I stand corrected, Dominic (I don't have my EX1 with me at the moment, as it's with the Prime Support for an overhaul) - with 720/50p, it should be 1/50th, same as the fps.

As to the slowest selectable shutter speed, I only meant standard shutters - not the SLS, or EX Slow Shutter.

I just tried all standard-framerates and got that result:
fps slowest-shutter
24 1/32
25 1/33
30 1/40
50 1/60
60 1/60
Interestingly at 60fps the slowest selectable shutter-speed equals the framerate.

Quote:
Originally Posted by Serena Steuart
Perhaps you're saying that 50i is actually 50P and the fields for 50i are derived from alternate frames?

Exactly

Are you sure about that? 1080/50i can't be 1080/50P and fields derived from those frames 'cos the camera can't do 1080/50P. Surely 50i is derived from 25P, with alternate lines extracted to make 2 fields.
Steve

Shutter Speed
 

As i understand,25p with ''shutter off ''means 1/25 th shutter.And because of that indeed lowest shutter setting with ''shutter on'' is 1/33.you can see it if u set at 25 p shutter on or off..picture much brighter with ''shutter off''..

RR

Yes it can! It can't bring it on the sxs-cards, but it captures and processes it.
Even if the sensors would support temporal delayed odd (or even) rows, it's not a good idea, because then vertical low-pass-filerting wouldn't be possible, so it would flicker a lot on interlaced screens because of the very good MTF of the sensors+lens (the sensors don't have an appropriate optical low-pass-filter, so progressive images are very sharp). And observation shows, that it does vertical filtering on the whole 1080-rows-frames.
And what about 720/50p? If it would be derived from 1080/50i, then there would be deinterlacing-artifacts.

Yes. To be more exactly, shutter-off means the additional electronic shutter is turned off. Then the exposure time is just the result of the periodic readout and reseting of the pixels, which depends only on the framerate.

Not arguing with you Dominik, but where did you find out that the EX can do 1080/50P? I thought that was just the F23. Surely if the sensor could do it then it could feed it out of HD SDI and with the Flash XDR you'd have an F23/SR kit (more or less!) for £5000 instead of £100,000.
Steve

I read it somewhere, but I can't remember where. But more importantly it makes perfectly sense and matches perfectly with all of my experience.
For sure it can be hacked. But why doesn't Sony offer it out of the box together with recording of 4:2:2 and 50MBit/s? And why do I have to use these ridiculously overpriced sxs-cards for the little throughput of 4 MByte/s, of which almost every other flash-memory out there is capable of? Hmm, I guess it could be concerned with their marketing-strategy. ;)

I agree with your sentiments. I've got a PDW700 and wonder why they won't put 160 mb/sec I frame on it as seeming the mpeg used is capable of it as it's the same one used by the Flash XDR.
Still very dubious about the 1080/50P though, AFAIK it certainly does not come out of the HD SDI. Having said that, my PDW700 apparently has the same chip as the HDC1500 studio camera and that can do 1080/50P which mine can't so maybe it's a similar situation?
Steve

I'm waiting for that firmware upgrade that let's me overcrank 1080 24p to 60p! Okay, I'm not exactly holding my breath.

If I were putting together an opinion on this I'd suggest that the greater gain in 50i is achieved by stacking frames. If you take 2 frames (50P) to output one, then there is no point in throwing away data that can be utilised. This is how we do it in astronomy. I'm very wary of technical arguments based on "I read it somewhere". References please.

EDIT: While my point may seem "aggressive", it arises from long experience in technical discussions where difficulties often arise because people fail to differentiate between what they think and what they know. It is extremely important to make clear what is fact and what is deduced or thought to be so.

Hi People,

I just wanted to get back to the subject, if i have the camera set to 720p50 and the shutter off, is the shutter speed 1/50 ?

I have tried both setting and can not seem to see the difference, any one have a idea what is better ?

rob.

Yes, shutter off when shooting progressive 50P is 1/50 sec. However that is not stated in the user manual and in accordance with my note above I add "I believe that to be so".

Thanks for your comments.

OK, I've made some measurements. At 25P shutter off is 1/25. At 720/50P the default shutter is 1/60 (shutter on), which may be the reason you could see little difference between on/off. Shutter off is 1/50. I suppose I should repeat for 50i.

edit: yes, 50i shutter off is 1/50.