whats holding them back?

[mark tipple]

after reading the info on the new 5D i was sold, but with only 3fps? maybe not. why only 3? surely they can turn 3 into 8 easily enough.  

wishful thinking i know.....but in the near future?

any thoughts?

[kbolin]

Well... they are counting on people like me.  I have owned a D30, D60, and currently own a 10D & 20D.  I will buy the 5D and give the 10D to my son.  Of course when the 5DMII or whatever comes next is faster, more features like an easy mirror lock up (did you hear that Canon) then I'll get it and offload the 20D.  What else would I spend my $$ on if it wasn't ugprades in technology... whether it be cameras, computers, printers, software... the list goes on.

[LeifG]

after reading the info on the new 5D i was sold, but with only 3fps? maybe not. why only 3? surely they can turn 3 into 8 easily enough.  

wishful thinking i know.....but in the near future?

any thoughts?

1) They don't want to compete with the 1Ds Mark2 and hence lose sales of the top end model.

2) The high speed electronics and extra memory required to support a high frame rate would increase the price, perhaps substantially, making it less competitive.

3) Canon haven't adopted Nikon's cropped frame mode which would partly satisfy you. Maybe it's patented (I doubt that but who knows), or maybe they just don't like the idea.

Leif

[BJL]

2) The high speed electronics and extra memory required to support a high frame rate would increase the price, perhaps substantially, making it less competitive.

That is the main reason; for several years now, there has been clear trade-offs between frame rate, pixel count, and cost. It seems that at  a given state of technology and a given cost, there is a limit on how many pixels can be read per second, "MP/s".

- The original 1Ds had a rather slow frame rate (for an EOS-1 model) of 3fps, while the cheaper 1D was 8fps; clearly Canon was not choosing to hold back the frame rate of their top priced product, but was limited to reading about 33MP per second in each camera.
- The Mark II versions follow the same pattern, but with new Digic II processors raising the rate to about 66MP/s.
- The Nikon D1h and D1x had the same speed/pixel count trade-offs.
- The Nikon D2X has the same trade-offs in the same camera: 12MP@5fps or 7MP@8fps, both about 60MP/s.
- The 20D and 5D follow the same pattern, at 40MP/s: thus the far more expensive 5D has a lower frame rate. (This makes me suspect marketing BS when Canon says the 5D has the same Digic II processor as the 1D Mark II models; same Digic II design yes, but in a slower, cheaper version, as also used in the 20D.)

[DiaAzul]

This makes me suspect marketing BS when Canon says the 5D has the same Digic II processor as the 1D Mark II models; same Digic II design yes, but in a slower, cheaper version, as also used in the 20D.

The 1D Mark II has two DIGIC II processesors, whereas the 20D & 5D have only one. This may explain some of the difference in capabilities of the two camera ranges.

As well as CPU processing power another limiting factor is the analogue to digital convertor and surrounding analogue circuits. There is a limit to how fast the voltages on an a2d convertor can change (slew rate) which limits how fast data can be processed from the sensor. The method used by most manufacturers to increase frame rate is to split the sensor into multiple regions and read pixels in parallel using more than one set of analogue to digital convertors, however, this is likely to increase the cost. We could probably expect that for the next generation of full frame Canon cameras an ability to read 8 or 16 channels of information in parallel in order to attain a decent frame rate and a high number of megapixels.

[Ben Rubinstein]

Given the huge buffer, the trade down from the 5fps of the 20D is dissapointing. Ditto the lowering of the x-sync which I find annoying.

[Andrew Larkin]

Given the huge buffer, the trade down from the 5fps of the 20D is dissapointing. Ditto the lowering of the x-sync which I find annoying.

I suggest that the change to the x-sync speed has to do with the change to a full-frame shutter - I also note that Canon claims much better life for the shutter on the 5D.

Andrew

[Ben Rubinstein]

Nah, that one won't wash, Canon have been making 'full frame' shutters for about 40 years, don't tell me they needed a new or innovative design for the 5D. It was probably far cheaper to organise the shutter for the 5D re the R&D than the crop DSLR's that needed a new design.

[BJL]

... Canon have been making 'full frame' shutters for about 40 years, don't tell me they needed a new or innovative design for the 5D.

Nothing new or innovative is needed, but perhaps a more expensive mirror and shutter than fits the "advanced amateur" component budget apparently used to get 24x36mm format down to the 5D's price target?

Reducing format by a factor of 1.6 allows teh same shuter speed to giv 1.6 times faster x synch, and as the shutter is lighter, evn more of  a speed edge is possibe. Similarly, the smaller mirror can be moved in a given time with less effort by a factor of 1.6^3, or about four, so if mirror movement is alimit on frame rate, smaler formats have an advantage there.

Relatedly, the recent high end Nikon DSLR's like the D2X have lower shutter lag than any EOS-1 model with a moving mirror, film or digital: another advantage of having a smaller, lighter mirror to be moved. (The other option is the fixed partially reflecting mirror, as used in some EOS-1 film cameras.)


But actually, the fact that the "Mark II's" use dual processors to process data faster seems a more likely explanation. Nikon uses similar parallel four channel read out to support high frame rates in the D2X.

[DiaAzul]

But actually, the fact that the "Mark II's" use dual processors to process data faster seems a more likely explanation. Nikon uses similar parallel four channel read out to support high frame rates in the D2X.

FYI, Canon also read data from the sensor using four channels...the division of effort between the processors is one dedicated for the auto-focus, and the other for image processing.

I guess the phrase 'Nikon uses similar...' was confusing me a little. When comparing Canon and Nikon processing capability it is also worth bearing in mind that Canon compresses its RAW file as a default whilst still achieving maximum frame rate, for Nikon the frame rate drops off when compression is activated.

[BJL]

FYI, Canon also read data from the sensor using four channels...the division of effort between the processors is one dedicated for the auto-focus, and the other for image processing.

Thanks! even more interesting. So it seems that the current bottle neck for high frame rate ("pixels per second") is specifically reading from the sensor, with the four channel parallel read-out limited to the high end sensors for now.

Anyway, these factors look very much like ones that will trickle down to less expensive cameras in time, moving the limits back to mechanical ones like how fast shutters and mirrors can be moved.

[madmanchan]

FYI, Canon also read data from the sensor using four channels...the division of effort between the processors is one dedicated for the auto-focus, and the other for image processing.

Thanks! even more interesting. So it seems that the current bottle neck for high frame rate ("pixels per second") is specifically reading from the sensor, with the four channel parallel read-out limited to the high end sensors for now.

Anyway, these factors look very much like ones that will trickle down to less expensive cameras in time, moving the limits back to mechanical ones like how fast shutters and mirrors can be moved.

Mechanical limitations aren't relevant yet.  Remember the Canon EOS 1-v?    It was (is?) the fastest SLR on the planet and it was 35 mm full-frame, capable of blasting away at up to 10 fps.

The bottleneck is in moving the data around and processing it.

Canon has already hinted that their next 1-series will be a combination of 1Ds and 1D: full-frame with fast rates, so just wait for their next announcement.

Eric