty of data to haul across a data-line.

[PackLight]

Is this not answered in Canons 1D X white paper;

"A full-frame, 18 Megapixel sensor shooting at 14 frames per second produces a large signal stream that needs to be removed from the sensor rapidly. To enable this, the EOS-1D X uses a 16-channel high-speed output with two-vertical-pixel simultaneous readout. It is around 1.4 times faster than the readout system found in the EOS-1D Mark IV and it's this that allows the 14 frames per second shooting speed — a first for a camera with a 35mm full-frame digital sensor. Note that at ISO 32,000 or higher the frame rate will be reduced to 10fps (which still equals the fastest shooting rate of the EOS-1D Mark IV)."

[PackLight]

could a dual digic 5+ powered camera deliver 10 FPS for a 21-24MP sensor?

I am going to speculate not yet.

The reason the 1D IV exists, is that the high speeds couldn't be obtained because of processing power. Processing power and frame rate is why we have crop sensors at all.

I bet the reason the 1D X has an 18mp sensor is that it couldn't have kept up with a 24mp sensor.

[tpatana]

Processing power and frame rate is why we have crop sensors at all.

how is an aps-c sensor reducing the bandwith?

21 mp from a fullframe or 21 mp from a aps-c .... where is the difference in bandwith or needed processing power?

Smaller pixels = smaller amount of data, of course.

 

[PackLight]

Processing power and frame rate is why we have crop sensors at all.

how is an aps-c sensor reducing the bandwith?

21 mp from a fullframe or 21 mp from a aps-c .... where is the difference in bandwith or needed processing power?

Smaller pixels = smaller amount of data, of course.

 

Which makes smaller RAW files, which take less time to process.

There was an old article I read a while back, put out by Canon explaining why we have crop sensors at all.  From memory the whole reason was file size and processor performance at the time. Cheaper sensor cost and other things were not an issue initially.

[tpatana]

Processing power and frame rate is why we have crop sensors at all.

how is an aps-c sensor reducing the bandwith?

21 mp from a fullframe or 21 mp from a aps-c .... where is the difference in bandwith or needed processing power?

Smaller pixels = smaller amount of data, of course.

 

Which makes smaller RAW files, which take less time to process.

There was an old article I read a while back, put out by Canon explaining why we have crop sensors at all.  From memory the whole reason was file size and processor performance at the time. Cheaper sensor cost and other things were not an issue initially.

Um, what?

I guess you missed my last line there.

21mp from crop = 21mp from ff

the actual data don't care of the sensor dimensions, it only cares about the number of pixels (and some other crap, but not the sensor size).

So I think you've either mis-read, or remember only parts of the explanation. E.g. for same pixel density, FF would yield more data thus needing more processing power. But for same MP count, it's the same between crop and ff.

I don't know if yield makes the difference between ff and crop, I know in ICs the big components get much lower yield.

[PackLight]

Processing power and frame rate is why we have crop sensors at all.

how is an aps-c sensor reducing the bandwith?

21 mp from a fullframe or 21 mp from a aps-c .... where is the difference in bandwith or needed processing power?

Smaller pixels = smaller amount of data, of course.

 

Which makes smaller RAW files, which take less time to process.

There was an old article I read a while back, put out by Canon explaining why we have crop sensors at all.  From memory the whole reason was file size and processor performance at the time. Cheaper sensor cost and other things were not an issue initially.

Um, what?

I guess you missed my last line there.

21mp from crop = 21mp from ff

the actual data don't care of the sensor dimensions, it only cares about the number of pixels (and some other crap, but not the sensor size).

So I think you've either mis-read, or remember only parts of the explanation. E.g. for same pixel density, FF would yield more data thus needing more processing power. But for same MP count, it's the same between crop and ff.

I don't know if yield makes the difference between ff and crop, I know in ICs the big components get much lower yield.

Yes, but what does it matter. If you are making the point that the 1D X could have used a larger sensor it probably could have and gotten 10fps vs 12fps.

The 1D X normal RAW file is about 23mb, the 1D IV's is 22mb. However the 5D II's is 25.8mb.  They apparently opted to get 2 more fps rather than offer a slightly larger sensor.
Still I think the limiting factor here is the processors.

It could be said that it is mechanically limited. But there were cameras shooting a high mechanical frame rate for years. Processors are catching up now.

And you can get a higher frame rate: Enter the 1D C.....

[tpatana]

Ok, now I have no idea what you're saying.

But it seems you still didn't understand that the sensor size, crop or not, does _not_ affect the file size, thus it doesn't affect the processing power required.

They apparently opted to get 2 more fps rather than offer a slightly larger sensor.

Sensor size itself has nothing to do with the fps.

[PackLight]

Ok, now I have no idea what you're saying.

But it seems you still didn't understand that the sensor size, crop or not, does _not_ affect the file size, thus it doesn't affect the processing power required.

They apparently opted to get 2 more fps rather than offer a slightly larger sensor.

Sensor size itself has nothing to do with the fps.

Slightly larger in this statement meaning a 21mp sensor rather than the 18mp they used. A 21mp sensor file wouldn't have written as fast.


http://cpn.canon-europe.com/content/education/technical/eos_1d_x_explained.do

[PackLight]

Ok, now I have no idea what you're saying.

But it seems you still didn't understand that the sensor size, crop or not, does _not_ affect the file size, thus it doesn't affect the processing power required.

Please show me the specs of the 21mp crop sensor you are talking about, and which camera it is in. Then we can compare to see how it matches up to Canon's 21mp sensor in the 5D II.

It doesn't exist because Crop sensors were made smaller so the files would be smaller. Of course if you made a FF sensor as dense as the 7D's the file would be huge.

The sensor you speak of may exist in the near future. Why camera makers started making 35mm bodies in the start, isn't the reason they will keep making them. I hope the 7D II does have a larger sensor.

[neuroanatomist]

...Crop sensors were made smaller so the files would be smaller.

Ahhh, so the crop sensor in my 7D will give me smaller files than the FF sensor in my 1D X?  Hmmmmmm...that doesn't seem to be the case.